POOR LEGIBILITY

ONE OR MORE PAGES IN THIS DOCUMENT ARE DIFFICULT TO READ DUE TO THE QUALITY OF THE ORIGINAL V

SFUND RECORDS CTR 2166-04905 Department of Water and Power

SFUND RECORDS CTR 88134326

OPERABLE UNIT FEASIBILITY STUDY FOR THE NORTH WELL FIELD AREA OF THE NORTH HOLLYWOOD-BURBANK NPL SITE, GROUNDWATER BASIN

NOVEMBER 1986 n

LOS ANGELES DEPARTMENT OF WATER AND POWER

OPERABLE UNIT FEASIBILITY STUDY

FOR THE

NORTH HOLLYWOOD WELL FIELD AREA n / OF THE

NORTH HOLLYWOOD-BURBANK NPL SITE, SAN FERNANDO VALLEY GROUNDWATER BASIN

a November 17, 1986 p*« fi

•i TABLE OF CONTENTS

EXECUTIVE SUMMARY . 1 FORWARD• 7

I. INTRODUCTION 10 Background 10 Importance of Los Angeles Groundwater 14 Regional Setting and Site Location 17 Hydrogeologic Setting1 18 Nature and Extent of Problem ' 19 n Characterization of Contaminant Incidence 22

II. IDENTIFICATION, DEVELOPMENT, AND SCREENING OF REMEDIAL TECHNOLOGIES . . 25 Overview of Screening 25 Screening Criteria . 26 Response Actions - 27 Summary of Preliminary Remedial Action Screening 58

III. DEVELOPMENT OF REMEDIAL ALTERNATIVES . 60 Description of Groundwater Extraction/Conveyance System . 61 Alternative A - Aeration 62 Alternative B - Granular Activated Carbon Adsorption 66 Alternative C - Combined Aeration/GAC 70 Alternative D - Ultraviolet Irradiation/Ozonation 70

IV. SCREENING OF REMEDIAL ALTERNATIVES 73 Environmental and Public Health Screening .74 Cost Screening 78 Recommendation and Summary of Candidate Treatment Methods . 83

V. TECHNICAL EVALUATION OF SCREENED ALTERNATIVES 86 Aeration ••'• ' ~ 87 Granular Activated Carbon Adsorption 90 Aeration/GAC 92 Summary of Technical Evaluation Process 95 Cost Comparison 98 . VI. INSTITUTIONAL REQUIREMENTS . 103 Federal Agencies 105 State Agencies 106 Regional Agencies . 107

VII. PUBLIC HEALTH EVALUATION ' 110 Alternative A - Aeration 111 Alternative B - Granular Activated Carbon Adsorption 113 Alternative C - Aeration/GAC 114 Groundwater Extraction/Conveyance System 115

VIII. SUMMARY AND RECOMMENDATION OF REMEDIAL ALTERNATIVE 116

APPENDIX 1 Acronyms APPENDIX 2 References . APPENDIX 3 Abstract-Use of Well Packers to Control TCE and PCE Contamination APPENDIX 4 SFVGWB Well Contamination Data APPENDIX 5 DHS Letter to SCAQMD.on Health Effects APPENDIX 6 Scope of Work for Aeration Facility Project APPENDIX 7 Analysis of Area of Influence of Shallow Aquifer Wells APPENDIX 8 Estimation of Granular Activated Carbon Requirements APPENDIX 9 Excerpt from "Initial Study and Proposed Negative Declaration for the Proposed North Hollywood-Burbank Aeration Facility Project" APPENDIX 10 Cost Analysis ri- ff [15 ' I ~ *~,

- ii - LIST OF FIGURES

Following Figure x> Page No. 1. Vicinity Map of the Los Angeles Metropolitan Area . \ . . 14 . I .-.'.. 2. Political Boundaries-San Fernando v Valley Basin .'..••:.." 14

'f-T^ ' - •'•.'•'•':' ji". 3. Los Angeles' Water Supply ' • ' * 15 ( '-':...... 4. Locations of Groundwater Basins and rf". NPL Sites in ULARA 17 5. San Fernando and Verdugo Basins r^ Groundwater Flow Map 18 ' •"" 6. Soil Infiltration-Groundwater Quality r. Management Plan Study, San Fernando r~N, Valley Basin ' . 18 7. Location of Wells Containing TCE pi1"' and/or PCE in Excess of DHS Action ] L; Levels 19 8. North Hollywood TCE Contamination - 1981 vs. 1985 19 9. Diagram of Typical Aeration Facility . 64 ft 10. Effects of Contaminant Loading On GAC Treatment Efficiency 68 fl 11. Schematic of a GAC Treatment System 68

rI.- - Hi - LIST OF TABLES

Appears Table on Page L .' .' 1. Cost Summary of Screened Alternatives 99 2. Cost Estimates for the Removal of Trichloroethylene (TCE), Using Packed . . Tower Aeration . 100 3. Cost Estimates for the Removal of Trichloroethylene (TCE), Using GAC . Contactors : 101 4. Cost Estimates for Aeration/GAC 102

n rG

ro r; P - •• (S\ ,: : ~" - :r-- EXECUTIVE SUMMARY :r.

. i. i ' ;r EXECUTIVE SUMMARY The enclosed document constitutes a report by the Los Angeles Department of Water and Power (LADWP) on an Operable Unit Feasibility Study (OUFS) of the North Hollywood-Burbank well field area of the San Fernando Valley Groundwater Basin. The purpose of the OUFS is to identify and evaluate candidate remedial response actions for the North Hollywood-Burbank well field area which are consistent with long-term contaminant cleanup and . mitigation efforts for groundwaters of the San Fernando Valley Groundwater Basin. The overall objective of the OUFS is to identify a recommended remedial alternative for development and implementation on the basis of demonstrated cost-effectiveness and feasibility. The North Hollywood-Burbank area is one of four sites in the Basin listed by the U.S. Environmental Protection Agency (EPA) on its National Priorities List for uncontrolled hazardous waste sites. Consequently, remedial action in the study area is eligible for Federal funding under the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (also known as Superfund). The OUFS represents a discrete element of an overall remedial investigation which is now in progress under a Cooperative Agreement between the EPA and the LADWP. Implementation of the recommended measure as described in the OUFS report would initiate urgently-needed cleanup action in the study area and provide • ' additional valuable information regarding the viability of future remedial measures. IV . . - ;-'- -

In contrast with the usual EPA definition of a feasibility study, an OUFS is essentially a fast-track action applicable to situations where a sufficient quantity of data exists to justify an expedient approach to remedial action. As documented in the OUFS report, this data has been collected and compiled by the LADWP through previous studies and investigations beginning in 1980. The findings indicate that contamination by trichloroethylene (TCE) and perchloroethylene (PCE) is spreading rapidly with an average of two additional groundwater. wells becoming contaminated each year. In view of this continuing threat, it is imperative that immediate remedial action be undertaken to halt the spread of contamination and to begin cleanup operations. Although the recommended action would not necessarily serve to increase or maintain the present water supply, it would act to protect the quality of the existing supply and preserve those supplies which would otherwise shortly become contaminated. In addition, the recommended action would enhance the efforts of the remedial investigation and have a potential beneficial impact on the cost and feasibility of future cleanup measures. The OUFS, being a fast-track action, is necessarily limited in scope in order to allow for a quick identification of candidate measures that could be implemented immediately; consequently, no attempt was made to conduct a comprehensive and exhaustive study of all possible remedial technologies. Further- ~ •>•'•• more, while the information on the relative costs of alternatives that were identified for consideration and screening is considered • accurate or representative for OUFS purposes, it is emphasized that in some cases costs for capital and operational details were unavailable, incomplete, or conflicting. • In these cases, a conservative approach was adopted in order to make the comparisons as objective as possible. The LADWP has identified, evaluated, and screened various candidate technologies with regard to cost-effectiveness/ environmental and public health impact, and other related considerations. It was determined that groundwater extraction and treatment is the only effective means for halting the spread of contamination. Three treatment alternatives were identified as primary candidates for the project; these alternatives and their estimated costs are summarized below: 1. Granular activated carbon (GAC) - Groundwaters are passed through a bed of activated carbon to remove the volatile organic compounds. The carbon is periodically replaced with fresh carbon to prevent the breakthrough of contaminants to the effluent. - 2. Combined Aeration/GAC* - Groundwaters undergo an aeration process to remove the volatile organic compounds which f: are then captured by vapor-phase activated carbon contactors to prevent the release of contaminants to the air. 3. Aeration - Contaminated groundwaters are conveyed to an aeration column where volatile organic compounds are stripped from the water by a countercurrent flow of air; the aerated organics are vented to the atmosphere. Treatment operations would be supplemented by a groundwater extraction and conveyance system, consisting of a number of shallow groundwater extraction wells and transmission pipeline. The estimated project costs shown below include these facilities with the costs of treatment: ••'•.••

1 '•' ESTIMATED PROJECT COSTS i-v^ (Assumes 15-Year Project Life at 10%) I ' • ' F:": . . Annual Total P_:-. Operating and Present Maintenance _ Worth p. Alternative Capital Cost Cost Cost |' 1. GAC $2,249,000 $495,000 $6,000,000 2. Aeration/GAC* 2,193,000 258,000 4,100,000 fi 3. Aeration 2,033,000 206,000 3,600,000 n ft

f \ *Recommended alternative r- - 5 -

On the basis of previous and ongoing studies, numerous public meetings, and on recommendations and assistance provided by the Region IX office of the EPA, the LADWP recommends the construction of a groundwater extraction, conveyance, and treatment facility to be located in North Hollywood. The recommended facilities would consist of extraction wells, transmission pipeline, a groundwater aeration tower, granular activated carbon air filtering contactors, and appurtenant facilities. In recommending aeration/GAC as a remedial action, the LADWP weighted the probability of success with regard to facility treatment efficiency and existing and/or proposed regulatory effluent quality standards. The reliability of the recommended alternative rests primarily on estimates of the extent of Basin r1" contaminants and local TCE and PCE concentrations. On the basis ! ij. ' • • of weighted TCE and PCE levels taken from well field data compiled ] for the study area (see Appendix 4), the concentrations which are expected to be encountered are on the order of 35 parts per [ L billion (ppb) for PCE and 215 ppb for TCE. However, as a _I contingency, the LADWP recommends design influent concentrations t- ••"""' of PCE and TCE for an aeration/GAC facility of 100 ppb and 650 ppb, rv • p. respectively. The capability of the aeration and GAG technologies is such that treatment plant removal efficiencies can be tailored I,_ or adjusted to meet and exceed the currently-mandated MCLs for • • these compounds. - 6 -

As detailed in the OUFS report, treatment of contaminated groundwaters by the recommended facility would achieve existing and proposed maximum contaminant levels (MCLs) as currently required by the EPA for all volatile organic contaminants.

r

I . [ ,"" FORWARD As lead agency for the San Fernando Valley Groundwater Basin (SFVGWB) Remedial Investigation (RI), the LADWP is responsible for investigating cleanup strategies in the best interest of the Basin as a whole. Potential cleanup locations and remedial action . alternatives, therefore, are by no means limited to the LADWP's oWn service area and concerns, but also include those of .Burbank, Glendale, San Fernando, and neighboring areas. In choosing a site location and remedial action for this first OUFS, the LADWP fully recognized the above consideration .and attempted to make its selections accordingly. Site selection for the OUFS was based primarily on the need for immediate interim action, which quickly narrowed the field r'"-': of candidate cleanup areas to those in the North Hollywood-Burbank area. As explained later in this report, extensive groundwater j .' testing in the early 1980's had shown this region of the SFVGWB to t i be the most heavily contamined. ! ,--' The cities of Los Angeles and Burbank both operate p-T." production wells in the North Hollywood-Burbank well field area, and excessive groundwater contamination has forced both cities '*•". P " to shut down a number.of their wells in this region. This situation has particularly impacted the City of Burbank, which lost a major part of its supply to groundwater contamination. - 8 - s . • • In order to objectively evaluate the relative needs of the two cities for interim action, the LADWP considered both cities' total yearly production and consumption/ and their respective abilities to purchase adequate quantities of replacement supplies. Additionally/ remedial action implementation time and aquifer hydrogeological response at the well fields were evaluated. As will be described in this report/ existing data on the knowledge of the hydrogeology of the North Hollywood well field area is sufficient to reliably permit interim cleanup .. operations; on the other hand/ knowledge of the hydrogeology of the extreme eastern San Fernando Valley and the Verdugo Basin is no by comparison inadequate to justify an interim remedial program. r- These groundwater supplies, important as they are to these cities jr s in guaranteeing an adequate- local supply/ are more easil• y replaced r-l by imported purchased water supplies than the LADWP's groundwater ! L4 v supply which has experienced extensive local contamination /:•'! ni ,• involving considerabl' y more volume. ,-., In view of the above considerations/ the LADWP selected j *-•' the North Hollywood well field area as the site for interim I remedial action. Because this well field is located upstream of fi." V,.T . .... I Burbank's production wells, the LADWP expects that remedial action n will at least partially attentuate Burbank's groundwater contami- nation problem. In addition, the results of this project and of K I ^-' the overall Remedial Investigation will permit a more comprehensive [' approach in solving the groundwater problems of other affected P"L' Ui;f (i :_„.-.. water purveyors in the study area through technology transfer. / V

\/ - 9 -

Once the North Hollywood well field had been selected for immediate attention, a number of remedial action alternatives were evaluated for the site, as detailed in this report. It should be stressed at this point, however, that in evaluating remedial actions for the North Hollywood site, the LADWP weighed heavily the effect of each alternative on halting basin-wide contamination spread. Specifically, the LADWP aimed to select a remedy that would be consistent with long-range plans for the basin-wide RI/FS. In accordance with this objective, extraction (rather than an in-ground technique) was chosen for its ability to remove existing contamination from the Basin. In summary, the LADWP believes that the operable unit approach must be local as well as expedient; however, every attempt was made to design an .operable unit in the best interest of all concerned agencies and one consistent with long-term remedial plans for the Basin. ti- nt- I. INTRODUCTION

n

r, - 10 -

I. INTRODUCTION

BACKGROUND With the development of highly sensitive analytical techniques and increased regulatory testing requirements has come the awareness that State groundwaters have become contaminated by a variety of volatile organic compounds that are either known or I V- suspected to be human carcinogens. Despite indications that the '\ present levels of contamination are, with a few exceptions, within rtt j interim regulatory guideline drinking water limits, there is little doubt that observed contaminant levels will increase unless

f_. measures are taken to both control the sources of pollution and to | treat.sources of supply which are now known to be contaminated. The SFVGWB is a natural underground reservoir located in Los Angeles County and provides a primary source of drinking water "; ^ to the cities of Los Angeles, Burbank, Glendale, and San Fernando, and to the County Water District. In early 1980, the industrial solvents trichloroethylene (TCE) and perchloro- • |-v ethylene (PCE) were discovered in approximately one-fourth of the 1 *"•' LADWP SFVGWB production wells. In response to these findings, the LADWP and the Southern Association of Governments (SCAG) applied for and received EPA funds to embark upon a two-year study which was begun in July 1981 [32] . The purpose of the study was to determine the

;_^. extent and severity of the contamination and to develop strategies to control the groundwater contamination problem. Specifically, -li-

the study sought to develop a basin-wide groundwater quality management plan to ensure the future safety of the Basin ground- water. Activities of the study included field investigations/ industrial site surveys, records and archives searches, literature reviews, and water quality analyses of more than 600 samples. The study determined that the contaminant occurs in plume patterns and is spreading with the natural flow of groundwater in a south- easterly direction. Additionally, the study identified several """[7 major causes of groundwater contamination and found varying levels of contaminants in most of the 11 producing well fields in the \ SFVGWB. A program for preferential pumping and blending of i , l—• ; .. groundwaters with uncontaminated surface supplies was instituted P*"\ i to offset the increasing loss of LADWP supplies. pf"" The LADWP's tentative solution to this problem was a decision to attempt to arrest the observed continued spread of ' p • • Pi groundwater contaminants by constructing a treatment facility at ; ., its most heavily affected well field. The North Hollywood well r h [ I— field, located in the vicinity of Vanowen Street and Lankershim i ' (.' Boulevard, is the LADWP's largest and most productive groundwater ' ~ source consisting of 37 wells varying from 600 to 800 feet in .. ,-. 1:'p- ~ depth and supplying approximately 10 percen' t of the LADWP'' • s total water supply. On the basis of results obtained from the 1983 -. f.-. Hj il-:_ study, it was determined that groundwater aeration might be a ;.-•. viable interim solution for the well field; consequently, I ; ~ •*-•>••• preliminary design plans were made for a network of groundwater i extraction wells and collector pipeline. • • - 12 -

In 1984, the EPA proposed four well fields within the SFVGWB on the National Priorities List (NPL) for uncontrolled hazardous waste sites, thereby making these sites eligible for federal (Superfund) assistance under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). In September 1985, the LADWP applied for a Cooperative. Agreement with the EPA to perform a remedial investigation (RI) for these sites in order to characterize the nature and extent of existing contamination. The North Hollywood well field project was included in this application as an Operable Unit Feasibility Study (OUFS). Under the proposed plan, the LADWP, serving as lead agency for the project, would conduct a Remedial Investigation of the SFVGWB to consolidate a comprehensive contaminant data. base. RI activities would include hydrogeological investigations, P drilling of new monitoring wells, additional water quality • sampling, and soil-gas surveys and analyses. Data from this study would then be used as support material for a Feasibility • i Study to develop a permanent, cost-effective solution to the 1; ' contamination problem. The North Hollywood well field RI/FS r-j. would be conducted as a separate subset of the basin-wide investigation. Mvpi • In late 1985, with the assistance of its contractor• , Camp Dresser and McKee, EPA Region IX evaluated existing water r> | . ._^.- quality, hydrogeologic, and other related data concerning the } North Hollywood-Burbank site to determine if adequate information I

% ' ~1 3 " n , •!•"' was available to justify a Fast Track cleanup action for the nr North Hollywood-Burbank site. The EPA subsequently concluded that sufficient hydrologic data appeared to exist to justify an j evaluation of a Fast-Track action for the North Hollywood well field portion of this area and proposed a mechanism known as an 'rT;. .-. • • ••'..• . • ••..••• J ,L, OUFS as a means for preparing this accelerated work effort.

;pT: Preparation of this OUFS report was subsequently initiated to '" document the LADWP's decision process in evaluating and recommending a candidate groundwater treatment alternative. n A Cooperative Agreemen" t was finalized between the EPA ni_ and LADWP in March 1986. Because EPA did not have funds to begin the project due to the fact that the Comprehensive Environmental r Response, Compensation and Liability Act (Superfund) was not H reauthorized by Congress, the Agreement was funded in part'by LADWP as an advance against any future match required for the 'I San Fernando sites.

I - 14 -

Importance of Los Angeles Groundwater The SFVGWB is an important source of drinking water for the Los Angeles metropolitan area (Figure 1). In addition to supplying annual water needs, the basin stores large quantities of replenishable groundwater which can be extracted during droughts or emergencies when sufficient water from the Metropolitan Water District of (MWD) may not be available. By recharging the basin, both naturally and through spreading operations, local water purveyors are able to maintain a fairly constant long-term water level in this underground reservoir. The Cities of Los Angeles, Burbank, Glendale, and San Fernando, and the Crescenta Valley County Water District all depend on extracted groundwater from the basin for supplemental and emergency water needs (Figure 2). Groundwater extractions typically provide 15 percent of Los Angeles' water supply and account for between 50 and 100 percent of the water needs of the other above-mentioned areas. Based on current (1986) MWD water rates, the estimated annual worth of SFVGWB-extracted water is $20 million. The North Hollywood-Burbank area of the SFVGWB contains the majority of LADWP and City of Burbank wells. Of the well fields in this area, the .North Hollywood Well Field is clearly the most important to greater Los Angeles; 80 percent of LADWP*s total SFVGWB groundwater is drawn from this site, and groundwater from this centrally located well field can be distributed to LEGEND HuS SAN FERNANDO VALLEY n • Vlolnltr Map »f th» L»« Ani»J«B M«trop*Ht*ii Area - - SCALE 0 3 10 IS Miles Figure 1 • ,-,-,-«.— ' ' ., . i ' ' rl—~— " * ,.- — • ^— — ^ . «| ' *---——i " >—'• '•""<" '""." :? 'I:..:-:; "C^.J T.-.J "I.'.7- J; '{,r.3 iV::J- ti'.iJ , m r~:r r~i

ITY OF SAN'FERNANDd

POLITICAL BOUNDARIES San Fernando Valley Basin

CRESCENTA VALLEY COUNTY WATER DISTRICT

ICITY OF LOS ANQELE91

ITY OF LOS ANGELES1

Political Boundaries O San F«rnando Valley Basin C r•o F!

- 15 -

various parts of the City through various reservoirs and supply lines (Hollywood Reservoir, Silver Lake Reservoir, or the river supply line). FT Groundwater resources, in general, are expected to become increasingly important to Southern California as imported "r-r-n r- i • . • . . • I [j surface water supplies are reduced in the near future. Upon >*--- completion of the Central Arizona Project, for example,'Southern . 1 '- California will lose in excess of 50 percent of the water now ["l~; provided from the Colorado River Aqueduct. The California State Water Project, which imports water from Northern California, was I j expected to offset this loss; however, the necessary State ,.- Project facilities for this compensation have been neither 1 approved nor constructed. The State Project, consequently, p" ; can currently deliver only 50 percent of the State's contracted water. Construction of the additional facilities is expected to i-F, ;'.; require about 10 years to complete, and approval of these 'I i ' facilities is not in the foreseeable future. j U: The importance of groundwater from the SFVGWB becomes _;' most apparent during years of drought, as was illustrated in the •*• •'" 1977 Los Angeles area drought. During this dry spell, water from H; the Owens Valley — LADWP's foremost source of water — was

r: reduced to less than half of its usual supply; consequently, the j L amounts of purchased water from the MWD and extracted groundwater j.- from the SFVGWB had to be.increased by 532 percent and 39 percent, I.,'" ;-*--- respectively (Figure 3). Since much of the MWD's water is supplied » via the State Water Project, which is itself susceptible to the NORMAL YEAR

LOCAL GROUNDHATER tie.ax) QUANTITIES (Acre-Feet) OWENS VALLEY 467, 000 GROUNDWATER 102.000 M W D _37._QOO> TOTALS GOG. 000

OWENS VALLEY (77.«)

1977 DROUGHT YEAR

OWENS VALLEY (34.7X)

QUANTITIES (Acre-Feet) M W D OWENS VALLEY (43.BX) aoo. ooo GROUNDWATER 142. 000 M W D 234._000 TOTALS 576. 000

1 r. *. LOCAL [24.7X> GROUNDWATER

LOS ANGELES' WATER SUPPLY

Figure 3, - 16 -

same drought conditions that restrict the Owens Valley supply, r*.-. water purchases from the MWD cannot always be depended upon as a ' - viable water supply alternative during times of drought. ~T Finally, litigation over Los Angeles' water rights in n.. • the Mono Basin and Owens Valley further threatens the security of imported water. The combined impact of the above losses could . ,_. prove to be catastrophic if drought or other emergency conditions I ; persist for extended periods. Groundwater quality management is, p"~ therefore, a vital concern in ensuring the continued safe use and protection of San Fernando Valley groundwater.

n "S •

Regional Setting and Site Location The North Hollywood well field lies within the North Hollywood-Burbank area of the San Fernando Valley Groundwater Basin. The latter is part of the Upper Area (ULARA), which consists of the entire Los Angeles River (LAR) watershed and its several tributaries above a point along the LAR rj— near its junction with the Arroyo Seco Flood Control Channel. • The entire area encompasses about 328,500 acres, of which 122,800 "~ acres are alluvial valley fill deposits, and 205,700 acres are n. .- • ' • hills and mountains. The region is bounded on the north and j ^ northwest by the Santa Susana Mountains, on the northeast by the

r_ , on the east by the San Rafael Hills, on ; I the west by the Simi Hills, and on the south by the Santa Monica •—r~ Mountains (Figure 4). . • The San Fernando Basin is the largest 'of four distinct r— fi hydrologic basins within the ULARA and constitutes 91.2 percent, or 112,000 acres, of the total valley fill. The Basin is enclosed I L by the San Rafael Hills, Verdugo Mountains, and San Gabriel ! Mountains on the east and northeast; the San Gabriel Mountains on (• the north; the Santa Susana Mountains, and Simi Hills on the i northwest; and the Santa Monica Mountains on the south (Figure 4). rI .*. Only the eastern half of the San Fernando Basin has |- ' . . PL widespread 'organic groundwater contamination problems, and it is I in this eastern area that the North Hollywood well field — along I ~ ._„,.-. with three other similar, but less contaminated well fields — is • located. n- ; i T- —i rri r~i ~i i- -i ~: ~; fl t..., I ::. -.1 i • -I i...... : . i

Location of Groundwater Basins and NPL Sites in ULARA

SAN GABRIEL MOUNTAINS N

No

SANTA SUSANA MOUNTAINS

.VERDUGO B^SIN

VERDUGO SAN RAFAEL MOUNTAINS HILLS

SIMI HILLS SAN FERNANDO BASIN

EAGLE ROCK BASIN

SANTA MONICA MOUNTAINS BOUNDARY OF VALLEY FILL 1 NORTH HOLLYWOOD NPL SITE LOS ANGELES RIVER NARROWS 2 CRYSTAL SPRINGS NPL SITE Tl

Hydrogeologic Setting The San Fernando Basin is supplied, in part, by the three other smaller basins in the ULARA (namely, the Sylmar, Verdugo, and Eagle Rock). Of these four basins, only the Verdugo Basin and the eastern portion of the San Fernando Basin contain NPL sites. The geology of each basin consists of alluvial deposits composed of unconsolidated gravels and sand interbedded with lenses of silt and clay. The general regional hydraulic gradient favors groundwater flow in a southeasterly direction toward the Los Angeles County Flood Control District Gage F-57 at the Los Angeles River Narrows (Figure 5) . ._, The eastern portion of the San Fernando Basin, in which El the North Hollywood well field is located, contains alluvial ~~ deposits consisting of coarser materials, such as sands and nt —' : gravels, interbedded with localized lenses of clays and silts. j I , This area of the basin also has characteristically high soil permeabilities resulting in higher surface infiltration rates fii (Figure 6). Two-thirds of the San Fernando Basin's groundwater i—|";. storage capacity is located in this eastern portion of the basin. The close spacing and high extraction rates of the M: San Fernando area production wells have caused several large - cones of depression to develop in the groundwater table. These I L: interfering cones of depression have significantly altered the i- groundwater flow patterns, and despite seasonal variations in I ;~~ - *. ' pumping activities, the cones persist throughout the entire year. - 19 -

Nature and Extent of the Problem The groundwater testing program of the 1981-to-1983 Groundwater Quality Management Plan-San Fernando Valley Groundwater Basin Study has shown that volatile organics contamination is affecting four water systems in the San Fernando Valley Basin (SFVB) (Los Angeles, Burbank, Glendale, and the Crescenta Valley County Water District). Tests revealed that concentrations of TCE and PCE which exceed the action levels recommended by the State p Department of Health Services (DHS) are present in approximately 45 percent of the water supply wells located in the eastern I portion of the SFVB. Figure 7 shows the location of wells exceeding these limits in 1983. i Groundwater in the North Hollywood area of the SFVGWB was p' shown by this report to be the most heavily contaminated, and • wells in the LADWP's North Hollywood, Erwin, Whitnall, and !":• Verdugo well fields are all affected by this contamination. TCE was the primary contaminant found; however, PCE contamination was [ also detected in several wells at lower concentrations. • An examination of Figure 8 suggests a correlation between '•' " TCE contamination and commercial and industrial developments for wells located in the vicinity of the North Hollywood well fields. n-' In general, wells located in residential zones, represented by the ji':-. uncolored areas in Figure 8, were uncontaminated. The contaminants in the groundwater, however, can either migrate in the direction n-I i." - > . of groundwater flow or be drawn toward an operating well from as »• ' far away as 2000 feet, depending upon pumping rates and the areal n transmissivity of the aquifer. BAN FERNANDO & -VEHDUGO BASINS

GROUNDWATER FLOW 1980 '

LEGEND o WELL FIELDS ' A. NORTH HOLLYWOOD 8. ERWIN • SAN GABRIEL C WHITNALL MOUNTAINS 0 CITY OF 8URBANK E. VEROUGO F. HEADWORKS SANTA SUSANA a CRYSTAL'SPRINGS MOUNTAINS K CITY OF GLENOALE • ( GRANOVIEW ) I. CITY OF GLENDALE ( CLORIETTA ) J. CRESCENTA VALLEY COUNTY WATER DISTRICT K. POLLOCK" t_ MISSION ' HILLS M. CITY OF SAM FERNANDO

SANTA MONICA MOUNTAINS

LOS ANGELES RIVER NARROWS

SAN FERNANDO AND VERDUGO BASINS GROUND^ATER FLOV/ MAP SOIL INFILTRATION

; V.«.«.< «....« _ .:'./:'"..../•V' / **.-5<-*^:-y-:/.,'. 1:' >^;A: / •/

>^^SftN««'°^a^<^^'q^^^V^--C3i^Tr:>. —f/if \

^iS^^^S^^^^^^^^i^f'.V' ..-/ y

Figure 6 . LOCATION OF WELLS CONTAINING TCE AND/OR PCE IN EXCESS OF DOHS ACTION LEVELS -•

fc-^^ ...... - • .•.••• . .•.- -

»hl llir» f»»» *;*i»»"•«»«'':«" * ' ' • ;i ';' '

Figure 7 _. .— —, • ,—. I —, —. .—. J :*T. -r:.:h jl t jl s, • f] i ..?! •;..,.-. i ,•;-.*)

NH-40 NH-30 H-38

NORTH HOLLYWOOD TCE CONTAMINATION 1981 VS. 1985 $CAtE : f : 1.000'

— t881 — — 1985 TCE > ACTION LEVEL IN 1980-81 t AT PRESENT (1984-85) TCE > ACTION LEVEL ONLY AT PRESENT (1984-85) MANUFACTURING ••• HEAVY INDUSTRIAL COMMERCIAL MANUFACTURING - 20 -

. The TCE and PCE concentrations observed in groundwater supply wells over the six years of testing indicate that the contamination occurs in plume patterns. Lack of an adequate r number of groundwater sampling and monitoring facilities, however, prohibited the tracing of contaminant origin and path and also Ir ~ prevented accurate plotting of definitive contaminan' t plume r-.; patterns. . . . I •- ' An inflatable well packer was installed in a highly P~ contaminated well, NH-24, at a depth of 300 feet, approximately 100 feet below the water table. The inflated packer, located at j _ the middle of a thick clay lense/ isolates the upper aquifer groundwater from entering the pump discharge column of the well. A comparison of TCE levels before and after installation of the rt~ well packer revealed a dramatic reduction on the order of about *• 50 to 1 (see Appendix 3). The results of these tests indicate the | .. concentration of TCE is much greater in the upper zone of the aquifer than in the lower zone. I - The aquifer in the North Hollywood area.in which this P:I" • packer test was conducted is comprised primarily of sands and t gravels with some localized lenses of silts and clays interbedded. - Conditions are characterized by high aquifer permeability and groundwater production throughout the area even though the w • L- thickness of the clay lenses may shift in location or thickness. ;". Further description of aquifer characteristics in the [ "" •--,.- . North Hollywood area of the SFVB is contained in Appendix 7 and f "^ • r . in References 27 and 33. L- In 1980, water from 11 of LADWP's wells within the P" ' North Hollywood area exceeded the State action level for TCE; by January 1983, 22 of the North Hollywood wells exceeded the [^ 5 ppb action level; and as of August 1985, 27 wells exceeded the limit -T several of the wells, in fact, exceeded 40 ppb. This I _ trend tends to indicate that the contaminant plume has moved over p- one-fifth of a mile (1100 feet) in just the last four years. This ; flow rate approximates that of the groundwater itself, indicating H that the soil has little effect on attenuating the spread of contaminants in the areas of interest. At this rate of migration, rl | contamination could potentially spread to another 5 to 10 wells .-.- within the next 2 years. 1 Figure 8 shows the spreading of TCE contamination in the rv North Hollywood, Ervin, Whitnall, and Burbank well fields of the North Hollywood Area NPL site during 1981-1985. (For specific f" well data, see Appendix 4.) The estimated horizontal flow velocity of the groundwater in this area is 300 to 400 feet per year. ft There are many relatively clean wells that are immediately down- P~ gradient of the heavily contaminated wells. The Whitnall Well L Field, in particular, appears to be susceptible to contamination F"! problems in the near future; Whitnall Well No. 4, for example, just recently (July 1985) went over the State TCE action level for the first time, with a reading of 9.5 ppb. f«. . r-' - 22 - •iI R'

PI Characterization of Contaminant Incidence p/ As a water purveyor, the LADWP conducts routine chemical i. • -' • and microbiological analyses on its source and distribution [! supplies. Since 1980, these analyses have been supplemented by investigations into the nature and extent of volatile organic I ... compounds (VOCs) detected in the groundwaters of the San Fernando p~ Valley Groundwater Basin. In 1985, additional data was collected in accordance with the requirements of Assembly Bill 1803. On the li, basis of these investigations and related work, the LADWP determine1 that the observed groundwater contamination is appreciable only [ ._; for the compounds trichloroethylene (TCE) and perchloroethylene r:^ (PCE) . Scanning results for a total of 45 VOCs indicate that ' ' • ' •!• trace quantities of other contaminants are also present in the p groundwater supplies (see Appendix 4). However, the measured concentrations of all detected contaminants was found to vary fl considerably according to sampling location and time, and no , - discernable pattern of contamination was observed for any 1 .,- compounds other than TCE and PCE. |4v Groundwater flow and quality models were developed for ' the North Hollywood area on the basis of historic flow and P : quality data. Results from these models, along with information obtained from in-house studies (specifically, the 1983 LADWP r' Groundwater Quality Management Study)' ', indicate that significant ! TCE and PCE contamination has occurred in the upper layer of a I _ -•>-•• three-component aquifer/aquitard formation. The upper layer, consisting of a highly permeable aquifer approximately 100 feet

L ' V - 23 - in thickness, overlies a broken, nonhomogeneous layer of relatively j : impermeable clay and silt. Below this, another aquifer extends some 500-800 feet below the ground surface. This lower layer is [,- the primary supply for the LADWP's most productive well fields. Model studies support the possibility that pumping has caused • • ' : ..'.''. n contaminants to migrate from the upper contaminated aquifer to the P ' relatively uncontaminated lower aquifer. In the AB 1803 VOC scanning study, a total of [ '\ 13 compounds were found to be present in detectable levels in _" specific wells located in the LADWP's North Hollywood, Crystal ' •" Springs, Erwin, Whitnall and Pollock well fields. Of these, all P"**! but 3 VOCs were found to be below state action limits. These were trichloroethylene (TCE), perchloroethylene (PCE), and carbon j L, tetrachloride. The incidence of carbon tetrachloride was slight, ( appearing in only two wells on three occasions over a 5-month ! '""' testing period. TCE and PCE, on the other hand, appeared : consistently at levels greatly exceeding the action levels. • • n These results confirmed those of previous studies. Appendix 4 P summarizes groundwater quality analyses over a multi-year period i." • I . of record. ( •-" TCE and PCE are relatively stable halogenated alkenes •. and do not degrade significantly in the natural groundwater I — i environment. It has .been demonstrated that TCE can degrade to i - p^_ vinyl chloride under anaerobic conditions; however, vinyl chloride "->,. * has never been detected in the wells of the study area.

I ; -«-

; ' Since the study area is characterized by highly p '', permeable groundwater aquifers, the migration of contaminants is dependent largely upon the magnitude and direction of the •r7 ' • • | ' groundwater flow. The lack of organic material in the soil is ••-. responsible for the relatively low retardation or attenuation t factors which are assumed to exist for the contaminants of '.{"*""] concern. On the basis of these facts, the occurrence of apparent contaminant plumes in the aquifer underlying the study area r— j; cannot be tied to specific sources; the correlation of well ,-. contamination to land use appears to justify the assumption that [ /-"• the contamination is a local phenomenon, but the observed steady, j-£^ rapid movement of contaminants precludes specific source identification at this time. | Since groundwater flow velocities and volumes are appreciable in the area, the effect of in-situ contaminant I - dilution must be significant. However, the rate of contaminant A" recharge may be equally significant, and it would be unwise to I. assume that the situation will eventually repair itself. $ •

i".; r r" r ' ' • ' II. IDENTIFICATION, DEVELOPMENT, AND SCREENING OF f REMEDIAL TECHNOLOGIES r r.r • • , - 25 -

II. IDENTIFICATION, DEVELOPMENT , AND SCREENING OF REMEDIAL TECHNOLOGIES Overview of Screening pi- Two broad approaches, applied singly or in conjunction, ' ' are available in implementing remedial activities for contaminated r\ aquifers: in-ground approaches, in which groundwaters are basically isolated, contained, abandoned, or diluted with recharge supplies; and extraction methods, in which the waters are removed and either r: disposed of or treated. { i- Upon shutting down its first few wells in 1980, the pV~ LADWP implemented a program of blending to maintain the groundwater supply as much as possible. On the other hand, the cities of f—r Burbank and Glendale, relying on relatively few wells for a majority of their independent supply, were forced to shut down [ '- numerous wells in full cognizance that make-up supplies would have _1,V to be purchased. In the ensuing years, the problem has worsened, ' ' both in the observed extent of the contamination, and the number n • • p of affected wells. The question of urgency, therefore, may be viewed differently by each of the affected water utilities. r*' = .- However, it was soon recognized that the in-ground approach could ("• not effectively control the spread of contamination, that the IP- .' problem would probably get worse, and that the value of the rv groundwater resource was being significantly eroded. - p, f; r(- - 26 -

In 1984, following a two-year joint study with the Southern California Association of Governments and funded in part by the EPA, the LADWP initiated plans to design and construct groundwater extraction and treatment facilities as a stop-gap ^- measure against the observed spread of contamination in the 1 •••' LADWP's most productive well field. The following discussion pH documents some of the considerations made by the Department in identifying, reviewing, and evaluating available remedial ]•'•;', alternatives for these facilities.

• t—7 ' . ' I • • Screening Criteria . The question of remedial action feasibility necessarily P involves a consideration of the criteria used in selecting p'. candidate response activities for further investigation. Such screening criteria may involve factors such as site and ] .: contaminant characteristics, project schedule, political • '" expediency, capital and operating costs, environmental impacts, iP - and public health considerations. Since these factors will p. normally compete with one another in terms of net benefit, or .offset each other completely, it is necessary to limit' the number I '_._ of screening criteria so that the remedial alternatives can be i :• weighted meaningfully. For this reason, the criteria selected [ ."* for screening of identified preliminary alternatives will be

! ._ limited to environmental and public health considerations and cost

I ~"~ "' , -s, ~ "*' 'effectiveness effectiveness. . A Amor more ecomprehensiv comprehensive escr screenin< g of candidate alternatives will be given in Section V. ri - ;ns

Response Actions Hi ' • • • • 1. No Action r~- | '•'.< Under this option, .no remedial response action would be taken. The observed spread of contaminants would continue unabated, and additional production wells would become contaminated.

Cost-Effectiveness

f_ . Since this option entails no facilities or costs, the 1 •-; no-action alternative could be put into effect immediately .-E^ by simply doing nothing. However, this would only defer the cost of mitigation to a later date, and force the LADWP to Pj . rely on outside purchases for normal and emergency water supplies from the MWD.

i r~ Environmental and Public Health Factors i In order to fully assess the public health and rv environmental endangerment of the no-action alternative, a risk assessment was performed in accordance with federal ; k: public health evaluation guidelines.

n_ - 28 -

In view of the number of volatile organic chemicals detected in groundwaters of the study area (see Appendix 4), trichloroethylene (TCE) and perchloroethylene (PCE) were .HI selected as indicator chemicals. The appropriateness of this selection is justified by the following: : . 1. TCE and PCE are the only volatile organics present in significant concentrations in the study area; 2. They are classified as Category 1 substances j .'. (known or probably human carcinogenics) ; ^ 3. Their removal from groundwater by any of the | r: candidate remedial alternative identified in this r- report is the most difficult at the concentrations >• present in the groundwaters. r* • Although no clear human exposure pathways can be' determined for the no-action alternative other than by j _v ingestion, it is conservative to assume that the Basin's p- groundwaters, representing major sources of supply to the x r4 "- surrounding population, will continue to be utilized to some

—' : extent regardless of.the extent of contamination. This assumption then implies that human exposure to TCE and PCE | __ will be the result of continuing groundwater supply practices , and that exposure itself will be in the form of ingestion of — public drinking water supplies. . I":": The actual levels of TCE and PCE present at the well 1 L "-* •"•• heads of groundwater production fields may be predicted with r the use of mathematical models based on existing data. In I. " -29-

the case of the North Hollywood well field, extensive modeling is not necessary since a considerable body of data has already been compiled; in addition, due to the many wells present in the study area, TCE and PCE concentrations can be monitored continuously, allowing an accurate estimate of the levels of contaminants which could reach the consumer. What i.s not known is the quantity of available 1 surface supplies (in the form of natural underground P : recharge or above-ground artificial blending) which would 1 •— serve to dilute the contaminants to acceptable levels. The T[ V„. availability of these supplies is largely dependent upon 7- precipitation on local and non-local watersheds; these i supplies cannot be reliably predicted. In addition, natural r— r*.. shortages may be compounded by outages and interruptions (both scheduled and unscheduled) in aqueduct flows, further j r~ I ^ . limiting blending supplies. r- Sound estimates of the impact of insufficient blending I ~~ supplies can be made on the basis of recent experience with P^ high-summer demands and aqueduct outages. The severe ' drought conditions of the mid-1970's undoubtedly contributed F P_ to higher contaminant concentrations in depleted groundwater r. aquifers. In September of 1985, high-summer demands [ p- contributed to TCE concentrations as high as 10 parts per I billion (ppb) in the LADWP's River Supply Conduit, with an I L ->••"• overall monthly average of 6 ppb. At that time, groundwater r . supplies accounted for 20 percent of the total supply, I . ' r-r:1 -•,...( ^__. -_

- 30 -

approximately 35 percent higher than the average. In October of 1985, an unscheduled aqueduct shutdown for emergency repairs contributed to TCE concentrations ranging from 8 ppb to 13 ppb during the month; the average was 10 ppb. Approximately 30 percent of the City's total water I ;.. demand was supplied by groundwater supplies during this 1*7 time, or 100 percent higher than the average. . During the'mid-1970's drought, well water comprised ffT -. approximately 26 percent of the City's total supply; the level of TCE present in delivered supplies ranged from 8 ppb [ 'J to 13 ppb. Given the increased spread of contaminants since' .IP that time, the concentrations resulting from another drought ' would probably be higher. In contrast to the levels of TCE, PCE measurements performed in 1985 were consistently below 4 ppb; concentrations of the 11 additional contaminants are r.- presented in Appendix 4. [ r The relevant and applicable requirements for comparison p"'; of projected exposure point concentrations to ambient (or existing) conditions are summarized in the EPA's regulations

H-v ' . regarding Maximum Contaminant Levels (MCLs) for TCE and PCE b I : and similar conditions promulgated by the California State [ ,'-' Department of Health Services in its Station Action Levels !• (SALs) . r- - 31 .-

The projected exposure point concentration for TCE exceeds the MCL and SAL, which are both currently set at 5 ppb. There are existing or proposed MCLs and/or SALs for most of the additional contaminants found in the groundwaters of the study area. Since these other substances occur in relatively few wells at extremely low levels, it is probable that their exposure point concentrations will not exceed regulatory limits. Exposure point concentrations for TCE could be reduced

rr, . by purchasing MWD water to replace groundwater supplies [ - during periods of aqueduct shortages or high demands. Ji^ However, concentrations of trihalomethanes (THMs) in MWD ' supplies are currently substantially higher than those of r*\- LADWP well and surface waters; the theoretical health risk due to THMs is approximately 400 times higher than the risk due to TCE.

2. Purchase Water Supplies Under this alternative, the LADWP would abandon or curtail operations involving contaminated wells and make up the supply deficit in the form of purchases from the MWD. However, this option would force the LADWP to rely on a source of supply which is currently.faced-with supply shortages of its own. rF-: - 32 -

Cost-Effectiveness In view of impending developments created by the recent Central Arizona Project ruling, LADWP entitlements to purchased MWD water would depend upon the availability of supplies from the State Water Project and the Colordado River. In times of drought, extended summer demand or emergency, the required imports could not be guaranteed, and the cost to the LADWP would be indefinite. The LADWP presently purchases approximately 45,000 acre-feet of water annually from- the MWD. This water, which represents a combination of interruptible and non-interruptible supplies, is purchased at an average cost of about $204 per acre-foot, or $9.1 million annually. Based on well locations and groundwater flow rates in the study area, it has been estimated that as many as 10 more production wells could be contaminated over the next 2 years unless remedial action is undertaken. Assuming an average production per well of 1,500 gallons per minute (gpm), a local reduction in supply of 15,000 gpm could result. This is approximately 25 percent of the total annual local groundwater supply (about 100,000 acre-feet). If purchased from the MWD at the current make-up cost of $230 per acre-foot (1986), the annual cost to the LADWP would amount to nearly $6 million -T^ (discounting well operating and maintenance costs). •s^ ""*"' Non-interruptible MWD emergency supplies would be even more costly. i - 33 -

Environmental and Public Health Factors The impact of purchasing water on the environment would be identical to that of the no-action alternative since no positive remedial action would take place. The impact on public health would be primarily dependent upon the quality • of purchased supplies. There is currently a concern over V . :_/-: the level of THMs in MWD supplies; , which are significantly rVI •;-• • • higher than the level' s 'now presen t in LADWP 'groundwaters. 'p"~: The MWD's future plans for treatment compound the problem of assessing the adverse impact of purchased waters on public I:' health.

3. Containment

JT; This alternative would serve to prevent the spread of '' contamination to relatively unaffected well fields through a P • program of preferential pumping and aquifer management. By containing the existing contamination in this manner, only --: those wells situated in the contaminated area would be /•"•;' affected; other remedial actions could be performed on the Lr contaminated area at a later date. H ' Construction of slurry walls as a containment alternative is precluded to be infeasible.due to the areal extent of n.-.. observed contamination and the fact that depth to groundwater j. in the North Hollywood area is 200 feet. rj > '"" • T•V • • • • .

. Cost-Effectiveness By containing the existing contamination to a limited area, water purchases from MWD could be minimized. However, n: it is estimated that approximately 5 producing wells would eventually be removed from service to maintain the containment, n resulting in an annual loss of about 12,000 acre-feet of r-n supply. Make-up purchases for this water would amount.to nearly $3 million per year. Furthermore, operation of local n producing wells would have to be adjusted to create and maintain the containment of groundwater contaminants, resulting in a further loss of supply. In addition, the '-"• contamination would still continue to exist, with future "• remedial action becoming more costly each year it is postponed. Under this option, preferential pumping would be utilized to help control the migration of contaminants. Although a '\ _ percentage of the pumped groundwater could be blended with r uncontaminated supplies, a potential contaminant disposal [ ,L" problem would exist. Currently available liquid-waste p' : disposal sites are very limited in number and the costs of disposal, including those associated with transportation i and insurance, are very high (current market rates for 1 ~ Class I facilities in California receiving hazardous wastes f- for treatment and disposal vary from $140-$190 per cubic yard; transportation cost is about $60 per ton of waste) and ' ^ '"" ^'" • will most likely increase. r. j- - 35 - rr In addition to the.controlled operation of local producing wells/ an indeterminate number of pumping and nr monitoring wells would have to be constructed to assist in rr the program of containment. These facilities would incur capital costs and, since the program life would be indefinite, IT unknown annual operating and maintenance costs. The containment alternative would also impact .recharge r' f. operations near affected areas. Currently, four spreading [T basins are operated in areas exhibiting high concentrations of volatile organics in groundwater. The containment alternative might require curtailment of storm and surplus water spreading at these facilities in order to maintain contaminant containment.

Environmental and Public Health Factors r-: f[ The same adverse conditions under the no-action alter- * / native would also apply to the containment option, although j I ( presumably to a lesser degree. n1 4. Extraction p | .The extraction of contaminated groundwaters by pumping . is .a positive action in that it serves to remove the - n < - contaminants from the supply. However, it brings into focus f the problem of what to do with the waters once they are - 37 -

depth of 300 feet (the estimated depth of the contaminated upper aquifer), would limit the spread of contamination to downstream production wells. Therefore, conjunctive containment schemes, which would be difficult to develop and implement on a [T, quantitative basis, would not be necessary. However, the IT operation of extraction wells could be adjusted in accordance with varying contaminant concentrations in order to prevent [' V;- further downstream groundwater degradation.

4.1 Disposal Under this alternative, the LADWP would pump out ,.. contaminated groundwaters and discharge them directly to I a sewer or storm drain. Disposal to storm drains would '": require a National Pollutant Discharge Elimination J L- ' ' System (NPDES) permit from the Los Angeles Regional . H. ' Water Quality Control Board, which would presumably set strict limits on the waste stream contaminant concentra- U- tion. Likewise, the Los Angeles County Sanitation I1.; District would set similar limits for sewer disposal. t f~ Should the concentration reach a point where sewer/storm '" drain disposal is not permitted, disposal would require " n pretreatment or hauling to an approved hazardous waste n.:. disposal site; either of these contingencies would f ; be costly. - 38 -

On the other hand, disposal of large quantities of contaminated groundwater represents the loss of a valuable resource. This loss would have to be compen- rn sated by increased purchases'of water from the Metropolitan Water District (MWD) at a cost far above }{_•'. • the present pumping costs for Basin groundwaters. r-t Furthermore, this source of supply cannot be relied on [ in times of drought or shortage. p-Fi In view of these problems, groundwater disposal would be an attractive alternative only for a very Pi •; short-term sampling and testing program involving

rr relatively small amounts of pumped supplies. The value [ of large quantities of groundwater is too great in the LADWP's view to consider disposal as a viable long-term remedial action.

4.2 Blending . - F— Blending consists of mixing contaminated ground- {".'• waters with quantities of blending water sufficient to [IT j" keep the concentration of selected contaminants below a i given action level. Given an adequate supply of blending water, this method serves to maintain a high level of I'.- PL*-, use of the ground supply while removing contaminants r, from the affected portions of the aquifer. .The alterna- ' Pi '•' .- . - tive becomes infeasible when contaminant levels in the - 39 -

! water to be blended exceed about 40 parts per billion 'p. (ppb) since the required quantities of blending water will then exceed the available supply or the hydraulic : ;•"' capacity of the collection system.

r~ Blending has the advantage that, given a supply of y- dilution water and a suitable collection/conveyance system, it can be implemented almost immediately. In 1980, the LADWP resorted to this method when the scope ft of the contamination problem in the Basin was becoming apparent and there was no long-range plan of action. | \-^' Conversely, blending can be looked on as simply a rr contaminant dilution scheme whereby the problem organics I ; '- are transferred from the ground to the distribu- H. .. tion supply system. Currently, the EPA considers blending of contaminated water supplies to be I L. less desirable as a treatment option, since other technologies may be used to achieve Maximum Contaminant Levels (MCLs). However, existing and pending federal *J ": regulations [7] are such that blending may be considered as a viable option, either in achieving _ Recommended Maximum Contaminant Levels [RMCLs] (which, n . p for TCE and PCE, are zero) or as a contingency for some M • ;~" other treatment process. - 40 -

4.3 Treatment

r-, Treatment of contaminated groundwater involves a ' ••' combination of the previous methods in that the problems p("; associated with extraction/ blending/ and disposal may still be present. However/ treatment provides a means of j I'". ultimate contaminant disposal which is preferred from the environmental and public health point of view. 113 All treatment alternatives discussed herein require -.P extraction of groundwater. Although some in-situ * • methods exist/ such as bacterial dosing/biodegradation, H ~ they are applicable only to a select number of volatile _ organic compounds; to date, no proven applications exist [ for TCE and PCE. r:: Treatment may or may not involve contaminant I r* removal, but the more applicable methods require separa- p ' tion of contaminants. The ultraviolet irradiation/ ozonation process is the one notable exception. rP Contaminant removal necessarily implies disposal, and since most volatile organic compounds are classified as - d hazardous materials, costs associated with disposal rise -J accordingly, depending on the process selected. ' The major benefit of treatment is that it is P . -• n.j preferred from the environmental and public health /•-. aspects: the contaminant is neither left in the ground- [ ^ ,_. . water nor consumed by an unknowing or reluctant public.

i • I

- 41 -

In addition, treatment is flexible in that the selected process can usually be modified to provide results consistent with changing regulatory contaminant limits. Costs associated with the treatment of groundwater are contingent upon the treatment method, the degree of treatment, and methods of contaminant disposal and groundwater reclamation. Not all of the available treatment methods have demonstrated application to all types of contaminants; some methods have still not progressed beyond the pilot plant stage. Neverthe- ; less, it is prudent to attempt a cost comparison by means of treatment dollars per 1000 gallons whenever possible. The treatment alternatives that will be pj'•' discussed here are: o aeration L o granular activated carbon adsorption (GAC) p o combined aeration/GAC i. . o ultraviolet irradiation/ozonation p.. o passive aeration o selective resin adsorption pU Since the individual requirements of these methods f.i vary considerably, it is difficult to make comparisons [ ' ' without entering into a detailed cost/benefit discussion for each. In addition, since several of these alterna- rp1 -.^ ""'*•". ' tives are still not proven, there is no need to include f '_, such processes in a detailed comparison. Therefore, a fv • H-r- ; '•• brief discussion of each alternative will be presented | •- here, while screened alternatives will receive a more i'.-'.' comprehensive treatment in Section V.

*-~ Treatment Alternatives I l:-' ; Aeratio' n .

'•\~f( Aeration involves a mass-transfer process by which a solute is removed by exposure to an air-solvent inter- J •'" face. The application of this process to groundwater _.,, treatment is made by running a volume of groundwater I " : ' -••- through a vertical column containing a packing media. r**^ The media serves to provide a tremendous surface area over which a countercurrent flow of air is introduced; I f; the contaminant is transferred from the groundwater to the air and subsequently removed. The efficiency of the I ..j process is primarily dependent on the nature of the • r1i\ contaminant, its influent concentration, the rate of air flow, and the available surface area afforded by the Hi- packing material. v Aeration of contaminated groundwater is basically |r Li. an extension of air-stripping applications, and is thus '- a proven technology. Aeration facilities are available * ••" from a number of vendors and can be obtained on a p;- turnkey basis. As such, it is one of the more commonly / "^\*"'*;". ' employed methods for treating groundwater. - 43 -

Granular Activated Carbon (GAG) Adsorption By passing contaminated groundwater through a bed of granular activated carbon, volatile organics are removed by direct adsorption onto the carbon particles. The effectiveness of the GAG process has been demon- strated and is generally considered to be reliable. r"j:-; However, there have been reports of adsorption facilities having fallen far short of expected performance. This ] l;i may occur if the design parameters are exceeded or if rn _.; . the process, designed primarily for one type of I v..-: contaminant, is expected to treat other types as well. GAG has the singular distinction of representing a true removal process. Selective contaminants are captured with routine removal efficiencies of 90-99 percent, leaving a mass of spent carbon that is rv> { '

P\; and performance efficiency can be demonstrated for the , •—«, •—-~--~ •• contaminant in question. - 44 -

Combined Aeration/GAC Adsorption As was noted, one primary disadvantage to the aeration process is that the contaminants are not contained, but vented to the atmosphere. The process of combined aeration and GAC adsorption is designed to overcome this drawback. Aeration tower gases, comprising mainly water, vapor and contaminant, are dehumidified and then directed to a gas-phase GAC unit for final processing. Either the entire tower gas outflow or some portion may be treated. Although disposal problems for the spent carbon media are still present, the GAC sf"; process is generally more effective in removing contami- nant in the gas phase, resulting in a greatly reduced tU; volume of spent carbon.

Ultraviolet Irradiation/Ozonation (UV/O-) r-. Volatile organic compounds are susceptible to breakdown by ozonation. Irradiation of the influent r- r- n ; with ultraviolet light enhances this breakdown. While ; originally developed as a batch oxidation process for ;r* ] • ._; organic compound removal and trihalomethane control,

UV/03 has shown promise in water supply treatment at the fit pilot plant level. •£,£ " ••••'• I: n . i

•-v.v - 45 -

UV/03 treatment performance can be a limiting :-^ D factor since the process must be specifically tailored for a given organic contaminant. Removal efficiencies of 70 percent are achievable, while in specific cases removal can approach 90-95 percent. Oxidation of organic contaminants by ozonation is an established process in pharmaceutical and reagent manufacturing. UV/0- is most attractive as a method of contaminant removal and ultimate disposal. Theoretically/ its only by-products are water vapor, carbon dioxide, and a small amount of chloride in the effluent line. Although the process is energy intensive, the electrical costs may be compensated by the total elimination of disposal costs. , •'• In addition, the process affords the benefits of little adverse environmental and public health impact, while . reducing the requirements for post-chlorination in the effluent line. The physical requirements of the process are very reasonable since typical ozone contact time is '-.: I! on the order of several minutes requiring relatively compact equipment. Currently, there are several West Coast manufacturers of UV/0. equipment which claim treatability of volatile organic wastes.

:: -K f:, < - - 46 -

•:•:••: c' •' • .*.•'' .'••. Passive Aeration r^" R This is a process in which water contaminated with volatile organic compounds is allowed to stand with contaminant removal being effected by air convection. The contaminants may then be vented to the atmosphere or 0 captured by air scrubbing. A similar version of this method involves conveyance of contaminated water to an aerated sump or reservoir. While being relatively inexpensive, passive aeration is not very effective in contaminant removal with typical efficiencies on the order of only 20-30 percent. Furthermore/ the method involves the same concerns as aeration in regard to environmental and public health f---. impact.

• Selective Resin Adsorption This method is identical to GAG adsorption with the exception that the adsorbing media is a synthetic resin material. Unlike ionic resins, this material is designed to adsorb specific organic compounds from the water. Its reactivity with such compounds is generally much greater than that of activated carbon despite the fact that the I; resin lacks the available surface area present in the rf f- carbon; the cost of the resin is, however, orders of , i magnitude greater than carbon. Consequently, selective •T "\:' resin adsorption is generally not cost-effective as a - 47 -

treatment alternative and offers the same disposal n c: problems as GAG. The applicability of this process to volatile r"--.- organics removal has not been demonstrated.

Screening Considerations for Extraction Alternatives

1. Disposal Cost Effectiveness Disposal of pumped groundwaters can be cost- effective if the contaminant concentrations or flow volumes are large enough to warrant a short-term approach in a region where significant contamination is known to exist and migration must be halted. This is especially true when regulatory agencies will permit the water to be discharged in an environmentally safe manner to a sewer or storm drain without substantial pretreatment requirements. :-; ti Discharge approval is generally dependent upon the disposal stream not exceeding a specific total volume or contaminant concentration; these require- ments will usually contradict the short-term conditions specified earlier. In the LADWP's case, however, the wastage of pumped groundwaters represents the loss of a valuable natural resource. With the exception of r £

- 48 - m specific entitlements, the Department, by judicial r/- o decree, owns the groundwaters of the SFVGWB. This water supply is of critical importance at times o of drought and emergency demand, and replacement supplies are costly. The Basin's groundwaters n:; E account for about $30 million in LADWP water f? n revenues, but their replacement value in terms of E purchased supplies is far greater. Environmental and Public Health Factors i The environmental impact of groundwater disposal depends on its ultimate fate after extraction. If the water is sewered or discharged to storm drains, it will result in an increase in energy costs at the treatment plant. The primary impact would be the dispersal of volatile organics in the environment. There is also the potential r for adverse health impacts of disposed contaminants on publicly owned treatment works which employ o aeration in the treatment process. 2. Blending Cost Effectiveness Blending provides a relatively low-cost method of groundwater and reclamation. It allows for K efficient well pumping in that wells can be shut r - 49 -

1 • down or operated part-time to maximize the total flow and keep within specified blended contaminant concentrations. Blending cannot be relied on in the long term since average contaminant concen- trations may increase beyond the availability of required dilution supplies. However, in the short term, blending provides the single most cost-effective alternative.

Environmental and Public Health Factors Blending of contaminated groundwaters as a means of reducing the concentrations of volatile organic compounds to acceptable levels presupposes the acceptance of this process by regulatory agencies. Although the State Department of Health Services has set strict limits on the use of blending to achieve State-recommended action levels for certain contaminants, the EPA currently T requires the application of best available treatment technology for contaminant removal ! ;_' whenever it is feasible and cost-effective. The r-" EPA has proposed a maximum contaminant level (MCL) 1 • ••- for TCE of 5 parts per billion. Furthermore, the EPA's present policy of recognizing TCE and PCE as "*"" ' Category I substances (known or probable human carcinogens) has resulted in the publishing of - 50 -

recommended maximum contaminant levels (RMCLs) of zero for both of these compounds. Since no treatment technology can effectively attain or guarantee this efficiency, it is likely that blending will continue to play a role in water treatment. By promulgating an RMCL of zero for any f"r.7 substance, regulatory agencies are coincidentally acknowledging a growing public attitude that the 1 P""; ingestion of a regulated substance in any concen- tration entails a finite and significant health 1 J ' risk. • p- 3. Aeration i ; Cost Effectiveness Capital costs for aeration may be based on | !_. typical operational parameters. Experimental data suggests that for TCE and PCE the following design n parameters apply to a typical (hypothetical) r4 facility: Volume to be Treated: 1000 gallons per minute j ^ Volume of Packing Media: 1000 cubic feet „:, Henry's Constant: 450 atm (0.34 dim) P •'• • I .-• Overall Mass Transfer Coefficient: 0.7/min. *-T Required Air Volume: 4000 standard cubic feet — :-- " • Contaminant Loading: 100 micrograms/liter TCE Effluent TCE Concentration: 5 parts per billion

(MCL) ['' It might be anticipated that extreme variations p- j •• in groundwater contaminant concentrations would render the aeration process partially ineffective I] for fixed designs, especially in regard to the — air/water ratio. However, the minimum air/water nl ; . - ratio required for efficient contaminant removal is j, actually related only to the ratio of efficiency to Henry's constant. For the above design, a minimum Pr . ' ( ' air/water ratio of 3:1 results so that the p., specified ratio of 30:1 would be quite adequate for * !- a range of contaminant loadings. Based on preliminary recommended equipment costs for pumps, blowers, tower fabrication and i ;•: erection, and packing media, the estimated cost for capital and operating is roughly $100,000 (23, 24), I ...-J not including design and engineering. On an annual

p~"': basis, including power costs and amortization, ~ this may approach $0.05/1000 gallons of effluent # ; [23]. Compared to the other alternatives that will rL .— be discussed, this is a very reasonable, albeit r* • I ;J probably very optimistic, figure. For this and _i • other reasons, aeration has been viewed traditionally ' ~ as the treatment method of choice, although there p..] have been reports of wide variations in terms of performance and overall cost. S - 52 -

,Environmental and Public Health Factors In contrast to the more-or-less proven techno- . logy and cost benefits afforded by the aeration I, process, a disadvantage of aeration is that • p~ contaminants are merely transferred from the water l<-' to the air.

•j:V Hence, the aeration alternative can be expected t to impact air quality to some extent, and for this •Pr. [ : reason, limits have been imposed on discharge —_ quantities which are tied to assessments of public r' '-?! health risk. 4. Granular Activated Carbon Adsorption (GAG) If; Cost Effectiveness Due to the carbon requirements and process I ._', facilities needed for GAG treatment, capital and p" . operating costs are relatively high and might ~ approach from $0.40 to $0.60 per 1000 gallons of :p'- effluent ([28], [29], and [31]), including carbon disposal or regeneration. Operational parameters { A for a typical (hypothetical) treatment facility might be: r~ Volume to be Treated: 1000 gallons per minute p - Required Volume of Carbon: 1,500 cubic feet / "V"'*-" (40,000 pounds) [ Contact/Retention Time: 10 minutes ft . .- . '. • S - 53 - fr'" • ' Carbon Life: 120 days .( 4 'months) '. Contaminant Loading: 100 micrograms/liter TCE I.-. (3.6 mg per gram carbon IR j" or 0.23 pound carbon p~ • per 1,000 gallons) '- Effluent Concentration: 5 parts per billion TCE (MCL)

Contingency costs should also be considered should carbon life fail to meet specifications. p—--, Environmental and Public Health Factors i GAC adsorption provides a means of treatment I ,- with little environmental impact to the local community, provided carbon disposal or regeneration [ .j is to be carried out at a remote site. The environ- •P-JT mental impact of landfilling spent carbon or "~ regenerating the carbon media using a low-pressure H steam or incineration process cannot be directly compared with aeration, but the magnitude is | [fj probably similar. Likewise, the public health iv aspects of GAC treatment are probably negligible at IP- —: the plant site, but the same cannot be said of the disposal/regeneration site. The environmental/ public health benefits of GAC treatment are therefore largely local. n - 54 -

: 5. Combined Aeration/GAC i ! Cost Effectiveness L- The aeration/GAC process is primarily the I j . aeration alternative with GAG treatment added for p_ contaminant capture. The effectiveness of the '-•• overall process depends to a large extent on how [""[7; . well the GAG unit performs. Currently available 1 L ' Gas-Phase GAC contactors.are designed primarily [ - for odor control, but equipment is now available —., for the control of volatile organics from air- ^ £•> stripping operations. The added cost of gas-phase j"""^ GAC is justified only if the untreated venting of "~ or'ganics from stripping operations is objectionable. However, the cost of an add-on facility to treat a R • ^ given quantity of contaminant in the gas phase is 1 ,_ considerably less than its liquid-phase counterpart p-p because overall efficiency is greater, thus reducing the carbon requirement and the size of the facility. : Gas-phase GAC treatment costs can be expected to n^-*> increase with cost of an aeration-only facility by ir T[_• as much as 50 percent.

* ^ Environmental and Public Health Factors rv. The impact on the environment and on public ^..^v-,.-. health are the same as for direct GAC treatment j '_. since the problem of contaminated carbon disposal r; is still present. - 55 -

6. Ultraviolet Irradiation/Ozonation Cost Effectiveness The major percentage of the costs associated re with UV/03 treatment come from the fact that the process is energy intensive. Ozone, the primary oxidizing agent, is a highly reactive gas and Pp cannot be stored; instead, it must be generated on-site just prior to use. The only practical r |r -•• method of ozone production is by electrostatic ' i~ coronal conversion of oxygen; approximate costs for ozone production are shown for the following r—N, hypothetical case: ^ Volume to be Treated: 1000 gallons per minute j P Ozone Dosage: 8 milligrams/liter Ozone Required: 0.07 pounds/minute [.['-.. Electrical Costs: $0.06/kilowatt-hour Ozonation Costs: $0.05/1000 gallons or roughly $30,000/year

Capital costs for ozonation equipment, however, may run as much as 30 percent to 50 percent of the total initial plant costs. Based on a survey of existing ozonation (no UV) disinfection plants, a very tentative capital cost estimate of about $1500/pound ozone/day of generating capacity would indicate a total cost of at least $150,000 for n • I-

te - 56 -

start-up. Assuming the validity of these cost figures and the efficiency of the plant (95 percent contaminant removal), UV/O- would be a very cost-effective alternative [26].

Environmental and Public Health Factors Due to the expected total destruction of LJ organic contaminants in the UV/0- process, no adverse impact on the environment or public health would exist. TfLeJ r ^A 7. Passive Aeration Cost Effectiveness [ • Assuming that a collection system and open storage reservoir are available, process costs for i- _• this alternative would be minimal; however, P"-" contaminant removal would be very inefficient without subsequent treatment.

Environmental and Public Health Factors rr: : : [ L_- The same as for aeration, but to a lesser r-r:- extent.

r4"" - 57 -

8. Selective Resin Adsorption Cost Effectiveness Unknown. The process is presently limited to small-scale treatment of electronic circuit board processing water and pharmaceutical manufacturing. Its applicability to water treatment has not been demonstrated.

Environmental and Public Health Factors Would be similar to those of GAG adsorption in regard to disposal. .

r „•__:..___ . ; J _

- 58 -

Summary of Preliminary Remedial Action Screening The review of general remedial response alternatives just presented is not intended to be exhaustive. A variety of high-cost, high-technology alternatives are available which have been developed for very specific types of organic wastes; the feasibility and/or applicability of these methods in regard to treatment of groundwater are very much in doubt and were therefore not included. Similarly/ considerations of implementation time, overall effectiveness of basin contaminant mitigation, and process reliability were deemed inappropriate for an initial screening. Nevertheless, the more conventional methods of water treatment are presently being challenged or augmented by other technologies and, given the current emphasis on groundwater contamination, a number of these new processes will certainly come into general use as the technologies are developed. This emphasis on the development of contaminant treatment methods overshadows more passive methods of dealing with the problem of groundwater contamination, such as containment. These methods only postpone more active approaches resulting (in the case of a water utility) in a loss of water revenue, immediate and indefinite operational expenditures, and decreased public confidence in the water supply. Other approaches, such as blending and disposal, are also subject to changing future conditions or belie the value of the groundwater. fp ftu.._, 1 "^ - 59 -

Therefore, .on the basis of preliminary considerations ;'f—> \\ T. of cost and environmental and public health impact, it was .^ determined that cjroundwater extraction and treatment must be implemented for the San Fernando Valley Groundwater Basin in order to effect a long-term and positive solution to the problem.

r^,_MEr

I; simmi~~o it

ITi .'•-•. rc no rtU iff ' Iff r, • Jr- r

T III. DEVELOPMENT OF REMEDIAL ALTERNATIVES r T i r n:

r-i I •- i " - 60 -

III. DEVELOPMENT OF REMEDIAL ALTERNATIVES On the basis of the discussion presented in Section.II, it was determined that contaminated groundwaters should be extracted and treated. In view of the size of the study area, and the rate of underground recharge occurring from upstream watershed sources, it would be impossible to extract and treat all of the area's groundwaters. Furthermore, it is very likely that much 'of the area's contamination is still located in the unsaturated zones of the overlying soil and has not yet reached the groundwater. The objective of an extraction/treatment scheme must therefore be to limit or halt the. spread of contamination to those areas of the groundwater aquifer which are as yet relatively free of contaminants. This may be accomplished by r""'- \ creating a depression in the groundwater table to which contaminants will be accumulated and from which they can be f.L. withdrawn. Such a depression is called a drawdown zone; it may pi-.- be effected by a series of pumped extraction wells located in ' •"' areas of known high contaminant concentrations. The feasibility H of this approach is largely due to the high permeability of the Basin's soils (primarily silt, sand and gravel) with respect to

[ |:. groundwater flow and contaminant migration. For a given groundwater extraction rate, the hydrogeology of the area will r£ determine the degree of drawdown and the extent of the resulting r-r . cone of influence. All groundwaters (and contaminants) within

'/ "^ * *-kecon e wiH be drawn to the source of extraction at a rate j i which is also a function of the area's hydrogeology. - 61 -

Description of Groundwater Extraction and Conveyance System In order to halt the migration of contaminants in the study area by groundwater extraction, it is necessary to determine the total extraction rate which can both overcome the existing downstream flow gradient of the groundwaters and effect contaminant recovery at a decent rate. This was accomplished through the analysis of mathematical groundwater flow and contaminant transport models developed for this purpose. This analysis indicated that a series, of eight shallow extraction wells pumping a total of 2,000 gallons per minute could accomplish the objective of containing the observed contamination and initiating cleanup efforts. The general locations of the extraction wells were I - also estimated in this manner. It was determined that the wells could be situated within an existing LADWP power line f[ ,---• right-of-way. —ir . Once extracted, the groundwaters need to be conveyed to ' ~ the treatment site. Hydraulic and routing studies indicated H . that a collection pipeline consisting of approximately two .miles of 12-inch steel pipe constructed through portions of [ L LADWP properties and dedicated streets would be adequate. ri-i - 62 - • .

Description of Post-Treatment Groundwater Disposition Treated groundwater leaving the treatment plant (regardless of the method of treatment) would be conveyed by gravity via an existing (non-distribution) pipeline to the LADWP's North Hollywood Pumping Station for disinfection and system distribution. There, the flows from the treatment plant would combine with an influx of existing flows of other groundwater and surface water sources.

Development, and Description of Remedial Treatment 1 . Alternatives Alternative A -' Aeration . The primary contaminants of concern in the groundwater _rf"- of the San Fernando Valley are volatile organic compounds (VOCs) and are amenable to removal by aeration. VOCs removal by air stripping has been successfully employed in many parts of the country, including the San Gabriel Valley (Los Angeles [ County), and is therefore an established treatment process. ,... A typical aeration system consists of a vertical column I — containing a packing material over which the influent is t-f. passed. A countercurrent stream of air is introduced by blowers stationed at the bottom end of the column. The p ; packing media serves to increase the effective air-water surface area; similarly, the flow of air is designed to , -'. . maximize the contact time in the column and effect an

(r - 63 -

efficient transfer of contaminant from the water into the j r air stream. The treated water is then collected at the bottom of the column in a clear well for subsequent I[_ disinfection and distribution or further treatment. .r~,~- ' The overall effectiveness of aeration as a treatment alternative is dependent upon the influent contaminant '.p~~ concentration, the nature of the contaminant, the volume :: '•41" • ratio of air to water, the physical characteristics of the j packing material, and the packing volume. Generally, ~- optimal air-to-water volume ratios are in the range of 20:1, i '- although ratios of up to 200:1 have been employed in specific r^S cases. Stripping of more easily aerated compounds (notably the short-chain alkyl .ethers) can result in almost complete f; removal, while aeration of compounds exhibiting polar affinities for water is less effective. Removal efficiencies | ;.'- for TCE and PCE can exceed 99 percent for a well-designed •4; facility, assuming moderate influent concentrations (on the order of 500 parts per billion). rj:.' The cost-effectiveness of aeration is reflected in the overall simplicity of the process, the availability of [ I...- equipment, and an expected short scheduling requirement. f.-. The main expenditures stem from the costs of influent i .'" pumping and air supply; maintenance .costs are relatively low. p^ 'Pretreatment or preconditioning of the influent stream may be I '/- 'l -v "••>•• required if biofouling of the packing media is a problem. [ _ Operational parameters are flexible, allowing on-site - 64 -

adjustments of air and influent flow rates for optimal operation. In addition, recycling of a portion of the effluent stream may be employed to increase overall removal efficiencies or to compensate for changing influent conditions. The model equations employed in aeration column design are well documented, but actual facility performance will fH vary due to the possible inapplicability of design assumptions. t '... Generally, aeration facility design models permit a degree p~ > •••"•. of optimization in the sense that certain operating parameters v r-^ ^ may be identified which will provide a least-cost design with I.- maximum effectiveness. As an example, Figure 9 details a p^S typical aeration facility from the available literature (23). The assumptions and characteristics used in the model are j fairly typical for a facility of the indicated capacity. The results are seen to agree reasonably well with the model ! :'l- predictions. U-'i As was mentioned earlier, aeration equipment, including ' ~ columns and packing materials, is readily available and can p be obtained on a standard or customized basis. In the full-scale literature prototype just described, the capitalized [ „ equipment cost accounts for about one-half of the total facility cost (about the same for operating costs), resulting ff in a favorable overall treatment cost of about $0.06 per 1000 gallons. Dual-column facilities which share portions of ft..* «^ .'•_.._ Air Exhaust Typical (2 ft dla.)

Damlstlng Scraan

Packing Madia

Packing Support Plata

Watar Inlat Lin* Watar Discharge

\ flroundwatar Inflow Air Blawar-A Traatad Groundwatar

Diagram of Typical Aeration Facility

Figure 9. ! S . . . - 65 -

the operational package can cost considerably less; in one instance (City of Arcadia/ County of Los Angeles) (24), amortized annual treatment costs (1985) were claimed to run about $0.03 per 1000 gallons. Despite the apparent high cost-effectiveness of the process/ the decision to utilize aeration must be weighted against the possibilities of lengthy regulatory permit processing and possible public objection to a treatment process that appears to transfer a contamination problem from , the groundwater to the air. Costs associated with public I t— hearings and permit processing and the attendant delays in j^^\ design and construction schedules are undefinable/ but are I nevertheless almost unavoidable. It would be accurate to say p ; that in .Southern California (and especially in Los Angeles)/ 1 '--' public concern over aeration is acute due to its association I L. with the already serious problem of air pollution. This ';•; concern translates into costs in the form of air quality * ~~ monitoring and modeling to establish actual or expected P! maximum levels of airborne contaminants resulting from the k i aeration process.

I- i - 66 -

Alternative B - Granular Activated Carbon Adsorption i , Dissolved trace volatile organic compounds may be removed by a process known as adsorption. In this process, contaminated water is passed over an adsorptive media which «-^_ attracts and holds the contaminant molecules by weak physical 1 L- forces. A variety of adsorptive materials may be .employed in .p~'.:. this process, including synthetic resins, plastics, and clays, but granular activated carbon (GAC) has been demonstrated to • i be especially effective due to its large adsorption surface area. This surface area, which may approach 10 million i i~: square feet per pound of media, results from the porosity of p^S the granules formed in the activating process. The available adsorption surface is generally dependent upon the nature of [• " the compound being adsorbed, the contact time, and the rate of desorption. The overall process may be described by the ( ;__ Freundlich adsorption isotherm model,

n rs (CQ - Cf)/M = K Cf

... where Co is the initial contaminant concentration, C-f is the | ;._.• concentration after treatment, M is the mass of activated /... carbon, and K and n are regression coefficients specific to I ~ the contaminate being removed. It is important to note that r-f - this model is strictly limited to systems in equilibrium; it f P . ("*}""*•'• does not take into account flow rate or contact time (see f Appendix 8). - 67 -

Optimal operating parameters are normally established by pilot studies or design recommendations based on existing facilities. However, the Freundlich model does provide information on the treatability of a particular contaminant and can be used to estimate preliminary loading rates and ru carbon requirements. p:-v It should be emphasized that general information in regard to adsorption isotherms and expected contaminant I loadings is generally not sufficient as a basis of design. . Physical characteristics of the influent stream will affect • '-; adsorption efficiency and, since parameters such as tempera- r""^ ture, turbidity, suspended solids, pH, and even VOCs concentration may vary appreciably with time, facility p ; efficiency will likewise vary. In view of these factors, facility design ..and operation should take into account flow t r* rate, contact time, depth of GAC bed, vessel number and size, >-r. bacterial accumulation in the bed, backwash rate and frequency, and carbon turnover, and be flexible enough to allow for j adjustments in the event of a major operational deficiency. I -• • < 1 1 The prediction of contaminant breakthrough (or, /r !_" ; equivalently, GAC bed life) is almost invariably only a '.•• design estimate. For large GAC beds handling relatively I ~ small flows and low contaminant loadings, a facility can be r*. expected to provide almost virtually 100 percent removal ^ -y~>-- efficiency up to the point of breakthrough, which may be F i_ rapid and distinct. Conversely, a facility treating large - 68 -

flows and/or appreciable contaminant loadings may provide only partial removal with an indistinct or nonexistent break- through event (see Figure 10). Breakthrough is a governing factor which determines to a large extent.the carbon require- n:-.-: ment, run time to backwash, and vessel number and size; it is therefore probably best to provide a conservative design &i o based primarily on reliable estimates of contaminant loading. Nevertheless, activated carbon adsorption is demonstrably effective, uses no chemicals (with the possible exception of anti-fouling pretreatment chemicals), is in use worldwide ft; (most notably in the Netherlands), and is competitively cost-effective in comparison with other methods. The lack of true design and operational parameters and the possibility of bacterial biomass accumulation are currently subjects of continued research. A typical GAC facility is shown in Figure 11. . Under normal operation, a GAC facility will require : periodic backwashing due to a buildup of suspended solids and bacterial biomass on the carbon bed. Backwashing is performed when the head loss through the .bed reaches a predetermined amount, at which time several bed volumes of backwash water are run through. An analysis of the discharged backwash water should be made to determine if a significant concentration of contaminant is present. If not, the water ,: C can be discharged to a storm drain or sewer. HIQH FLOW, HIGH CONTAMINANT LOADING

Design Breakthrough Concentration

Tim* to Breakthrough RUN TIME

LOW FLOW. LOW CONTAMINANT LOADING

Design Concentration

CONTAMINANT CAPTURE EFFICIENCY ^ 100%

Time to Breakthrough

Effects of Contaminant Loading on GAC Removal Efficiency

Figure 10 T~"-~T

r~ r~

Q A C Contactors

Treated Water

Ground Water from Upper Aquifer

\ £2>\ t (=±\ f^\ J pTU .«:, J J I

Shallow Extractor) Wells

Schematic of a GAG Treatment System I CD- - 69 -

The costs associated with GAC treatment are heavily o tied to the availability of the activated carbon; of equal importance are the costs of carbon removal, disposal, and regeneration. As was mentioned previously, the beneficial environmental and public health aspects of total contaminant removal by GAC treatment are largely local due to the fact that the contaminated carbon is normally removed from the community for disposal or regeneration. Since the "spent carbon is classified as a hazardous waste, its removal and transport must be documented on a waste manifest and disposed of at a Class I landfill or other approved site. Current uncertainties in regard to the availability and cost of activated carbon, the availability of disposal sites and regeneration facilities, and transportation regulations make it difficult to fully assess the cost of the GAC treatment process as a whole. For example, the Calgon Corporation, a major supplier of carbon for water treatment, supplies : L: activated carbon for about $1 per pound and will accept spent carbon for disposal or regeneration purposes at a current price of approximately $0.60 per pound of material (25). There is no guarantee that either this price or the service itself can be relied upon or that a long-term contract can be negotiated for these fixed conditions.

<• r - 70 -

Alternative C - Combined Aeration/GAC - o A variation of the two processes discussed above may be employed in which the air discharged from the aeration column r is itself treated by GAC. Since gas-phase contaminant removal is more efficient than water-phase treatment, the ' •1 Q carbon requirement is proportionately less. The primary 1 D advantage of this process over the aeration-alone alternative is realized in terms of greatly reduced air emissions. Detailed cost information for aeration/GAC from the available literature is not available, but the cost of the combined treatment process would probably be on the order of 50 percent more of an equivalent aeration facility with no id added benefit with regard to groundwater treatment efficiency, r. • 0 Alternative D - Ultraviolet Irradiation/Ozonation In contrast to other methods which rely on a separa- £; E tion process, UV/O- is designed to effectively alter the contaminants in the influent stream through oxidation to elemental compounds. Although the effectiveness of ultra- violet irradiation alone is unproven, ozonation can be effective with or without UV as a catalyst. Although originally developed as a disinfection process, ozonation of contaminated water has been demonstrated for a number of commonly encountered volatile organic compounds. In cited cases, oxidation by ozonation is enhanced when combined with ultraviolet irradiation. n - 71 -

Chemical oxidation of trace organic contaminants may be undertaken with a variety of oxidants, notably potassium permanganate, potassium chromate/dichromate, chlorine dioxide, and persulfuric acid. However, these chemicals leave unwanted residues in the effluent and this alternative was therefore not considered. The attractiveness of the ozonation process lies in its potential to destroy the contaminants completely while providing pre-disinfection for chlorination; the problems

* associated with contaminant separation and disposal would therefore be eliminated. While disinfection processes normally require an ozone dosage in the 1-3 parts per million (ppm) range, treatment of water supplies containing trace quantities of chlorinated volatile organic compounds might require 8-10 ppm. In addition, modifications in regard to contact time and contactor design are required. Due to its reactivity, ozone must be produced on-site and used immediately. A variety of ozone generation equipment is commercially available in a wide range of production capacities. Although the overall electrical costs for ozone production are not prohibitive, capital costs for the equipment and auxiliaries are high. Due to the corrosive nature of the gas, much of the process hardware must be ozone resistant. - 72 -

• i*

A review of existing ozone-disinfection facilities indicates that capital costs are in the neighborhood of $1500 per pound of ozone; and maintenance costs, $0.50 per '{. r< pound of ozone. If these figures could reliably be extrapolated to ozone treatment of volatile organic compounds, f-f then ozone would be very attractive from a cost-effectiveness standpoint. . It is known that ozone is almost completely ineffective in oxidizing some organics; therefore, a comprehensive program of pilot testing would be required to establish the effectiveness of an ozone process in treating contaminated groundwater. The LADWP is currently involved in a research program with the University of California at Los Angeles to investigate the effectiveness of UV/0- in treating volatile organics in distribution supplies. This program is estimated to be completed in two years. Until that time, however, definitive answers in regard to ozone effectiveness and probably cost will not be available.

'P. IV. SCREENING OF REMEDIAL ALTERNATIVES n

! l.

I L.

P

f! - 73 -

IV. SCREENING OF-REMEDIAL ALTERNATIVES This section will present a discussion on the cost-effectiveness and environmental and public health aspects of remedial alternatives screened earlier. The purpose of this section is to further refine the screening process prior to a technical evaluation of primary treatment candidates. It should be noted that the preliminary costs derived for these alternatives are independent of the costs associated with the groundwater extraction and conveyance system discussed in Section III. The costs presented in this section may be used | i'. as a method of comparing the cost aspects of treatment alone, and not those for an entire system. ' —. Before describing the processes-and costs associated H'~ with the treatment alternatives, the physical details of the ~~ groundwater extraction/conveyance system should be addressed. As I mentioned in the previous section, this system is proposed to consist of eight shallow (about 300 feet deep) wells, each [ i_ drilled, cased and equipped with a submersible pump capable of p- providing the necessary lift to transport 250 gallons per minute ~ to the surface and through the collection pipeline to the point | •' of the treatment. The pipeline would consist of approximately 11,000 feet of 12-inch steel pipe installed under various I _; dedicated streets and in LADWP property. The combined system of pumps would therefore have to lift the groundwaters a total of i about 400 feet, including pipe friction losses. f- - 74 -

The probable cost of the entire groundwater collection system would be approximately $1.7 million. A cost breakdown for the various elements of the system is detailed in Appendix 10.

Environmental and Public Health Screening

Alternative A - Aeration . •''.'''• In contrast to the widespread industry acceptance of aeration and cost benefits afforded by the technology, a major disadvantage of this treatment process is that : • contaminants are merely transferred from the water to .^. the air. Another disadvantage is that, despite the ! •- dilution provided by the air-to-water ratio and typical r*"" resulting air concentrations on the order of parts per trillion, the public may be distressed at the disposal j - aspects of the process. Nevertheless, the aeration alternative can be [ — expected to impact air quality to some extent, and for -.-T^ this reason, limits have been imposed to discharge ' ~ quantities which are linked to assessments of public p- health risk. This risk is usually related to an individual's lifetime cancer risk; consequently, inter- . ;_ pretation of factors used in defining or determining the i ;• true public health impact are open to debate. Further- Ir ' :_.^_.-.. more, there is the open question as to what constitutes (r ' r-r ' • - - 75 -

,. [._-. "acceptable" risk and who has the right to impose this p-- risk on the public. A more detailed discussion of 'i•» i '" public health risk assessment is presented in [ ' Sections VII. It is possible that a very localized threat to

•I f public health may occur at the plant site as a result of p— . routine operation and maintenance activities. These 'i .'' •-- safety-related aspects are discussed in detail in " Section V-A.

TT Alternative B - Granular Activated Carbon (GAC) Adsorption GAG adsorption provides a means of treatment with r little environmental impact to the local community P : provided carbon disposal or regeneration is to be carried out at a remote site. The environmental impact of landfilling spent carbon, or regenerating the carbon media using a fluidized incineration process, cannot be ' i-: directly compared with aeration; however, the magnitude p"' is probably similar. ~ Disposal of spent, contaminated carbon involves H' the hazards associated with transfer handling, dust formation, long-distance trucking and unloading. .' / . i n Although the concentration of contaminant in the spent _i; carbon would only be on the order of 1 percent by ' "^-;>.--.. weight, accidental spillage during handling or T transport represents a significant threat to public health on a local and non-local level. - 76 -

Regeneration of spent carbon may involve a low-pressure desorption process or the carbon may be incinerated to destroy the entrained contaminants. The degree of contaminant release by these processes is indefinite and may be an issue for concern from a public health or environmental quality standpoint. GAG treatment is unlikely to pose any threat to public health at the plant site except for those on-site activities associated with routine operation, maintenance, and carbon disposal. _ In contrast to GAC's unlikely public health impact P—^ on-site, off-site impacts may be complex and far-reaching. ' — For example, after landfilling, contaminants which had P ; adsorbed onto GAG particles may be leached into the local groundwater supply. Once the contaminants reach r~ I the water table, they will most likely migrate through the soil/water matrix and contaminate adjacent ground- •n water supplies resulting in a situation similar to the one in the SFVGWB. Furthermore, if conditions exist at the landfill which allow for the leaching of TCE from r. spent carbon, then it is likely that other types of hazardous elements may also leach from the landfill into n. the groundwater. It would then be possible that the combination of these leached elements could create -*..-;.. adverse effects, thereby contributing increased complexity to an already difficult and problematic situation. - 77 -

Alternative C - Combined Aeration/GAC Filtration As has been previously noted, one primary drawback to the aeration process is that the contaminants are not contained, but vented to the atmosphere. The process of combined aeration/GAC is designed to overcome this problem. The qualitative impacts on the environment due to combined aeration/GAC are therefore identical to those for direct GAC treatment since the problem of contaminated carbon disposal is still present. However, the effectiveness of gas-phase activated carbon i adsorption is substantially greater than the liquid-phase counterpart (typically 20% weight-to-weight adsorpability vs. 0.3%); therefore, a combined aeration/GAC process would require far less carbon for equivalent overall treatment efficiency. The decreased cost in the carbon requirement would tend to be offset by the fact that the spent carbon would"be classified as a hazardous waste according to the State Administrative Code (Title 22).

Alternative D - UV/Ozone 'Hi The possible environmental and public health impacts resulting from ultraviolet irradiation/ozonation I •_ are minimal. In well-designed facilities, the treatment j~ process involves the complete oxidation of contaminants. t :^ _..„..-.. Theoretically, the only byproducts of the process are f water vapor, carbon dioxide, and a small amount of \'r - 78 - .

l At hydrogen chloride. These compounds would not be expected to have any adverse effects on the environment or public health. • ft The treatment process also affords the side benefit of reducing the need for post chlorination of the effluent. By reducing the chlorination requirement, the tendency to produce trihalomethanes [THMs] (known carcinogenic compounds produced via a reaction between chlorine and organic compounds) is reduced.

Cost Screening For purposes of comparison, estimated costs for hypothetical treatment processes were adapted extensively from the available literature (3, 7). They are intended only to provide an indication of the range of expected costs. (For purposes of comparison, simplicity and adherence to data provided by available literature, a 1000-gallon-per-minute (gpm) design flow is assumed. Later, cost figures for a 2000-gpm facility are developed for a recommended treatment option.) The costs associated with groundwater extraction and transport to the plant are not considered. V:.-

I-': Alternative A - Aeration Basis: Single aeration column and appurtenances to treat 1000-gallon-per-minute groundwater flow containing design concentration of 70 parts per billion of TCE. Treatment to MCL is assumed. (Cost of collection system not included). All figures are in 1986 dollars. Capital Costs Column shell, 7.0 feet x 24.0 feet, including packing support, plate, influent nozzle, demisting screen $ 20,000 Column packing media (plastic) 6,500 Engineering 25,000 15-hp blower 5,000 Booster pump 10,000 Electrical 10,000 D Valves, piping 40,000 Miscellaneous (landscaping, etc.) 10,000 Hi Total capital cost 126,500 Annualized cost (20 years, 10.0%) 14,860

Operation and Maintenance Costs

Pump power consumption, 400 kW-hr/day $ 28* Blower power consumption, 200 kW-hr/day 14* Inspection, general maintenance (per day) 15 * Based on $0.071/kW-hr Total daily O&M cost $ 57 Equivalent annual cost ? 20,800 Total annualized cost $ 35,660 Cost/1000 gallons $ 0.068 f: ni • - 80 -

L: Alternative B - Granular Activated Carbon Adsorption The design of a GAG facility will normally involve a combination of ..practice and theory. Ideally, the design is preceded by pilot testing, although for small L. facilities this is probably unnecessary. EPA Publication 600/8-83-019 ("Treatment of Volatile Organic Compounds in Drinking Water") recommends an organic loading rate of 0.20 pounds of carbon per 1,000 gallons of influent containing 100 parts per billion of TCE (assuming a 99.9 percent removal efficiency). This translates, in this case, to approximately 4.0 milligrams of TCE per gram of carbon. This figure compares favorably with the adsorption isotherm for TCE (see Appendix 8). For the following example, the Freundlich model predicts a slightly more conservative loading rate of about 3.0 milligrams TCE per gram of carbon (assuming a 95 percent removal efficiency).

Basis: Two (2) single-pass GAG contactors to treat 1000-gallon-per-day influent flow containing 70 parts per billion TCE. Removal efficiency: 99%+ (treatment to MCL). Carbon requirement p-:: based on thepretical loading of 3.0 milligrams <• ^ ••—*--•.. TCE per gram of carbon, or 0.20 Ibs. f • carbon/1000 gallons, or 100,000 Ibs./yr. Run life: 120 days. n -

Capital Costs Two GAC contactors, pressurized 10 ft. diameter x 11 ft. length ... $150,000 Engineering 15,000 Site work 15,000 Valves, piping 10,000 Electrical 5,000 Miscellaneous (carbon holding tank, pretreatment, clarification) 50,000 Total capital cost ... $245,000 Annualized capital cost 20 years, 10.0%t $ 28,800

Operation and Maintenance Costs Carbon, 100,000 Ibs./yr $100,000 Carbon disposal, $0.60/lb 60,000 Transfer pumping 5,000 Maintenance, labor 15,000 Total annual O&M cost $180,000 Total annualized cost $208,800 Cost/1000 gallons $ 0.397

Alternative C - Combined Aeration/GAC Basis: Identical to specifications for aeration alone. Assume additional 20,000 cfm GAC vapor phase adsorption system. Effluent concentration (water): 5 parts per million (MCL) I ;•'- Removal efficiency (GAC) : 99%+ H," Capital Costs Aeration system $126,500 •v Adsorption system 120,000 I "^:-,^.-. Total capital cost ... $246,500

1 Annualized capital cost 20 years, 10.0%t $ 28,950 £ r.

- 82 -

Operation and Maintenance Costs Pump power consumption, ' . 400 kW-hr/day $ 28 Blower power consumption, 200 kW-hr/day 14 Carbon, 20,000 Ibs./yr 20,000 Carbon disposal, $0.60/lb 12,000 Transfer pumping 2,000 Maintenance, labor 15,000 Total annual O&M cost $ 64,300 Total annualized cost $ 93,250 Cost/1000 gallons .... $ 0.177

Alternative D - Basis: Single-contactor UV/ozonation facility to treat 1000-gallon-per-minute influent flow containing 70 parts per billion TCE. Removal efficiency: 95%. Capital equipment costs based on $1100/lb./day generating capacity. Capital Costs Equipment to produce 120 Ibs./ozone/day $132,000 Annualized capital cost, 20 years, 10.0% $ 15,500 Operating Costs Electricity, 10.0 kW-hr./lb. ozone .. $ 31,000 Maintenance, labor 100,000 Total operating cost $131,000 Total annual cost $146,500 Cost/1000 gallons $ 0.279 Note: Costs for pilot studies not included for any of the above alternatives. f:

- 83 -

Recommendation and Summary of Candidate Treatment Methods The treatment methods discussed in the preceding were screened on the basis of overall.expected cost-effectiveness and r environmental and public health impact. In addition, consideration was also given to compatibility with future remedial actions and n alternative design and implementation schedules. In the.latter, it was decided that, based on the measured rate of contaminant migration in the North Hollywood well field area, a maximum r, implementation time of 6 months should be allowed. Furthermore, only those alternatives which were considered to be reasonably, reliable were addressed. Lastly, the levels of achievable site cleanup for each alternative were not directly considered since they could not be estimated. In weighting these screening criteria, - cost-effectiveness was considered to be the most tentative element since available cost data which appeared to vary significantly did ft not always apply directly. Other uncertainties in process design and operation were similarly addressed. •'. U Alternative A - Aeration Aeration was accepted as a candidate alternative based •;E on its record of reliable and efficient operation, applica- bility of design standards, complexity of operation and maintenance, implementation schedule, and overall costs. Project feasibility with respect to effective dispersion of air-borne contaminants was demonstrated through the analysis of an air quality modal developed by an LADWP consultant. fl hi The potential adverse public health impact resulting from the release of aerated contaminants to the atmosphere is, however, a major drawback which might be translated into ' •• • i- r . •' : higher costs in the form of required air quality modeling and monitoring and permitting difficulties. In addition, I :••: •i ••'• L'. public disfavor of the aeration process represents an indefinite factor with respect to cost-effectiveness and feasibility.

. Alternative B - Granular Activated Carbon Adsorption ;r* -.-. r— • ;» ' : [ ' GAG adsorption was selected as a candidate treatment \^-'l'_ r- alternative based on its expected high contaminant removal • '•-' capability, demonstrated performance, cost-effectiveness, and :p-; j' overall current availability of equipment and adsorption ; media. In spite of the suspected uncertainties in design standards and operational parameters and problems associated :n.1 -.; with carbon disposal, GAC treatment would provide a highly , effective means of contaminant removal and would have little or no adverse environmental and public health impact, at least on a local level. In view of the ready availability Pf». • of equipment and reasonable carbon delivery schedules, the implementation time for this alternative compares favorably with that of aeration providing that pilot testing is not '-* E: required. "••*»-• s F- • -85 -

Alternative C - Aeration/GAC Based on air emission models for the aeration alternative and subsequent approval of the Department of Health Services of this data (see Appendix 5), the aeration process was considered to be preferred over aeration/GAC since the public health impact was determined to be insignificant. However, indications of the overall public disapproval of the aeration- alone concept and its drawbacks were sufficient to justify further consideration of the aeration/GAC alternative as a candidate remedial measure.

Nonselection of Alternatives In view of combinations of uncertain reliability, operational parameters, cost/ implementation time and effectiveness, the ultraviolet irradiation/ozonation alternative was rejected for further treatment consideration. Although ozonation equipment and their processes have been established for water disinfection purposes, its applicability to the treatment of contaminated groundwater is still being researched and could not be utilized without a lengthy program of pilot testing. ^

V. TECHNICAL EVALUATION OF SCREENED ALTERNATIVES - 86 -

V. TECHNICAL EVALUATION OF SCREENED ALTERNATIVES As indicated by the discussions presented in Section II, groundwater extraction and treatment represents the only feasible method of mitigating the observed contamination problem in the study area. Section III addressed the applicability of groundwater extraction in attenuating the spread of contamination and in proving a means of conveying the extracted groundwaters to a treatment site. The technical feasibility of the extraction/treatment proposal will now be examined in terms of the desirability and effectiveness of each alternative with respect to given criteria. The technical feasibility of the extraction system, consisting essentially of a series of pumped extraction wells and transmission pipeline, is demonstrated by the results of ongoing groundwater quality monitoring and preliminary mathematical modeling efforts and the fact that there is simply no other feasible method available for removal of groundwaters from the study area. Therefore, this section will concentrate on a technical evaluation of each of the " r-V I J- treatment alternatives. ' '•'. The alternatives screened in Section IV were evaluated P'1 > based largely on the criteria established by EPA for feasibility studies under CERCLA (EPA/540/G-85/003) . The technical evaluation of candidate alternatives involves investigations into the following: "•-"- 1,.... I i '•• - 87 -

i-.. 1. Performance of the alternative, including effectiveness J"" and useful life; ^ 2. Alternative reliability, including demonstrated performance and operation and maintenance requirements; 3. Implementability, including time constraints and constructibility; and 4. Alternative safety, including worker and community safety factors. I :. Each of these items will be discussed separately for each screened alternative; lastly, the technical feasibility of each rL. alternative will be summarized in matrix form, indicating the p-s relative desirability or ability to meet different technical criteria. r: 1. Alternative 1 - Aeration I I A. Performance The performance of the aeration process is measured in its effectiveness in removing contaminants from the groundwater supply in a safe manner and in its ability to maintain this effectiveness over the useful life of the facility. Aeration effectiveness is primarily determined by design specifications, although actual performance data is beneficial in providing an optimum process. On-site «_,,.. and local conditions would not affect this performance, I.

providing that unexpectedly high contaminant loadings do not occur for extended periods of time; otherwise, operational parameters would have to be modified, which ~^ might impact the ability of the treatment system to n.: mitigate the spread of contamination. Treatment to ( [J maximum contaminant level (MCL) could probably be pr-- maintained regardless. ' *- The useful life of an aeration facility with n • regard to treatment effectiveness is a function of r!:._» operation and maintenance practices. The combination \ [•'• of water and air will introduce potential corrosion and ^^^ biofouling problems; however, these can be minimized I with the use of corrosion inhibitors such as sodium p[:! hexametaphosphate and disinfectants such as chlorine or rc • sodium hypochlorite. • B. Reliability ] L.- The operational and maintenance requirements of the aeration alternative have been touched on; the materials and labor required are easily provided on a H ! routine, rather than frequent, basis. 4. . In regard to demonstrated performance, aeration I L has a history of reliability that is evident from the f quantity of available experimental and operational rt v ~-,,.--.. data. As such, it is an established treatment method. f ' * ' - 89 -

C. Implementability Given the ready availability of aeration equipment on a modular and turnkey basis, the constructibility of the equipment presents no problems. This in turn results in time savings/ since plant construction/ break-in and start-up can be accomplished on a short schedule. Problems associated with treatment performance are documented/ so that the time required to achieve beneficial results can be minimized. In contrast to these benefits, the aeration option normally requires extensive planning with respect to air quality permits and expected negative public reaction. . Applicable air quality regulations may require atmospheric modeling studies. These problems pose a serious impediment to this aspect of implementability.

D. Safety Aeration facilities offer almost no risk with regard to fire/ explosion, or chemical contamination to r jr-) -"'; on-site workers. However, contaminant air emissions pose serious problems with regard to community public {n '-!• health. The health risks due to community exposure are r discussed more fully in Section VII. In spite of the fr • - 90 -

minute air concentrations involved, the aeration alternative suffers from a combination of a indefinite cancer risk assessment and probable resulting public opposition.

Alternative 2 - Granular Activated Carbon (GAG) . ' A. Performance • A properly designed GAG facility can treat selective contaminants to non-detectable levels; its applicability to zero-discharge treatment alternatives is probably higher than any of the alternatives investigated. GAG is resilient to large changes in influent contaminant concentrations. One difficulty is the fact that multi-component waste streams may exhaust the carbon before its calculated useful life, making carbon replacement more frequent. The useful life of a GAG treatment process is dependent upon periodic maintenance of the facility. Assuming that virgin or regenerated carbon will always be in supply, the overall service life of a facility is probably on the order of 20 years. - 91 -

B. Reliability GAG treatment is a demonstrated technology, as evidenced in its routine application throughout the world. It is probably unsurpassed in removal capability with respect to the more easily-treated organic contaminants. Operation and maintenance requirements of GAG treatment are the most demanding of any of the screened alternatives. Frequent, sometimes unscheduled carbon replacement may be required due to contaminant exhaustion or biofouling. The carbon turnover is ^ labor-intensive and cannot be automated, and t < necessarily exposes workers to contaminants through H ; handling and transfer processes.

-,' "• t ,.- C. Implementability The availability of "materials for GAG treatment [P •_' makes the constructibility of this process fairly ,_{'., straightforward, although a turnkey approach would t :.-• 1 • • probably be expensive. No local or non-local site

f • pi conditions would have any adverse effect on actual 4 •."..' construction. JLv The time to implement a GAG facility can be (•• extensive, since ideally a pilot study would precede 1 '" ;._^.-.. final design and construction. The initial shipments r , of carbon might be a problem with respect to time since •: • - 92 - I *-s I I • . .

t«. its supply is subject to current demand. The time to achieve beneficial results is probably indeterminate, since carbon fines will be introduced into the effluent stream for some time. D. Safety GAC treatment imposes a significant health threat to plant workers since the contaminated carbon must be removed manually. Although vacuum equipment could be used to assist in this operation, workers could still be exposed to carbon dust. . Research on the physical chemistry aspects of GAC treatment has indicated that the reaction of activated carbon to certain contaminants may create toxic compounds which leave the plant in the effluent flow. Since a disinfection process normally would follow t :. GAC treatment (or be available for biofouling control) , the presence of activated carbon near a large quantity i !- of liquid chlorine involves an explosion hazard.

3. Alternative 3 - Aeration/GAC A. Performance This alternative is a combination of the aeration and GAC technologies with the exception that the GAC process operates in the vapor phase. GAC contactors .-. for vapor-phase odor-control equipment area available f off the shelf and have demonstrated performance - 93 -

capabilities in applications involving volatile organic compound removal. The VOC removal effectiveness of the aeration process in this treatment option is identical to that of aeration alone/ but with the added benefits of air emissions control. The useful life of an aeration/GAC facility would be limited only by corrosion and biofouling problems, which can be managed by a program of periodic maintenance and chemical control.

B. Reliability Operation and maintenance of an aeration/GAC plant would be similar to that of aeration alone; the GAG contactors, which involve much less carbon than the liquid-phase process, are nevertheless much more effective in terms of contaminant-to-carbon weight ratio, extending the carbon replacement schedule. The aeration aspect of the alternative has demonstrated performance capabilities; similarly, vapor-phase GAG contaminant removal is a demonstrated process (see reference 30 in Appendix 2). -. 94 -

I.- C. Implementability Constructibility of the alternative would be identical to that of the aeration option. The GAG contactors, being completely closed systems/ present no special construction problems. The time to implement and time to achieve . . beneficial results for this alternative would be nearly identical to that of the aeration alternative, since the effectiveness of the GAG process would not influence effluent water quality.

D. Safety One major drawback to the aeration/GAC process would be the level of contamination of the spent carbon and the attendant hazard of handling and transporting this material. Assuming a 2,000-gallon-per-minute time of carbon replacement would be on the order of 5 percent by weight. However, this hazard would be offset by the relatively small quantities of carbon involved compared with the liquid-phase GAG process. - 95 - '

Summary of Technical Evaluation Process Performance ~~ Effectiveness was considered to be one of the most important evaluation criteria, since it determines to a t_ large degree the extent to which an alternative will prevent or minimize adverse impacts to public health and environment. Alternatives involving well-established design criteria were judged to be more effective. In addition, the relative abilities of each alternative in achieving treatment to maximum contaminant levels and controlling air emissions 'were compared. On the basis of these considerations, the GAG and aeration/GAC alternatives were rated equally and slightly higher than the aeration-alone option. The useful life criterion was applied in terms of the projected service life and future resource availability for each alternative; on this basis, the alternatives were ranked equally.

Reliability The reliability criterion was applied in order to rate ~ the ability of each alternative to provide continuous, effective treatment without delays, interruptions or shut-downs. In evaluating the frequency and complexity of the operation and maintenance requirements of the screened alternatives, aeration was rated highest, followed by >.-•- aeration/GAC and GAG. The demonstrated performance of the - 96 -

alternatives have been relatively well-established. On this basis, GAG and aeration/GAC were ranked equally, followed by aeration.

Implementability Time to implement and time to achieve beneficial ?S G results were considered to be major factors in ranking the i; :v". • alternatives since a remedial action is required as soon as in--'.:-m- . Lr.;~ possible. For this reason, aeration and aeration/GAC were ranked equally, followed by GAG.

Safety Site safety in terms of explosion and fire hazard to workers and the local community was considered to be insignificant. However, the safety factors involved with the handling of contaminated carbon were considered to be

I . very important. Likewise, the potential for contaminant emissions to air was considered in assessing overall alternative safety. On the basis of these factors, aeration/GAC and GAG were ranked equally, while aeration alone received a low rating. These results are summarized in the following evaluation matrix: - 97 -

Relative Alternative Evaluation

Aeration GAG Aeration/GAC CRITERION Performance ** *** *** L. Effectiveness Useful Life *** *** ***

Reliability O&M Requirements *** ** Demonstrated Performance ** *** ***

Implementability Constructibility **** ** **** Time to Implement **** * **** Time to Achieve Beneficial Results **** ****

Safety ** **

Relative Ranking Indicators: * Fair **** Superior

L - 98 -

Cost Comparison of Screened Alternatives The screened alternatives were evaluated on the basis of cost data presented in Appendix 10. These costs were developed from a variety of sources, including manufactuerer's quotes, in-house (LADWP) estimates, consultant's estimates, and [7 available and applicable literature. While not intended to be exhaustive, the derived costs represent reasonable estimates and thus permit a fairly accurate comparison of the cost-effectiveness of each alternative. Since Appendix 10 presents costs in the form of low and high ranges,.the higher costs were adopted for c comparison purposes in order to be conservative. r- The cost of the screened alternative is presented in Table 1. The costs assume a 15-year annualization period discounted at 10 percent. The costs include estimates for a groundwater extraction and conveyance system, treatment plant, !$E annual energy requirements, and nominal maintenance estimates. The entire treatment process assumes an extraction flow rate of 2,000 gallons per minute with contaminant removal efficiencies sufficient to provide treatment to maximum contaminant level (the maximum expected influent TCE and PCE concentrations are 650 parts per billion (ppb) and 100 ppb, respectively).

E

L - 99 -

Table 1 Cost Summary of Screened Alternatives (1986 Dollars)

Total 15-Year 15-Year Present Present Capital Worth O&M Worth Cost Costs ($) Costs ($) A. Aeration- $2,032,895 $1,570,655 $3,603,550 B. GAC System '2,248,895 3,765,009 6,013,904 C. Aeration/GAC 2,192,895 1,964,650 4,157,545

Details of major cost items for each of the alternatives are summarized in Tables 2 through 4, along with expected treatment costs in dollars per 1000 gallons of influent. As can be seen from these figures, the aeration-alone alternative is the least costly option, followed closely by the aeration/GAC alternative. In consideration of the uncertainties in the cost estimates, however, the difference in overall cost between these two alternatives is probably not significant (see Appendix 10). The most costly option is to treat the groundwater directly with n jr l_ granular activated carbon. - 100 -

Table 2. Cost Estimate for the Removal of Trichloroethylene (TCE) Using Packed Tower Aeration (1986 Dollars)

CAPITAL COST * •- Aeration equipment $ 97,000 Engineering . 50,000 site preparation, foundation 25,000 n Site appurtenances 75,000 : •" Wells, pumps 300,000 '.—.••' Pipeline , 1,163,000 ;| Contingencies 323,000 Total capital cost $2,033,000 T-' I ;. Annualized capital cost (15 years, 10 percent) $267,000

OPERATION AND MAINTENANCE f I Energy (water, air conveyance) $159,000 Chemicals . 37,000 Labor 10,000 Total O&M Cost $206,000 r: TOTAL ANNUAL COST $473,000 Cost/1000 gallons $0.45 - 101 -

Table 3. Cost Estimate for the Removal of Trichloroehtylene (TCE) Using GAC Contactors (19-86 Dollars)

CAPITAL COST GAC equipment $ 295/000 Engineering 65,000 Site preparation/ foundation 30,000 Pilot study 10/000 Site appurtenances 36,000 Wells, pumps 300,000 Pipeline 1,163/000 Contingencies 350,000 Total capital cost $2,249,000 Annualized capital cost (15 years/ 10 percent) $296,000

OPERATION AND MAINTENANCE Carbon $210,000 Carbon disposal 126/000 Energy (water conveyance) 134/000 Labor 25,000 Total O&M cost $206/000 $495,000

TOTAL ANNUAL COST $791,000 Cost/1000 gallons $0.45 $0.75

rf:

H" - 102 -

Table 4. Cost Estimate for the Removal of Trichloroethylene (TCE) Using Aeration/GAC (1986 Dollars)

CAPITAL COST Aeration equipment $ 97,000 GAG contactors 120,000 Engineering 50,000 Site preparation, foundation 25,000 Pilot study . 10,000 Site appurtenances 75,000 Wells, pumps 300,000 Pipeline . 1,163,000 Contingencies 353,000 Total capital cost . $2,193,000 Annualized capital cost (15 years, 10 percent) $288,000

OPERATION AND MAINTENANCE Carbon $ 45,000 Carbon disposal 21,000 Energy (water, air conveyance) 159,000 Labor • 33,000 Total O&M cost $258,000

TOTAL ANNUAL COST • $546,000 Cost/1000 gallons $0.52 r I

f VI. INSTITUTIONAL REQUIREMENTS r i.

•r P R. d rt

n n - 103 - '

VI. INSTITUTIONAL REQUIREMENTS The proposed site of the treatment facility is located in an area designated for light industrial land use in the North j| Hollywood Community Plan, and it is not expected to have any significant impact on the Plan. The North Hollywood Community [ [_. Plan is a part of the General plan of the City of Los Angeles, i—j- prepared by the Los Angeles Department of City Planning, approved *-- by the Los Angeles City Planning Commission, and adopted by the . The purpose of the Plan is to provide an official guide for the future.development of the community. The Safe Drinking Water Act requires that recommended maximum contaminant levels (RMCLs) be established for any/all ! substances for which there are known or anticipated effects. pi": These RMCLs are "goals" for water quality achievement and are nonenforceable. The Federal Government, acting through the M.. U.S. EPA, promulgated an RMCL of 0 ppb for TCE and proposed an s RMCL of zero in November 1985 PCE [7]. At the same time, the EPA (1 proposed another class of contaminant levels which would account for technical and economical feasibility. Included on this list is TCE at a proposed maximum contaminant level (MCL) of 5 ppb. rt promulgation of these MCLs is pending an industry-wide review and public comment period. Implementation of any of the three ft alternatives would ultimately attain and exceed the applicable health standards of 5 ppb of TCE and 4 ppb of PCE (California . State Department of Health Services action levels). - 104 - .

Groundwater pumping in the San Fernando Valley Groundwater Basin is controlled by the City of Los Angeles vs. City of San Fernando, et al, Judgment (signed 1/26/79) and administered by a Court-appointed Watermaster. This judgment restrains DWP from extracting groundwater from the San Fernando Basin in any year in excess of the native safe yield (43,660 AF) plus any import return water credit (±40,000 AF) and stored water credit (180,370 AF as of 10/1/85). If the native safe yield and import return water credit are exceeded in any year and the stored water credit has been used up, DWP may extract underlying native waters (±2,000,000 AF) subject to an obligation to replace such excess as soon as practical. r An evaluation of institutional requirements has been performed for the aeration, granular activated carbon adsorption, and combined aeration/GAC alternatives. Institutional issues examined in the evaluation include applicable and relevant environ- mental and public health standards, interagency coordination needs, and community relations activities. Implementation of any of the three alternatives would ultimately attain and exceed the applicable health standard of 5 ppb of TCE and 4 ppb of PCE (California State Department of Health Services action levels) and simultaneously meet similar federal MCL requirements. Several agencies have authority over, or conduct r~v activities associated with, the regulation or control of the 1.J

- 105 -

contaminants currently residing in the SFVB groundwater. Implemen- j"7- tation of any of the alternative technologies would require the coordination of many of these agencies relative to their particular nI -I interests and activities. Describe'd below are the federal, state, regional, and local regulatory agencies for which an activity '^ coordination mechanism must be developed regardless of the ; p--. alternative: j : Federal Agencies Environmental Protection Agency 'IH J The U.S. Environmental Protection Agency (EPA) ' '

•—N administers water quality programs pursuant to the Safe Drinking ' Water Act and the Clean Water Act. Hazardous waste control Pi programs are administered pursuant to the Resource Conservation and Recovery Act and CERCLA (Superfund). All of these .laws except :,--,.. [ . Superfund provide for the delegation of enforcement authority to individual states when it is established that the state program is I !» at least as stringent as the federal guidelines. rT. The Safe Drinking Water Act sets forth a national ' strategy for attaining drinking water standards. The National P Pollutant Discharge Elimination System (NPDES) is the primary enforcement mechanism provided in the Clean Water Act. In P.- [ L California, authority for these programs has been delegated to the state and is administered by the State Water Resources Control f-L • Board. -' 106 -

The Resource Conservation and Recovery Act (RCRA) sets forth a national strategy for the cradle-to-grave regulation of hazardous wastes through permitting of the storage, transport and disposal of hazardous wastes. In California, Phase I interim authorization has been granted to the state, and the program is administered by the State Department of Health Services. . Superfund provides funding and enforcement support to respond to. uncontrolled hazardous waste sites.

State Agencies . California State Water Resources Control Board The California State Water Resources Control Board (CSWRCB) is responsible, under California's Porter-Cologne Act, for the formulation and adoption of a statewide policy for- the control of water pollution. Enforcement of the CSWRCB requirements is delegated to nine Re'gional Water Quality Control Boards (RWQCB) throughout the State. The SFVB falls within the jurisdiction of the Los Angeles r*~ RWQCB, Region 4. n California State Department of Health Services The California State Department of Health Services (DHS) [ _: has specific statutory authority for public health aspects of

(J,'-- water supply, hazardous waste handling and disposal, and toxic t _-•>••. substances control. - 107 -

The Hazardous Materials Management Branch (HMMB) of the DHS currently issues hazardous waste facility permits under the California equivalent of the Federal RCRA program. The DHS (a) permits facilities that transport, treat, store, or dispose of hazardous wastes as defined in Title 22 of the California Administrative Code, and (b) administers the "cradle to grave"' manifest system for hazardous wastes. :

California Occupational Safety and Health Administration The California Occupational Safety and Health Agency (CALOSHA) has the authority to inspect and, if warranted, issue n citations for unsafe conditions discovered at Superfund sites. '.'• Regional Agencies Regional Water Quality Control Board In addition to implementing the State policy for water quality control, the Los Angeles RWQCB is responsible for the development of a regional water quality control plan that establishes the policies and goals necessary to ensure that the beneficial uses of the State's water resources are preserved.

Local Agencies . r- , I L: Los Angeles City Fire Department f. The Los Angeles City Fire Department (LAFD) conducts *• i"' ' • <"" i-.p,_--.. on-site inspections of commercial facilities to acquire information and enforce regulations concerning the use and storage of certain - 108 -

hazardous chemicals. These activities indirectly protect groundwater quality by preventing conditions that could result in the release of contaminants to the groundwater basin. Differences between the three alternatives with respect to coordination complexity occur as a result of (a) whether or not the contaminants are released into the air, and (b) whether or not a generated hazardous waste by-product (i.e., spent GAG) wouid require disposal. Alternatives A and C, which incorporate aeration technology, would require the involvement of the South Coast Air Quality Management District (SCAQMD). The SCAQMD is responsible for the development of a regional air quality management plan that establishes the policies and goals necessary to attain P compliance with provisions of the Clean Air Act. The SCAQMD regulates and permits all. stationary emissions of air pollutants | j and currently requires permits on all facilities storing potential , . air pollutants, including gasoline, solvents, and other volatile IJ- organic compounds. p^: Alternatives B and C, which incorporate GAG technology, would require the involvement of the California Department of M Transportation, the California Highway Patrol, Los Angeles County *- «*"""" ,. Department of Health Services, Los Angeles Department of Sanitation, { ;-- and possibly several other state, regional, and local agencies < • involved in the transportation, handling, and disposal of hazardous *• -^- T- " materials depending upon the material's final destination. - 109 -

Community relations activities provide a meaningful opportunity for public comments and are used as management and planning tools. Public concern has been voiced regarding the possible detrimental effects to air.quality that Alternative A may impose if implemented. The SCAQMD and DHS have both already indicated that emissions resulting from the implementation of:Alternative A would not pose an unacceptable health risk (Appendix 5). Concern has also been expressed on some possible drawbacks of land disposal for hazardous materials, including: the fact that landfilling of hazardous wastes is really only a temporary means of storage — not final disposal; the availability of landfill facilities that will accept hazardous materials is uncertain; and liability for a hazardous material can never be transferred or relieved from the waste generator. In summary, the DHS action levels of 5 ppb of TCE and 4 ppb of PCE would ultimately be attained and exceeded using any of the three treatment alternatives. The possible environmental impacts of both aeration and granular activated carbon treatment technologies have been cause for public concern. Based upon a consideration of all institutional require- ments, it would appear that the abilities of each of the three alternatives in meeting applicable, effluent quality standards are equivalent. 1- VII. PUBLIC HEALTH EVALUATION

r \. ri fr •• n IV • - no -.. 1 • • .

VII. PUBLIC HEALTH EVALUATION ; I. • r*~ An air quality model approved by the South Coast Air Quality Management District (AQMD) was used to predict the '*r-•I ; maximum and average VOC concentration• s which would occur due to operation of an aeration facility. A .series of conservative assumptions was used to ensure that the analysis would overestimate the possible health risk. For example, the concentration of VOCs in the water to be treated was assumed to be three times higher than the measured values; meteorological data from a year where air dispersion was poor was used. EPA unit risk factors for the contaminants to be emitted were then used to determine the unit risk for an individual standing at the point of maximum concentration for 70 years; the total excess cancer burden for the affected area was also determined. The maximum individual risk was just under one in a million; the maximum excess cancer burden was 0.03 (i.e., no more than 0.03 persons would be expected to contract cancer as a result of a 70-year operation of this facility — effectively zero). For a more detailed description of the model/ refer to the Air Quality Health Considerations excerpt from the LADWP's document entitled "Initial Study and Proposed Negative Declaration for the Proposed North Hollywood-Burbank Aeration Facility Project, May 1986" in Appendix 9. The DHS reviewed the analysis and concluded that the -7- • analysis was adequate. The DHS approval letter is included in Appendix 5. - Ill - •

The impacts of the aeration and GAG alternatives on the public health will be discussed in the context of contaminants removed from extracted groundwaters and transferred into the community. In the following discussion/ the potential impact of these contaminants will be treated without regard to method of ingestion; that is, contaminant exposure due to consumption of drinking water or inhalation will be assumed identical in overall impact. .••'••"

Alternative A - Aeration By transferring volatilized contaminants from the groundwater to the air/ the aeration process raises the issue of air quality degradation and the possibility of low-level/ long-term cancer risk in the adjoining community. These two issues are important in view of the rv P-; current air quality problems that Los Angeles and its environs already face and the fact that several of the contaminants found to be present in the groundwaters of the study area are known or probable human carcinogens. rl In addition to these issues/ the efficiency of the r~ • PI aeration process in removing contaminants from groundwaters determines the residual levels of these substances that j p remain in supplies ultimately destined for distribution. «. * f For groundwaters containing TCE and/or PCE in the P;': { •-•>-"• concentration range of 100 parts per billion (ppb) to f 1000 ppb, the aeration process can be designed to routinely n

- 112 - r provide efficiencies capable of providing treatment down to i the required maximum contaminant levels (MCLs) published by i • n1 ' the EPA. For the study area, additional concentration 1 j reductions would result through the process of blending into the distribution system. The LADWP's North Hollywood U Pumping Station, which receives supplies from a variety of surface and groundwater sources, has the capability of . ' ' •- . ' •••• ' ' n providing an eight-fold dilution factor beyond that provided n* by an aeration process. The contaminant TCE is the focu s of the publi: c impact {r i of the aeratio' n alternative since' this is the primary —-^ contaminant which would be emitted into the atmosphere. ' Small or trace amounts of PCE and/or benzene would also be present but at level orders of magnitude below current 0. ambient air concentrations. Pi "| The bul'k of scientific evidence currently suggests that the cancer risk due to TCE ingestion/inhalation at minute n levels is insignificant. However, at least one study has demonstrated a link between TCE exposure and human cancer incidence. Detailed information on these studies are given n in References 1 through 21 (see Appendix 2). Although the design parameters for an aeration process [ I may be tailored to provide for treatment to MCL, the air _t • emissions resulting from the process represent a serious I' . iws,' ." ?•-• '• source of concern with regard to local public health. o[. ; ' -. - us - . .1 {. In adherence to a conservative approach in assessing

r-f- public health impacts, the adoption of the "no-safe threshold" ;- attitude would appear to be appropriate. In other words, by JT. adopting a policy that any non-zero level of airborne or waterborne contaminant is unacceptable, maximum public health til benefits will result. However, zero-level discharge treatment n is costly and very difficult, if not impossible, to attain. Alternative B - Granular Activated Carbon Adsorption n-•'• ''..':' • Although GAG offers the advantage (from a public health standpoint) of removing and holding groundwater contaminants, n-- • . it presents the problem of what to do with the spent carbon. I — Exhausted carbon is classified as a hazardous material since H", it contains contaminants in a concentrated form. Transport of this carbon to a disposal or regeneration site must be '.- made in accordance with local and state laws which may vary n-• for interstate transport. If the carbon is to be disposed [rr t _ of, it mus't be placed in an approved Class I or equivalent _-;• landfill. The number of operating Class I landfills in ' California is shrinking. At the present time, only the i £-• Casmalia and Kettleman Hills sites are within a reasonable n^ r* distance from Los Angeles; their future is in doubt. j !_: Alternatively, the carbon can be trucked out of state at I. significantly higher cost. If the carbon is to be regenerated, ILL ~~--"- the carbon must still be transported to an appropriate site. Regeneration consists of heating the carbon under low-pressure {L- [s" . . .. • ;.'..-. 0 steam to release the contaminants (which must be captured), p. followed by a reactivating process. The impact on public health at the GAG treatment plant might therefore be minimal, jl whereas the impact resulting from waste transport and disposal/ regeneration would be much more pronounced. . Due to the proliferation of "cradle-to-grave" regulatory regulations governing the ultimate fate of hazardous materials . in the environment/ there is the question of continued responsibility for the waste on the part of the generator. This responsibility for the potential impact of the waste on the public health and environment would likely continue .far past the disposal date, imposing potential indefinite economic liens on the generator throughout the viable life of the waste. Thus, the impacts of distant disposal practices are still a concern from both public health and liability aspects.

Alternative C - Aeration/GAC The most notable difference between this alternative and aeration alone is that.in this alternative aerated VOCs do not enter the atmosphere but are instead captured by the vapor-phase GAG contactors. This results, however, in an extremely contaminated waste carbon (much more contaminated than the carbon used in liquid-phase processes). This carbon, which is normally not regenerated, must be removed, transported, and disposed of in an analogous manner. The (V • . ' -115- n' aeration/GAC process, designed as a closed system with regard f"j to contaminant air emissions, must be regularly monitored to insure that the air-phase carbon does not become exhausted. M The efficiency of the aeration tower in removing VOCs from the influent supply stream would alone determine 1 I residual contaminant concentrations in the effluent water, p However, operational parameters could be adjusted to r maintain required effluent quality. '.'. •' " Groundwater Extraction/Conveyance System p ' •'•.••-.•••.-•• • • ; • (I Since the alternatives discussed previously all require - supplemental groundwater extraction and transport facilities, I the public health impact of these facilities should be addressed. The construction of groundwater extraction wells n: • ' necessarily provides a conduit for the transfer of j| contaminants both into and out of the groundwater aquifer. The greatest risk by far is the possibility for surface In ! 'contaminatio n being introduced into the •aquifer . Stat• •e p regulations, however, impose strict provisions with regard to protection against surface-to-ground contamination, and thus fl serve to minimize this threat. Additionally, the construction •i ' • • • . of groundwater conveyance pipelines involves a minimal threat . T.}~• to public health in view of the low concentrations of contaminants present in transported waters. . t

VIII. SUMMARY AND RECOMMENDATION OF I :

REMEDIAL ALTERNATIVES

I Pi - 116 -

VIII. SUMMARY AND RECOMMENDATION OF REMEDIAL ALTERNATIVE I. Based on the evaluations and considerations developed .in this report for various treatment alternatives and technologies, the LADWP has concluded that an interim remedial action consisting of groundwater extraction followed by aeration/GAC treatment appears to be the preferred alternative for mitigating the observed rapid spread of groundwater contamination in the North Hollywood- Burbank area. It is emphasized that this recommendation is applicable only within the context of this Operable Unit Feasibility Study. Although the recommended action is consistent with potential future remedial action in the study area, the recommendation in no way implies that such future action will consist of the same or similar treatment processes. Instead, the overall remedial investigation/feasibility study for the San Fernando Valley Groundwater Basin will address that issue on a r—».- n more comprehensive basis. In recommending aeration/GAC as a remedial action, the I L LADWP weighed the probability of success with regard to facility _i treatment efficiency and existing or pending regulatory effluent *• '" quality standards. The reliability of the recommended alternative fj, rests primarily on estimates of the extent of Basin contamination. . On the basis of weighted TCE and PCE levels taken from well field 1 L'J data in the study area (see Appendix 4), the concentrations of substances which are expected to be encountered are on the order I " ^ *••'- of 35 parts per billion (ppb) of PCE and 215 ppb of TCE. However, O ' - - ' r,. in order to provide a factor of safety with regard to treatment - 117 -

. • . nr plant reliability, the LADWP recommends design influent concentra- tions of PCE and TCE of 100 ppb and 650 ppb, respectively. The [1 capability of the aeration and GAG technologies is such that '~- treatment plant removal efficiencies can be tailored to meet and n'••'• exceed the currently-mandated maximum contaminant levels (MCLs) Pi . for these compounds. • . ' P^' Earlier investigations by the LADWP determined that a [ system of shallow-level groundwater extraction wells, collection _[". and discharge pipelines, and packed-tower aeration facilities could arrest the spread of localized contamination in the North F' Hollywood well field area and begin the process of Basin cleanup on a limited scale. The results of these investigations, . [ ' consisting of groundwater flow, quality modeling, and other F" engineering feasibility studies, are detailed in Appendix 6. I r More recent studies have since shown that this preliminary design p-' can be modified to eliminate contaminant air emissions while achieving treatment efficiencies down to MCL. -I.:•.-::•: !•

• t f

- . APPENDIX 1 r

r ACRONYMS

n n n

r ACRONYMS

ji} ADI Acceptable Daily Intake CALOSHA - California Occupational Safety and Health Agency CDC Center for Disease Control CERCLA - Comprehensive Environmental Response, Compensation and Liability Act ' - :: CFM Cubic Feet Per Minute - : CWRCB • - California State Water Resources Control Board DHS California Department of Health Services DNA Deoxyribonucleic Acid . EPA United States Environmental Protection Agency GAC Granular Activated Carbon •n HMMB Hazardous Materials Management Branch IARC . International Agency for Research on .Cancer IRM Interim Remedial Measure LADWP Los Angeles Department of Water and Power 1 LAFD Los Angeles Fire Department LAR Los Angeles River MCL Maximum Contaminant Level MWD Metropolitan Water District NCI National Cancerl Institute NPDES National Pollutant Discharge Elimination System NPL National Priorities List OUFS Operable Unit Feasibility Study I? ffi -2-

PCE - Perchloroethylene PMCL - Proposed Maximum Contaminant Level PPB - Parts Per Billion PPM - Parts Per Million RCRA - Resource Conservation and Recovery Act RI/FS - Remedial Investigation/Feasibility Study ; RMCL - Recommended Maximum Contaminant Level RWQCB - Regional Water Quality Control Board SCAG - Southern California Association of Governments SCAQMD - South Coast Air Quality Management District SFVB - San Fernando Valley Basin SFVGWB - San Fernando Valley Groundwater Basin SNARL - Suggested No Adverse Response Level TCE - Trichloroethylene THM - Trihalomethane ULARA - Upper Los Angeles River Area

UV/03 - Ultraviolet Irradiation/Ozonation VOCs - Volatile"Organic Compounds

ft ft ri-y ji , "V r APPENDIX 2

fi" REFERENCES i i . n n: r;. n- n ... •:•.• REFERENCES

1 • ' - • 1. Axelson, 0.; Andersson, K.; Hogstedt, C.; Holmberg, B.; ""•• Molina, G.; and De Verdier, A. (1978). A cohort study on ;.'•' trichloroethylene exposure and cancer mortality. J. Occup. Med., 20:194-196. •*—•* ' '.'- 2. Bergman, K. (1983). Interactions of trichloroethylene with DNA in vitro and with RNA and DNA of various mouse tissues in vitro. Arch. Toxicol., 54:181-193. o; 3. Blair, A.; Drople, P.; and Grarrman, D. (1979). Causes of death among laundry and dry cleaning workers. Am. J. Public Health, ^9_:508-511. TL 4. Bull, Richard. February 1986. Testimony before EPA Office. . of Drinking Water in proposed VOC regulations. :' 5. Elcombe, C. R.; Rose, M. S.; and Pratt, I. S. (1984). Biochemical and histological changes in rat and mouse liver following administration of trichloroethylene: possible relevance to species differences in hepatocarcinogenicity. Tox. Appl. Pharmacol., (in press) 6. Federal Register, 40 CFR Part 141 (June 12, 1984, Vol. 49,

NO.- 114) . .. . •.''.. : ...... • : :,' . ••: . • . 7. Federal Register, 40 CFR Part 141 (November 13, 1985, P Vol. 50, No. 219). 8. Green, T. and Prout, M. S. (1985). Species differences in response to trichloroethylene. II. Bibtransformation in rats and mice. Toxicol. Appl. Pharmacol., 79:401-411. 9. Katz, R. M.; and Jowett, D. (1981). Female laundry and dry cleaning workers in Wisconsin: A mortality analysis. Am. J. Public Health, 71:305-307. 10. Kimbrough, R. D.; Mitchell, F. L.; and Houk, V. N. (1985). Trichloroethylene: An update. J. Toxicol. Environ. Health, .15:369-383. rJ. 11. Laib, R. J.; Stockle, G.; Bolt, H. M.; and Kunz, W. (1979). Vinyl chloride and trichloroethylene: Comparison of alkylating effects of metabolites and induction of preneoplastic enzyme deficiencies in rat liver. J.:Cancer Res. Clin. Oncol., 9±: 139-147. 12. Lin, R. S.; and Kessler, I. I. (1981). A multifactorial model # for pancreatic cancer in man. J. Am. Med. Assoc., 245:147-152. 13. Malek, B.; Krcmarova, B.; and Rodova, O. (1979). An epidemiological study of hepatic tumor incidence in subjects , working with trichloroethylene. II. Negative results of retrospective investigations in dry cleaners. Prakov. Lek., 31:124-126. 14. Marano, V. P.; and DeFreitas, I. M. (1979). J Trichloroethylene in hepatic cancer. Rev. Bras Saude Occup. ,-1.7:31-38. 15. Novotna, E.; David, A.; and Malek, B. (1979). Epidemiological study on hepatic tumor incidence in subjects working with trichloroethylene. I. Negative results of retrospective studies in subjects with primary liver carcinoma. Prac. Lek.,

' ' ' ' • ' 14 16. Parchraan, L. G.; and Magee, P. N. (1982). Metabolism.of.[ C] trichloroethylene to C02 and interaction of a metabolite with liver DNA in rats ana mice. J. Tokicol. Environ. Health 19:797-813. : ; . , . •': : : 17. Prout, M. S.; Provan, W. M.; and Green, T. (1985). Species differences in response to trichloroethylene. I. Pharmacokinetics in rats and mice. Toxicol. Appl. Pharmacol., _79_: 389-400. 18. Stott, W. T.; Quast, J. F.; and Watanabe, P. G. (1982). The pharmacokinetics and macromolecular interactions .of.trichloro- ethylene in mice and rats. Toxicol. Appl; Pharmacol., .6J2:137-151. ; " 19. Tola, S.; Vilhuner, R.; Jaruinen, E.; and Korkale, M. L. (1980) A cohort study on workers exposed to trichloroethylene. J. Occup. Med., 2.2:737-740. ' 20. USEPA. December 1983. Health Assessment Document for Trichloroethylene, EPA-600/8-82-006B. 21. USEPA Science Advisory Board. 1984. Key ;findings and conclusions of the Environmental Health Committee oh the" Draft Health Assessment Document for Trichloroethylene. Transmitted to W. Ruckleshaus, EPA Administrator, December 17, 1984. 22. USEPA. May 1983. Treatment of volatile organic compounds in drinking water, EPA-600/8-83-019. 23. Crittenden, J. C., et al. Design and economic evaluation of a full-scale air stripping tower for treatment of VOCs from a contaminated groundwater. Water Engineering Research Laboratory, Cincinnati, Ohio, 1985. 24. Ahmad, S. Packed Tower Aerators Put End to VOC's, Water Engineering and Management, November 1985, p. 12. 25. Personal Communication, Richard T. Lynch (Calgon) to J. K. Bibel, January 17, 1986 (letter and telephone correspondence). .26. Rice, R. G. and Browning, M.E., editors, Ozone for Water and Wastewater Treatment, International Ozone Institute, Inc., 1975. 27. Personal Communication, Walter W. Hoye (LADWP) to Craig Von Bargen (Camp Dresser & McKee, Inc.), September 5, 1985 0j (copy to EPA). 28. Clark, Robert M., et al, VOCs in Drinking Water; Cost of ^ Removal, ASCE Journal ;of Environmental Engineering, I .; Vol. 110, No. 6, pp. 1146-1162, December 1984. 29. Clark, Robert M., et al, GAC Treatment Costs: A Sensitivity Analysis, ASCE Journal of Environmental Engineering, Vol. 110, No. 4, pp. 737-750, August 1984. 30. Crittenden, John C., et al, Removal of Volatile Organic n Chemicals From Air Stripping Tower Off-Gas Using Granular Activated Carbon, Journal of American Water. Works ": Association (to be published) . n ; • . • • 31. Clark, Robert M., et al, The Cost of Removing Chloroform and Other Trihalomethanes From Drinking Water Supplies, EPA Office of Research and Development, EPA Pub. No. 600/1-77-008, March 1977. 32. Los Angeles Department of Water and Power, Groundwate'r Quality Management Plan, June 1983. 33. James M. Montgomery Consulting Engineers, Inc., Well Siting North Hollywood-Burbank Aeration Facility, Analysis of Shallow Well Extraction System, June 1986. -i r

L APPENDIX 3

p ABSTRACT-USE OF WELL PACKERS p- TO CONTROL TCE & PCE CONTAMINATION r r.'. r.

C- r ABSTRACT ' • USE OF WELL PACKERS TO CONTROL TCE AND PCE CONTAMINANTS! by .Gene Coufal, Virginia Smith, and Robert Haw r..];•• . . The City of Los Angeles pumps approximately 15% of its water from the San Fernando :Groundwater Basin, The San Fernando Besin is located in the upper Los Angeles River area, and consists of 112,000 acres. It is surrounded by hills and mountains or topographic divides. Groundwater leaves the basin (when full) as rising water into the Los Angeles River, in the southeast corner of the basin. • ' ••••<• ••'••• • •• •.••••••• ':' • • • • •• n 1 Organic contaminants were discovered in Los Angeles .: . wells in early 1980. Since that time TCE and/or PCE contaminants have been found in 35 of Los Angeles 80 production wells in con- t centrations greater than limits set by the California State De- partment of Health Services. About 1/2 of the 35 wells can be used by blending with water containing little or no TCE and/or PCE',' However, the remaining wells have been placed out of service. Alternatives being considered so these wells can be placed back in service include treatment of the contaminated water and pumping It from the lower portion of the aquifer. •• This paper deals with the second alternative. A well packer was installed in -a well in the North Hollywood area of the r San Fernando Valley in an attempt to restrict the vertical movement of groundwater containing organic contaminants (TCE and PCE) to the zone above a clay lens where the greatest concentration of contam- .ft- inants was believed to occur. The results from the aquifer test and .the water .quality samples collected while pumping with the packer deflated versus when inflated indicated.that water and organic contaminants from the upper zone were effectively prevented from reaching the lower zone and the" pump suction. ' The effectiveness of the packer as a seal was demonstrated by the following observations: 1. Drawdown in the pumping well increased by over 10 feet p while pumping with the packer inflated as compared to pumping with the packer deflated. fai >« 2. The upper zone water level declined approximately one . ' and a half feet while pumping with the packer inflated whereas the lower zone water level drewdown approxi- mately 25 feet.

\1 ^ . Los Angeles Department of Water and Power •>""*' P.O. Box 111, Room 1466 - Los Angeles, California 90051 -

• f- -2-

Transmissivity values decreased when the upper zone was sealed off, while the flowrate was virtually unchanged. During the test pumping period with the packer deflated; the TCE level was at least 100 ppb. During the test pumping period with the packer in- flated, TCE averaged only 7 ppb. PCE concentrations also declined when pumping with the packer inflated (from 4 to 0.5 ppb). The well packer continued to be effective for almost eight months of continuous pumping. The average TCE concentration over a 7-month ;period was 9 ppb. PCE averaged '0.6 ppb during this period. Later, while pumping with the packer deflated, TCE and PCE jlevels increased, from 0.1 to 136 ppb and from 0.2 to 5.4 ppb, respectively, within a 6 day period. •••••••.

p fi

^ r*r. USE OF WELL PACKERS TO CONTROL TCE AND PCE CONTAMINANTS by . Gene Coufal, Virginia Smith, and Robert Haw

: INTRODUCTION : • •' ;: . .. . •'- : :' ' " ' ' .: . : : : :

In early 1980, organic contaminants were discovered in Los Angeles' wells in the San Fernando Groundwater Basin. Since that time TCE and/or PCE contaminants have been.found in 35 of Los Angeles 80 production wells in concentration greater than limits set by the California state Department of Health Services. About 1/2 of the 35 wells can be used by blending with water containing little or no trichloroethylene (TCE) and/or tetrachloroethylene (PCE). However, the remaining wells have been placed out of service. The City of Los Angeles pumps approximately 15% (85,000 AF) of its water from the San Fernando Groundwater Basin. A two year project administered under the direction of the Southern California Association of Governments with the City of Los Angeles Department of Water and Power (LADWP) acting as the

Los Angeles Department of Water and Power, P.O. Box 111, Room 1466, Los Angeles; California 90051 lead agency was initiated in 1981 to identify toxic waste sources pr- to develop waste control plans for local industry and commerce, "' - and to specify strategies for the management and/or treatment of n~ contaminated groundwaters in areas of significant degradation in the San Fernando Groundwater Basin. As a part of the project I j_ several aquifer tests were performed using a well packer. The pr-- purpose of these aquifer tests (hereinafter referred to as "Well *• ll- Packer Test") was to (1) evaluate a well packer's effectiveness in PT' restricting the vertical movement of water containing organic l •»-"—' ...... contaminants, TCE and' PCE, from entering the discharge flow from r[^ jrj • a well; 2•) furthe• r evaluate and verify the aquifer characteristics _.r-- in the North Hollywood area; and, (3) evaluate the effects of a n« •' " well packer on groundwate•• r. flow. ' . GEOHYDROLOGIC BACKGROUND; fl: Geology and Groundwater Occurrence The San Fernando Basin is located in the upper Los Angeles River area (Figure 1), and consists of 112,000 acres. It is surrounded by hills and mountains or topographic divides. [t Groundwater leaves the basin (when full) as rising water into the Los Angeles River, in the southeast corner of the basin. Groundwater in the San Fernando Basin occurs in the sedimentary deposits which comprise the valley floor. The portion Pj.i of the San Fernando Basin westerly of Pacoima Wash is generally — composed of valley fill materials with a high clay content, •^ I. ^ a ^ -3-3 a- a' ^ R

SAN FERNANDO VALLEY BASIN (SFVB)

OR

UPPER LOS ANGELES RIVER AREA (ULARA) GROUND WATER BASINS

SAN GABRIEL MOUNTAINS

SANTA SUSANA MOUNTAINS

.VERDUGO BASIN

SAN FERNANDO BASIN

EAGLE ROCK BASIN SANTA MONICA MOUNTAINS

BOUNDARY OF VALLEY FILL •n i 5 ! C i » !-• m i rr • L- whereas the portion easterly of Pacoima Wash is generally composed ...» _• of coarse deposits of sand and gravel. The valley fill westerly •-•L: of Pacoima Wash is essentially fine-grained material derived from Pp'-' the surrounding sedimentary rocks. The valley fill material easterly of Pacoima Wash is composed of coarse detritus eroded .~ n mainly from the granitic Basement Complex of the San Gabriel if- Mountains.. :Th e valley..•:.. fill materia. l westerly of Pacoima Wash i 1-- transmits water at a relatively slow rate whereas, valley fill pi'" material easterly of Pacoima Wash transmits water at a relatively rapid rate. The eroded debris of the eastern portion of the basin /*"*i—r ' jj'.' is generally very coarse; in places boulders up to three feet in diameter are common. These deposits are essentially sand and FI T?!~ gravel with some fines in the interstices. The Eastern portion constitutes about one-third of the surface area of the groundwater reservoir and contains approximately two-thirds of the groundwater f"|'/ storage capacity of the San Fernando Basin. . _ The majority of Los Angeles' large well fields/ | L including the North Hollywood, Crystal Springs, Whitnall, Verdugo, Erwin and Pollock Fields, are located in the eastern portion of ft: the San Fernando Basin. In addition to the City of Los Angeles fp pumping wells, the Cities of Burbank and Glendale also extract large quantities of water from this portion of the basin. Pumping i L_ in excess of safe yield from these well fields caused a decline in r ' [., water levels in the eastern half of the basin. This heavy t .*" • concentration of pumping is reflected by the large change in r-( ' groundwater levels that developed in the area between 1944 and [. ^ •...-'..

i i- :; ' 1968. Beginning in 1968 pumping in the San Fernando Valley was ' ' limited to the safe yield by the Superior Court water rights .1 i • Judgement of the Upper Los Angeles River Area. Since that time rv' due to regulated pumping, spreading of native runoff, and above normal precipitation, groundwater levels in the valley have been jj relatively stable. Water levels have fluctuated in certain areas . due to the changes in pumping patterns after adjudication of the I ._•_: . basin. Water levels since 1968 have and will continue to increase I • • . • . '....'. ' - : " pf"; due to spreading of imported water and decrease due to overpumping during drought periods. m: ' ' ' •' t;-- ' • • - .' ; . North Hollywood Well Field [)_ Wells in the North Hollywood Well Field, (Figure 2) . -^ along with those in the Headworks Well Field, are ithe most •• productive in the San Fernando Valley. Located in the eastern part of the basin, the North Hollywood area aquifer consists of sands and gravels laid down by the . These materials ft1 are very permeable and result in high transmissivity values of /'-: about 1,000,000 gpd/ft. Although there are clay lenses which may I.n" provide some confinement, the North Hollywood area is generally /-( considered unconfined. Because the well field is not situated I ^ near the mountains, and there are no known faults in the area, it if is believed that there are no barriers to groundwater movement in the North Hollywood area. For these reasons groundwater moves ' * d more freely and at a faster rate in the North Hollywood area than •4 . in other parts of the basin. - 1 • - -| " "••" - 1 j ^" J" '~ . •)

GABRIEl/'MbUNTAINS

POLLOCK WELL

SAN FERNANDO VALLEY WELL PACKER TEST Introduction Los Angeles Departmentjof Water and Power (LADWP) personnel conducted a Well Packer Test in the North Hollywood (NH) area using TCE contaminated Well No. 24 as the pumping well. For . the test an inflatable well packer was installed in NH Well No. 24 at a depth of 298 feet. During the test, two constant discharge drawdown and recovery tests were performed. One with the.packer deflated, and one with it inflated. ; . . NH Well No. 24 is perforated both above and below a thick clay lens that exists between 281 and 318 feet below the surface (Figure 3). The well was'drilled in 1954 by cable tool method. There is no gravel pack, and therefore no direct. connection for water to flow vertically between the upper and lower zone other than inside the well casing itself. Installation of the well packer at the mid point (298 feet) in the clay lense, served the function of providing a flow restriction within the bore of the well. This configuration was intended to prevent -T; water from the upper unconfined aquifer zone from reaching the _ '~ pump suction below the clay lense at a depth of 354 feet.

Test Procedure [ j- The Well Packer Test consisted of two parts, .'.-. (1) drawdown and recovery with the well packer deflated and I--'" (2) drawdown and recovery with the well packer inflated. During r1 each part, NH 24 was pumped for 24 hours at full capacity, then t r -*--.. ' . /•"-s . allowed to recover. The first, part of the test began at 10:30 r- FIGURE 3

WELL LOG NORTH HOLLYWOOD 24

. (3800 C)

<-7>A-^ 20 — » I-: :^p:;: u. 4O r>- i^j.frftru o voi M 60 •:B§ CJ n 80 K UJ SVrtf L< •0 ' ....:.'.'••' .' .' -' ' • 1 «•'•:' •''.•'. • . ' " . : I2O ^:Q '•'.'•'• • ,;C?J-t ' ' El I 140 H OL UJ 160 0 ui ISO ^ 1 •n/v^ g 200 !^^>.w«^r 22O &*.':•:.»•: ^_ v,viv« • , H. 240 .wrs UJ £III 26*ir»r\0 N^•:*•:••>.^: — 280 I X aH-. 3OinnO — c iM nrATION OF WFLl PACKPR UJ ^ O •.«.* 320 MI^W ii 340 US l^MM 360 « 0*ol 380

4OO •^•» ii ^V» ;St!f • 420 ^^M ••^W .•o>r- 440 $fe& rr/at* 460 •T?^ 1^1^ 480 w

^^» ir?/ir:^i 500 •V/ri: V^JCX J* 520 Kvi * * •$$

540 ••^ •SJ*J> »«^" t • -'/-"V 560 ^n» • T AREA OF PERFORATION

&S CLAY, SANDY CLAY, HARD TO >•*•». SAND, GRAVEL, AND BOULDERS Hfj MEDIUM M (2-3 INCHES) ' •« .N SAND, MEDIUM GRAVEL, AND !•-«£ FIND SAND, SAND TO SMALL O'O •g§i GRAVEL '^in IBOULDERS{4- 6 INCHES)

, a.m. on February 8, 1982 with the packer deflated. NH 24 pumped at 6.1 cfs until 10:30 a.m., February 9. Recovery was.observed until 10:30 a.m., February 10, at which time the second part of the test began. The well packer was inflated, and NH 24 started pumping again. The well pumped at 6.0 cfs until 10:30 a.m., TL February 11. Recovery with the packer inflated was observed until p.. 2:30 p.m., February 11 when the test ended. 1 ----- .The water level in three wells, NH 24, 30, and 42, were p" observed throughout the test. Monitoring of some observation wells was stopped and monitoring of others was started during the I '.; test due to water level measurement difficulties. 'On the first . day of testing, February 8, the water levels in NH wells 5, 10, ' '•'- 24, 30, and 42 were monitored (Figure 4). Monitoring of NH 5 was P^S, stopped on the second day because^the M-Scope probe kept getting caught in the well. On the following day, February 10, monitoring { I of NH 31 was begun to replace NH 5, and monitoring of NH 10 was . .„.. stopped because the M-Scope probe got caught in the well and broke :t L- off. Water quality (TCE:and PCE) was monitored at NH 24 during.the test. Samples of the pumped water were .taken while the 'fli- well.packer was deflated and inflated. The water pumped from NH 24 was wasted because it was not known if the TCE concentration rt-would be low enough to blend with other system water and still meet State Department of Health Services standards.

fp n- NHIO \ \ NORTH HOLLYWOOD WELL PACKER TEST \\ FEB. 10 - II, 1982 NH24. \ \

NH30 f

NH5 \ 4 NH3I

\

1000 FEET

I I I I

\i\ '\

NHI9*

i NH35] (•) PUMPING WELL WITH PACKER \ \ • OBSERVATION WELL NH NORTH HOLLYWOOD \ \ \\ v \.\ \ \ \ \ ER5 ^ \ \ \ Test Results and Discussion The transmissivity calculated .from the data collected at NH 24 while pumping with the packer deflated was determined to be about 500,000 gpd/ft. The transmissivity values calculated from the drawdown and recovery data were consistent, yielding 520,000 gpd/ft, 450,000 gpd/ft, and 480,000 gpd/ft for the Modified Theis, Calculated Recovery, and Residual Drawdown Methods, respectively (Table 1). These values agree with the results of previous tests in the North Hollywood area. . The transmissivity calculated from the data collected at NH 24 while pumping with the packer inflated was determined to be between 200,000 gpd/ft and 300,000 gpd/ft. The transmissivity value calculated from the drawdown data, 510,000 gpd/ft (Modified Theis Method), was not consistent with the recovery values, 220,000 gpd/ft for both the Calculated Recovery and Residual Drawdown methods. Compared to pumping with the packer deflated, a decrease in transmissivity was expected because by inflating the packer 63 ft. of the 219 ft. (29%) of perforations were p, eliminated. In order to maintain the flowrate, the groundwater discharge thru the reduced open area had to increase. This * caused greater headless through the aquifer, resulting in greater L.:< .• • drawdowns and a lower transmissivity. il- Other factors that support the reliability of the above n • [• - transmissivity values when the packer is inflated are: (1) the [r-' i increased drawdown (10 feet) and minimal change in flowrate (6.•1 ^ to 6.0 cfs) with the packer inflated; (2) the transmissivity value n calculated from the data collected at NH 24 while pumping with the [r nj • r . ••/

Table 1 North Hollywood Well No. 24 Aquifer Test* I. Packer. deflated (Feb. 8 & 9, 1982). 12.14AF pumped during a 24 hr. 10 min. period (6.1 cfs. avg.) North Distance Per- Recovery Test Total Hollywood Well • From forated, Drawdown Test Calculated Recovery Residual Drawdown Draw- Well LACFCD Depth NH 24 Static Zone -' T S T S T down No. No. (ft.) (ft.) DTW (ft.) gpd/ft gpd/ft Rpd/ft (ft. ) 5 3810S 414 1300 197 160 1,360,000 .0005 0.89-/ 10 3800A 583 450 208 326 280,000 .0037 340,000 .0018 370,000 2.91 -._ -_ 24 3800C 555 204 219 520.000 -- 450,000 480,000 14.79 30 3800D 770 1350 190 U331JH> "2*880 j 000 .0003 1,500,000 .0007 1,470,000 0.81 42 3810R 735 1550 205 (2159 2,250,000 .0005 1,680,000 .0008. 1,640,000 0.84 II . Packer inflated (Feb. 10 & 11, 1982). 12.28AF pumped during 24 hr. 45 min. period (6.0 cfs. avg.) Drawdown Above Packer ._ (ft.) -- • 7 24 3800C 555 205 156?/ 510,000 -- 220,000 220,000 25.42 1.3- 30 3800D 770 135—0 191 133 1,180,000 .0004 1,110,000 .0004 1,080,000 1.26 31 3810T 687 1350 196 189 640,000 .0003 590,000 .0003 780,000 1.84 42 3810R 738 1550 205 215 1,160,000 .0007 1,110,000 .0005 1,250,000 1.12 • III. Packer inflated (Feb. 22 & 23, 1982 1st 24 hours of Long Term Pumping (6.0. cfs) 24 3800C 555 -_ 205 1562/ 320,000 24.83 1.7 31 3810T 687 1350 196 189 620,000 .000—3 " „ 1.74 .0006 39 3810N 850 2500 203 315 1,270,000 i .77 Note:T = Transmissivity S = Storage Coefficient *T and S values were calculated for "• -._, I/ = Perforated zone below static water level . all wells. The use of these values 2/ = Perforated zone below packer. as to aquifer characteristics may 3/ = . 45j hrs. be invalid or misleading. See "Test 47 = May be low due to air leaking from packer. Results and Discussion" section. '• packer inflated for 24 hours on February 22 and 23, 1982 (Table 1) ---. was about 300,000 gpd/ft and (3) transmissivity values calculated for the observation wells declined while pumping NH 24 with the "*"• packer inflated compared to when the packer was deflated (Table 1); and (4) transmissivity values derived from recovery •*—> ;. data are considered more reliable than those derived from drawdown data because of lack of interference by the physical aspects of pumping (such as fluctuating flowrate, pump vibrations, and turbulent flow into the well). Factors 1, 2, and 3 are discussed below. , . An increase in drawdown of 10 feet and virtually unchanged flowrate when pumping with the packer inflated indicates that the aquifer zone below the packer was still capable of . . ' ' a. qrtofor releasing the same total amount of water. However, -addi-tiona4- head/swas required to drive the water toward the well in the lower zone. NH 24 was pumped for 24 hours on February 22 and 23, 1982 with the packer inflated and no other nearby wells pumping. The drawdown data for this 24 hours period test was analyzed and a transmissivity of 320,000 gpd/ft was determined. As this value is ' consistent with the recovery values for pumping with the packer inflated, this transmissivity is considered to be reliable. The transmissivity values for observation Wells NH 30 and NH 42 were much greater (over 1,000,000 gpd/ft) than for NH 24. This difference is probably due to aquifer heterogeneity, different well depths, different perforated zones, and/or blocked perforations. An observation well not in direct, complete /• 13 hydraulic connection with a pumping well only partially responds to pumping. These conditions probably caused the higher 9 calculated transmissivity values for NH 30 and NH 42 than actually exist within the aquifer. Transmissivity values for observation wells NH 30 and NH 42 decreased while pumping with the packer inflated from values obtained with the packer deflated. This' decrease in transmissivity indicates that the upper zone was sealed off from the lower zone while pumping with the packer inflated, and caused greater drawdowns in those wells which tap the lower zone. Water levels in observation wells NH 30 and NH 42 each drew down about • 0.8 feet after twenty-four hours of pumping with the packer. deflated, and with the packer inflated they drewdown.1.8 ft. and 1.1 ft., respectively. No definite boundary effect was noted at NH 24 while pumping with the packer deflated, but a recharge boundary was seen <§ , in the pumping well and in observation wells NH 30, 31, 39, and 42^" between 55 and 110 minutes while pumping with the packer inflated. The recharge boundary was again noticed in NH 24 during the first part of NH 24's long-term pumping with the packer inflated. The evidence clearly suggests that the boundary effect was influenced by the presence of the well packer. The recharge boundary was >-' probably due to either delayed vertical leakage through the clay .'": lense, or expansion of the pumping cone into a region of the I.', aquifer that may be thicker or more permeable. It is likely that p""j within the pumping cone the clay lense either feathers out, in nt "*"""!•*'•- r- 14 effect, enlarging the aquifer or thins allowing vertical leakage v. • to the lower zone. Storage coefficients calculated from NH 30 and NH 42's data collected while pumping before and after the packer was inflated were relatively unchanged. These storage coefficients, on the order of magnitude of 0.0001 (Table 1), indicate confined conditions. Whatever confinement exists in this area is probably localized and due to clay lenses that are noted in well logs. Contaminant concentrations in NH 24 decreased while pumping with the packer inflated, indicating that the clay layer •formed at least a partial barrier to vertical movement of the contaminate. Contaminant levels during the Well Packer Test are n shown on Tabie 2. TCE levels were higher than 500 ppb in March p^ 1981. During the. February 1982 Well Packer Test, the TCE level was at least as high as 100 ppb while pumping with the packer | deflated, and was only 6 to 8 ppb while pumping with the packer inflated. The PCE level was at least as high as 3.8 ppb while ' [\\~ !'•• pumping with the packer deflated, and was only 0.5 to 0.7 ppb -I; while pumping with the packer inflated. The results of the four *• ~ day Well Packer Test indicated that the well packer and clay lense effectively prevented the contaminants from reaching the lower zone. ft i Post Packer Test Pumping nI .' After several months of pumping NH 24, the well packer /••• • n continued to be an effective method of maintaining manageable levels of the contaminants. Beginning February 22, NH 24 was n- 15 Table 2 Groundwater Quality Data Collected From North Hollywood Well #24 (During Well Packer Test) Well TCE PCE Time Since Pumping Packer Date (ppb) (ppb) Began When Sampled Status 3-11-81 480 4.5 2 hours * 3-20-81 528 4.1 .1 day * • 3-25-81 495 3.7 2 days * ' 1-6-82 2.5 0.4 5 hours .''.*" 1-12-82 7.4 0.2. 24 hours * 2-8-82 14 2.2 1 hour Deflated** 2-9-82 100 3.8 1 day Deflated 2-10-82 7.2 0.7 1 hour Inflated 2-10-82 8.2 0.6 5 hours Inflated r 2-11-82 6.2 0.5 22 hours Inflated • 2-11-82 6.2 0.5 24 hours Inflated

* Well Packer installed January 27, 1982 **Well Packer Test Started On 2/8/82

16 pumped continuously with .the packer inflated for almost eight months. TCE and PCE contaminant levels were monitored throughout this period. Table 3 shows the water quality analysis results. TCE levels ranged between 0.5 and 41 ppb, averaging 9 ppb. PCE .levels ranged between 0.1 and 1.7 ppb, averaging.0.6 ppb. Fluctuations in the concentration levels of the two contaminants seemed to correspond to each other. The highest levels of TCE were detected in the same samples that the highest levels of PCE were detected, and likewise for the low levels. Therefore, both 'contaminates appeared to have been controlled by the well packer. Another indication of the effectiveness of the well packer is the water level response in the pumping well and the observation wells. After twenty-four hours of pumping 6.1 cfs without the packer inflated, the water level in NH 24 drew down 15 ) .... ^c^ r feet. After twenty four hours of pumping 6.0 cfs with the packer ^ v j inflated, the piezometric level below the packer in NH 24 drew ^ >^ r / Cl a down 25 feet and less than two feet above the packer. This f ; amount of, if any, groundwater was pumped from the upper zone. ^ ^< \ -X^T |Li I • The increase in drawdown in the observation wells (as discussed ^

n,7 earlier) and in NH 24 (below the packer) reaffirms that the upper I I" zone was sealed off from the lower zone, causing greater drawdowns [f in those wells which tap the lower zone. '--.: During the last week in October 1982, after continuously d pumping for almost eight months, the North Hollywood pumping plant operator found NH 24 shut off due to electrical problems. Water '~' :^ i,. - n>~^ * Operating Personnel discovered that the well packer's pressure lr .' • - ' f. • 17 Table 3 Groundwater Quality Data Collected From North Hollywood Well #24 (Post Well Packer Test) Date TCE PCE Date TCE PCE (1982) (ppb) (ppb) (1982) ppb PPb 2-22 1.3 0.1 4-16 14 5.4 2-22 1.6 0.3 4-23 1.7 0.3 2-23 2.7 0.3 4-29 12.9 0.6 2-23 3.3 0.3 4-30 14 0.7 2-23 3.1 0.6 5-3 16 0.5 2-24 3.9 0.6 5-4 15 0.7, 2-24 3.4 0.3 5-5 17 0.7 2-25 5.1 0.5 5-6 , 17 0.7 2-26 9.6 0.7 5-7 ; is 0.7 2-26 4.8 0.3 5-12 18 0.8 3-1 22 0.8 . ' . . 5-14 11.4 1.0 3-2 6.2 0.3 5-17 12.3 1.0 3-3 8.0 0.4 5-18 14 0.6 r 3-3 6.2 0.3 5-20 13 0.7 3-4 8.2 0.3 5-24 10.5 0.7 3-4 6.0 0.7 5-26 10 0.6 3-5 7.0 0.7 6-1 9.6 0.6 3-5 7.8 0.8 6-3 11 0.7 3-8 5.8 0.4 6-7 11.4 0.7 3-9 7.8 0.4 6-9 10.8 0.8 3-10 8.2 0.3 6-14 10.5 . 0.9 3-11 7.0 0.3 6-16 9.9 0.8 3-17 5.5 0.4 6-18 8.4 ' 0.7 3-19 6.0 0.5 6-29 5.2 0.5 3-30 41 • 1.7 7-7 0.9 0.3 4-1 32 1.2 7-13 4.6 0.5 7-16 6.3 0.8 7-20 6.5 0.5 7-28 4.3 1.0 8-25 1.0 0.4 9-23 0.5 0.1 Average 9.4 0.6 NOTES: NH 24 turned on 2/22 • Grab sample collected on 4/16 was from above packer/ and not included in average. During the first week of March a bottle of nitrogen gas and a regulator were connected to the well packer to maintain constant : -.. pressure in the packer. Prior to this the packer lost pressure at '• night and had to refilled ieach morning.

r 18 system had developed a leak and drained the bottle of nitrogen gas used to maintain constant pressure in the packer. The packer ' . ' • ; could not be refilled without repairs. This incident provided an " ' r ideal opportunity to pump NH 24 with the packer deflated to check whether the reduction of contaminants in NH 24 was due to the effectiveness of the well packer or to the movement of the plume of contaminated water: away from the well. {r -'-.- LP. The NH •2 4 -moto ' r was repaired and started on November 2, _.' '. r, 1982. The well continued to pump until November 8. During the ' """ six days of pumping with the packer deflated five water quality P- j samples were taken. The pumped water was wasted since it was not known if the TCE concentration could be adequately reduced to meet State Department of Health Services standards by blending with r~ other system water. Table 4 summarizes the water quality sampling i . ' results. • • After six days of pumping without the packer inflated, i... - TCE contamination of the pumped water increased from 0.1 ppb to 136 ppb without leveling off. The level of PCE .also showed a substantial increase. These results indicate that heavy volatile organic contamination was still present in the upper zone of the aquifer in -the NH 24 area and was prevented from entering the well 1"' .. casing by the well packer and the clay lense at NH 24. Therefore, [ ' the short term (eight months) effectiveness of a well packer to n:-.,; - 4 "..'.- .'.- contain organic contaminants above a clay lense was confirmed by •p ••••:• I.;:. | I"-: *"" continued pumping after the Well Packer Test. _- .-•• f - The NH 24 pump column was pulled from the casing in i-" '-••»•'•• December 1982, to examine the packer and determine the cause of r 19 Table 4 .-' • •• Groundwater Quality Data North Hollywood Well 24' With Packer Deflated . • Time since Date TCE PCE pumping began Sampled ( ppb ) • ( ppb ) 0.5 hours 11/2/82 0.1 0.2 4 hours 11/2/82 7.5 0.9 1 day 11/3/82 92 5.1 3 days 11/5/82 124 : 5.8 6 days 11/8/82 . 136 5.4

K fi

20 r.v n( the problem. Water Operating Personnel discovered that the "S • " - • ,-- airline to the packer was cut. It was apparently cut by a jet of ' water escaping from inside the pump column through a hole in the casing at a welded joint in the recess installed to relocate the electrical cable at the well packer. The well packer itself was nn in good shape. The airline is presently being replaced and the casing repaired. In addition, a small submersible pump will be rt;attached to the pump column in a recess installed above the well fe packer to collect water quality samples in the upper zone.

Conclusion The transmissivity of the North Hollywood area aquifer was found to be over 500,000 gpd/ft, based on values calculated pf from data collected during the Well Packer Test. This value is "> • consistant with previous aquifer tests. Storage coefficients of 0.0005 calculated from the Well Packer Test data indicate that in the North Hollywood area around NH 24 the aquifer is locally rf confined. The purpose of using a well packer in NH24 was to isolate and pump from the lower zone, which was believed to be less contaminated than the upper zone. The results of the Well Packer Test indicate that the well packer created a seal with the clay lense that separates the upper zone from the lower zone, preventing water from the upper zone from falling through the well casing to the lower zone and the pump intake. The effectiveness n. of the packer as a seal was demonstrated by the following

J—v observations:

21 1. Drawdown in the pumping well increased by over 10 feet while pumping with the packer inflated as compared to pumping with the packer deflated. 2. The upper zone water level declined approximately one and a half feet while pumping with the packer inflated whereas the lower zone piezometric level drewdown approximately 25 feet. 3. Transmissivity values decreased when the upper zone was sealed off/ -while the flowrate was virtually unchanged. The transmissivity of NH 24 while pumping with the packer inflated was between 200,000 and 300,000 gpd/ft verses 500,000 gpd/ft with the packer deflated.

Water quality analysis of samples collected at NH 24 while pumping with the well packer deflated versus when inflated indicated that organic contaminants appeared to be effectively prevented from reaching the lower zone. The following observations lead to this conclusion: 1. Prior to installation of the well packer at NH 24 TCE contamination averaged 500 ppb (3 samples in March ft 1981). During the 24 hour test pumping period with the packer deflated, the TCE level was at least 100 ppb. During the 24-hour test pumping period with the packer inflated, TCE averaged only 7 ppb (Table 2). PCE concentrations also appeared to decline when pumping . [t- with the packer inflated.

22 2. The well packer continued to be effective over several months of continuous pumping. Table 3 indicates that the average TCE concentration over a 7-month period from February 22, 1982 to September 23, 1982 was 9 ppb. PCE averaged 0.6 ppb during this period. 3. Additional testing in November 1982 confirmed that the well packer contained the contaminants above the clay lense. While pumping with the packer deflated, TCE levels increased from 0.1 to 136 ppb within 6 days and . • PCE increased from 0.2 to 5.4 ppb.

From the test it could not be determined how the vertical distribution of TCE varied. It is not known if the small amount of TCE and PCE detected while pumping with the packer inflated was present in the lower zone, or if the lower zone was clean and during pumping the contaminants were pulled through the clay lense or from elsewhere in the aquifer. To answer this question another kind of controlled pumping test with special f- equipment is required. '$ ft

23 r

r

f APPENDIX 4 r r SFVGWB WELL CONTAMINATION DATA C f

i i

r~ I "" r r i

V • •

ri BESU11S Or THE YDMlllt OTCMIC AXfUTStSIA III leosKPflfSEITMIVi E KUS Of S«« FF.WAKW VALIir USII :SI«TE : I.M.I.P. urns IWKH or ; NEILS JI or Kusiiunci ori VXMIIE O«H«ICS iiEvu i : : : : i i : : i : i : : : i i : »wvt : KUS 1 !IS«U 1 NH-7 !NH-4 ilH-13 !NH-IM;iW-U .'W-21 !M)-24 IW-77 IIH-30 IIH-32 ilH-34 l«H-3t IKH-2 !VN-41 it-3 !M :v-u :r-4 JCS-44 »IK-27 JW-30 1RKES OF ! SAL : USKI 1 iipft) : i i t : ; : t : ; : : i : h 1 OR6MICS 1 i 0.7 1 1 : n i n : n ; o.i i n : 0.4 : 0.2 : NO i - iti.ii : nn : NO :n t n iio.ii .; n i 0.2 : n io : 20 : IEIIEKE i :it- '• - i - : no : - '. - ; w i - '. - ; is i « - 5 n s • )|l} \\ o : :io.ii : J : 0.2 : - i n i - i n i n : NO i - t n : NO t - - 1 NO 1 NO j „ i: ?n • - i - : n ; - : - i : o : 13 i i 130 1 i : 19 : n : n i n : NO i 19 : 19 ; n t - : n ; nii : n : ID i - 1 M) : n : n : it : it : n o : o : n 1,4-oiCH.oftOKUEit : ; 2 : - : - i - i 19 i - : - : NO i - i - : NO : NO - : NO i I m : - : ID 0 1 ,\ :io.3> i 3 : 1.3 : - : i : - : n : - t NO : - i 0.3 : NO ; • - 1 NO 1 it 1 NO i n i - i - i n i 7 1 Ji 11 ! : 130 : i : o.i : n : it : 3.3 : n i n : n : n i - : ID : IDn : ii i n I NO : n : ID : n n, : ID o : 1,3-Diw.oroKHEir. i : } i - : - i - : 2.2 : - t - : NO : - i - : 1.1 : NO- : NO : i NO ! - : NO1? ! i ?! tio.s) : ) : NO i - i> : - : 19 : 19 i NO i - i NO : NO : - - t no : NO ! n 1 NO i n i n : - ii - u'i : : i : 2.2 : w : i.i : i.! : ii : t ! o.i : it : - : n i J.o io : 3 : : ID i 0.4 • : n : to : o : 20 1 CHKMOFORK ! 12!- t - ! - ! 3.4 ! - i - ! 2.5 ! - t - ! 2.4 I 10 - ; i.e : i W i !•» i - : - 4 ; :io.3> : i : 1.4 : - : 3.1 : - : n : i.i : NO i 0.7 t - i NO i - - i 2.4 : NO : 0.3 1 2.4 1 0.5 i 0.3 i - : - i : Ji : s.o : i : (in : • : (in : (441 i 4.0 1 3.1 : 2.1 : • i - : NO i 0.I 7 i (141 i 0.3 ! (331111.01 : n : 7.7 Ini (721 i (411 ' 4 : 43 : 20 1 - : 1441 : ! I3BI : - td.ii i ! 7 ! !io.5) : J i 7.7 1 - :t7ni i - :n.3i t « : 2.0 i - I • i • t - - lllOb) 1 * ilMl ) 145) i - i - i (231 i : ti III 13 ! : J.o : i tii.ii : • : i.o : i : 7.1 : n \ n in:- : n : n i - 1 2.4 : 0.5: n K7.11 J 1.4 1 doi ni.ii 20 : TtTIAMOTOEtHEK (fCH ! i 2 1 - ! - ! - 1 3.1 1 - 1 - 1 3.J 1 - ! - i I.I 1 NO 5 i !:! ! i 2.1 : ~ : (22' MO.II : J : 3.7 : - 114.21 i - i 1.0 : 7.3 : 1.7 1 - : i i NO i - - : 2.1 i n ! 1 1 2.4 i 1.7 : - : - 1 II 'Ji 13 .' : n : n 300 : i : 1.2 ! • i n i n i it j n ! n ! ii : - : n : it n- :; iNtO : : : no :t n- :j NnI i •••! ID i m 2 : o : - i NO :NO : ID : NO i n : t.t : o : 13 ! 4.0 ! i : 0.3 : 19 : » i • t m : n : n : it t - : it i n NI : o.i ; ! 10 i ID : ID ! n i n t n I.I.OICHOROETHEtt ! 2 ! - ! - ! - ! 1.4 ! - ! - ! 0.7 j - ! - ! NO 1 NO- : n : i ? ; - : n o : , Ti- 10.3) 1 3 1 n : - : 0.3 : - i n i n : o.t i - : n : *o : - - 1 NO 1 19 : NI ! ID in ! w : - i - i •!! 0 1 ll i 5.0 1 1 : n : » : o.i : n : n : n : n : n : - i n : n ID : iii t n j - : (in i ID : io : 0.7 ;0.3 : n 4 : 20 | CMtO* TEmOlORIK ! 2 ! - ! - ! - ! NO ! - ! - ! 10 ! 1 - ! 10 ! 10 1 - 1 2.1 i t M : 10.3) : 3 : n : - i 3.7 : - : n 1(4.21 : 10 i i NI i n i • - i 0.7 : n i i.i i i.i 4 : 13 : i.o i 1 1 - : - s - s - '. - t • i - i : - t - i - i - ins - : - i - ! - 0 ! o : 20 5 l,2,OICHLO«IElHWf ! 2 I - !- '• - ! n ! - I- !»! !- ! 19 ! It i n 0>l o : ' io.3) : J i w ! - ! «i ! - i n i w : «o : i w i M : - : i iTi ;, : n i U : no : ' i i n i : i : ii o : u : too ! i i io i n : no : ID i 10 : 0.4 : n ; n i - i n i 10 n i n : n i - : n i n : n i it i n i n i n 20 j Tout* : 7 1 - ! - : - : NO : - : - i 10 : - : - : NO : NO - i NO 1 i NO o i to.)) : 3 : n i - : n i - : 0.2 : n ; » : - : n s « : - - : NO :n : NOin i - i - i n : - i - i! o : 13 :' 420 : i j - s- i- :- i- :- :- !- :- :- i - j - o : o : 20 I inwj :2J- :- i- :- !- t - i - i • : - :- : - i - | - o : o : io.li : 3 : 0.3 : - i 0.4 1 - i ID : n : n i - i - t n t - : in! n i - \: i n i « i : i: 7 i o : 13 : 49 : i : i : i : ii : • i n : • : no : NO i - : m i • i : NO : i - i .n : it : it : » i 19 1 1.4 10 : - i no : ! - i NI •Ii o : io.3) : 3 : i i - : • i • : 7.i ; n : NO : - t n i n : - - I NO 1 n i n Is : it i it i : j .- i : o : n : vim* v COTTOUS : 2: o: i: i: i : 2: 01 o: o: i: i: 01 i: 0 : 2 : i 7 : 7 MOVE sim ACIION : : : i : : : : i : : : i i 3 ! '| i Ltva/icu. i i : : : i i : i : : : i : i ' i' 1 'i i ,21-N»y-B4 ( 1 : In ficru el ftitf iclion Iml 1 ) I Dilution liiit 1 > Firit iiiplmg (12-4-14 Io I-23-B3) . NO t Not dttctrt 2 i Furt MU.JI'M C2-20-B t« 3-24-83) • t tiloi tkf lutl »l »«jnliltc«lio» 3 i Stcond rrtiipliiit 14-30-63 to 5-15-65) - I Cottond not JUlflH • SAN FERNANDO VALLEY WELLS STATUS OF TOE CONTAMINATION

No. of Wells No. of Wells No. of containing containing • r WELL GROUP Wells TCE >5 ppb TCE >5 ppb . 1981 Latest value i ri( - LADWP WELLS ' D.., North Hollywood 35 13 20 Erwin 7 0 • 2 n: Whitnall 10 1 3 Verdugo 8 0 1 HI Headworks 6 2 6 Crystal Springs 3 2 3 n- Pollock 3 0 2 •^ Mission 3 0 0 PL ( Sub Total ) 75 18 37 i R- GLENDALE WELLS Grandview 8 2 5 r:^ Glorietta 3 0 - o r. ( Sub Total ) 11 2 5 r BURBANK WELLS 10 4 6 L 1SAN FERNANDO WELLS 4 0 0 i 0- CRESCENTA VALLEY COUNTY 1 WATER DISTRICT WELLS 1.0 0 I p-I I r ' Total 110 24 48 | l ."- -?•••" • *1985

! . it HOKTB BOLLWOOD UPPER AQUIFER Tg/PCE CWTAMIHAIION DAIA

' VEIL HH S 01 (Well Depth • 287 Feet) Surple Date ICE Concentrttloc PCE Concentntion (In ppb) U• J1 U-l-84 160 ..*•'• U-28-84 175.00 ! : . 8.90 ' . i ' '• rj 140.43 " ' ' '' ''7^.89 U-29-84 11-30-84 145.59 8.31 n 12-3-84 167.46 9.63 12-4-84 143.28 8.04 ni ' 12-6-84 121.00 6.90 p-r 12-10-84 151.00 8.85 1 *\_' 12-12-84 • :••'• 167.58 9.39 . • »>*i 2-4-85 164.00 8.60 [3 2-11-85 150.00 9.00 __ **i 4-10-85 57.72 • 3.63 n 6-5-85 • • ' 150 10

J WELL HH 10 (Well Depth - 300 Feet)

D«te TCE.Concentration (in ppb) PCE Coocentntion (in ppb)

7-2-85* 214.00 26.00 V 7-2-85* 101.00 11.00 7-2-85* ' 82.00 9.10

• These n»ple* were all taken on Che u»« «Uy during « pus? test. IXZ/PCZ HAIA COLLECTED AiOVE WELL PACKER AT WELL HH 24

(Well Packer Depth - 298 Feet)

ICE f\*fr ICE PCE Saxple Concentration Concentration Sarple ^Concentration Concentration Date (In ppb) ~- '-(In ppb) •"— I . Date (In ppb) (I* *n *• cobK K *•)' » 11-28-83 0.50 ' • '. ' i 0.10 7-2-84 65.00 6.80 1-10-84 0.90 ' 0.10 7-9-84 74.36 8.00 1-11-84 2.90 0.30 7-16-84 66.20' 6.68 1-17-84 39.00 2.30 ill 7-23-84 63.62 5.65 1-18-84 40.00 2.70 7-30-84 83.46 7.98 1-19-84 45.00 2.70 8-6-84 96.99 8.84 ITJ 1-24-84 45.00 2.90 8-13-84 87.00 3.30 1-25-84 51.00 3.40 8-20-84 84.04 8.70 r-i 3-2-84 66.00 5.60 8-27-84 94.71 9.96 3-5-84 64.90 5.91 9-4-84 84.30 9.00 3-6-84 ' 62.50 5.73 9-10-84 115.00 10.81 3-7-84 70.70 6.51 9-17-84 129.49 10.71 • 3-8-84 73.90 7.30 9-24-84 91.50 11.16 3-9-84 68.50 6.41 10-1-84 174.34 11.52 3-12-84 61.60 5.82 10-9-84 125.40 11.73 3-13-84 67.50 6.44 10-15-84 140.22 11.40 3-19-84 63.80 6.64 10-22-84 161.00 15.87 3-26-84 59.90 6.39 10-29-84 126.00 12.99 4-2-84 61.30 6.47 11-13-84 167.58 16.02 4-16-84 59.10 6.53 11-26-84 169.80 18.66 4-30-84 59.90 6.78 12-3-84 189.90 20.88 5-14-84 54.70 5.97 12-10-84 fP" 155.00 16.74 5-29-84 64.47 .7.18 1-24-85 66.45 8.31 6-11-84 62.50 6.90 5-29-85 96.0 12.0 6-18-84 65.60 8.30 6-5-85 105.6 13.0 6-25-84 69.50 8.86 TCE/PCE RECORDS OF SFVGWB WELLS CS-46 10. 1.3 23-Jul-81 CS-46 9.2 1.6 29-Oul-Bl i _ WELL TCE PCE DATE CS-46 5.6 0.8 23-Sep-81 . ;.• .CS-45 4 0 24-Jan-BO CS-46 10. 1. 1 30-Sep-Bl CS-45 6 0 25-Jan-SO CS-46 9 0.7 26-Nov-Sl CS-45 4.9 1.3 05-Aug-80 CS-46 7 0.4 12-Jan-82 CS-45 5.1 1.8 06-Aug-BO CS-46 13 1.3 23-Feb-82 fl3" CS-45 4.5 1.5 07-Aug-80 CS-46 17 1.5 24-Feb-B2 CS-45 5.8 1.3 08-Aug-BO CS-46 19 2.3 19-Mar-82 - CS-45 5.9 1.2 09-Aug-BO CS-46 14 . 1.7 23-Apr—82 CS-45 4.9 1.4 10-Aug-8O CS-46 13 1 02-May-B2 n' ~* CS-45 5 1.5 ll-Aug-80 CS-46 10. 1.2 lB-May-82 CS-45 5. 3 1.5 12-Aug-80 CS-46 12 1.1 16-Jun-82 - . CS-45 6.2 1.7 13-Aug-80 CS-46 10 0.4 02-Ju1-82 n» CS-45 5.6 0.8 14-Aug-80 CS-46 : 14. 0.2 16-Jul-82 ; CS-45 6.4 0.6 15-Aug-80 CS-46 12. . 1.4 29-JLI1-82 r CS-45 5. 1 1.6 16-Jul-Sl CS-46 14 1.9 16-Aug-82. , ; . CS-45 6.2 2.5 17-Jul-81 CS-46 13 1 08-Oct-82 CS-45 7 1.3 '23-Jul-Bl CS-46 19 1.9 03-Nov-82 — CS-45 6.6 1.4 29-Jul-81 CS-46 14 1. 1 1 l-Jan-83 CS-45 4. 1 1.3 23-Sep-81 CS-46 13. 1.2 26-May-S3 _• 13. n CS-45 6.2 1. 1 30-0ct-81 CS-46 1 . 09 14-Jun-83 CS-45 5 O.5 26-Nov-Sl CS-46 12. 1.08 19-Jul-S3 r^' CS-45 6 1.2 12-Jan-B2 CS-46 13 1.2 03-Nov-B3 CS-45 8.2 1.8 24-Feb-82 CS-46 . 12 1.4 28-Nov-83 CS-45 9.6 1.7 19-Mar-B2 CS-46 14 1.4 06-Dec-83 '*" CS-45 6.2 1.5 23-Apr-82 CS-46 13 1.5 10-Jan-84 : ) CS-45 6.4 1.1 lB-May-82 CS-46 13 1.3 01-Feb-B4 CS-45 6 1.3 16-Jun-82 CS-46 13. 1.31 29-Mar-84 CS-45 5.2 2.8 02-Jul-B2 CS-46 13. 1.36 O3-Apr—64 CS-45 7 16-Jul-82 CS-46 14. 1.2B O9-May-84 n. J--: CS-45 9 2 29-Jul-82 CS-46 15 1.09 06-Jun-84 CS-45 6.3 2.4 16-Aug-S2 CS-46 14. 1.08 05-Jul-64 CS-45 2.7 1. 1 27-Sep-82 CS-46 13. 1. 14 21-Aua-B4 f: CS-45 6 1.5 08-Oct-82 CS-46 17. 1.47 19-Sep-84 CS-45 9.8 2.9 03-Nov-B2 CS-46 19. 1.46 03-Oct-B4 r- CS-45 5.5 2.9 1 l-Jan-83 CS-46 17. 1.34 14-Nov-84 CS-45 7.3 1.01 26-May-B3 CS-46 19. 1.43 04-Dec-64 CS-45 6.5 0.96 14-Jun-B3 CS-46 ' 17. 1.44 09-Apr-S5 CS-45 7. 1 1.33 19-Jul-83 CS-46 22 1.3 14-May-65 CS-45 9.4 5.6 O2-Aug-B3 CS-46 14 1.2 ia-Jun-85 T CS-45 8.7 1.66 29-Mar-B4 CS-46 16 1.5 OB-Jul-85 C5-45 9.0 1.82 O3-Apr— 84 CS-46 18 1.5 06-Aug-85 _f;: CS-45 8.2 1.61 09-May-84 CS-46 16 1.4 07-Aug-85 : '' CS-45 7.7 1.32 O6-Jun-B4 CS-46 24 1.9 02-Sep-85 CS-45 7. 1 1.2 05-Jul-84 CS-46 IB 1.5 06-Sep-85 rr~ CS-46 9 0 24-Jan-SO CS-46 24 1.9 02-Oct-85 "V. CS-46 8 0 25-Jan-80 CS-46 24 1.6 02-Oct-B5 CS-46 14 0.6 O5-Aug-aO CS-50 2.6 1 22-5ep-Sl CS-46 12 1.3 06-Aug-80 CS-50 3. 1 1.3 28-Sep-Bl r~ CS-46 8.6 1 07-Aug-80 CS-50 1.7 0.3 08-Oct-8J. 1— • CS-46 11 1. 1 08-Aug-BO CS-50 5.6 6 26-Nov-ei " "CS-46 9 0.8 10-Aug-80 CS-50 3.7 0.6 12-Jan-82 /) CS-46 11 0.6 09-Sep-BO CS-50 4.B 0.9 04-Feb-82 CS-46 9.3 1 16-JLil-Bl EW-1 0. 1 0.1 30-Jul-ai .:- CS-46 8.7 1.6 17-Jul-Bl EW-1 0. 1 0. 1 17-Aug-Bl EW-1 1 0.3 19-Mar-B2 EW-2A 0.6 1. 1 12-Oct-83 EW-1 1. 1 0. 1 19-Jan-B3 EW-2A 1 1.4 21-Dec-B3 •s EW-1 0.6 0.19 23-May-83 EW-2A 1.2 1. 1 ll-Jan-84 EW-1 2 0.4 23-NOV-83 EW-2A 4.B 2. 17 25-Sep-B4 EW-1 2.3 0.3 14-Feb-84 EW-2A 4.3 1.87 02-Oct-84 EW-T 6.3 0.6 13-Jun-85 EW-2A 5.8 2 07-Aug-85 EW-1 5 0.5 18-Jun-85 EW-2A 5.6 2.2 13-Aug-85 fT; EW-1 5. 5 0.5 18-Jun-85 EW-2A 4.9 1.8 06-Sep-85 EW-1 4.8 0.4 09-Jul-85 EW-2A 6.4 2.5 02-Oct-85 EW-1 0.4 0.4 09-Jul-85 EW-2A 6.4 2.5 05-Oct-85 EW-1 0.3 0.1 12-May-91 EW-2A 4.7 1:7 05-NOV-85 EW-10 0 0.2 25-Aug-SO EW-2A 4.7 1.7 04-Dec-85 EW-10 0. 1 0: 1 10-Apr-81 EW-2A 5.9 1.9 03-Jan-66 EW-10 0. 1 0. 1 02-Sep-Bl EW-2A 7.4 2.5 15-Apr- 86 •:rr EW-10 0 0 Ol-Qct-81 EW-3 .- 2 . 0 25-Jan-80 EW-10 B.4 2.3 19-Mar-82 EW-3 2 0 21-Jul-BO EW-10 0. 1 0. 1 23-Apr-82 EW-3 0 0 02-Qct-BO EW-10 0.2 29-Apr-82 EW-3 0.1 0. 1 30-Mar- 81 I !•- 0. 1 EW-10 0. 1 0. 1 18-May-82 EW-3 0.5 0. 1 29-Jan-82 EW-10 0. 1 0. 1 02-Jul-B2 EW-3 0.7 0.2 ll-Jan-B3 EW-10 0. 1 0. 1 16-Ju1-82 EW-3 2.4 3. 5 Ol-Aug-83 EW-1O O.7 O.9 2B-Jul-B2 EW-3 3. 8 0.2 12-Oct-83 EW-10 0. 1 0.2 16-ALig-82 EW-3 0.2 0.21 OS-Mar- 84 EW-10 0. 1 0. 1 20-Oct-82 EW-3 0.2 0.2 27-Apr-B4 EW-10 0. 1 0. 1 17-Dec-82 EW-3 5.9 0.29 07-May-84 EW-10 O. 1 0. 1 ll-Jan-83 EW-3 5.4 O.45 04-Jun-B4 EW-10 0. 1 0.3 25-Feb-83 EW-3 3.9 0.24 03-Jul-84 EW-10 0. 1 O.O2 23-May-83 EW-3 5.6 0.32 OB-Aug-64 EW-10 25-Sep-84 EW-3 5. B 0.41 14-Sep-84 EW-10 0.2 0.2 ll-Jan-B5 EW-3 5. 6 0.42 02-Oct-B4 EW-10 0.2 0.2 ll-Jun-85 EW-3 8.6 0.46 14-Nov-84 n: EW-10 0.2 0.2 18-Jun-85 EW-3 7.9 0.42 04-Dec-B4 EW-2A 2.3 2.9 27-Jan-Bl EW-3 9.3 0.44 03- Jan -85 EW-2A 0.3 15.6 06-Aug-Bl EW-3 9.4 0.49 09-Jan-85 EW-2A 0.4 8.7 10-Aug-Bl EW-3 9. 1 0.41 20-Feb-85 EW-2A 0.6 5. 5 17-Aug-Bl EW-3 8.5 O.42 25-Mar-B5 EW-2A 0.2 5.5 24-Aug-Bl EW-3 9.3 0.51 10- Apr— 85 EW-2A 0. 1 6.2 31-Aug-Bl EW-3 7.6 0.4 Ol-May-85 EW-2A 0. 1 1.5 30-Nov-Bl EW-3 9.3 0.6 04-Jun-85 EW-2A 0.8 5 08-Feb-B2 EW-3 7. 1 0.4 09-Jul-85 EW-2A 2.4 3.6 19-Mar-82 EW-3 6.8 0.4 07-Aug-S5 EW-2A 0. 1 1.7 23-Mar-82 EW-3 6.6 0.4 06-Sep-S5 EW-2A 0 . 3 2.4 'lS-May-82 EW-3 8.2 0.5 02-Dct-35 EW-2A 0.4 1.7 02-Jul-B2 EW-3 6. 1 0.5 05-Nov-BS EW-2A 0.7 2.9 19-Jul-B2 EW-3 4.9 0.2 03-Dec-85 ft EW-2A 1.7 3 2B-JLI1-B2 EW-3 7. 1 0.4 15-Apr-86 EW-2A 1. 1 3. 1 06-Aug-82 EW-4 0 0 23-Jan-aO EW-2A 0.6 1.5 16-Aug-B2 EW-4 O.B 0.6 21-Jul-60 EW-2A 0.3 1.5 23-Sep-82 EW-4 0 O . Ol-Oct-30 ft EW-2A 0.8 2.7 20-Oct-B2 EW-4 0. 1 0. 1 10-Apr-Bl EW-2A 0.7 2.3 17-Dec-82 EW-4 0. 1 0.1 12-Aug-Sl EW-2A 0.8 1.4 19-Jan-B3 EW-4 0.1 0.3 19-Mar-82 t- >EW-2A 0.6 2.04 23-May-83 EW-4 0.3 0.2 21-Dec-83 EW-2A 0.7 1.44 09-Jun-83 EW-4 0.6 0,21 29-Mar-84 EW-2A 0.8 1.6 OS-Jul-83 EW-4 0.4 0.83 30-Jul-84 EW-2A 0.7 1 .4 01-Aug-B3 EW-4 3 1.7 07-Aua-BS L EW-4 0.3 1.7 07-Aug-B5 HW-25 8.8 0.97 19-Jul-83 EW-4 2.7 1..4 06-Mar-B6 HW-25 12 1.2 02-'Aug-83 EW-5 1 0 23-Jan-80 HW-25 15 1.3 06-Sep-B3 r EW-5 2 0 OB-Apr-80 HW-25 14 1.3 31-Oct-B3 '!••! EW-5 8.2 2 14-Aug-BO HW-25 18 2 23-Nov-83 EW-5 5.8 0.3 18-Aug-BO HW-25 11. 1.63 29-Feb-84 I.' EW-5 5.4 0.2 19-Aug-80 HW-25 12. 1.49 05-Mar-84 EW-5 0.5 0.4 20-Auq-BO HW-25 13. 1.49 21-Mar-B4 n: EW-5 5.5 0.8 21-Aug-80 HW-25 14. 1.63 O3-Apr-S4 EW-5 3.5 0.4 25-Aug-BO HW-25 15. 1.69 ll-Apr-84 EW-5 o •• O Ol-Oct-80' HW-25 17. 1.94 09-May-84 . EW-5 3.8 0. 1 10-Apr-81 HW-25 IB. 1.64 06-Jun-84 EW-5 5 0.8 07-May-81 HW-25 22. 2.32 20-Jun-84 EW-5 3.2 1. 1 2B-JLil-81 HW-25 21. 2 02-Jul-84 n: EW-5 2.4 0.7 30-Jul-81 HW-25 24. 2.24 21-Aug-84 EW-5 3.9 0.9 29-Jan-82 HW-25 27. 3.51 18-Sep-84 l-»", EW-5 4.7 2.1 OS-Feb-82 HW-25 22. 2.08 03-Oct-S4 1 '. EW-5 5.5 1.3 19-Mar-B2 HW-25 31. 3.21 13-Nov-84 EW-5 1.3 0.5 23-Apr-82 HW-25 37. 4.24 04-Dec-84 EW-5 4.7 1 18-May-B2 HW-25 12 2.7 30-Oct-65 rr EW-5 6.2 1.4 02-Jul-82 HW-25 21 3.9 lS-Nov-85 ,..-J EW-5 14. 0.2 16-Jul-82 HW-25 16 2.9 14-Apr-86 EW-5 8 1.5 28-Jul-82 HW-26 6 0 22-Jan-80 EW-5 9.3 1.5 06-AUQ-B2 HW-26 7 0 25-Jan-BO EW-5 9.4 1.7 16-Aug-B2 HW-26 1. 1 0.8 02-Dct-BO T1 t "~: EW-5 4.6 0.8 23-Sep-B2 HW-26 1.2 0.8. 03-Dct-BO EW-5 7.8 1. 1 20-Oct-B2 HW-26 1 0.4 08-Oct-BO "S EW-5 12 0.7 1l-Jan-83 HW-26 1.2 0.5 O9-Oct-BO EW-5 31 1. 1 lS-Jul-83 HW-26 1.4 0.3 10-0ct-80 EW-5 2.4 0.61 21-Dec-83 HW-26 7 0.5 17-Nov-80 EW-5 55. 2. 19 Ol-May-84 HW-26 11 1. 1 06-Jan-81 Kf " .:- EW-5 31. 1.23 O4-May-B4 HW-26 9.4 0.9 20-Jan-Bl EW-5 23. 0.92 12-Dec-84 HW-26 14 1.6 10-Jan-82 EW-5 62 2.2 15-May-B5 HW-26 0.2 0.3 21-Jun-82 EW-5 37 1.6 07-Oct-85 HW-26 0.4 0. 1 02-Jul-82 1 ~" EW-5 26 1.3 15-NOV-85 HW-26 5.6 0.7 16-Jul-B2 EW-5 18 1' 14-Api—86 HW-26 6.2 0.9 29-Jul-82 EW-6 0 0 23-Jan-80 HW-26 12 1.3 16-Aug-&2 EW-6 0.5 0.2 21-Jul-SO HW-26 8.4 1 OB-Sep-82 rp EW-6 0 0 10-0ct-80 HW-26 22 1.7 07-Dct-52 r ' f^ EW-6 0. 1 0. 1 10-Apr-81 HW-26 32 3. 3 03-Nov-B2 EW-6 0. 1 0. 1 12-Aua-Bl HW-26 40 4.5 05-Nov-B2 . t EW-6 0. 1 0.09 22-May-84 HW-26 42 2.9 OB-Nov-82 EW-6 1.8 0.2 07-Aug-85 HW-26 35 4.5 J~ 12-Nov-82 EW-6 1 0.2 15-Apr-B6 HW-26 53 3.9 15-Nov-52 HN-36 2 0 29-Jan-80 HW-26 54 5.6 22-NOV-B2 HW-25 0.5 1 29-Jul-82 HW-26 15. 1.78 26-May-83 HW-25 7.5 1.7 05-NOV-B2 HW-26 20. 2. 1 23-Jun-S3 HW-25 8.6 1 12-Nov-82 HW-26 27. 2.66 13-Jul-83 f- HW-25 12 1.5 15-NQV-B2 HW-26 30. 2.92 19-Jul-B3 >• HW-25 12 0 3.87 2O-Apr-34 p4- lS-Nov-82 HW-26 34. HW-25 13 2.2 22-NOV-B2 HW-26 63. 7 09-Apr-85 i - ;..HWT-25 4.9 0.9 1l-Jan-83 HW-27 4 0 22-Jan-8O f^ HW-25 2.0 0 . 53 26-May-S3 HW-27 11. - 0 05-Feb-BO f HW-25 6.6 0.84 14-Jun-83 HW-27 14 0 07-Feta-BO \~ HW-25 8.6 1.03 12-Jul-63 HW-27 10 0 11-Feb-SO is 1" HW-27 11 0 13-Feb-80 HW-28 16 2.8 04-Jun-81 -v HW-27 1.4 0.3 08-Oct-BO HW-28 18 2.6 1 2- 3 un -81 1 ; HW-27 2.5 6.8 09-Oct-BO HW-28 8.2 1.3 28-Jun-ai ' , • HW-27 2.6 0.4 10-Oct-BO HW-28 7.8 1.3 29-Jun-Bl f '" . .HW-27 3. 6 0.4 14-0ct-80 HW-28 9.9 1.3 23-Jul-ai HW-27 4. 1 0.6 15-0ct-80 HW-28 7.4 0.3 13-Aug-81 -: HW-27 5.6 0.6 21-0ct-80 HW-28 5. 1 1.2 23-Sep-81 HW-27 12. 1.6 06-JanT-Bl HW-2B 9.4 1.5 30-0ct-81 n.-- 1.4 20- Jan -81 HW-27 11. HW-2B 12. 1.3 26-Nov-81 25-Feb-81 ~ HW-27 12. 1.3 HW-28 6.2 0.7 12-Jan-B2 HW-27 12. 1.4 27-Mar-81 HW-2B 7.8 1:3 22-Mar-82 n.. HW-27 15. 1.4 10-Apr-81 HW-2B 8 1.2 23-Apr— 82 HW-27 22 3 . 28-May-81 HW-2B 9.9 .1.3 26-May-82 HW-27 19 2.4 04-Jun-Bl HW-28 11. 1.4 16-Jun-B2 •f•. * *r— HW-27 27 2.5 12-Jun-81 HW-2B . 8 1.2 02-Jul-82 •HW-27 . 7.2 0.5 27-Jul-ei HW-2B 16. 0.5 16-Jul-B2

"! HW-27 8.8 1. 1 28-Jul-81 HW-28 16. 2.4 29-Jul-82 ' HW-27 7.2 0.2 12-Aug-Bl HW-2B 29 3.3 16-Aug-82 n- ' HW-27 12. 1.3 OB-Aug-82 HW-28 16 2.7 08-Sep-82 : HW-27 35 2.4 07-Oct-B2 HW-28 32 3. 5 07-Oct-B2 r^ HW-27 67 4.7 03-NOV-B2 HW-28 '49 8.7 03-Nov-82 1 ;.; HW-27 90 5.4 05-Nov-B2 HW-28 65 6.9 OB-Nov-B2 HW-27 88 5. 1 08-Nov-a2 HW-2B 70 11 15-Nov-82 " HW-27 108 5. 8 lS-Nov-82 HW-28 47 6.6 15-Nov-82 • HW-27 112 7 lB-Nov-82 HW-28 1O8 16 22-Nov-82 d- HW-27 110 0 22-NOV-B2 HW-29 280 0 22-Nov-B2 HW-27 224 0 24-NOV-82 HW-29 33 4.7 lO-Jan-33 HW-27 172 0 26-Nov-82 HW-29 22 0.4 19-Jan-83 rs HW-27 168 0 29-Nov-82 HW-29 33 6. 1 23-Jun-53 HW-27 178 9 02-Dec-S2 HW-29 44 9.9 26-Oct-B3 : HW-27 135 6.2 06-Dec-S2 HW-29 36. 8.7 ' 13-Apr— 84 HW-27 83 5.5 10-Dec-82 HW-29 39. 6.98 09-May-84 • I . n HW-27 55 4 14-Dec-S2 HW-29 36. 6.44 06-Jun-S4 , - HW-27 42 3. 5 17-Dec-82 HW-29 48. 10.4 20-Jun-84 •jj '• HW-27 45 4 2O-Dec-B2 HW-30 0.3 0.8 25-Mar-81 'I ."" HW-27 40 3 22-Dec-B2 HW-30 11 3.4 05-NOV-82 HW-27 43 3.3 27-Dec-82 HW-30 12. 2.3 12-Nov-82 HW-27 38 3. 5 30-Dec-82 HW-30 16 4 lS-Nov-82 •jf HW-27 46. 4.5 23-Jun-83 HW-30 19 0 lS-Nov-62 HW-27 63 7.7 10-Apr-84 HW-30 16 3. 3 22-Nov-B2 •_J- HW-27 58 7.24 ll-Apr-84 HW-30 14 1.9 O4-Jan-83 P - HW-28 5.2 0 27-Feb-BO HW-30 12. 0 06-Jan-S3 -t H HW-28 6.5 0 28-Feb-aO HW-30 13 2.3 11 -Jan -33 . HW-28 6.6 0 29-Feb-BO HW-30 16. 2.47 07-Jun-83 HW-28 7 0 03-Mar-BO HW-30 13. 1.9 23— Jun-83 n- HW-2B 1.8 0.5 OB-Oct-BO HW-30 16. 3.3 12-Jul-83 HW-28 1.2 0.3 09-0ct-80 HW-30 18 2.76 19-Jul-83 i." HW-28 2.4 0. 1 10-Oct-BO HW-30 19. 7.5 02-Aug-83 HW-2B 3.9 0.3 14-Oct-BO HW-30 22 3. 6 06-Sep-B3. iP •- HW-28 4.9 0.3 21-0ct-80 HW-30 23 3. 5 23-Oct-83 1 HW-28 5.4 0.7 17-Nov-BO HW-30 27 5 23-Nov-83 ,- • HW-2B 8.4 1.4 02-Jan-Bl HW-30 28 4.9 06-Dec-83 n"" '-- J-IW-28 4 0.3 27-Feb-81 HW-30 28 5.4 10- Jan -84 /••*>> .HW-28 6 0.2 03-Mar-Bl HW-30 28. 4. -88 lB-Apr-84 i HW-28 8.7 1. 1 lO-Apr-81 HW-30 19. 3. 11 09-May-54 ( HW-28 19 2.6 28-May-Bl HW-30 IB. 3. 1 06-Jun-84 I'.-- —._._. «.—•-» — "' •••*• -~i ! '

"HW-30 30. 5.12 02-Jul-B4 NH24D 14 5.4 16-Apr-82 HW-30 57 .12 23-Oct-B5 NH24D 1.7 0.3 23-Apr-82 M-l 0. 1 0.07 25-Apr- 84 NH24D 12. 0.6 29-Apr-82 M-l 0 0 31-Jul-B4 NH24D 14 0.7 30-Apr-82 M-l 1.5 0. 1 14-NOV-84 NH24D . 16 0.5 03-May-82 M-l 0 O 04-3un-B5 NH24D 15 O.7 04-May-B2 M-2 0. 1 0.18 06-Jul-83 NH24D 17 0 . 7 05-May-82 M-2 0 0.23 31-Jul-83 NH24D 17 0.7 06-May-B2 M-3 0. 1 0. 15 25-Apr— 83 NH24D 18 0.7 07-May-82 M-3 0. 1 0. 1 06-Sep-83 NH24D 18 O.B 12-May-82 M-3. 0 0.18 31-Jul-84 NH24D ' 11. 1 14-May-82 M-3 0. 1 0. 1 14-Nov-B4 NH24D 12. 1 17-May-82 . M-3 : 0 0 04-Jun-B5 NH24D 14 0.6 18-May-S2 M-4 0. 1 0.11 06-Jul-B3 NH24D 13 0.7 20-May-B2 M-4 0 0 31-Jul-84 NH24D ' 10. 0.7 . 24-May-82 M-5 0 0 31-JU1-B4 NH24D 10 0.6 : 26-May-82 M-5 0. 1 0. 1 14-Npv-84 NH24D .9.6 0.6 Ol-Jun-32 M-6 0 0 31-ji-il-B4 NH24D 11 0.7 03-Jun-B2 M-6 0 0 09-Oct-84 NH24D 11. 0.7 07-Jun-32 M-6 0. 1 0. 1 14-Nov-B4 NH24D . 10. 0.8 09-Jun-B2 NH24D 160 1.5 ll-Mar-81 NH24D 10. 0.9 14-Jun-82 NH24D 528 4. 1 20-Mar-Bl NH24D 9.9 O.B 16-Jun-82 NH24D 495 3.7 25-Mar-Bl NH24D 8.4 0.7 lB-Jun-82 NH24D 2.5 0.4 06-Jan-B2 NH24D 5.2 0.5 29-Jun-B2 NH24D 7.4 0.2 12-Jan-82 NH24D 0.9 0.3 07-Jul-82 NH24D 14 2.2 OB-Feb-82 IMH24D 4.6 0.5 13-Jul-B2 NH24D 100 3. 8 09-Feb-82 NH24D 6.3 0.8 16-Jul-82 NH2AD 7.2 0.7 10-Feb-82 NH24D 6.5 0.5 20-Jul-62 NH24D 8.2 0.6 lO-Feb-82 NH24D 4.3 1 28-Jul-32 NH24D 6.2 0.5 ll-Feb-82 NH24D 1 0.4 25-Aug-B2 NH24D 1.6 0.3 22-Feb-82 NH24D 0.5 0. 1 • 23-Sep-82 . NH24D 1.3 0. 1 22-Feb-B2 NH24D 0. 1 0.2 02-Nov-S2 NH24D 3.3 0.3 23-Feb-82 NH24D 7.5 0.9 02-NOV-82 NH24D 2.7 0.3 23-Feb-82 NH24D 92 5. 1 03-Nov-B2 NH24D 3. 1 0.6 23-Feb-82 NH24D 124 5.B 05-NOV-82 NH24D 3.9 0.6 24-Feb-B2 NH24D 136 5.4 OB-Nov-82 NH24D ' 3.4 0.3 24-Feb-B2 'NH24D 0.3 0.2 10-Jan-84 NH24D 5. 1 0.5 25-Feb-82 NH24D O.3 0.3 10-Jan-84 NH24D 9.6 0.7 26-Feb-S2 NH24D 0.2 . 0. 1 10-0 an -84 NH24D 4.8 0.3 26-Feb-B2 NH24D 0.2 0.2 10-Jan-B4 NH24D 22 O.B 01 -Mar -82 NH24D O.3 O.I lO-Jan-B4 NH24D 6.2 0.3 02-Mar-82 NH24D 0.6 0.2 . ll-Jan-B4 NH24D 8 0.3 03-Mar-82 NH24D 1.8 0.6 ll-Jan-B4 NH24D 6.2 0.3 03-Mar-S2 NH24D 1.2 0.2 12-Jan-B4 NH24D 8.2 0.3 04-Mar-82 NH24D 9.6 0.9 13-Jan-84 NH24D 6 0.7 04-Mar-82 NH24D 16 1.3 14-Jan-B4 NH24D 7.8 0.8 05-Mar-82 NH24D 19 1.6 15-Jan-34 NH24D 7 0.7 05-Mar-82 NH24D 21 1.6 16-Jan-B4 NH24D 5.8 0.4 08-Mar-82 NH24D 21 1.6 17-J5n-84 NH24D 7.8 0.4 09-Mar-B2 NH24D 13 1 17-Jan-84 NH24D 8.2 0.3 10-Mar-82 NH24D 21 1.5 lB-Jan-84 NH24D 7 0 . 3 ll-Mar-B2 NH24D 23 1.6 19-Jan-84 5.5 0.4 17-Mar-82 NH24D 19 1.6 20- Jan -84 '.NH24D 6 O.5 19-Mar-62 NH24D 24 1-. B 21-Jan-B4 NH24D 41 1.7 30-Mar— 32 NH24D 25 1.9 22-Jan-84 NH24D 32 1.2 Ol-Apr-82 NH24D 27 2. 1 23-Jan-B4 NH24D 27 2. 1 24-Jan-84 NH24D . 19. 1.94 13-NOV-84 NH24D 28 2.2 25-Jan-B4 NH24D 24. 2.71 26-NOV-84 NH24D 29 2.2 28-Jan-84 NH24D 25. 2.85 03-Dec-S4 NH24D 30 2.3 30-Jan-B4 NH24D 22. 2.42 10-Dec-B4 NH24D 35 2.7 01-Feb-B4 NH24D 12. 1.6 24-Jan-85 NH24D 32 2.5 04-Feb-B4 NH24D 24. 2.37 ll-Feb-B5 NH24D 35 2.8 06-Feb-84 NH24D . 42 4.5 29-May-85 NH24D 36. 3 09-Feb-B4 NH24D 28 3.8 05-Jun-B5 NH24D 35. 2.97 ll-Feb-84 NH24D 20 2.8 18-Jun-85 NH24D 34.. 2.96 13-Feb-B4 NH24D 23 3.2 25-Jun-B5 NH24D 36. 3.1 16-Feb-84 NH43A O.B 1.9 22-NOV-83 NH24D 32. 2.89 lB-Feb-84 NH43A 0.6 1.56 16-Feb-S4 NH24D 31. 2.8 21-Feb-84 NH43A 0.8 3.5 29-May-84 NH24D 30. 2.7 23-Feb-84 NH43A 1.7 4.6 31-Jul-B5 NH24D 35. 2.95 25-Feb-84 NH43A 1.4 4.2 13-Aua-85 NH24D 36 3.32 27-Feb-B4 NH43A 1.7 4. 1 05-5ep-85 NH24D 3B. 3.67 02-Mar-84 NH43A 2.5 5.8 Ol-Oct-85 NH24D 37. 3.47 05-Mar- 84 NH43A 1.6 3.7 OS-Nov-85 NH24D 14. 1 . 33 06-Mar-84 NH43A 1.6 3.2 OS-Nov-85 NH24D 14. 1.37 06-Mar- 84 NH43A 1.4 3.3 ll-Dec-85 NH24D 16 1.56 07-Mar- 84 NH43A 5.4 1-4 03- Jan -86 NH24D 75. 1.36 07-Mar-84 NH43A O. 1 3. 1 O8-Jan-86 NH24D 15. 1.43 OS-Mai— 84 NH43A 1.6 3.7 23-Jan-86 NH24D 15. 1.4 09-Mar-B4 NH43A 1.5 3.7 04-Feb-86 NH24D 12. 1.26 12-Mar- 84 NH43A 1.3 3.5 04-Mar-86 '[; NH24D 12. 1. 18 13-Mar-84 NH43A 1.2 2.6 03-Apt— 86 NH24D 11. 1.2 19-Mar-84 NH-10 255 0.9 25-Mar-ai NH24D 12. 1.26 26-Mar- 84 NH-10 360 0.6 Ol-Apr-81 NH24D 10. 1.23 02-Apr-84 NH-10 288 0.8 Ol-Apr-31 NH24D 9.8 1 .09 16-Apr-84 NH-10 270 02-Jun-Bl NH24D 9.6 1.06 16-Apr-84 NH-10 300 02-Jun-81 NH24D 10. 1.2 30-Apr— 84 NH-10 320 02- J un -81 NH24D 10. 1.24 14-May-84 NH-10 230 02-Jun-81 NH24D 16. 1.84 29-May-84 NH-10 296 04-Jun-Bl NH24D 25. 2.9 ll-Jun-84 NH-10 330 04-Jun-81 NH24D 9.9 1.23 18-Jun-B4 NH-10 101 11 02-Jul-85 NH24D 10. 1.34 25-Jun-84 NH-10 214 26 02-Jul-85 NH24D 9.4 1 . 07 02-Jul-64 NH-1O 82 9. 1 02-Jul-B5 NH24D 9.B 1. 16 07-jLil-84 NH-11 ' 6 21 -Jan -80 NH24D 9.4 1.01 16-Jul-84 NH-11 14 22- Jan -60 NH24D 10. 1. 13 23- Ju 1-84 NH-11 9 25-Jan-8O NH24D 9.7 1. 14 30- Ju 1-84 NH-11 43 0. 1 21-0ct-80 NH24D 9.9 0.94 06-Aug-84 NH-11 44 0. 1 22-Oct-80 NH24D 11. 1.27 13-Aug-B4 NH-11 47 0. 1 23-Oct-80 NH24D 10 2 13-Aug-84 NH-11 34 0. 1 24-Oct-8O NH24D 7.9 0.88 20-Aug-B4 NH-11 34 0. 18 28-Oct-BO NH24D 13. 1.3 27-Aua-84 NH-11 216 1.3 ll-May-81 NH24D 8.5 0.7 04-Sep-B4 NH-11 192 1.2 ll-May-81 : NH24D 14. 1.61 . 10-Sep-84 NH-11 624 3.8 ll-May-81 n NH24D 13. 1.43 17-Sep-84 NH-11 276 1.7 11-May-Bl NH24D 15 1.57 24-3ep-S4 NH-11 204 1.2 11 -May-Si NH24D 14. 1.6 Ol-Oct-84 NH-11 29 0.4 04- J un -81 ^NH24D 14. 1.63 lS-Oct-84 NH-11 105 0.9 10-Aug-81 :.NH24D 17. 1.82 22-Oct-B4 NH-11 92 0.8 11-Aup-Bl r-> NH24D 15. 1.74 29-Oct-84 NH-11 83 0.7 12-Aug-81 NH24D 14. 1.35 06-NOV-B4 NH-11 53 0. 1 17-Aug-Bl .1* rV NH-11 45 0.8 24-Aug-81 NH-16 1.3 0.8 O3-Jul-85 i -v NH-11 55 0.. 8 26-Aug-Bl NH-17 2 0 24-Jan-BO i NH-11 32 0. 1 31-Aug-81 NH-17 0.3 0.2 05-Aug-BO r NH- 1 1 110 0.6 27-Aug-B5 NH-17 2 2 06-Aug-80 1 NH-11 72 0.5 29-Aug-85 NH-17 2 2 07-Aug-80 NH-11 68 0.5 03-Sep-85 NH-17 2 2 OB-Aug-80 NH-11 51 0.5 12-Sep-85 NH-17 0.2 0.3 07-May-81 NH-11 59 0.5 Ol-Oct-85 NH-17 0. 1 0.2 23-Jul-81 NH-13 9 28- Jan -80 NH-17 0.6 0.7 08-Feb-82 NH-13 7 B 30-Jan-BO NH-17 0.5 0.5 28-Jul-82 NH-13 64 18-May-Bl NH-17 O.B 0.3 26-Jan-33 r NH-13 69 11 19-May-81 NH-17 0.2 0.26 14-Feb-84 NH-13 .- 54 6.3 22-May-Bl NH-17 8.3 2.1 04-Feb-B6 ' NH-13 315 4.8 14-May-B5 NH-1B 2 O 25- Jan -80 NH-14 2.5 0 17- Jan -BO NH-18 2.7 0.8 14-Aug-80 r NH-14 4 2 21-Jul-BO NH-1B l.B 0.3 18-Aug-80 NH-14 4.6 0.7. 05-Aug-BO NH-1B 1.8 0.3 19-Aug-SO ; p NH-14 4 .1 2 06-Aug-BO NH-1B 1.3 0.3 21-Aug-BO i NH-14 5. 3 2 07-Aug-80 NH-1B 1 0.6 06-0ct-80 NH-14 4.8 2 OB-Aug-BO NH-1B • O.I 0.2 23-Jul-Bl NH-14 4.7 0.2 06-0ct-80 NH-1B 1.6 1.8 08-Feb-S2 ^ NH-14 8.2 0.2 13-Mar-Bl NH-1B 2.2 1.6 02-Auq-82 r NH-14 10. 2.5 15-Jun-Bl NH-18 1.6 1.2 20-Aug-B2 NH-14 21 2.4 15-Jun-81 NH-1B 1.6 1. 1 pjr* 1 l-Jan-83 r NH-14 23. 1.6 14-Jul-Sl NH-18 2.5 1. 1 24-May-33 l NH-14 10. 1 15-Jul-81 NH-18 3. 1 1. 1 07-Sep-63 1 NH-14 10. 0.8 16-Jul-81 NH-18 4.3 1.27 14-Feb-S4 r ^ MH-34 6.9 0.3 21-Jul-Bl NH-18 4 2 25-Sep-B4 [ ' NH-14 7.8 1 31-Aug-81 NH-18 4. 1 2.02 06-Dec-84 NH-14 8.8 0.8 18-Sep-Bl NH-18 4.7 2.42 18-Dec-B4 J," NH-14 8.7 0. 1 OB-Oct-Bl NH-18 6.9 3.43 . 14-Jan-85 p NH-14 22 0.2 21-Oct-Bl NH-18 7.5 3. 1 30-Apr — 85 1 " NH-14 36 0.5 25-Nov-Bl NH-18 5.8 2.7 22-May-65 1I NH-14 44. 0.91 28-Jan-B5 NH-1B 6.5 3.2 05-Jun-85 r NH-14 62 1.4 27-Aug-B5 NH-1B 6.7 4.2 03-Jul-B5 1. NH-14 36 1.2 30-Aug-B5 NH-18 5.4 2.8 07-Aug-B5 - NH-14 36 1.1 03-Sep-85 NH-18 4.8 2.5 05-Sep-85 J,"; NH-14 42 3. 1 12-Bep-B5 NH-18 6. 3 4. 1 01-Oct-B5 1 ;_ NH-14 48 1.5 Ol-Oct-85 NH-18 5.4 3.4 04-NOV-S5 i NH-14 48 1.6 04-NOV-85 NH-18 3.7 2.6 03-Dec-85 NH-15 2 0 19-Feb-aO NH-18 3.8 3 03-Jan-B6 NH-15 1.2 0.71 23-May-BO NH-18 3. 1 3.8 04-Mar-86 r NH-15 1.7 1.41 15-Aug-34 NH-18 3.2 2.7 03-Ap»— 36 , NH-15 2.3 1.57 24-Sep-B4 NH-19 2 0 28-Jan-BO •J NH-15 10 4.4 13-Aug-B5 NH-19 3 o 21-Jul-SO fi- NH-15 • 10 4.2 20-Aua-B5 NH-19 2.6 1 05-Aug-eO i NH-15 6.8 3.2 30-Oct-85 NH-19 2 2 06-Aug-8O j;< NH-15 10 4 15-NDV-B5 NH-19 4 2 07-Aug-80 fI". NH-16 2 0 19-Feb-80 NH-19 3 2 08-Aug-SO !! NH-16 2 2 22- J LI 1-80 NH-19 4 2.9 oi-Jui-ei NH-16 0. 1 0. 1 04-Jun-81 NH-19 5. 1 1 23- J LI 1-51 HL NH-16 0.5 0. 1 23-Jul-Bl NH-19 11 2.3 OB-Feb-82 [i 'r • NH-16 0.5 0.3 21-Oct-Bl NH-19 8.6 1.4 18-May-S2 L "'K/H-16 6. 3 1.5 08-Feb-82 NH-19 7.4 1.6 lB-Jun-B2 \^ ' NH-16 1.3 0.53 1 8- J un -84 NH-19 26 2.3 16-Jul-32 I NH-16 0.4 0.27 25-Jun-B4 NH-19 16 2.2 23-Jul-B2 NH-19 17 2.7 28-JU1-82 NH-20 5.7 ' 1.5 OB-Feb-82 NH-19 18 2.2 Ol-Sep-82 NH-20 16 1.5 19-Mar-B2 NH-19 45 3.2 18-Oct-82 NH-20 24 1.7 lS-Dct-82 NH-19 62 5.2 04-Nov-82 NH-20 8.9 O.6 ll-Jan-63 NH-19 54 3.2 OB-Nov-82 NH-20 6.2 0.6 24-May-83 NH-19 45 4.7 30-NOV-82 NH-20 6.6 0.6 08-Aug-B3 NH-19 31 2.5 19-Apr- S3 NH-20 21 1 25-Oct-83 NH-19 35 3.2 27-Apr- 84 NH-20 4.7 0.6 31-Oct-83 NH-19 26. 3. 11 Ol-May-84 NH-20 7 0.9 22-Nov-S3 NH-19 90 8.8 OB-Aug-B4 NH-20 2.7 0.74 14-Feb-B4 NH-19 46. 5 • lO-Aug-84 NH-20 4.5 0.8 05-Mar-64 NH-19 39 4.3 13-AUQ-84 NH-20 7.B 1.07 Ol-May-84 NH-19 35. 3. 83 21-Aug-84 NH-20 14. 1.64 04-Jun-S4 NH-19 Ill 8. 1 29-Aug-B5 NH-20 14. 1.4 ll-Jun-B4 NH-19 73 5. 3 03-Sep-e5 NH-20 19. 1.72 25-Jun-84 NH-19 86 11 12-Sep-B5 NH-20 19. 1.52 02-Ju1-84 NH-19 60 4.8 02-Oct-85 NH-20 22. 1.67 08-Aug-84 NH-2 ' 2 3 2S-Jan-60 NH-20 21. 1 . 35 14-Sep-84 NH-2 2 2 21-Jul-8O NH-20 23. 1.66 02-Oct-84 NH-2 2 • 2 06-Aug-BO NH-20 12. 1.47 14-Jan-B5 NH-2 2 2 07-Aug-80 NH-20 11 1. 1 lB-Jun-85 NH-2 2 2 OB-Aug-80 NH-20 .38 1.9 03-JLil-B5 NH-2 2. 1 3 07-May-81 NH-20 35 2. 1 07-Aug-S5 NH-2 1.2 1.8 21.-Jc.il -81. NH-20 53 2.3 03-Sep-85 NH-2 0.7 1.7 31-Aug-Sl NH-20 77 7.3 12-Sep-85 NH-2 1 ' 2.2 21-0ct-81 NH-20 60 2.3 02-Oct-85 NH-2 1 1.4 19-Mar-82 NH-21 1.5 0 25-Jah-8O NH-2 2.2 1.6 29-Jun-82 NH-21 22 1.6 05-Aug-80 NH-2 0.9 1.2 ll-Jan-83 NH-21 31 1.6 07-Aug-aO NH-2 2.5 2.2 19-Oct-83 NH-21 26 1.2 OS-Aug-60 NH-2 2.5 2.53 13-Feb-84 NH-21 24 1.2 12-Aug-SO NH-2 3.6 3 . 38 05-Mar-84 NH-21 31 1.5 13-Aug-80 NH-2 6.2 4.43 30-Jul-84 NH-21 36 2 06-Qct~80 NH-2 7.3 4.87 07-Aug-84 NH-21 142 3.6 27-Jul-81 NH-2 3.9 4. 17 17-Sep-84 NH-21 73. 2.4 2B-Jul-81 NH-2 3.0 2.2 Ol-Oct-84 NH-21 86 1.9 29-Jul-Bl NH-2 9.0 5.56 Ol-Nov-84 NH-21 32. 0.6 06-Aug-81 NH-2 8.2 5. 34 OS-Dec -84 NH-21 29 1.3 14-Aug-Bl NH-2 4.8 5.5 14-Jan-85 NH-21 5O 1.9 26-Aug-81 NH-2 8. 1 5.72 ll-Feb-B5 NH-21 32 1.3 31-Aug-Bl NH-2 2.3 2.97 30-Apr— 85 NH-21 53 0. 1 02-Sep-Bl NH-2 4.2 3.57 22-May-85 NH-21 42 2 16-Sep-Bl NH-2 6 4.7 O5-Jun-85 NH-21 41 1.7 lS-Sep-81 NH-2 10 7.5 16-Jul-B5 NH-21 2* 1.4 08-Oct-Bl NH-2 7.9 5.9 06-Aug-a5 NH-21 30 1.3 08-Det-81 NH-2 6.6 4.3 05-Bep-B5 NH-21 60 1.9 21-Oct-Bl NH-2 9.8 7.9 Ol-Oct-85 NH-21 68 1.7 O3-Dec-8l NH-2 6.6 5.6 2S-Oct-85 NH-21 80 2 14-May-85 NH-2 10 7.8 15-Nov-SS NH-22 2 O 29-Jan-8O NH-20 2 O 28-Jan-BO NH-22 0.3 0.1 17-Mar-82 NH-20 2 2 21-Jul-SO NH-22 0.6 0. 1 1l-Jan-83 NH-20 2 2 05-Aug-BO NH-22 0.8 0.09 25-May-83 f-. .NH-20 2 2 O6-Aug-80 NH-22 0.7 0.03 25-Oct~83 "KlH-20 2 2 07-Aug-80 NH-22 0.6 0.1 01-Feb-B4 NH-20 1.3 1 13-Jul-Sl NH-22 1.3 0.01 15-Jul-85 NH-20 2 0.8 23-Jul-81 NH-22 0. 1 0. 1 OS-Jan-B6 rL: NH-22 0.6 0.1 04-Feb-86 NH-24 161 15.87 22-Oct-84 NH-23 2 . 0 29-Jan-BO NH-24 126 12.99 29-Oct-84 NH-23 2 2 21-Jul-BO NH-24 167 16.02 13-Nov-84 NH-23 1.2 6.2 29-NOV-B2 NH-24 169 18.66 26-Nov-B4 NH-23 0.4 1.8 1 l-Jan-83 NH-24 189 20.88 03-Dec-34 NH-23 0.9 11 19-Oct-83 NH-24 155 16.74 10-Dec-84 NH-23 0.8 10.7 25-Oct-83 NH-24 66. 8.31 24-Jan-85 NH-24 0.5 0.1 2B-NOV-83 NH-24 96 12 29-May-B5 NH-24 0.9 0. 1 lO-Jan-84 NH-24 105 13 05-Jun-B5 NH-24 0.9 0.2 10-Jan-84 NH-24 20 2.8 18-Jun-85 ' NH-24 0.6 0.2 10- Jan -84 NH-24 23 3.2 25-Jun-B5 NH-24 1.5 0.2 10-Jan-B4 NH-24 23 3. 6 02-Jul-85 NH-24 2.9 O.3 ll-Jan-84 NH-25 2 O 28-Jan-8O NH-24 2.7 O.3 ll-Jan-B4 NH-25 2.6 0 03-Aug-BO NH-24 2.4 0.3 ll-Jan-84 NH-25 1.6 0.1 IS-Aug-aO . NH-24 39 2.3 17-Jan-84 NH-25 1.5 0.4 19-Aug-BO NH-24 40 2.7 lS-Jan-84 NH-25 2. 1 0.3 20-Aua-aO NH-24 45 • 2.7 19-J'an-B4 NH-25 1.7 0.2 21-Aug-80 NH-24 45 2.9 24-Jan-84 NH-25 2.6 0. 1 04-Jun-81 NH-24 51 3.4 25-Jan-B4 NH-25 0.9 0.4 30-Jul-81 NH-24 66 5.6 02-Mar- 84 NH-25 1.6 0. 1 28-Jul-82 NH-24 64. 5.91 .' 05-Mar- 64 NH-25 1.4 0. 1 . ll-Nov-83 rf NH-24 62. 5.73 06-Mar- 84 NH-25 0.9 0.14 13-Feb-84 NH-24 70. 6.51 07-Mar-B4 NH-25 0.4 0.3 30-Jul-64 NH-24 73. 7.3 OS-Mar- 84 NH-25 1.6 0.2 31-Jul-85 if NH-24 68. 6.41 09-Mar- 84 NH-25 1.5 0.4 28-Jan-86 NH-24 61. 5.82 12-Mar- 84 NH-26 2 O 29-Jan-80 NH-24 67. 6.44 13-Mar- 84 NH-26 2 2 21-Jul-BO. NH-24 72. 7.14 13-Mar -84 NH-26 2.7 0. 1 lO-Apr-81 t* NH-24 63. 6.64 19-Mar-B4 NH-26 0.5 0. 1 02-Sep-Bl NH-24 59. 6.39 26-Mar-84 NH-26 O.6 0. 1 . 17-Mar-82 NH-24 61. 6.47 02- Apr — 84 NH-26 2. 1 0.6 28-Jul-S2 if NH-24 59. 6. 53 16-Api— 84 NH-26 0.8 0. 1 17-Dec-82 NH-24 59. 6.78 30-Apr— 84 NH-26 1.4 0.2 10-Jan-83 NH-24 ' 54. 5.97 14-May-B4 NH-26 1.4 0.2 1 l-Jan-83 NH-24 64. 7. 18 29-May-B4 NH-26 2.3 2.34 13-Feb-B4 NH-24 62. 6.9 ll-Jun-84 NH-26 2.1 2.34 16-Feb-84 NH-24 65. 8.3 18-Jun-B4 NH-26 1.7 3. 17 25-Sep-64 NH-24 69. 8.86 25-Jun-84 NH-26 2. 1 1.9 Ol-May-B5 NH-24 65 6.B 02-Jul-B4 NH-26 2. 1 1.6 OS-Nov-85 NH-24 74. 8 09- Ju 1-84 NH-26 1. 1 1.3 20-Feb-86 NH-24 66. 6. 68 16-Jul-84 NH-27 2 23-Jan-80 NH-24 63. 5.65 23-Jul-84 NH-27 4.8 1. 1 21-Jul-aO NH-24 B3. 7.98 30-Jul-B4 NH-27 7 1.6 05-Aug-BO NH-24 96. 8.84 06-Aug-B4 NH-27 4.6 1.3 06-Aug-8O NH-24 B8. 9.9 13-Aug-B4 NH-27 9.5 1.7 O7-Aug-BO NH-24 87 3. 3 13-Aug-B4 NH-27 9 0.9 08-Aug-8O NH-24 84; 8.7 20-Aug-B4 NH-27 10. 1.6 25-Aug-BO NH-24 94. 9.96 27-Aug-84 NH-27 03-Oct-SO NH-24 64. 9 04-Sep-B4 NH-27 0. 1 0. 1 04-Bec-SO NH-24 115 10.81 lO-Sep-S4 NH-27 0.2 0. 1 07- Jan -81 NH-24 129 10.71 17-Sep-B4 NH-27 5.4 0/2 21-Jan-81 NH-24 91. 11.16 24-Sep-84 NH-27 2.2 0.2 O3-Feb-81 r *" NH-24 174 11.52 01-Oct-B4 NH-27 13 0.6 ll-Mar-81 / NH-24 125 1 1 . 73 09-Oct-84 NH-27 12. 1 20-Apr-ai l NH-24 140 11.4 15-Oct-B4 NH-27 25 3.2 15-Jun-Bl .(!•'. NH-27 45 3.2 15-Jun-Sl NH-29 22 0.4 19-Jan-83 NH-27 36 4.5 21-Jul-Bl NH-30 2 25-Jan-80 r i— NH-27 28. 1 23-Jul-81 NH-30 2 2 21-Jul-80 I :.: NH-27 11 0.1 12-Aug-Bl NH-30 02-Oct-BO A ! '. NH-27 .8.1 1. 1 31-Aug-Bl NH-30 0.5 0.6 04-Jun-81 NH-27 12 0.1 02-Sep-Bl NH-30 0.6 0. 1 21-Jul-Bl P" NH-27 0.9 0. 1 OB-Oct-ai NH-30 0.1 0.2 31-Aua-81 i !., NH-27 1 0. 1 OB-Oct-81 NH-30 0.4 0.8 17-Mar-B2 NH-27 O.B 0. 1 25-Nov-ai NH-30 O.5 1 28-Jul-82 — NH-27 3.6 0.2 19-Mar-B2 NH-30 O.6 0.5 19-Jan-B3 NH-27 8.8 1.4 lB-Oct-82 NH-30 0.3 0.58 24-May-83 n.. NH-27 0.4 0. 1 23-NOV-82 NH-30 0.3 0.4 17-Oct-83 NH-27 1.2 0. 1 ll-Jan-B3 NH-30 0.2 0.5 06-Feb-84 NH-27 1.7 0.24 24-May-83 NH-30 0:5 O.43 24-Sep-84 11H": NH-27 0.8 0.07 09-Jun-83 NH-30 0.2 • 0.2 Ol-May-85 NH-27 8.5 0.51 04-Aug-B3 .NH-30 0.2 0.2 13-Aug-85 --. NH-27 0. 1 0. 1 25-Oct-83 NH-30 1.8 2. 1 28-Jan-86 ' NH-27 9.9 0.3 31-Oct-B3 NH-31 3 29-Jan-BO n-" 12 0.5 22-Nov-83 NH-27 NH-31 2.0 0.26 OS-Mar -80 NH-27 10 0.9 2B-NOV-83 NH-31 24 3.9 23-Jul-BO \ NH-27 11 0.5 06-Dec-83 NH-31 13 2 05-Aug-8O n• • NH-27 30 0.9 27-Apr-B4 NH-31 11 2.6 06-Aug-BO NH-27 30 1.44 Ol-May-84 NH-31 13 1.8 07-Aug-BO NH-27 40. 2 21-Aug-84 NH-31 12 1.6 OB-Aug-80 ft.NH-27 0. 1 0.03 19-Dec-B4 NH-31 4.9 0.8 03-Oct-BO NH-27 0. 1 0.06 19-Dec-84 NH-31 l.B 0.2 04-Dec-BO " NH-27 0.1 O.03 19-Dec-S4 NH-31 13. 0.7 27-Feb-Bl •> NH-27 44 1.8 27-Aug-B5 NH-31 12 0.6 03-Mar-Bl r NH-27 23 1. 1 29-Aug-85 NH-31 48. 2.7 14-Jul-81 NH-27 20 0.9 03-Sep-85 NH-31 2. 1 0.2 02-Dec-Bl NH-27 16 O.B Ol-Oct-85 NH-31 37. 2.9 19-Mar— 82 tfNH-27 7.4 0.5 04-Nov-BS NH-31 14 0.9 26-May-B3 : : NH-27 5 0.3 03-Dec-85 NH-31 12 0.7 21-Sep-83 f-j' NH-27 6.6 0.5 07-Jan-B6 NH-31 1.5 0. 17 06-Mar- 64 NH-2B 7 22-Jan-BO NH-31 1.8 0.21 07-Mar-34 P-* .-— NH-2B 9 30-Jan-BO NH-31 2.5 0.29 09-Mar-84 NH-28 44 0.8 02-Oct-8O NH-31 3. 7 0.35 12-Mar-84 NH-28 48 0.7 03-Oct-BO NH-31 4.3 0.37 13-Mar-B4 rt- NH-28 46 0.5 oa-oct-ao NH-31 5.5 0.53 19-Mar-B4 NH-2B 38. 0.2 14-Oct-BO NH-31 6.4 0.56 26-Mar-B4 . NH-28 48 15-oct-ao NH-31 6.6 0.59 02-Apr-34 . NH-2B 4 0.3 27-Feb-81 NH-31 6. 1 0.57 16-Apr-84 n NH-28 194 1.7 14-Jul-Bl NH-31 6.3 0.6 16-Apr-84 ,- NH-28 126 0.5 15-Jul-Bl NH-31 19. 1.3 30-Apt— B4 n NH-28 83 0.7 16-Jul-81 NH-31 12. 0.99 Ol-May-84 i ."'"' NH-2B 0.9 0. 1 07-Dec-Bl NH-31 16. 1. 1 04-May-64 NH-28 235 1.5 25-Aug-82 NH-31 17. 1. 19 14-May-34 •j NH-29 7 28-Jan-BO NH-31 18. 1.25 22-May-B4 1 L NH-29 5 30- Jan -SO 1 NH-31 17. 1.26 29-May-84 NH-29 5. 1 2 2B-Apr-81 NH-31 16. 1.49 04-Jun-B4 J. • NH-29 28 29-Apr-81 NH-31 17. 1.2 ll-Jun-84 NH-29 26 2 30-Apr— 81 i P NH-31 17. 1.22 18-Jun-84 ftL -7 • >NH-29 27. 1.8 06-May-Bl NH-31 17. 1.32 25-Jun-84 r ^; •NH-29 2 0. 1 07-Dec-Bl NH-31 IB 1.-23 02-Jul-B4 NH-29 32 2.6 06-Aug-82 NH-31 19. 1.36 09-Jul-84 ;/ _ ( > NH-29 16 1.9 20-Oct-B2 NH-31 16. 1.07 .16-JLI1-B4 NH-31 17. 1.21 23-JU1-B4 NH-34 0.3 1. 1 16-Jul-85 ts NH-31 8.6 OrB3 30-JU1-84 NH-34 0.9 1.7 23-Jan-86 NH-31 9.6 0.7 06-Aug-84 NH-35 2 0 25-Jan-BO NH-31 7.4 1 13-Aug-84 NH-35 2 0 29-Jan-BO NH-31 8.2 0.67 20-Aug-S4 NH-35 2 3 21-Jul-ao NH-31 8.7 0.64 27-Aug-B4 NH-35 2 2 05-Aug-80 NH-31 8.8 0.97 lO-Sep-84 NH-35 . 2 2 06-Aug-SO NH-31 8.5 0.86 15-Sep-84 NH-35 2 2 07-Aug-80 NH-31 7.7 0.71 17-Sep-B4 NH-35 0 0 06-Oct-aO NH-31 7.7 0.72 24-Sep-B4 NH-35 0.9 O.7 13-Jul-Bl NH-31 8.6 0.8 01 -Get -84 NH-35 3.3 0.3 23-Jul-81 NH-31 7.9 0.77 09-Oct-84. NH-35 3.9 0.8 21-Oct-Bl NH-31 8.5 0.67 22-Oct-84' NH-35 11 •O.B 24-Feb-82 NH-31 7.5 0.64 29-Oct-84 NH-35 17 1.1 19-Mar-82 NH-31 9.6 0.85 Ol-Nov-84 NH-35 ' 2 1.5 lB-Oct-82 NH-31 11. 0.78 06-Nov-84 NH-35 0.4 0.5 1 l-Jan-B3 NH-31 9. 1 0.71 13-Nov-84 NH-35 .0.4 0.6 05-Aug-83 NH-31 9.8 0.79 26-Nov-84 NH-35 • 1. 1 0.5 17-Oct-B3 ft NH-31 9.5 0.84 03-Dec-84 NH-35 1.7 • 0.6 22-Nov-83 NH-31 9.0 0.79 04-Dec-84 NH-35 0.3 0.58 14-Feb-B4 NH-31 9.4 0.72 10-Dec-84 NH-35 1O. 1.34 25-Sep-84 n~ NH-31 9.6 0.77 12-Dec-84 NH-35 11. 1.46 02-Dct-B4 NH-31 6.9 0.5B 24-Jan-85 NH-35 26. 1.63 •14-Nov-84 NH-31 9.7 0.68 ll-Feb-85 NH-35 6.3 1. 16 24-Jan-85 NH-31 4.9 0.4 30-Api— 85 NH-35 0.7 0. 1 ll-Feb-B5 NH-31 6. 1 0.4 22-May-85 NH-35 9 1.2 29-May-85 : NH-31 7 0.6 05-Jun-85 NH-35 11 1.4 ll-Jun-85 NH-32 2 29-Jan-BO NH-35 10 1.2 03-Jul-B5 NH-32 0.4 0.4 13-Aug-SO NH-35 14 1.3 07-Aug-a5 NH-32 06-0ct-80 NH-35 19 1.4 03-8ep-85 NH-32 0. 1 0. 1 21-0ct-81 NH-35 17 1.4 13-Sep-a5 .[T NH-32 0. 1 0. 1 17-Dec-B2 NH-35 22 1.8 02-Oct-85 NH-32 0. 1 0. 1 1 l-Jan-83 NH-35 - 34 1.8 04-Nov-85 . NH-32 0. 1 ' 0. 1 13-Feb-84 NH-36 2 2 22-Jul-SO NH-32 0. 1 0. 1 ll-Feb-B5 NH-36 0 0 08-0ct-80 ft NH-32 0.6 0. 1 15-Nov-BS NH-36 0. 1 0. 1 10-Apr-Bl NH-33 0.2 29- Jan -80 NH-36 0.3 0.3 19-Mar-B2 NH-33 0.4 0.2 14-Aug-BO NH-36 1.3 0.9 28-Jul-B2 f, NH-33 OB-Oct-8O NH-36 ' ' 0.4 0. 1 ll-Jan-83 NH-33 0. 1 0. 1 14-Jul-Bl NH-36 0. 1 0. 1 07-Feb-84 NH-33 0.2 0.2 17-Mar- 82 NH-36 0.3 0.09 10- Apr -85 NH-33 0. 1 0. 1 02-Aug-B2 NH-36 1.3 0.2 20-Aug-65 ft NH-33 0. 1 0. 1 1 l-Jan-B3 NH-36 1. 1 0.4 20-Feb-86 NH-33 0. 1 0. 1 ll-Apr-83 NH-37 2 0 29-Jan-80 NH-33 0. 1 0. 17 Ol-Aug-83 NH-37 0 o 14-Aug-80 ft NH-33 0. 1 0. 1 O6-Feb-B4 NH-37 26-Sep-60 ' NH-34 2 28-Jan-80 NH-37 0. 1 0. 1 07-May-ai NH-34 1 1.2 07-May-80 NH-37 4.8 1.2 19-Mar-82 NH-34 2 2 21-Jul-aO NH-37 0.7 1.1 28-Jul-32. tf NH-34 26-Sep-80 NH-37 0.2 0. 1 1 l-Jan-B3 NH-34 0.2 0.5 15-Jul-Bl NH-37 0.2 0. 185 13-Jul-63 NH-34 1 0.9 19-Mar-82 NH-37 0. 1 0.16 19-Oct-83 '- ?-NH-34 1.4 1.5 28-Jul-82 NH-37 0.2 0.17 03-Nov-83 NH-34 1. 1 0.6 1 l-Jan-83 NH-37 0.1 0.-21 09-Feb-84 NH-34 0.2 0. 19 07-Feb-84 NH-37 1. 1 2.8 16-Jul-B5 NH-34 0.2 0.42 29-May-84 NH-37 1. 1 0.28 16-Jul-B5 f NH-37 1.3 3. 6 23-Jan-86 NH-39 7.0 0. 1 Ol-May-84 NH-38 3.6 - 0 OB-Feb-80 NH-39 7.4 0.51 04-Jun-84 NH-38 4.9 0 13-Feb-80 NH-39 9.0 0. 15 03-Jul-B4 NH-3B 4.2 0 14-Feb-80 NH-39 10. 09-Jul-B4 NH-38 4.4 0.4 21-Jul-SO NH-39 10. 0. 17 16-Jul-a4 NH-38 0.5 0.2 05-Aug-BO NH-39 16. 07-Aug-84 NH-38 4.4 0 06-Aug-SO NH-39 10. 0. 14 14-Sep-84 NH-38 6. .5 0 07-Aug-BO NH-39 11. 02-Oct-B4 NH-38 5.9 . 0 OS-Aug-80 NH-39 12. 0. 16 06-Nov-84 NH-3B 0 0 25-Aua-BO NH-39 0.5 0.04 lB-Dec-84 NH-38 5.2 0. 1 13-Mar- SI NH-39 7.8 0. 16 14-Jan-35 NH-38 8.8 0. 1 20-Apr-Bl NH-39 6.1 0.06 20-Feb-B5 NH-38 8 0.2 15-Jun-Bl NH-39 7.3 0.1 10- Apr -85 NH-3B 7.2 0. 1 21-Jul-Bl NH-39 9 0.1 Ol-May-85 NH-38 27 0. 1 29-Jan-B2 NH-39 15 0.2 04-Jun-35 NH-38 4.6 0. 1 09-Mar-82 NH-39 16 0.2 03-Jul-B5 NH-38 18. 0. 1 lO-Mar-82 NH-39 15 0. 1 05-Sep-85 NH-38 19 0.5 19-Mar-82 NH-39 18 0. 1 Ol-Oct-85 NH-38 19. 0.5 16-Jul-82 NH-39 21 0.2 OA-Nov-95 NH-38 43 0.5 28-Jul-82 NH-39 11 0. 1 06-ALIQ-B6 NH-38 40 0.5 06-Aug-82 NH-4. 2 0. 1 29-Jan-80 NH-38 46 0. 1 25-Aug-B2 NH-4 0. 1 0. 1 08-Oct-Bl NH-38 32 0.3 27-Aug-S2 NH-4 . 0. 1 0.1 19-Mar-B2 NH-38 29 0.2 27-Aug-82 NH-4 0. 1 0. 1 ll-Jan-B3 NH-38 32 0.9 18-Oct-B2 NH-4 0. 1 0. 1 ll-Apr-33 NH-38 12 0. 1 19-Jan-B3 NH-4 0. 1 O.OB 19-Jul-B3 NH-38 09-May-84 NH-4 0. 1 0. 1 28-Nov-83 NH-38 14. 0. 14 lB-Jun-B4 NH-4 .0.2 0.06 13-Feb-84 NH-38 18. 0.28 03-Jul-84 NH-4 0. 1 0. 1 OS-Dec-84- NH-38 22. 0.23 09-Jul-B4 NH-4 0. 1 0. 1 13-Aug-B5 NH-38 21. 0.38 16-Jul-84 NH-40 2 0 28- Jan -SO It NH-3B 31. 0.38 07-Aug-84 NH-40 1 0 13-Aug-80 NH-38 29. 0.54 14-Sep-84 NH-40 0 o 08-Oct-BO NH-38 32. 0.42 02-Oct-84 NH-40 4.3 0. 1 13-Mar-81 NH-38 7.4 0. 1 22-May-85 NH-40 • 3.7 0. 1 lO-Apr-81 NH-38 . 22 0.3 05-Jun-B5 NH-40 5.2 0.2 15-Jun-81 NH-38 34 0.5 03-Jul-85 NH-40 2.3 0. 1 21-Jul-Bl NH-3B 40 0.5 06-Aug-85 NH-40 12 0.3 29-Jan-82 NH-38 37 0.5 05-Sep-85 NH-40 25. 0. 1 09-Mar-S2 NH-38 53' O.B 01-Oct-B5 NH-40 24. 0. 1 10-Mar-B2 NH-39 2 0 28-Jan-aO NH-40 30. 0.4 30-Mar-82 NH-39 4 2 21-Jul-BO NH-40 1.9 0. 1 29-Apr-82 ft NH-39 3.9 0.3 05-Aug-aO NH-40 21. 0.3 16-Jul-82 NH-39 3 2 06-Aug-8O NH-40 91 O.4 2S-Jul-B2 NH-39 4.3 2 07-Aug-BO NH-41 4 0 28-Jan-SO [t NH-39 3.8 2 OB-Aug-80 NH-41 14 0 OB-Feb-80 NH-39 4.7 0.4 06-0ct-80 NH-41 10 0 13-Feb-SO NH-39 11. 0. 1 13-Mar-Sl NH-4 1 13. 0 15-Feb-BO NH-39 36 0.6 1 5- J un -81 NH-41 1.5 0. 1 16-0ct-80 NH-39 59. 0.6 15-Jun-81 NH-41 3.6 0. 1 22-Oct-80 NH-39 13 0.2 13-JLil-81 NH-41 5 O 23-Oct-aO NH-39 15 0 21-Jul-Bl NH-41 4.3 0.2 24-Oct-BO :~ >NH-39 5.4 0.4 2B-Apr-82 NH-41 3.8 0.2 28-Dct-80 < NH-39 6.2 0.2 29-Apr-B2 NH-41 1 0-. 3 02-Dec-BO NH-39 10. 0.7 16-Jul-82 NH-41 4. 1 0.2 10-Feb-31 [, NH-39 8.9 O. 1 27-Apr-B4 NH-41 7.2 0.4 ll-Mar-81 NH-41 0.9 0.4 Ol-Jul-81 NH-42 0.4 0.2 10-Api—81 NH-41 1.2 O. 6 13-Jul-Bl NH-42 1 0.4 06-May-81 NH-41 0.8 0.2 21-Jul-81 NH-42 1.5 0.6 15-Jun-81 NH-41 1. 1 0.2 12-Aug-Bl NH-42 0.3 0.3 13-Jul-Bl NH-41 6.4 0.4 16-Sep-81 NH-42 0.3 0. 1 21-Jul-ai NH-4 1 11 0. 1 08-0ct-81 NH-42 0.1 0. 1 • 12-Aug-Bl NH-41 31 0.5 05-Nov-Sl NH-42 1.2 0.4 16-Sep-81 NH-41 13 0.4 14-Nov-Bl NH-42 0.4 0.8 OB-Oct-81 IT: NH-41 1.3 0.4 29-Jan-82 NH-42 1.5 0.6 OS-Nov-81 NH-41 5.2 0.2 02-Mar-B2 NH-42 . 1 0. 1 14-Dec-Bl NH-41 10. 0.3 03-Mar- 82 NH-42 0.5 0.3 01-Mar.-82 ft NH-41 9 0.3 03-Mar-B2 NH-42 0.3 0.3 O2-Mar-82 NH-41 13. 0.3 04-Mai — 82 NH-42 0.5 0.3 03-Mar—82 NH-41 . 13. 0.4 05-Mar-B2 NH-42 0.5 0.2 03-Mar-82 NH-41 20 0.2 OS-Mar- 82 NH-42 O.S 0.1 04-Mar-82 NH-41 21 0.6 09-Mar-B2 NH-42 0.5 0.2 05-Mar-82 NH-41 21. 0. 1 10-Mar- 82 NH-42 0.7 0.2 08-Mar-82 NH-41 15. 0.6 16-Jul-B2 NH-42 1.4 0.5 29-Apr-82 r:. NH-41 20. 1.2 28-Jul-82 NH-42 1.7 0.3 lS-May-82 NH-41 25 0. 1 06-Aug-B2 NH-42 3 0.4 18-Jun-82 NH-41 39 0.9 25-Aug-S2 NH-42 3.5 0.3 28-Jul-82 NH-41 22 0.4 27-Aug-82 NH-42 2.4 1 25-Aug-82 NH-41 21 0.3 27-Aug-B2 NH-42 '2.3 1.5 lB-Oct-82 NH-41 .40 1 18-Oct-B2 NH-42 3 1 03-Nov-B2 NH-41 20 0. 1 18-Jan-83 NH-42 1.6 0.3 1l-Jan-83 NH-41 1.6 0.2 31-Oct-83 NH-42 0.4 0.28 25-May-B3 NH-41 1.2 0.29 05-Mar-84 NH-42 0.5 0.32 19-Jul-83 NH-4 1 2.3 0.37 03-Apr- 84 NH-42 0.7 0.42 01-Aug-B3 NH-41 3 . 0 0.28 07-May-84 NH-42 0.4 0.35 28-Feb-84 NH-41 4.6 0.67 04-Jun-84 NH-42 1. 1 0.72 01-May-B4 NH-41 2.7 0.32 03-Jul-S4 NH-42 1.2 0.7 17-Jul-85 NH-41 4.6 0.51 07-Aug-84 NH-42 1.2 0.4 O7-Jan-86 NH-41 4. 1 0.59 21-Aug-84 NH-44 0.2 0. 1 30-Api—84 NH-41 3.9 0.54 14-5ep-B4 NH-44 0.7 0.3 05-Nov-84 NH-41 5.1 0.83 02-Dct-84 NH-44 0.6 0.2 lS-Nov-85 NH-41 13. 0.52 15-Nov-84 NH-45 0 0.5 07-Mar-86 NH-41 9.5 0.59 14-Jan-85 NH-45 0 0.6 13-Mar—86 NH-41 7.3 0.29 25-Feb-B5 NH-5 6 0 21-Jan-BO NH-41 7.4 0.41 10-Apr-85 NH-5 2 0 22-Jan-80 NH-41 5 0.3 01-May-B5 NH-5 B 0 25-Jan-BC> NH-41 6. 1 0.5 04-Jun-85 NH-5 22 1.8 03-Oct-SO NH-41 5. 3 0.4 03-Jul-B5 NH-5 33 1.9 OB-Oct-BO NH-41 5.8 0.3 06-Aug-85 NH-5 31 1.2 09-0ct-80 NH-41 8.7 0.3 05-Sep-B5 NH-5 29. 0.6 10-0ct-80 NH-41 12 0.2 18-Dec-85 NH-5 28 1.4 29-Oct-80 NH-4 1 15 0.4 03-Jan-86 NH-5 13 1.4 15-Dec-BO NH-42 0 0 29-Jan-SO NH-5 18 1.7 03-Feb-81 NH-42 4 0 21-Jul-BO NH-5 50 2.6 21-Jul-Bl NH-42 6.4 0.5 05-Aug-8O NH-5 53 3.3 22-Jul-Sl NH-42 4.5 0 06-Aug-BO NH-5 40. 3.2 27-Jul-81 NH-42 9.5 2 07-Aug-SO NH-5 35. 3 29-Jul-81 NH-42 7.5 0.2 OB-Aug-BO NH-5 24 2.9 12-Aug-ei NH-42 1.3 0. 1 16-Oct-SO NH-5 13 1.4 31-Aug-81 NH-42 0. 1 0.2 06-Nov-BO NH-5 12 • 3 16-Sep-Bl NH-42 0.2 0.2 17-Feb-81 NH-5 14 2.8 18-Sep-81 NH-42 0.2 0.4 ll-Mar-81 NH-5 9.3 1.4 06-Oct-ei T. NH-5 10 1.9 08-0ct-81 P-4 0.8 5.6 09-Sep-Bl 1.8 21-0ct-81 "SJ NH-5 21 P-4 1. 1 5.1 19-Sep-Bl NH-5 18 3.1 05-Nov-Bl P-4 1.2 5.4 23-Sep-Bl ip~ NH-5 97 6.6 18-Oct-82 P-4 0. 1 5.8 OB-Oct-81 1 'I:'. NH-5 23 1.53 06-Mar-84 P-4 0.8 5.5 21-0ct-81 NH-5 25. 1.75 07-Mar-B4 P-4 0.3 2.3 23-Nov-Sl NH-5 29 1.92 08-Mai—84 P-4 • 1. 1 4.7 02-Dec-81 NH-5 31. 1.9 09-Mar-B4 P-4 1 4.5 07-Dec-81 n; NH-5 33. 2. 12 12-Mar-S4 __ P-4 0.5 3 13-Jan-B2 NH-5 33. 2. 11 13-Mar-84 P-4 0.7 3.7 28-Jan-82 NH-5 37. 2.54 19-Mar-84 P-4 0.2 1.3 24-Mai—82 n: NH-5 34. 2. 16 26-Mar-84 P-4 O.3 1.7 25-Mar-82 NH-5 34. 2. 17 02-Apr-84 P-4 0.3 2.6 26-Mar-82 NH-5 34. 2. 1 16-Apr-B4 P-4 0.4 3.2 29-Mar-82 d NH-5 58. 3.54 Ol-May-84 P-4 ,V0.9 3.7 23-Apr—82 NH-5 160 8.7 Ol-Nov-B4 P-4 0.6 3.1 lB-May-82 r*~'- NH-5 175 8.9 28-NOV-B4 P-4 0.5 3.2 16-Jun-B2 i\ iL. NH-5 140 7.89 29-NOV-84 P-4 0.3 2.7 02-JLil-B2 NH-5 145 8.31 30-Nov-84 P-4 0.8 4.1 16-Jul-B2 NH-5 167 '9.63 03-Dec-84 P-4 0.6 3.8 29-Jul-B2 NH-5 143 8.04 04-Dec-84 P-4 0.7 3.9 03-Aug-82 IT NH-5 121 6.9 06-Dec-84 P-4 . 0.8 5. 1 16-Aug-B2 NH-5 151 8. 85 10-Dec-84 P-4 0.3 3.9 08-Oct-82 -_ NH-5 167 9.39 12-Dec-84 P-4 0.8 5.8 03-NOV-B2 NH-5 164 8.6 04-Feb-S5 P-4 0.9 3.7 08-Dec-82 n~ 150 9 ll-Feb-85 NH-5 P-4 0.4 2.9 07-Feb-B3 NH-5 57. 3. 63 10-Apr-85 P-4 0.4 2.95 16-Mar-83 NH-5 150 10 05-Jun-85 P-4 0.3 3.4 19-Apr-83 n NH-7 0.2 0 25-Jan-8O P-4 0. 3 2.4 04-May-B3 NH-7 0.3 0.2 06-Aug-BO P-4 0.3 2. 13 14-Jun-B3 NH-7 0. 1 0. 1 07-May-81 P-4 0.5 2.9 12-Jul-83 /. NH-7 0. 1 0. 1 19-Mar-82 P-4 0.3 2.3 03-Aug-B3 NH-7 0. 1 0. 1 02-Aug-82 P-4 0.2 2. 1 06-Sep-83 : NH-7 0. 1 0.2 18-Jan-83 P-4 0.2 2.4 07-Oct-83 Fl • NH-7 0. 1 0. 1 19-Oct-83 P-4 0.4 2.6 03-Nov-83 NH-7 0. 1 0.07 13-Feb-84 P-4 0 2.9 29-Nov-83 NH-7 0. 1 0. 1 O7-May-84 P-4 0.3 3 06-Dec-83 . NH-7 O 0 07-Aug-84 P-4 0.4 2.7 10-Jan-B4 d.-.: NH-7 0. 1 0. 1 ll-Sep-84 P-4 0.3 2.7 Ol-Feb-84 NH-7 0. 1 0. 1 ll-Oct-84 P-4 0. 1 0. 13 Ol-Mar-84 '- NH-7 1.1 0.19 Ol-Nov-84 P-4 0.3 2.55 03-Apr—84 '. NH-7 0. 1 0. 1 28-Dct-85 P-4 0.2 2.52 02-May-84 d P-4 11 0 — 17-Jan-80 P-4 1 2.3 21-Aug-84 ... P-4 9 36 21-Jan-BO P-4 1.8 2.01 14-Nov-84 P. . P-4 7 25 04-Aug-80 P-4 0.1 1.54 26-Feb-85 I !••' P-4 7 23 05-Aug-BO P-4 0.5 1.4 06-NDV-65 P-4 7 31 O6-Aug-80 P-6 10 0 17-Jan-80 P-4 6 23 07-Aug-80 P-6 8 18 21-Jan-BO P-4 5.7 24 O8-Aug-8O P-6 6. 1 16 O4-Aug-8O r? P-4 5.6 22 09-Aug-80 P-6 5.5 15 05-Aug-80 .. P-4 4.8 21 15-0ct-80 P-6 5 15 06-Aug-aO •: P-4 0.7 5.2 29-Jul-Bl P-6 4 11 07-Aug-BO d~ :-• «P-4 1 5 30-Jul-Bl P-6 4.5 11 OS-Aug-80 r~> •P-4 0.3 3. 3 31-Aug-Bl P-6 4.4 9.6 09-Aug-80 / . P-4 0.3 4.4 02-Sep-Bl P-6 2.6 9 10-Aug-80 r P-4 ' 1 4.5 04-Sep-Bl P-6 3.6 9.6 11-Auq-BO • P-6 3.6 9.6 12-Aug-80 V-ll 1.7 0.26 09-May-84 k p-6 5 .11 13-Aug-80 V-ll 1.8 0.33 25-Sep-B4 ^ P-6 4.4 10 14-Aug-80 V-ll 2.4 0.3 12-NOV-B5 P-6 5.3 9.6 15-Aug-80 V-ll 1.7 0.3 25-Feb-86 ., P-6 f 3 5.8 15-Oct-BO V-13 0. 1 0 Ol-Feb-80 P-6 ,•' 0. 1 1.7 06-Aug-Bl V-13 1 1.6 2B-Jul-BO r; P-6 •' 0.2 1 07-Aug-81 V-13 0.1 0.1 25-Aug-BO : p-6 0.1 1.3 27-Aug-Bl V-13 0 0 OB-Oct-BO P-6 0. 1 0.7 28-Aug-81 V-13 0.3 0.1 25-Jan-B3 ..... P-6 0. 1 1.9 31-Aug-81 V-13 0.3 0.21 Ol-Jun-83 P-6 0.2 2.8 02-Sep-81 V-13 r 0.3 0.2 O6-Sep-83 P-6 0 0 04-Sep-Bl V-13 •O.4 0.2 31-Oct-B3 P-6 0.8 3. 6 09-Sep-81 V-13 0.4 0.2 30-Jan-84 P-6 1.3 4.3 IB-Sep-Bl V-13' 0.2 0.17 09-May-B4 P-6 1.5 5.2 23-Sep-81 V-13. %1 i *, 25-Sep-84 P-6 0.9 7.6 08-0ct-81 V-13 '•''. 0.1 .0.18 14-Nov-B4 -, P-6 2.3 7.8 21-0ct-81 V-13 0.3 0. 1 25-Jun-S5 . P-6 0.9 0.2 23-Nov-Bl V-13 1.4 1.7 12-Sep-85 "'• .P-6 3.6 9.2 02-Dec-Bl V-13 0.2 0. 1 14-Jan-86 r- F'-6 3.2 8.8 07-Dec-Bl V-16 0. 1 0 24-Jan-80 r: p-6 1.5 4.7 13-Jan-B2 V-16 0. 1 0 OS-Apr-80 P-6 4. 1 10.2 2B-Jan-B2 V-16 0.1 0. 1 22-Jul-BO pP-6 0.8 3 24-Mar- 82 V-16 0.2 0.3 25-Feb-B3 r -6 2. 1 7.5 25-Mar- 82 V-16 0.1 0. 1 07-Sep-B3 P-6 2.9 10 26-Mar- 82 V-16 0. 1 0. 1 lO-Jan-84 P-6 2.8 12 06-Aug-82 V-16 25-Sep-B4 P P-6 1. 1 11 04-Jan-83 V-16 O.O 0.09 04-Dec-84 -s. P-6 0.9 5.3 19-Apr— 83 V-2 0. 1 0 25-Jan-BO 1 P-6 3. 1 17.2 04-May-83 V-2 O. 1 0. 1 22-Jul-BO P-6 6. 1 16 12-Jul-B3 V-2 0 0 26-Sep-BO r p-6 6 14. 1 03-Aug-B3 V-2 0. 1 0.1 • 02-Sep-Bl L P-6 2.2 7.69 09-Jan-B5 V-2 0. 1 0.4 02-Apr-82 J p_7 • 19. 25.5 18-Apr-84 V-2 0.1 0. 1 28-Jul-82 f P-7 18. 24.6 19-Apr-B4 V-2 0. 1 0. 1 25-Jan-B3 P-7 17 21.4 02-May-B4 V-2 0.2 0. 1.4 26-May-83 P-7 16. 18.9 20-Jun-B4 V-2 0.1 0. 1 07-Sep-B3 ... P-7 16. 16.37 05-Jul-B4 V-2 0. 1 0.1 12-Oct-B3 ! : p-7 17 16 21-Aug-84 V-2 0.2 0. 15 05-Mar-84 P-7 15. 12.86 18-Sep-84 V-2 25-Sep-84 P-7 17. 14.98 03-Oct-B4 V-2 0.8 0.2 30-Oct-85 r. p-7 17. 15.86 14-Nov-84 V-22 0.1 0 24-Jan-BO V- P-7 19. 16.99 04-Dec-B4 V-22 0.1 0. 1 14-Aug-BO P-7 15 17 06-Nov-B5 V-22 0 0 08-Oct-SO p. v-i 0.6 0. 18 21-Mar-84 V-22 0. 1 0. 15 '01-Jun-B3 j: v-1 0.5 0. 14 24-Apr- 84 V-22 0. 1 0. 1 06-Dec-83 : V-l 0.5 0. 13 09-May-84 V-22 0.2 0. IB 09-May-B4 V-l 0.8 0. 36 30-Jul -84 V-22 25-Sep-84 V-l 1. 1 25-Sep-B4 V-22 1 0.2 12-Nov-BS v_.: v-i 3. 1 0.2 12-Nov-BS V-22 0.4 0. 3 14-Jan-86 V-ll 0. 1 0 24-Jan-BO V-24 0. 1 0 24-Jan-BO [ V-ll 0. 1 0 OB-Apr-80 V-24 0. 1 0. 1 22-Ju1-80 • : v-ii 0. 1 0. 1 22-Jul-80 V-24 O 0 OB-Dct-BO V-ll 0 0 26-Sep-80 V-24 0. 1 0. 1 02-Sep-81 ^ " v-ii 0. 1 0. 1 02-Sep-81 V-24 0. 1 0.8 28-Jul-B2 K v-ii 2.3 0. 1 29-NOV-B2 V-4 0. 1 0.1 22-Jan-8O •- '" v-ii 0.5 1 ll-Jan-83 V-4 0.1 0. 1 18-Aug-80 V-4 0 0 06-Oct-8O WH-1 97 1.3 07-Oct-85 V-4 6.4 O. 5 22-Mar- 82 WH-10 1.5 2 25-Jan-BO V-4 8.2 0.9 02-Apr-82 WH-10 0. 1 0.5 22- Ju 1-80 V-4 6.2 O.B 23-Apr-82 WH-10 1.5 1 15-Jun-81 V-4 5.8 0.3 lB-May-82 WH-10 3.6 1. 1 19-Mar- 82 V-4 5.8 0.4 18-Jun-B2 WH-10 0.9 0. 3 17-Jan-B3 V-4 3. 6 0.2 02-Jul-82 WH-10 0.6 0.3 OB-Jul-B3 V-4 5.7 0.2 19-JL11-B2 WH-10 0.5 0. 1 ll-Jan-84 V-4 6.6 1.7 2B-Jul-82 WH-10 0.6 0.1. OS-Jul-85 V-4 9.8 1.2 16-Aug-B2 WH-2 5 0.9 16-Sep-81 V-4 3. 3 0.2 23-Sep-82 WH-2 5.8 0.2 29-Jan-82 V-4 8.2 0.9 20-Oct-B2 WH-2 12. 3.7 23-Feb-82 V-4 6.4 0.7 17-Dec-82 WH-2 14 5.4 19-Mar-82 V-4 8.2 0.25 26-May-B3 WH-2 11 0.9 02-jLil-B2 1 V-4 7.2 0.24 14-Jun-83 WH-2 •:';•• 11. 2.8 16-Jul-82 V-4 7.8 3.6 13-Jul-B3 ' WH-2 11 4.6 29-JU1-B2 V-4 7.7 0.4 02-Aug-83 :WH-2 12. 5. B 06-Aug-82 V-4 6.9 0. 3 07-Sep-B3 WH-2 14 4.8 16-Aug-B2 V-4 8.5 0.2 31-Oct-83 WH-2 8. 1 4.3 23-Sep-S2 V-4 •8.2 0.4 23-NOV-83 WH-2 17 2.9 19-Oct-82 V-4 7.6 0.3 06-Dec-B3 WH-2 81 3.8 23-NOV-82 V-4 8.6 0.24 05-Mar-B4 WH-2 66 13.5 01 -Dec -82 V-4 7.7 0.33 03-Apr — 84 WH-2 16 4.3 04- Jan -83 V-4 5.9 0.27 09-May-B4 WH-2 20. 1 . 16-Mar-B3 V-4 6. 1 0.27 06-Jun-84 WH-2 18. 3 19-Apr- 83 V-4 6.0 0.32 05-Jul-B4 WH-2 17. 2.83 25-May-83 V-4 3.7 0.44 lB-Sep-84 WH-2 14. 1.66 08-Jul -83 V-4 6.3 0.42 03-Oct-B4 WH-2 14 1.88 lS-Jul-83 V-4 7.0 0.53 14-Nov-84 WH-2 16 0.8 28-Dec-83 V-4 7.0 0.42 04-Dec-B4 WH-2 13 0.5 ll-Jan-B4 V-4 6.3 0.37 03- Jan -85 WH-2 30 1.4 27-Apr-84 V-4 6.8 0.47 09-Jan-85 WH-2 23. 0.86 07-May-B4 V-4 7. 1 0.39 20-Feb-B5 WH-2 20. 1.7 02-Jul-B4 V-4 8. 1 0.41 09-Apr-B5 WH-2 23.' 2. 17 18-Jul-84 V-4 7.9 0.8 Ol-May-85 WH-2 39. 2.77 10-Sep-84 V-4 7.9 0.5 04-Jun-85 WH-2 31. 1.94 ll-Sep-84 V-4 7.4 0.4 09-Jul-85 WH-2 34. 2.7 02-Oct-84 V-4 7.8 0.4 07-Aug-B5 WH-2 70. 1.85 12-Dec-B4 V-4 7. 1 0.4 06-Sep-85 WH-2 ' 92 2 14-May-85 V-4 10 0.6 02-Oct-B5 WH-27 8 0.7 •17-Nov-BO V-4 9.8 0.6 12-Nov-SS WH-3 4 0 29-Jan-30 , WH-1 14 0.9 22-Jul-BO WH-3 4 0 08-Feb-BO WH-1 12 1.2 O6-Aug-BO WH-3 4 .3 22-Jul-80 WH-1 16 1.2 07-Aug-BO WH-3 4. 1 3 05-Ang-80 WH-1 13 1.3 . 08-Aug-80 WH-3 3 2 06-Aug-8O WH-1 11 1.5 11-ALig-BO WH-3 5.3 3 07-Aug-BO WH-1 25 0. 1 04-Nov-SO WH-3 4.4 •j" ; OS-Aug-BO WH-1 23 0.2 17-Feb-81 WH-3 10. 3. 3 10-Apr-81 WH-1 51 2.8 2B-Jul-ai WH-3 11 6.6 07-May-81 WH-1 36 1.4 29-Jul-Bl WH-3 14 9 01-Jun-Bl WH-1 16 1.3 02-Sep-81 WH-3 12 6.3 21-Jul-81 WH-1 11 1.5 16-Sep-Bl WH-3 15 3.6 22-Jul-81 : WH-1 11 0.7 08-Oct-Bl WH-3 12. 4.4 23- Ju 1-81 WH-1 35 0. 1 25-Nov-Bl WH-3 5.7 i. 1 12-Aug-Bl WH-1 21 0.2 02-Jul-82 WH-3 4.6 2.3 lB-Aug-81 WH-1 48 0.2 19-Jul-B2 WH-3 4.5 1.7 02-Sep-Bl WH-3 3.5 3 02-Dec-Sl 'WH-5 1. 1 0.2 17-Jan-83 WH-3 3. 3 2.9 02-Dec-Bl WH-5 2.4 0.6 21-Dec-83 WH-3 3.1 2.7 07-Dec-ai WH-5 2 O.5 ll-Jan-B4 WH-3 3.7 3. 3 18-Dec-Bl WH-5 2.2 0.7 04-Mar-86 WH-3 4.2 2.4 21-Dec-Bl WH-6A 0. 1 0. 1 27-Feb-81 WH-3 3.6 4.1 27-Jan-82 WH-6A 0.2 0.3 li-Mar-81 WH-3 3.9 5.4 08-Feb-B2 WH-6A 0. 1 0.1 12-Jun-81 WH-3 4.2 6. 3 23-Feb-B2 WH-6A 0.1 0. 1 12-Auq-Bl WH-3 3.6 6.6 22-Mar-B2 WH-6A 0. 1 0.1 lB-Aug-81 WH-3 5.6 7.2 02-JU1-B2 WH-6A 0.1 0.5 22-Mar-82 WH-3 7.5 1.8 ' 16-Jul-82 WH-6A 0.4 0.34 lB-Jul-83 WH-3 5.5 7.5 28-JU1-82 WH-6A . 0.2 .0. 1 23-Nov-83 WH-3 5.5 1O O6-Aug-B2 WH-6A • o. i 0.07 28-Feb-84 WH-3 8. 1 4.3 23-Sep-82 WH-6A\. v'O.3 O.33 30-Jul-B4 WH-3 4. 1 8. 1 20-Oct-82 WH-6A ' 0.1 0.08 12-Dec-84 WH-3 7.2 10.6 23-NOV-B2 WH-6A 0.2 0.4 Ol-May-85 WH-3 4.2 9.2 02-D6C-82 WH-6A 0.6 0. 1 05-Nov-85 WH-3 6.5 12 04-Jan-83 WH-6A 0 0. 1 03- Apr -86 WH-3 7.5 11.3 16-Mar-83 WH-7 0.2 0. 1 17-Jan-83 WH-3 8.9 15 ll-Apr- 83 WH-7 0. 1 0.09 01-Jun-B3 WH-3 8.4 10 25-May-83 WH-7 0.6 0.1 07-Sep-83 WH-3 8.9 8.77 09- J tin -83 WH-7 O.B 0. 1 05-Mar-B4 WH-3 8.4 7.61 23-Jun-83 WH-7 0.6 0. 1 ll-Jun-85 WH-3 10. 7.67 OB-Jul-83 WH-7 0.7 0. 1 08- J LI 1-85 WH-3 10. 6.79 ia-Jul-83 WH-7 • 1.5 0.2 02-Oct-35 WH-3 4.3 2.5 30-Nov-BS WH-7 0.9 0. 1 14-Apr-B6 WH-3 41 5.8 14-Apr-S6 WH-8 1 0.5 15-Jun-81 WH-4 2 0 24-Jan-BO WH-B 1.2 0.3 17-Jun-81 WH-4 0.6 0. 1 10-Apr- 81 WH-8 7.2 0.6 29-Nov-82 WH-4 0.1 0. 1 12-Jun-81 WH-B 8.6 1.2 ' 06-Dec-82 WH-4 0.3 0. 1 23- Ju 1-81 WH-8 1.8 1. 1 ll-Jan-83 WH-4 0. 1 O. 1 12-Aug-81 WH-8 2.2 0.3 11 -Apr— 83 WH-4 0.5 1 19-Mar- 82 WH-8 1.7 0.37 25-May-83 WH-4 0.9 0.2 2B-JU1-82 WH-B 1.6 0.34 09-Jun-83 WH-4 0.5 0.5 06-Aug-82 WH-B 1.7 0.43 08- Ju 1-83.. WH-4 0.3 1. 1 ll-Jan-83 WH-B 1.6 0.43 Ol-Aug-63 WH-4 2.2 0.3 26-Jan-84 WH-B 2. 1 0.5 07-Feb-84 WH-4 2.7 0.56 07-May-84 WH-B 2.3 0.5 23-Jul-B5 WH-4 9.2 O.6 23- Ju 1-85 WH-9 0.3 0. 1 21-Dct-81 WH-4 9.5 0.7 31-Jul-85 WH-9 1.6 0.8 19-Mar-S2 WH-4 8.4 0.6 13-Aug-85 WH-9 0.9 0. 33 Ol-Jan-83 WH-4 8 0.6 06-Sep-85 WH-9 1. 1 0. 1 • 17-Oan-B3 WH-4 11 0.8 02-Oct-B5 WH-9 0.7 0. 1 07-Sep-83 WH-4 8.9 O.B 05-Nov-BS WH-9 0.9 0.2 12-Oct-B3 WH-4 7. 1 0.6 03-Dec-B5 WH-9 0.8 0.2 ll-Jan-84 WH-4 7.7 0.6 03-Jan-B6 WH-9 0.8 0.22 22-May-84 WH-4 9. 1 0.9 15- Apr -86 WH-9 1.2 0. 1 08-Aug-34 WH-5 4 2 22-Jul-8'o WH-9 1.2 0. 17 14-NOV-B4 . WH-5 2 2 06-Aug-SO WH-9 1.4 0.3 30-Dct-85 WH-5 2 2 07-Aug-BO WH-5 2 2 Oa-Aug-80 %WH-5 0.9 O.B ll-Aug-80 'WH-5 1.8 O.B 12-Jun-81 WH-5 0.9 0.2 22-Mar-B2 WH-5 2.5 1.5 28-Jul-82 WH-5 1.4 0.6 06-Aug-82 APPENDIX 5

DHS LETTER TO SCAQMD ON

HEALTH EFFECTS O*O»O« •PARTMENT OF HEALTH SERVICES -..»» Uin WAt ' UUT. . CCA WO* ' '• 540-2669

March 20, 1986

Mr. Sanford V. Veiss Director of Engineering South Coast Air Quality Management District 9150 Flair Drive : El Monte, CA 91731 ; ! /

Dear Mr. Veiss: ......

Thank you for sending us the additional information and the revised risk assessment for the proposed North Hollywood air stripping tower. Ve reviewed the risk assessment and have been in contact with Mr. Villiaa Ryan of Engineering Science for clarification of several points. The risk assessment, as supplemented by discussions with Mr. Ryan, appears adequate, except as noted below. : • This risk assessment may overestimate the true health impact on the surrounding occupational and residential population. All of the risks were calculated assuming a full lifetime exposure, i.e., 70 years, for both residential and occupational exposures.

The maximum calculated excess lifetime individual risk, 9.9 x 10* , occurs VSV of the air stripping tower in a light industrial zone. Even assuming a full working lifetime of 40 years, the projected risk to the occupationally exposed population would be 1.2 x 10* (i.e., by adjusting for hours [8/24], it: days [240/365] and years [40/70] of occupational instead of general residential exposure). The greatest residential exposure nay occur SSE of the site in two-story apartments. .Adjusting for the greater concentrations expected at this height, the individual lifetime excess cancer risk may be as great as 4.9 x 10* . Hence, even if an individual worked in the highest concentration area and lived in the high impact residential area, the Individual excess cancer risks would not exceed 10* .

In addition, the Los Angeles Department of Vater and Power (LADVP) applied for a permit for emissions 3 times greater than those suggested by maximum water sampling data, suggesting that the iproponent has estimated a worst case scenario for exposure. •rv. ;i rch 20. 1986 *«« 2

It eust be rtaeabered that the lifetiae excess cancer risk* are derived froa the upper 95% confidence interval of the data. This suggests that there is A 95% probability that tht "true" excess ri»ka ara lovtr than th« calculated ri«k. Although the project proponent*! risk asicssaent did not consider possible effects of acute exposure, DHS staff has done so, in large part because there is a child care center approximately 1/3 of a kiloaeter froa the proposed eaission source. Taking into account nodeled vorst-case exposures, the naxiaua potential exposures are approximately 1000-fold below concentrations of TCE and perchloroethylene reported to cause any toxicity. Ve vould suggest that the proponent perform;similar calculations to demonstrate to the South Coast Air Quality Management|District that no acute health effect would be expected to occur from the'projected facility. : Sincerely,

Nonaan Cravitt, Ph.ttT, M.P.H. Science Advisor/Toxlcologist Epideaiological Studies and Surveillance Section

Mich'ael J. Lips etc, M.D., J.D., Chief Air Toxics Unit Epidemiological Studies and Surveillance Section

cc: Drucc Choi; Groundwater Quality 3/27 - D. Georgeson J. Hegenbart H. Venegas

BAR -2 7685" orvjs/ow South Coast AIR QUALITY MANAGEMENT DISTRICT 9150 FLAIR DRIVE. EL MONTE. CA 91731 (818) 572-6200

January 21, 1986

Dr. Raymond Neutra Chief, Epidemiological Studies Section Department of Health Services 2151 Berkeley Way Berkeley, CA 94704 • • • ,- Attention: Dr. Norman Gravitz: Gent!emen: . The South Coast Air Quality Management District has received an application for a permit to construct an Air Stripping Tower to remove organics from ground water. This has been filed by the Department of Water & Power of the City of Los Angeles. As part of the District's evaluation of this project, a health risk assessment is required. The air quality modeling phase has been done by Engineering Science in Berkeley. A copy-of their report is attached hereto. We request that the Department of Health Services provide a health risk assessment of the proposed facility and advise us of their conclusions. This recent application involves a replacement and relocation of a prior water stripping tower proposed by DWP for which you furnished a health risk assessment. As a public hearing has been scheduled tentatively for February 4, 1986, your expediting the review, so that we can have an answer prior to that date, would be appreciated. We understand that your department has been contacted by DWP and that you have informed them that you will give highest priority to this request. Dr. Raymond Neutra -2- January 21, 1986

If you have any questions please contact Mr. George Ames at (818) 572-6249. Very truly yours-,

San'ford M. Weiss Director of Engineering

RCM:11 . ATTACHMENT

r-r: South Coast APP LICAT1ON NUMBER: AIR QUALITY MANAGEMENT DISTRICT 135479 9160 Flair Drtvt, El Monte, CA 91731 PERMIT TO CONSTRUCT ft- GRANTED AS OF 08/29/86

LEGAL OWNER DEPARTMENT OF HATER AND POWER n: OR OPERATOR CITY OF LOS ANGELES P. 0. BOX 111 LOS ANGELES, CA 90051

ATTENTION: MR. W. W. HOYE

. The equipment dmcribvd below wx) H rfiowi on ttw approvvd pt»ni •rx) gwcificaltont »nd Kjbtvct to tt»« »>»ci»i condition, or conditions titnd. n EQUIPMENT LOCATED AT 11845 VOSE STREET, NORTH HOLLYWOOD, CALIFORNIA .-_- EQUIPMENT AERATION TOWER, WELL WATER, PACKED BED TYPE, 12'-0" D1A. X 4B'-0" H., i DESCRIPTION WITH A MIST ELIMINATOR. ILL-.. • ANDD . • • •.--'•.•'' CONDITIONS: -CONDITIONS- ps 1. THE AERATION TOWER MUST NOT BE OPERATED UNLESS IT IS VENTED ONLY TO AIR POLLUTION CONTROL EQUIPMENT WHICH HAS BEEN ISSUED A PERMIT TO CONSTRUCT OR OPERATE BY THE EXECUTIVE OFFICER. 2. A FLOWMETER WITH A RECORDER SHALL BE INSTALLED IN THE 6ROUNDWATER SUPPLY LINE TO THE AERATION TOWER TO PROVIDE A RECORD OF THE DAILY AMOUNT OF WATER GOING TO THE AERATION TOWER. THESE DATA SHALL BE KEPT FOR A It MINIMUM OF TWO YEARS AND MADE AVAILABLE TO THE DISTRICT UPON REQUEST. .

PAGE 1 OF 2

Approval or denial of this application for permit to operate the above equipment will be made after an inspection to determine if dJ— the equipment has b*en constructed in accordance with the approved plans and specifications and if the equipment can be operated in compliance with all Rules of the South Coast Air Quality Management District.

Please notify G. AMES .1572-6249 when construction of equipment is completed.

rj;'•-• This Authority to Construct is based on the plans, specifications, and data submitted «s it pertains to the release of air contaminants and control measures to reduce air contaminants. No approval or opinion concerning i - safety and other factors in design, construction or operation of the equipment is expressed or implied.

T»» H*-»- to Cantiiici ««f bccernt mte 1 1» ^rwr to Opr-ttr • orma e> I Us TKS««MTTOCONTmuC't«AUEX»W[TWO»l*«£ twcuwt One*-

RMP:fcd t. PUtRTA RECORDS SECTION SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT

CONTINUATION OF PERMIT TO CONSTRUCT

DATE: 08/29/86 n- APPL. NO.: 135479

,— 3. THE GROUNDWATER GOING TO THE AERATION TOWER MUST BE TESTED FOR VOLATILE f 1 ORGANIC COMPOUNDS AND INCLUDE AT LEAST THOSE COMPOUNDS IDENTIFIED IN 11 CONDITION NO. 4 AT LEAST ONCE A MONTH. THE RESULTS WILL BE SUBMITTED TO THE DISTRICT AND KEPT ON FILE BY THE DEPARTMENT FOR A MINIMUM PERIOD OF TWO H • ' YEARS. " 4. THE MAXIMUM DAILY EMISSIONS FROM THE AERATION TOWER, BEFORE ENTERING THE rT CONTROL SYSTEM, MUST NOT EXCEED THE FOLLOWING AMOUNTS: COMPOUND . J/DAY r| TRICHLOROETHYLENE 16 PERCHLOROETHYLENE 2.5 Tt!- BENZENE 0.02 CHLOROFORM 0.5 1,1 DICHLOROETHANE 0.1 1,1 DICHLOROETHENE 0.2 METHYLENE CHLORIDE 0.1 f 1,1,1 TRICHLOROETHANE 0.5 TRICHLOROFLUOROMETHANE 0.5 CIS-1,2 DICHLOROETHENE . 0.2 THE ABOVE MAXIMUM DAILY EMISSIONS MAY BE EXCEEDED ON AN INDIVIDUAL BASIS, PROVIDED THAT THE AIR EMISSIONS EXITING THE CONTROL SYSTEM DO NOT EXCEED THE AMOUNTS SPECIFIED IN AIR POLLUTION CONTROL EQUIPMENT PERMIT CONDITION NO. 7.

PAGE 2 OF 2 PAGES South Coast AIR QUALITY MANAGEMENT DISTRICT

HEADQUARTERS, »I»C C. FUAtft DM.. Kk MONTC. C» (1711 Application Number: 144890

rZRHIT TO COBSTRDCT

Granted ai of OB/29/86 Legal Owner L.A. CITY. DEPT. OF WATER 6 POWER or Operator P.O. BOX 111 LOS ANGELES, CA 90051 i . Attn: MR. W. W. HOYE

EQUIPMENT LOCATED AT 11845 VOSE STREET, NO. HOLLYWOOD, CALIFORNIA

The equipment described belov and at shovn on the approved plans and TC specifications and subject to the special condition, or conditions listed. s Equipment Description and Conditions: AIR POLLUTION CONTROL SYSTEM CONSISTING OF: r 1. TWO CARBON ADSORBERS, EACH 10'-0" DIA. X 12»-0" H., WITH A CARBON BED DEPTH OF 3*-0~. 2. EXHAUST SYSTEM WITH A 20 B.P. BLOWER AND WITH AN IN-DUCT ELECTRIC HEATER, 70 K.W.. VENTING ONE WELL WATER AERATION TOWER. -CONDITIONS- 1. THE CARBON USED IN THE ADSORBER SHALL BE BPL OR EQUIVALENT GRADE. 2. A PLAN FOR MINIMIZING THE RELEASE OF CARBON PARTICLES DURING SPENT CARBON REPLACEMENT SHALL BE SUBMITTED BY THE APPLICANT AND APPROVED BY THE DISTRICT PRIOR TO START-UP. 3. THE FOLLOWING SAMPLES MUST BE COLLECTED AND ANALYZED FOR CONCENTRATIONS OF INDIVIDUAL VOLATILE ORGANIC COMPOUNDS (VOC): A. WITHIN 60 DAYS OF STARTUP, ONE SET OF SIMULTANEOUS SAMPLES [t MUST BE'COLLECTED OF THE WATER STREAMS AT THE INLET AND OUTLET OF THE AERATION TOWER AND OF THE AIR STREAMS AT THE INLET AND OUTLET OF THE CARBON ADSORBERS. THE SAMPLES SHALL BE ANALYZED IN ACCORDANCE ft WITH METHODS'APPROVED BY THE EXECUTIVE OFFICER. SIMULTANEOUS FLOW MEASUREMENTS MUST ALSO BE OBTAINED SO THAT MASS FLOW :RATES CAN BE CALCULATED FOR THE VOC'a OF EACH SAMPLING LOCATION. THE RESULTS SHALL BE SUBMITTED TO THE DISTRICT. [f B. SAMPLING;AT EACH POET OF THE ADSORBER WILL BE PERFORMED ONCE A WEEK BEGINNING WITH PORT NO. 1 UNTIL VOC'a ARE DETECTED. SAMPLING!WILL THEN CEASE AT PORT NO. 1 AND COMMENCE AT PORT -\ NO. 2 UNTIL VOC'a ARE DETECTED AT PORT NO. 2. AT THAT TIME SAMPLING ;WILL STOP AT PORT NO. 2 AND WILL START AT PORT NO. 3. South Coast AIR QUALITY7WANAGEMENT DISTRICT

HtADOUAftTCRS. nit t. FLAIM DM., cu MONTC. CA tint j Application Ruaber: no 144890 ONCE VOCfs ARE DETECTED AT PORT HO. 3, AIR SAMPLES WILL BE TAKEN WEEKLY AT TEE OUTLET OF TEE CARBON ADSORBERS TO VERITY TEAT VOC AIR KMISSIORS ARE WITBIH TEE LIMITS; SPECIFIED IR AIR POLLUTIOR CONTROL EQUIPMENT PERMIT CONDITION HO. 7. WHEN CONCENTRATIONS ARE ;DETECTED WITHIN 10 PERCERT OF THE LIMITS UNDER AIR POLLUTIOR CONTROL EQUIPMENT CONDITION HO. 7. DAILY SAMPLING;MUST COMMENCE. i . ].!'. . C. ONCE TEE VOC EMISSIONS AT TEE OUTLET R£ACH TEE LIMITS SPECIFIED IN AIR POLLUTION EQUIPMENT CONDITION HO. 7. TEE AERATION FACILITY OPERATION WILL BE BALTED AND TEE SPENT CARBON WILL BE REPLACED. 4. TEE DISTRICT MAY REVISE TEE MONITORING PROGRAM SPECIFIED IN CONDITION 3B SAMPLING FREQUENCY WEEN1SUFFICIENT TEST DATA HAS BEEN COLLECTED. fi 5. TEE GASiSTREAM ENTERING TEE CARBON ADSORBERS MUST BE KEPT AT A RELATIVE BTJMIDITY OF 60 PERCERT OR LESS. • 6. TBERMOMETERS MUST BE INSTALLED PRIOR TO THE DUCT jHEATER AND AT TEE INLET ! AND I OUTLET OF TEE CARBON ADSORBERS. 7. TEE CONTROL SYSTEM EMISSIONS BBALL HOT EXCEED 2 POUNDS PER DAY p^--. TOTAL VOC1* AND HOT EXCEED iO.02 POUND PER DAY OF BENZENE. 0.5 POUND { ) PER DAY !OF CBLOROFORM. AND 0.2 POUND PER DAY OF 1.1 DICBLOROETHENE. tlE Approval or denial of this application for permit to operate the above equipment vill be Bade after an inspection to determine if the equipment has been constructed in accordance vitb the approved plans and specifications and if the equipment can be operated in compliance vith all Rules of the South fit Coast Air Quality Management District.

Please notify C. AMES at 818/572-6249 when construction of equipment is complete.

This Authority to Construct is based on the plans* specifications, and data submitted as it pertains to the release of air contaminants and control measures or reduce air contaminants. Ho approval or opinion concerning safety and other factors in design, construction or operation of the equipment is expressed or implied. South Coast AIR QUALITY MANAGEMENT DISTRICT

HEADQUARTERS. »il» C. ruAlM DR.. >L MONTI. CA »|Tlt Application Humbert 144B90 Thia Permit to Conatruct ahall aerve a» a temporary Pens it to Operate provided the Executive Officer ia jiven prior notice of »ucb intent to operate.

Thia Peinit to Conatrvct will become invalid if tbe Perait to Operate is n1 denied or if tbia application ia cancelled. THIS PERMIT TO CONS TED CT SHALL EXPIRE TWO TEARS FROM THE DATE OF FILING OF APPLICATION unleat an exten«ion it •-»-, granted by the Executive Officer. • [ -,\ ' Sanford M. Veiaa^ n•-•>" „Director of Ei RAQDEL M. POERTA

[ RMP/aoj

' J.. fl

i r South Coast AIR.QUALITY MANAGEMENT DISTRICT 91 SO FLAIR DRIVE, EL MONTE, CA 81731 (818) 672-6200

August 22, 1986

South Coast Air Quality • Management District Board REPORT ON APPLICATION BY THE DEPARTMENT OF WATER AND POWER TO CONSTRUCT AN AIR STRIPPING TOWER IN NORTH HOLLYWOOD A ground water management plan for the San Fernando Basin recommends a reduction of trace quantities of chlorinated solvent compounds detected at levels above the standards set for drinking water. The Department of {Water and Power (DWP) proposed a water stripping tower as a method of reducing the level of contamination. The proposal consisted of the construction of an air stripping tower which will be 12 feet In diameter and 48 feet high. The water to be purified 1s pumped over the packing and air 1s blown Into the tower. As a result, volatile materials are transferred to the air and discharged. The maximum amount of- organlcs discharged 1s 20 pounds per day. A risk assessment shows that there 1s not an excess risk. Strong public opposition was voiced to the proposed project. On December 6, 1985, the District Board approved a recommendation by the SCAQMD Executive Officer that the staff conduct a Public Hearing on the DWP application This hearing was held on May 12, 1986 1n North Hollywood and was well attended by the local citizenry, public Interest groups, and representatives of local and state government. Most of the testimony was 1n opposition to the air stripping tower project as 1t was then configured.. On May 22. 1986, Mr. R1ck Caruso, Vice President of the Los Angeles Board of Water and Power Commission, announced that the DWP Board and staff had decided to filter the chemical vapors emitted by the aeration tower through granular activated carbon. According to DWP officials, the filters will reduce solvent vapor emissions by at least 90 percent.

L." South Coast Air Quality Hanagenent District Board - 2 - August 22, 1986

I.e.i from & aaxlnum of 20 pounds dally without control, to a naxInuB of I pounds dally. The Hearing'Offleer's report dated August 22, 1986 to the Acting Executive Officer takes note of the May 22, 1986 IT action by DWP to use a carbon filtering system. With that additional precaution, the staff has Issued a permit to (i: construct for the aeration tower and Its carbon unit. THEREFORE, IT IS RECOMMENDED THAT YOUR BOARD: - Receive and file this report. i Respectfully, James H. Lents, Ph.D. Acting Executive Officer EFC:SKW:aa rj I ' lr

* i APPENDIX 6 ri: f( SCOPE OF WORK FOR

H AERATION FACILITY PROJECT n ii n. n n ' NOTE

The following Scope of Work Document describes an aeration facility originally planned ;for the North Hollywood well field area. Since this design did not include contaminant emissions control utilizing granular activated carbon adsorption, it is incompatible with the recommended alternative as discussed in the OUFS report. Many of the'. engineering details, however, are compatible with the recommended alternative; therefore, the document has been included to provide additional background for the recommended remedial action: ' i : . ! ' rf s

r. [I SCOPE OF WORK DOCUMENT

L-- I. TITLE: Groundwater Quality Management Plan - North Hollywood-Burbank Aeration Facility Project I] • II. Project Team • Project Manager: Harold Kobata, WEDD Project Team Members: Aquiles Descallar, GSD James J. King, WQD jr-p Scott Munson, WEDD { fj Bob Chow, WEDD =: Bruce K. Tramm, WEDD Kuno Lill, WOD Thomas L. Ellis, WOD Eugene L. Coufal, AD

III. Approvals

Water Engineering Design Division Date

Water Operating Division Date

Water Quality Division . • Date nov_ General Services Division Date

Aqueduct Division Date r» f. rI

- 2 -

IV. Project Overview f i In early 1980,' the industrial chemicals, trichloroethylene (TCE) and perchloroethylene (PCE)> were discovered in the groundwater of the San Fernando Valley Groundwater Basin (SFVGWB) which.provides drinking water for the!cities of Los Angeles, Burbank, Glendale,| and ;San Fernando. The TCE rr concentration in many wells exceeded the action levels recommended by the California State Department;of Health Services (DHS) for drinking water. ;Groundwater normally provides about 15 percent of the water supply for Los Angeles. In the event of future water shortages or droughts, the; . groundwater supply will be more important. .:_!.. PE A two-year U.S. Environmental Protection Agency (EPA)- funded study was completed in July, ;1983 by the Water Quality Division of the Los Angeles Department of Water and Power (LADWP) and the Southern California Association of Governments rc to determine the extent and severity of the contamination and to develop strategies to control the groundwater contam- ination problem. The study produced the "Groundwater Quality Management Plan -• San Fernando Valley Basin" (GWQMP) report, which indicated that most of the contaminants reaching the wells probably resulted from past industrial practices before hazardous material classification and regulations were established. Eight specific recommendations were made in the GWQMP to prevent future contamination of the groundwater basin and to provide for remedial action for the current contamination problem. t The proposed project, the North Hollywood-Burbank Aeration Facility, addresses one of the recommendations - "Aquifer Management and Groundwater Treatment Program", which is to investigate the economics and effectiveness of halting TCE migration and improving groundwater quality. This project was initiated by the Water Quality Division and is now budgeted under Water Engineering Design Division (WEDD) Functional Item No. 243-15, Groundwater Quality Management Program. Financing by the EPA Superfund program is being sought. Aeration is a method whereby volatile organic compounds (VOC's) are removed by an upflow of clean air in intimate contact with the dispersed downflow of water. The basic mechanism for aeration is a complex combination of Henry's r Gas Law and liquid-to-gas mass transfer rates. n: Other methods of contaminant removal were investigated by the Water Quality Division, including granular activated carbon (GAG) systems and a new ultraviolet-ozone method now in development. At this time, the aeration method is the t most efficient and economical method of TCE/PCE removal. A summary of treatment methods currently available for removing VOC's from drinking water is given in the Appendix, Subtask III-D of the GWQMP. ft it: 1 --

"n _ 4 _ ff V. Project Facilities Description The proposed project consists of installing a nominal 2,000 gallons per minute (gpm) aeration facility that is Of; commercially available. The unit will be installed in the LADWP Lankershim Yard at 11845 Vose Street to treat the groundwater from a proposed system of eight to twelve shallow nr wells. Influent and Affluent water and air will be closely monitored to determine the performance of the facility. The proposed facilities will consist of the following: A. One aeration facility - nominal 2000 gpm capacity unit to treat contaminated water as specified and designed ft by James M. Montgomery Consulting Engineers, Inc. (JMM) that will be built and installed by contract. The ; facility, which is 12 feet in diameter and 48 feet in n height, will be designed to remove a minimum of 95 percent of the TCE and PCE contaminants from the influent ground- water with a maximum emission rate of 16 pounds per day of TCE and 2.4 pounds per day of PCE. See Figures 1 and 2 for facility locations. . •

B. Drill and case approximately eight to twelve new 8-inch diameter wells, approximately 300 feet deep. See Figure 1 for proposed well locations. A 400+-foot-deep, 6-inch diameter pilot hole will be drilled for each no well. The depth of the 8-inch diameter cased well and the location of perforations will depend on drill log and E-Log data. Specific well locations may shift to alternate sites as determined by continuing analysis of the aquifer characteristics.

C. Pumping units for each well will be approximately 300+ gpm with 420+_-foot head, electric-motor-driven, submersible vertical turbine pumps. The motors will be approximately 40 hp each. The wells will be automated so as to shut off if the aeration blower shuts off. The actual pumps and motors will be sized based on pump tests at completion of each well. ;' The 420-foot lift consists of the following: rf Groundwater table to ground surface (741'-485') 256' -" Lankershim Yard ground surface to facility *-•' _i..-.. inlet distribution C 'Groundwater drawdown (from computer analysis) Well efficiency (drawdown inside casing) Pipe friction loss Maximum total lift 418' ,. j 'V "

ORTH HOLLYWOOD-BURBANK AERATION FACILITY PROJECT PROPOSED SHALLOW WELL LOCATIONS AND COLLECTOR LINE ROUTE _JUUUUUUUUl SHERMAN

AERATION.^ ALT. SITE'A £J FACILITY,

VOJt »T. i ji^j\ -j)NH4e •KV*/« Jj "in rm§fHAUTl B:£fe91. >_^Js -XJ " n 1C nI w JU I (3 J JuU LgU-LJ^UUUl nr n n r-1 noKITTNIDOE • g IT. fc,.,L~—.•••••,.- 3

C JLJUUL n VICTONY • tvo. _ LEGEND n n n n n n nnnnnnr 0 EXISTING PRODUCTION WCLL • PKOPOJID SHALLOwPUMPlNGWELLtlTES ' _ EN EKWIN WELL . ~ TH wH?TTrAL°LL«£tLOD "UL ^-STUB-OUTS FOR FUTURE EXPANSION >"• COLLICTOH LIME MOUTE ICALCi I" • 1,000'

FlfillPP MO LADWP LANKERSHIM YARD NORTHERN PORTION

NORTHS-HOLLYWOOD TRUNK COLLBOTOR LINE PROPOSED .CHLORINATION STATION.

ZQf 23' X 37' fil r

FACILITY rs I' PAD) to U4 SHALLOW W ELL NO. 1

Ul Ul CO z z O oc tr Ul Ul Ul AERATION FACILITY z J- OUTLET LINE I E Ul o CO X AERATION FACILITY o INLET LINE

L •4' §"«• METAL SHED Q S! n 51' X 122' X 15' H lr TOIL AT # Q O VOSE ST. IV L FIGURE 2 r vm 7/85 - 7 -

D. Piping 1. Water influent from wells to facility: approximately 11,700 feet of 12-inch diameter pipe. Three stub-outs will be provided, as shown on Figure 1, to allow for possible future expansion of cleanup of SFVGWB. 2. Water effluent from facility: approximately 450 feet of 16-inch diameter pipe connected to existing 16-inch diameter collecting line at the Lankershim Yard. The existing 16-inch diameter collection line runs south to the Vanowen Well Collector Line which connects to the North Hollywood Sump. • E. Electrical measurement equipment and controls for .pumps, fans, and instruments. F. Instruments or sampling points for determining equipment efficiencies by' measurement of water and air flow, concentration of contaminants in :water and air influent and effluent streams.

K The contract with JMM for this project has been extended another year. They will recommend the overall '' p aeration facility height, prepare the design and. specifi- ji L cations, and obtain the air quality permit (permits to I• construct and operate) from the South Coast Air Quality i r Management District (AQMD). The pad design, building permit, U. and Cultural Affairs Commission approval for the aeration n facility will be provided by JMM. They will also provide • • support services during the installation of the aeration L f.' facility. . : !, 'i The aeration facility was originally planned to be sited ! [;"• at the North Hollywood Pumping Station property at [_ 11803 Vanowen Street. Approval from the Department of City n Planning and an AQMD permit, which approved influent concen- i p.- trations of 300 parts per billion (ppb) of TCE and 20 ppb of 1 . PCE for continuous operation at 2000 gpm, had already been ^- obtained for this site. However, the aeration facility, with n; its height of 45+_ feet, would be out of place in this p residential area. Therefore, the aeration facility site I*"- LJ has been changed to the LADWP's Lankershim Yard in an 1.1 industrial-zoned area. This new site is about.1800 feet ; r; north of the original site. The closest residential zone pi • is over 200 yards to the 'south of the new aeration facility \-i —-*.-.. . -•• site. - . P ' "• ' r ; f'• V i - 8 -

According to AQMD officials/ solvent (TCE) emissions from the aeration facility would cause airborne concentra- tions in the parts-per-trillion range. If feasible, air quality sampling will be performed 'by contract at the aeration facility site before and during testing of the facility to help reduce public concerns on its emissions. VI. Operating Criteria The contaminants (TCE and PCE) are concentrated mostly in the top zone of the water-bearing strata above an'inter- mittent stratum of clay located approximately 300 feet below ground level in the North Hollywood area. The wells used for this project will pump from above the clay stratum thus extracting water with a high concentration of TCE and PCE. i The well discharge will be piped to the aeration facility where forced counter-current airflow will contact the cascad- ing water to strip the TCE and PCE from the contaminated water Depth to the groundwater table in this area is about 200 feet. The well pump will need!to lift water about 420 feet-to allow for aqui'fer drawdown, lift to the top of the aeration unit/ and pipe friction. The treated water effluent from the facility will be routed into the North Hollywood Sump ^ r by gravity flow. If all the wells are operating at the same time, there is a possibility that the total well field capacity could exceed 2000 gpm. In that case, a well(s) would be selected to remain idle, or operated at a reduced flow fate, until the area of influence of one of the operating wells is cleaned up. The total inflow to the aeration facility will be limited by the maximum emissions of TCE and PCE that are specified by the AQMD permit. The aeration process is designed for a minimum 95 percent effectiveness in removing TCE from the influent. The expected initial 2000 gpm water influent TCE concentra- tion from the shallow cleanup well field is estimated to be 200 ppb but may increase to a maximum concentration of 650 ppb (equivalent to AQMD permit maximum emission rate of u; 16 pounds per day). If the influent TCE concentration increases above 650'ppb, the flow of well water will be reduced to keep the facility TCE emission rate below 16.0 pounds per day assuming 100 percent efficiency for the aeration facility. The PCE emission rate will be limited to 2.4 pounds per day which is equivalent to 100 ppb in the water. The total maximum allowable concentration of total hydrocarbons, including TCE plus PCE, in the facility influent approaches 800 ppb. The 2000 gpm (4.5 cfs) effluent with a maximum 33 ppb TCE from the aeration facility will be routed to the North Hollywood Sump to be blended with other water n supply to produce water with a concentration of less than 5 ppb of TCE. The 5 ppb TCE concentration is based on the recommended DHS interim action levels for TCE. The State interim action level for PCE in water is 4 ppb. Currently, the DHS interim action levels are at the lower limits of the EPA's "Suggested No Adverse Response Levels" (SNARL). - 10 -

VII. Project Status ;! A. Project Report This pilot project is a direct result of the report entitled "Groundwater Quality Management Plan, San Fernando Valley Basin"/ issued July 1, 1983. This report was prepared by the Water Quality Division of the LADWP in conjunction with the Southern California Association of Governments. This study was initiated in July, 1981, and funded in part by a grant from the United States Environmental Protection Agency. i I • • * - : J ' .--.,... ! ;...-., . ; To incorporate the input and comments of private citizens, concerned interest groups and affected public agencies, a Citizen's Advisory! Committee and a Technical Advisory Committee were formed. The Citizen's Advisory Committee was composed of representatives from local governments, public interest groups, economic interest groups, and private citizens. The Technical Advisory Committee was composed primarily of engineering representatives from City, County, and State agencies that have extensive technical and management experience in the water supply industry.

B. Environmental Documentation A Draft Initial Study was distributed to responsible agencies on January 31, 1986. he A preliminary analysis of the air emissions indicates tha't the maximum concentrations of TCE and PCE are sufficiently small to pose no significant adverse -G effect on the environment. The analysis is being reviewed by the AQMD and DHS, and their approval is n' necessary for receiving an AQMD permit. A Negative Declaration will be prepared based on the approval of the air emissions by AQMD.

C. Land Acquisition and Right-of-Way The aeration facility, water lines, and wells will be located'on LADWP property or in City streets.

fr - 11 - fn D. Conditional Use Permit p- '- ': r--- A conditional use permit from the Department of City !' • .:-'.: I .• Planning will be required for this installation at the •? v :. ••; ""' Lankershim Yard site. The Water Engineering Design . -.-" •'•• Division will work with the Real Estate Division to P, " . • I obtain the necessary approvals.

; • . .. ; E. Other Permits , • '...-"•••' ' •"•• P^ , ,_'.': Permits from the AQMD to construct and to operate the ;'.':;; H aeration facility at the Lankershim Yard site will be ; . \'\ . required. James M. Montgomery Consulting Engineers, r. ' .''•-• ""'' Inc. will secure the necessary AQMD permits, City . .... , _ . building permits and Cultural Affairs Commission approv ' '•'•"/ • I • and necessary mechanical and electrical permits, as a r. V i L-' part of their contract work.

F. Geology .The Dams, Geology, Materials and Survey Section has determined the foundation requirements for the facility and have obtained Department of Building and Safety (DBS) approval for the geotechnical report. Further coordination with DBS will be required during construction, including approval of site excavation and compaction of fill report.

G. Design i '• •' :- . ' /•* iyi ;.-..'.• .-;: The Projects Design Section, Water Operating Division, ('1 .* . •' I— and the Aqueduct Division will be responsible for a certain portion of the engineering and design of the \ • •-"• ' r project facilities as indicated in Article X of this • f";' .•-.: jj . report. James M. Montgomery Consulting Engineers, Inc. 4 ;•••. • .-. is designing and preparing the specifications for the ', ..; ..':•••'.;'_ p aeration: facility, itself. The Project Manager is p \ -:..- j responsible for coordination of the entire project.

H. Related Construction or Project Plans for the reconstruction of North Hollywood Pumping Station include expanded use of the San Fernando Valley Groundwater Basin during droughts or emergencies. V . 'Other projects that are scheduled for construction at ] approximately the same time as the aeration facility ar r ' r - 12 -

| j-';:"r.-.' {_' the 60-inch North Hollywood Trunk-Collector Line, and ' •:.-"•.-. the North Hollywood Complex Chlorination Station. The chlorination station and a portion of the 60-inch pipeline will be located in the Lankershim Yard (Figure 2). These projects will require close coordination to avoid conflicts.

I. Political Contacts A Letter of Notification, indicating that the LADWP has ,". applied for an AQMD permit, was sent to residents and ;" ;:.'J: r~, ' owners of property within. 330 feet of the Lankershim ;. •Y\ Yard property on October 29, 1985. A Fact Sheet to n•'•'.: -'• describe the project was included with the notification. , • '.."'"• J-': A public workshop to inform the public of this project p'••'.-.' I'-' was held November 26, 1985 in North Hollywood. In addition, the following political officials were also sent this notification: , Tom Bradley, Mayor, City of Los Angeles Council District Nos. 1-14 State Senators Robbins, Rosenthal, Roberti, and :i? Russell State Assemblypersons Katz, Bane, Davis, LaFollette, Margolin, and Nolan County Supervisor Edelman - 13 - 7 VII. PROJECT SCHEDULE FEB. 25, 19B6

GROUNDHATER QUALITY MANAGEMENT PROGRAM F.I. 243-15 \L: NORTH HOLLYWOOD-BURBANK AERATION FACILITY PROJECT

PROJECT MANAGER: HAROLD KOBATA x 6256 HEDD-PROJECTS DESIGN SECTION

FRE-PROJECT COORDINATION: ERNEST WONS x 6075 ' . KEDD-PLANNIN6 SECTION i

ACTIVITY - ' •. PERSON DIVISION PHONE DUE . STATUS IT RESPONSIBLE DATE ..

I AERATION TOWER

. A. ENGINEERING 1. SITE LOCATION OF TOWER BOB PAGAN UEDD 6113 9/85 COMPL. 0: 2. SOIL TEST, REPORTS fc OBTAIN BUILDING AND SAFETY APPROVAL WINSTON UU . HEDD 6134 10/85 COMPL. 3. DETERMINE CITY PLANNING PERMIT NEEDS ERNIE UQNG HEDD 6075 12/85 4. EHV1ROKMENTAL DOCUMENTATION ERHIE HONB HEDD 6075 2/86 STARTED NE6 DEC 5. TOWER DESIGN • BOB CHOW HEDD 6102 3/86 BRUCE CHDH •• MONTGOMERY CONSULTING ENGINEERING . 6. DESIGN TOHER PAD SCOTT HUNSON HEDD 6145 3/86 BRUCE CHOH - MONTGOMERY CONSULTING ENGINEERING 7. ELECTRICAL DESIGN BRUCE TRAMM HEDO 6137 • 3/86 B. DESIGN HATER PIPING TO TOHER . TOM ELLIS HOD 6126 3/86 ft 9. PREPARE SPECIFICATIONS FOR TOMER BIDS BOB CHOW HEDD 6102 4/86 BRUCE CHOW •• MONTGOMERY CONSULTING ENGINEERING 10. OBTAIN AQHD CONSTRUCTION PERMIT BOB CHOH HEDD 6102 4/86 to- BRUCE CHDU •• MONTGOMERY CONSULTING ENGINEERING 11. OBTAIN CITY PLANNING CONDITIONAL USE PERMIT MEL WILSON HEDO 5977 6/86 12. OBTAIN BUILDING AND ART-COMMISSION PERMITS SCOTT MUNSON UEDD 6145 6/86 BRUCE CHOH •• MONTGOMERY CONSULTING ENGINEERING rt 13. OBTAIN HEALTH DEPARTMENT PERMIT TOM GIBSON HQD 3163 6/86 iftADVERTISE AERATION TOHER CONTRACT - JUNE, 1986m

B. CONSTRUCTION 1. SECURE AND ADMINISTER TOHER CONTRACT BOB CHOH HEDD 6102 5/86 2. BUILDING AND SAFETY APPROVAL JOHN HOLMSTROM HEDO 6128 6/86 3. CONSTRUCT TOHER PAD AQUILES DESCALLAR GSD 3657 5/86 4. INSTALL ELECTRICAL HOOKUP AQUILES DESCALLAR GSD 3657 10/86 5. INSTALL AERATION TQHER CONTRACTOR fr 6. TEST AERATION TOHER BOB CHOH , HEDD 6102 1/87 JIM KING HQD 3171 1/87 7. OBTAIN AQMD OPERATING PERMIT AND PROVIDE ENGINEERING SUPPORT SERVICES DURING BOB CHOU HEDD 6102 2/87 CONSTRUCTION • ERUCE CHOH - MONTGOMERY CONSULTING ENGINEERING n 8. MONITOR AERATION TDHER I..' WATER DUALITY PERFORMANCE Jltt KINS W90 3171 INDEFINITE 9. OPERATE AERATION TOHER KUNO LILL HOD 6231 INDEFINITE H: i«»AERAT10N TOHER IN SERVICE - MARCH, 19B7»" II WELLS

A. ENGINEERING 1. RENOVATE NORTH HOLLYWOOD NO. 10 AQUILES DESCALLAR 6SD 3657 6/E5 HELL NOT (MAY NOT TO BE USED AS SUPPLY WELL) USEABLE 2. SITE NEH HELLS GENE COUFAL AQUE 6194 12/BS ERNIE HONG HEDO 6075 12/85 MICHAEL CAVANAUGH MONTGOMERY CONSULTING ENGINEERING 3. PREPARE HELL DRILLING SPECIFICATIONS GENE COUFAL AQUE 6194 2/86 MICHAEL CAVANAUGH MONTGOMERY CONSULTING ENGINEERING 4. OBTAIN HEALTH DEPARTMENT DRILLING PERMIT JIM KING HQO 3171 2/86 5. PREPARE WELL PUMP AND MOTOR SPECIFICATIONS BOB CHOW HEDD 6102 2/86 ' 6. DESIGN ELECTRICAL HOOKUP BRUCE TRAMM HEDD ' 6137 2/86 7. COMBINE HELL DRILLING AND PUMP AND MOTOR SPECIFICATIONS FOR TURN KEY CONTRACT BOB CHOW UEDD 6102 3/B6

f itAKARD HELL DRILLING CONTRACT - MAY, 1986»»

B. CONSTRUCTION . 1. SECURE AND ADMINISTER HELL DRILLING, PUMP AND MOTOR CONTRACT BOB CHOU HEDD 6102 5/86 2. HELL DRILLING INSPECTION KUNO L1LL HOD 6231 7/86 3. INSTALL ELECTRICAL HOOKUP AQUILES ! DESCALLAR GSD 3657 10/86 4. PERFORM PUMPING TEST CONTRACTOR ' 5. PERFORM AQUIFER TEST MICHAEL CAVANAUGH MONTGOMERY CONSULTING ENGINEERING 6. CONNECT HELLS TO PIPELINES AQUILES DESCALLAR GSD 3657 12/Bi 7. HELL OPERATION AND MAINTENANCE KUNO LILL UOD 6232 INDEFINITE

inHELLS IN SERVICE - FEBRUARY, 1987**!

III PIPELINES

A. ENGINEERING 1. REQUISTION UOD SERVICES TO DESIGN PIPELINE DICK BENTON HEDD 6123 6/85 2. OBTAIN SPRR R/H PERMIT NOT HEEDED n- 3. DESIGN, PREPARE DRAWINGS AND PROVIDE STANDARD SPECIFICATIONS TOM ELLIS UOD 6126 4/86 4. PREPARE PIPELINE SPECIFICATIONS DICK BENTON HEDD 6123 5/86 5. DESIGN, PREPARE SPECIFICATIONS Jf - AND PURCHASE VALVES, METERS, ETC. BOB CHOW HEDD . 6102 5/86 B. CONSTRUCTION [f 1. SECURE AND ADMINISTER PIPELINE CONTRACT DICK BENTON UEDD 6123 9/86 2. INSPECT PIPELINE INSTALLATION UEDD 11/86 tf ttiPIPELINES IN SERVICE - FEBRUARY, 19B7«« 1IV GENERAL ri^1. PERPARE SCOPE OF HORK DOCUMENT BOB PAGAN UEDD 6113 1/86 DRAFT COMPL. 2. PROVIDE HATER QUALITY DATA TO MONTGOMERY ENGINEERING JIM KING UQD 3171 7/85 COMPL.

3. CLEAN UP LANKERSHIM YARD AQUILES DESCALLAR GSO 3657 9/85 COHPL. REMOVE SUBSTRUCTURES 7/86 - 15 -

IX. Cost Estimate : ,..-, The cost breakdown is as follows: ; L- o Engineering (Aeration Facility - LADWP) $ 50,000 o Engineering Consultant (JMM) . 260,000 o Aeration Facility - Purchase & Install 200,000 o Wells ...... Drill 8 - 300-foot deep wells (400-Foot Bore Hole, 300-Foot-8-Inch Diameter Cased Well) Drill & Case 25,000 Pump & Motor 10/000 l\- Installation 10,000 :••'-• r- Cost per Well 45,000 ^-;:_ [•' 360,000 •*:'.' o Collecting & Discharge Lines wPN'- F' 1. Wells to Facility (Inlet Line) ;k T-.: f a. 16-inch Diameter Pipe r- L: 50'-16" @ $6.40/in./ft. 5,000 '*.. .-. b. 12-inch Diameter Pipe •"^ '• 7100'-12" @ $9.80/in./ft. I ^ (paved) 835,000 V 4600'-12 @ $6.40/in./ft. > ("" . (unpaved) 355,000

f 2. Facility to Existing 16" V- L' (Outlet Line) 1! L 450'-16" @ $6.40/in./ft. •••• ' (paved) 45,000 • !•'. Pipe Cost $1,240,000 1,240,000 || SUBTOTAL $2,110,000 • i-j: Contingencies 400,000 TOTAL $2,510,000

Note: The engineering costs included in this estimate are for this aeration facility project only and do not include indirect if costs for the entire Groundwater Quality Management Plan. - 16 -

The annual operating and maintenance (O&M) expense for the wells and aeration facility is roughly estimated at $150/000, including energy. These costs will be borne by the Water Operating Division. Water quality testing is not included in this O&M estimate. Water sampling and testing expenses of the Water Quality Division is estimated at $20,000 per year. Air quality monitoring will be an additional operating expense, and the initial monitoring is expected to be rigorous and may require a significant cost. Annual cost for.air quality monitoring is not determinable at this time. r1:'-<^ r: m e - 17 - X. Responsibilities of Participating Managers (See attached list on page 14 for detailed work assignments) A. Water Engineering Design Division 1. The Projects Design Section will be responsible for: a. reviewing and coordinating all project design activities; F~;-VV E b. monitoring the preparation of plans and specifi- cations for the purchase and installation of the aeration facility as prepared by James M. Montgomery Consulting Engineers, Inc.; c. requisition WOD services, to design pipelines; d. preparing specifications and secure the contracts for the pipelines, well drilling, and well pumping equipment'. 2. The Planning Section will be responsible .for: a. the Scope of Project report which establishes the design parameters; b. preparing the Negative Declaration; c. obtaining Department of City Planning approval; d. project coordination between LADWP Water System Divisions; e. coordinating with Real Estate Division for Department of Planning approval. 3. Dams, Geology, Materials and Survey Section will be responsible for: a. soil tests and reports; m t* b. obtaining Building and Safety approval of foundation report. r - 18 - .-'' B Water Operating Division - The Water Operating Division will be responsible for: ;.' 1. operating and maintaining of all the wells and the aeration facility; 2. preparation of plans and standard specifications for n.':- ; the well collecting pipeline and the aeration facility discharge pipeline.

C. Water Quality Division - The Water Quality Division will be responsible for: 1. obtaining Health Department permit for the water treatment facility;. 2. obtaining Health Department permits for well drilling; 3. monitoring the water quality and the performance of the aeration facility; . ; 4. the monitoring of related instruments and pv controls; 5. issuing a report on the results of the pilot aeration program.

D. Aqueduct Division - The Aqueduct Division has

1. established a recommendation for the'number, location, size, and depth for the shallow wells; 2. prepared the specifications for the well drilling 0 to be included in WEDD's contract. E. General Services Division - Water Maintenance and Construction Group will be responsible for: ft 1. all construction by DWP forces related to the aeration facility; 2. the installation of: '•-.'' •.'•-•"' '". a. the aeration facility connections, (Note: The aeration facility will be installed by contract, GSD will make final pipe connections to well inlet and discharge lines) :P - 19 - ( '•'.•••.. '.I . ...• • '-. t - '.•'••.• .. t : instrumentation and controls, any other mechanical or electrical equipment as requested by the Projects Design Section or Water Operating Division.

F. James M. Montgomery, Consulting Engineers/ Inc. (JMM) ; JMM will be•responsible for: 1. design of the aeration facility and appurtenant structures; 2. preparing plans and specifications for the aeration .facility; 3. acquiring permits and approval for the aeration facility from the SCAQMD, Cultural Affairs Commission, and Department of Building and Safety; 4. providing technical assistance during construction 5. reviewing the Aqueduct Division's recommendation for the shallow wells and for the well drilling specifications; :!""!-•• ' "'"•'[• **• performing and (or) monitoring necessary aquifer and well efficiency tests on the completed wells.

" V-'/ '''.''• '[} n'•'<> •!;'.: : •' 3

Note: The installation of the 60-inch diameter North Hollywood Trunk-Collecter Line is also scheduled for this approximate time period and is also planned to go through the|Lankershim Yard. Coordination of these tw j jV.--•*-:.'.••• l" projects and the North Hollywood Complex Chlorination /"""V. • -,'\."; Station — how being designed and also located at the r .-•':.']'.'••' [: • Lankershim Yard — will be needed (see Figure 2). r

APPENDIX 7

ANALYSIS OF AREA OF INFLUENCE OF

i SHALLOW AQUIFER WELLS r S°SE 2-e MEMORANDUM

LOS ANGELES AQUEDUCT DIVISION

MEMO BY" L. Lund Tn W. W. Hoye n&TF October 16, 1985 FILE TITI E San Fernando Valley - North Hollywood Aeration Tower Project '. Analyses of Area of Influence of Shallow Aquifer Wells

Transmitted herewith is the report on the Analyses of Area of Influence of the Shallow Aquifer Wells being planned for the North Hollywood Aeration Tower:Project. This report will be used to locate the new shallow wells that will be installed to supply water to the aeration tower. £ If you have any questions regarding the above, please contact Mel Blevins on extension 5339 or Gene Coufal on Hi extension 6194. PDRisaa '. H] Enclosures . . cc: L. McReynolds n W. W. Hoye R. Sosa . L. Lund/D. C. Williams E. Wong n- A. VanOrden M. L. Blevins E. E. Horst G. Coufal P. Rogalsky nJ R. Haw/L. Watanab. e n

n

fi GROUNDWATER - San Fernando Valley -. 1

il CITY OF LOS ANGELES DEPARTMENT OF WATER AND POWER

SAN FERNANDO VALLEY - NORTH HOLLYWOOD fl AERATION TOWER PROJECT rs ANALYSES OF AREA OF INFLUENCE OF SHALLOW AQUIFER WELLS f: OCTOBER 1985 ff t? I? AQUEDUCT DIVISION

SAN FERNANDO VALLEY - NORTH HOLLYWOOD AERATION TOWER PROJECT ANALYSES OF 'AREA OF INFLUENCE OF SHALLOW AQUIFER WELLS

OCTOBER, 1985 Pi

PREPARED BY nr Melvin L. Blevins Senior Hydrologic Engineer Eugene L. Coufal Hydrologic Engineering Associate 112-' Peter D. Rogalsky Hydrologic Engineering Assistant- Moseis R. Garcia Senior Engineering Aide n Susie Aguilar Clerk Typist

IE UNDER THE DIRECTION OF Le Val Lund Engineer Los Angeles Aqueduct ft Dennis C. Williams Asst. Engineer Los Angeles Aqueduct

r-- d TABLE OF CONTENTS .

TEXT Page Number Introduction 1 Method of Analysis 2 Discussion 3 Conclusion ' 4 .

FIGURES .''.'-'•-' '•'''•:''•'. North Hollywood Aeration Tower Project Well Location - Alternative 1 6 . n Resultant Groundwater Gradient and Capture Zone Boundary - Alternative 1 7 Shallow Well Location Map - Alternative 2 8 Resultant Capture Zone Boundary and Groundwater Gradient - Alternative 2 9 Computer Modeled Drawdown Contours for Eight Shallow Wells - Alternative 1 10 • Resultant Groundwater Gradient and Capture Zone Boundary - Alternative 1 11 North Hollywood TCE Contamination . 12 rt rt-!, O: (r rt San Fernando Valley - North Hollywood Aeration Tower Project Analyses of Area of Influence of Shallow Aquifer Wells

INTRODUCTION

In order to properly evaluate the best location for shallow contaminant recovery wells for the North Hollywood aeration tower project an analysis was performed to determine the limits of the shallow wells' capture zone. Figure 1 is a plot of the existing North Hollywood wells near the North Hollywood Sump and eight possible shallow well locations (Alternate 1) that were used for the analysis. The capture zone is defined as that area from which groundwater will ultimately be drawn to the wells under long term steady-state conditions. Figure 2 shows the capture zone boundary, and the resultant groundwater flow directions predicted for the upper aquifer in the North Hollywood area during long term shallow well pumping. Figure 2 was constructed using Fall, 1984 aquifer conditions as pre-pumping conditions. The figure was constructed by dividing the geographic area surrounding the wells into a grid system and then analyzing the combined effects of the natural groundwater gradient and the shallow well pumping induced groundwater gradient in each grid section. A more detailed analysis of the area immediately surrounding the proposed shallow wells was performed to verify that the pumping cones of the shallow wells overlapped. The results of a similar analysis of an alternate well configuration (Alternate 2 Figure 3), that . includes the contaminated area of the North Hollywood Well Field r • east of Tujunga Avenue, are presented in Figure 4. t-r -l- , **> Method of Analysis -V-'

The analysis to determine the capture zone limits began by creating a computer generated plot of the drawdown produced by eight shallow wells pumping 300 gpm each for 180 days. A transmissivity value of 20/000 gpd/ft., based on an aquifer test performed at North Hollywood Well No. 5, and a storage coefficient of 0.03, assuming unconfined aquifer conditions, was used for the analysis. The transmissivity and storage coefficient were assumed constant over the entire well field. A computer generated plot of the drawdown that was created by shallow zone pumping (Alternate 1) and used for analysis is shown in Figure 5. A grid system was laid over the plot and'the magnitude and direction of the pumping induced groundwater flow gradient were determined for each grid section. The gradient direction was described by the angle it made with the horizontal.

.. Next, a similiar scale plot of the Fall, 1984 groundwater contours was prepared for the same area. The same grid system was overlaid this figure and the magnitude and direction of the natural groundwater flow gradient were determined for each grid section.

The effects of the pumping induced and natural groundwater flow gradients were then added to yield a resultant gradient for each grid section. The horizontal (x) component of the natural gradient for each grid section was added to the x component of the

-2- pumping induced gradient. The vertical (y) components of each gradient were similarly added. For each grid section, the magnitude t and direction of the resultant gradient were calculated from these x and y components. The gradient direction was calcuated as an angle 6 with the horizontal. The result of this is shown in Figure 2. The same method was used to derive Figure 4 for Alternate 2. . .

Discussion ' .

The capture zone was determined by analysis of the groundwater gradients' magnitude and direction. The limits of the capture zone are indicated by the direction of the resultant, gradients, (Figures 2). Gradients pointing toward the pumping wells indicate areas within the capture zone and gradients pointing away from the pumping wells indicate areas outside the capture zone.

The capture zone area does not appear to be significantly- impacted by production well pumping in the area as seen when comparing: 1) the zone developed using the North Hollywood area groundwater contours for Fall, 1984 (Figure 2), which has a pumping hole near the Erwin and northerly end of the Whitnall Well fields; and 2) the zone developed using Spring, 1984 North Hollywood area groundwater contours which contained no pumping hole (Figure 6). One concern is that dewatering of the aquifer during pumping the production wells may impact the ability to pump water from the

-3- r- •• ••: • " f- •

r/ • shallow zone. This can be alleviated somewhat by: 1) locatinc I1 > the shallow wells as far from pumping wells as possible; and ^i. 2) when practical limit production well pumping in the P North Hollywood area.

^ '_

I { Also, by comparing the drawdown contour maps developed for various configurations of shallow wells it can be seen that as I I . ' .'-.. long as approximately 8 wells are somewhat evenly spaced across H~ the contaminated area and perpendicular to the natural flow gradient, a continuous cone will develop around the area and no flow will escape through gaps between wells in the shallow _- aquifer zone. Figures 2 and 4 illustrate this point. Figure 4 ' shows the capture zone for a configuration of shallow wells that P^ reaches several thousand feet further to the east than the configuration shown in Figure 2. Even with the wells spread out [ _ as shown the capture zone is contiguous and the upper zone groundwater is not allowed to flow past the wells, provided that v r1 . ' the pumping cone is given adequate time to develop. Changing the specific well locations from what is shown in Figures 2 and 4 may slightly skew the drawdown contours in localized areas but generally will not effect the limits of the capture zone. rtConclusions o The exact location of the shallow zone pumping wells is \H .| - . - not critical provided that they are relatively evenly f-^ ••"tr.- 1 spaced across the contaminated area and perpendicular to the natural flow gradient. -4- o The limits of the capture zone will not be significantly effected by the amount and location of production well pumping provided that shallow well pumping is not seriously restricted by the production well Hp drawdown cones.

••« . ' " ' • o It appears that the capture zone of Alternative 1 (Figure 1) will encompass .the : entire TCE contaminated area centered near Vanowen Street and Lankershim Blvd (delineated by a dashed line in Figure 7), and may encompass the contaminated area re centered near Vineland and Kittridge Streets. This alternative would be less expensive than Alternative 2 1 and could be expanded upon in the future. According to -.,-• Figure 4 the capture zone of Alternative 2 will •' ^ encompass both of these contaminated areas. This :|~f alternative will cost more due to increased piping and energy costs, but will add greater assurance that both rc contamination plumes will be contained. H: PDR:saa

-5- TL FIGURE 1 North Hollywood Aeration Tower Project **\ r I Well Location Map - Alternative 1 1 1- Shallow Aeration Tower e Supply Well n: O LADWP Production Well

I U •

•

1 O Vose NH-24

[""^ Hart ^ ONH-42 O ONH-41 £ * ONH-4 ) f- NH-39O NH-38O I - Vanowen ONH-31 NH-I3O CDNH-II 9 8 0 ONH-28 O NH-27 E NH-I4A NH-29 r- CO T3 r ~ &•• •Q IE CO CO O •S i. ^ c ~ I ""*" ^Q ^ o> C 1 CO ••M .C* GC [-. DC ffl P • —1 w-iO 1 Kittridge • £ OW-2 ' •*• -*> • -

^ _ _ •

ron 10/15 FIGURE 2

Resultant Groundwater Gradient and Capture Zone Boundary - Alternative 1

Based on 8 Shallow Pumping Wells and the Fall, 1984 Groundwater Gradient rc

I vJ

r

GW Flow Direction Capture Zone Boundary

Shallow Well Scale: 1^4000' FIGURE 3

Shallow Well Location Map - Alternative 2

© Shallow Aeration Tower Supply Well

o LADWP Production Well

• •— CD •C c 73 « co "O i. o 3 O 0) a O JC. c *D C; .2 0) JD CO co '5 ^c oc gNH-24 — ' O Hart QNH-42

ONH-40

Vanowen NH-38,HH, NH-3^1 QNH-I3U fj> Q NH-I6O O O NH-I4A Nnl29V^NH-27 NH-IT NH-18

Kittridoe WHO NH-20 O CtSD Q3NH-2I OW-2 NH-19 NH-35

Scale: 1m= 1600' r rot io/tB FIGURE 4 Resultant Capture Zone Boundary and Groundwater Gradient - Alternative 2

Based on 8 Shallow Pumping Wells and the Spring, 1984 Groundwater Gradient

A/ rt nr -r.

Capture Zone Boundary GW Flow Direction Shallow Well

Scale: 1*« 4000'

POM IO/»» tv Resultant Groundwater Gradient and Capture Zone Boundary - Alternative 1

Based on 8 Shallow Pumping Wells and the Spring , 1984 Groundwater Gradient

P^

P] P"? ft

Pii flj p] GW Flow Direction p: Capture Zone Boundary Shallow Well n h- Scale: 400 r*" io/*t FIGURE 5 Computer Modeled Drawdown Contours for 8 Shallow Wells - Alternative 1 ORflHDOWN CONTOUR HflP '- NORTH HOLLTHOOD flERflTJON TOWER PROJECT EIGHT SHflLLOH HELLS PUHPJNG 300 CPM EflCH T * 20000 CPD/FT. 5 * 0.03000 TIHE * 180.00 CRTS

3C003.00_ JSSOO.OO_ zs3ao.oo_ i«seo.oo_ laooo. op_ J7SOO.C3. J7030.03_ ZtS03.03_ t»ooo.oo_ JSSOO.eO_ «S008.00_ »nsoo.oo_ IU300.00_ Z3S00.03_ Z3000.00_ «S00.03_ «000.00_ 11SOO.OO_ lJOCfl.30. zosoo.op_ *003fl.00_ usoo.op_ 1S009.00. USOO.OO_ uooo.og_ nso3.og_ 17030. 00_ itsoo.oo_ 11300. 00_ JSSOO.OO.

IM030.00_ I3SOO.OO_ 13000. 0£_ 12S00.03_ uooo.oo_ \JSOO.OO_ iiaoa.oa_ iosoo.oa_ 10000. 03_ »soo.so_ J000.03_ ISOO.OO_ • 003. 00_ 7SOO.OO_ 7000. 00_ IS00.03_ 1000. 00_ S400.00_ 5030. 00_ M«0.00_ «000.03_ 3SOO.OO_ 300S.OO_ tS08.00_ zooo.oo_ ISOO.OO_ I000.00_ soo'^oo _ 0.00 DRAWDOWN IN FEET Scale: 1V 400 |O jo |w jo |w» |Q |w* jc \v> |Q |£ |o |t/» |o |M |o |* |c |* )Q JO |— |- |A/ )«g |u Jw |f |« jtn |v* |*« |»* |Z |tJ |* |» |w |« |o |o |— |- |M |^f jti |2 |f |c Jin |tn |ffl )*« |w jo |» |« fu |

^ & t o t t t ^ t c 'o £ £ £ £ o e t 'e "c -S -S P ? ? ? 5 ?????????? 5 ? ? P ? ???????????????? ? QOC.OCtCtOOCiObCbbOOOOCCCCCCC.C.OO^^C.C.C^CC.^CtC.CC.' - O~ -O O- O- O- QQCCQQOQCOOQ^OQOO'

PDR lO/«8 X RXIS ft FUaUKEf n FT n; rr rr tS -.r,

n; x / ', • II !?-»•«. / re VY IUE-iiA IL^e-WcYL / rt n;.: r; • rI -.-. 1 k r 4

! . APPENDIX 8 [.. ESTIMATION OF

GRANULAR ACTIVATED CARBON REQUIREMENTS r r r'

r/ r r f- f,T ' • 1 ',: ESTIMATION OF GRANULAR ACTIVATED CARBON REQUIREMENTS ff.; The cost estimates provided for the granular activated t ; . carbon (GAG) alternatives discussed in this report are necessarily heavily dependent upon the quantities of carbon n . ' L. required to effect a given treatment efficiency (this is true for ip-". both liquid-phase and gas-phase adsorption systems) . Methods of i i• '. estimating the required carbon appear to be based on theory (Freundlich adsorption isotherm) and experience, with information from the latter being available primarily from literature and product manufacturer sources. . Several manufacturers of GAG were contacted for "• • information relating to carbon adsorption efficiencies and costs. These sources disclosed widely varied information based primarily on system performance claims. Therefore, it was I . decided that the information obtained from the Calgon Corporation (the acknowledged leader in the field) would be used in sizing . / r the different GAG processes, although it was recognized that .p ' similar processes based on other data could be substantially different with respect to overall cost. I The following information documents the LADWP's .. rationale for estimating carbon requirements. Freundlich '- :..' isotherm data was obtained from EPA Publication No. 600/8-80-023, "^ "Carbon Adsorption Isotherms for Toxic Organics". As described *~-^'~ ^ in the report, TCE and PCE are the only significant contaminants f found thus far in the affected groundwater basin and, since TCE - 2 - s f/ __ . t ti . .- ! : exhibits the greater resistance to treatment by aeration and GAC

r*. .' adsorption, it was selected as the "design" contaminant.

'+ Overview of Liquid-Phase Carbon Adsorption Process It has been demonstrated that the equilibrium adsorption characteristics of specific organic compounds with granular activated carbon may be accurately described by the semiempirical Freundlich equation

where C0 - Cf _ „ „ n ~ K Cf

C0 = influent adsorbate concentration, mg/1 Cf = effluent adsorbate concentration, mg/1 M = carbon required to effect required adsorption, g/1 [""'"S K,n = regression coefficients specific to adsorbate

The quantity of required carbon can be estimated for single-stage, f equilibrium adsorption processes if C0, K, and n are known and Cf is a predetermined or maximum allowed residual contaminant concentration. It may be shown that more efficient use of carbon may be realised by a multiple stage process in which a volume of influent is successively treated with given doses of carbon to •fi achieve the same predetermined residual concentration. The efficiency of this process may be maximized by providing an infinite number of stages in the adsorption process for a given fL- volume of influent; this approach may be approximated by the use of a long column of carbon to treat the influent. The Freundlich r equation may then be expressed as

rr . r~ dC _ „ _,n t dM j.! which, after integrating, is

1 0 1 •IT M = ]rTiZHT [C, - - Cf -"] ' L r This equation necessarily implies sufficient carbon/ n, . • contaminant contact time to achieve equilibrium at every point in •PJ •" the column. Since this condition can never be completely achieved by any finite column, it will only provide an estimate of the carbon requirement. However, based on published GAC performance •FT- data for volatile organic compounds (see, for example, EPA Publication No. 600/8-83-019,."Treatment of Volatile Organic l Compounds in Drinking Water"), the above expression appears to be valid and reliable for estimation purposes. Therefore, a more .LL detailed analysis employing mass-transfer principles was not

:rf- performed. '••' Consequently, this approach was used to determine the [7. carbon requirements for the adsorption processes considered in this report. It is conservative in that it does not require total | j carbon exhaustion to the point where the effluent concentration is P... equal to that of the influent; this increases the required quantity ' ; - of carbon for treatment but allows a more realistic model of an n.: actual column process. Overview of Vapor-Phase Carbon Adsorption Process The activation process used in the manufacture of activated carbon may be modified to produce a species of carbon which is highly effective in the adsorption of organic compounds in the gas or vapor phase. Since the transfer of the adsorbate to the carbon is effected directly (without a solvent intermediary), vapor-phase carbon adsorption is much more efficient than its liquid-phase counterpart, with typical capacities of 10 percent to as high as 80 percent by weight. Since the adsorbate must be introduced as a gas, treatment facilities for contaminated groundwater necessarily require a preceding volatilization '—•^ process; this is usually provided by an aeration column. Efficient utilization of the vapor-phase carbon process I ." is normally dependent on the relative humidity of the influent air/contaminant stream; normally, provisions must be included to '[ , ' reduce the relative humidity to a maximum of about 50 percent; ',_ most efficiencies above this figure fall off rapidly. In I - addition, the species of carbon used in the process is more T" • expensive and, since the percentage of adsorbed contaminant is high, the spent carbon is classified as a hazardous waste,' | necessitating more costly methods of removal, transport, and disposal. ' ft Adsorption isotherms for vapor-phase carbon are used to r* ' estimate the carbon requirement for a given facility and ^^~^'~ contaminant. Although most organic compounds do not exhibit f Freundlich-like adsorption characteristics, they may be closely

r • • i '- ' '' - 5 -

approximated by similar mathematical expressions. For TCE adsorption at 25° C and 50 percent relative humidity, the capacity W as a ratio of contaminant adsorbed per unit weight of carbon may be expressed as W = 0.11 M°-263 where M is the mode fraction of contaminant in the air stream

measured in parts per million. If C0 is the contaminant concentration in the air stream measured in micrograms per liter (parts per billion) , then W = 0.07 Co0'263

C0 may be determined simply by dividing the contaminant concentra- tion in the water phase by the air/water ratio specified in the aeration process. Thus, if TCE is present in the water supply at a concentration of 100 parts per billion, W will be approximately 0.10 (10 percent) if the air/water ratio is 30:1. Therefore, each pound of carbon will be able to adsorb 0.1 pound of contaminant, which translates into approximately 120,000 gallons of influent. The carbon cost in this case is on the order of $0.01 per 1,000 gallons. *" The carbon adsorption capacity for low vapor-phase P. . contaminant concentrations is correspondingly low. If, for the above example, the concentration of TCE in the water is just r* ' 10 parts per billion, the carbon capacity would be only about 5 percent. However, the capacity of one pound of carbon in this P*^ i !-•' case would be sufficient to treat 600,000 gallons of influent. S~* ^ *" r | . 1 :• r- . APPENDIX 9

EXCERPT FROM "INITIAL STUDY AND PROPOSED

NEGATIVE DECLARATION FOR THE PROPOSED

NORTH HOLLYWOOD-BURBANK AERATION FACILITY PROJECT" r - 13 -

AIR QUALITY/HEALTH CONSIDERATIONS Air Quality/Health Risk Assessment Model Since the proposed aeration facility will result .in air emissions which contain small quantities of VOC, predominantly ^ TCE, an air quality/health risk assessment model was prepared for 'L_ • the LADWP by Engineering-Science, an independent consultant, to ,Pi determine the effects of the proposed operation. This model, : I j l- which simulates the maximum emissions of 16 pounds per day Ib./day • rv. | 1 TCE, 2.4 Ib./day TCE, and smaller amounts of other VOC, was submitted to the SCAQMD with the permit application and was also IJ_. evaluated by the DHS. P-<\ The following is a model description and the parameters ' that were used in developing the model. Refer to Appendix IS-C n . for excerpts of reports by Engineering-Science.

(;. Model Description p.- The maximum annual average PCE, TCE, and trace organics concentrations were calculated using the Industrial Source Complex fl Short Term (ISCST) air quality dispersion model. The model, which is accepted by the SCAQMD for this application, is designed to use [ ! hourly meteorological data to calculate concentrations produced by p emissions from multiple stack, volume, and area sources. Hourly meteorological data collected in 1981 were provided by the SCAQMD P , for input into the model. f"~V . The air quality model assumed the facility would operate I; . 24 hours per day, 365 days per year. ' The model considered the _i possible effects of adjacent buildings and trees on the air i " - 14 -

dispersion. Table 1 lists the exhaust stack parameters used in the ISCST model. It was determined from an initial model run that the "affected area" was that area included within a 6 kilome'ter (3.7 miles) radius from the facility. A distance of 6 kilometers was calculated as that distance where the total cancer risk is rv- less than 1 in 10 million. • •Beyond this distance, the contaminants ! , will continue to disperse and become more dilute. r- The affected area was broken up into 88 census tracts t '": ( : and the model was run to determine the maximum annual average 'P concentration within each census tract. » ^"". The population used in the risk assessment included [ '* both worker plus the residential population. The population i. .. _. figures used in the model were extended to the year 2000 ll population since it is anticipated that the facility operation may be required for approximately IS years. The total population nh ' - . within the 6 km-radius affected area is assumed in the health risk •[P j"' assessment model to be 652,000 people. A detailed description of methodology can be found in <• L_ Appendix IS-C. rv

i. • ! '- TABLE 1 [ Aeration Facility Exhaust Stack Parameters Used in the ISCST Modeling p Height (above ground surface) 48 Ft. Diameter 2 Ft. l^_n . Volumetric Air Flow Bate 8021 Ft.3 /Min. P.. Corresponding Mass Air Flow Rate 868,000 Ibs./Day ^ Corresponding Exit Speed 42.6 Ft./Sec. f"j~ Ambient Temperature • 68 F. "R:- • ..-»- <^>

Establishing Emission Levels The emissions levels from the proposed aeration facility are dependent on the contaminant levels in the groundwater that | i will be treated. Table 2 shows the maximum contaminant concentra- _,.. tions in the influent groundwater, corresponding maximum emission ^-•- rates and maximum annual average ground-level concentrations. ;p"' The influent contaminant concentrations shown in Table 2 :',!'.! . • • • are conservative. Existing LADWP groundwater-guality data indicates that the actual groundwater contaminant concentrations will be about 3 to 6 times lower and hence the actual air emissions and concentrations are expected to be 3 to 6 times lower. A discussion of the representative 'water quality for the groundwater to be treated can be found in Appendix IS-A. The resultant maximum annual ground-level concentration was calculated to be 0.10 ppb for TCE and 0.01 ppb for PCE at a location about 0.5 km northwest of the facility. - 17 -

TABLE 2 Air Emissions and Resulting Concentrations

Maximum * * (2) Maximum Annual Water Maximum Average Ground- Cone . Emission Level Cone. (3) in ug/1 Rate Contaminant (ppb) (Ib/day) (ug/m ) (ppb)

TCE 650 16 0.546 0.101 PCE 100 2.4 0.086 0.013 •r. Trace Organics Benzene 0.58 0.014 0.0005 0.0002 Chloroform 19.5 0.048 0.019 0.0038 1,1-Dichloroethane 3.3 0.080 0.003 0.0007 1,1-Dichloroethene 6.5 0.160 0.006 0.0015 Methylene Chloride 3.3 0.080 0.003 0.0008 1,1,1-Trichloroethane 19.5 0.480 0.019 0.0035 Trichlorofluromethane 19.5 0.480 0.019 0.0034 cis-1,2-Dichloroethane 6.5 0.160 0.006 0.0015

(1) These concentrations are 3 to 6 times greater than that found to be typical for the upper zone of the aquifer. (2) Maximum emission rate is based on a continuous flow of 2000 gpm. Results of computer air 'quality model at a location about 0.5 km northwest from facility. -18-

Health Risk Assessment The health risk assessment concludes that the maximum risk for any individual to contract cancer is less than 1 in 1,000,000 and that the additional number of individuals within i .•.: the affected area that may contract cancer is 0.03 (much less } than 1 person) for a 70-year exposure to the maximum contaminant —,-, emissions from the proposed facility. . ' -; The health risk assessment is based on the maximum !"*" contaminant concentrations, population, and EPA-established' Unit i, Risk Values for each contaminant to calculate the probabilities, I the Maximum Individual Risk, and the Excess Cancer Burden. These . "\ terms are defined as follows: 1 Unit Risk Values r4 The Unit Risk Value, which is established by the EPA, is the estimated probability of contracting cancer as a result of a I constant exposure to an ambient concentration of one microgram per _, cubic meter (1 ug/m ) for a 70-year period. r4 Maximum Individual Risk The Maximum Individual Risk is defined as the probability P that an individual would contract cancer as a result of exposure r •• to the maximum contaminant concentration for a 70-year period. • [ The Maximum Individual Risk is calculated by multiplying the i maximum contaminant concentration by the Unit Risk Factor for that I I- ^ L-J* contaminant. The Total Maximum Individual Risk is obtained by r adding the Maximum Individual Risk for each contaminant. - 19 -

Excess Cancer Burden The Excess Cancer Burden is defined as the total number of people within the affected area that may contract cancer as a result of exposure to the maximum contaminant emissions from the proposed project within the affected area for a 70-year period. The Excess Cancer Burden is calculated by multiplying the Maximum Individual Risk by the-population. The model calculated the Excess Cancer Burden for each census tract by 'multiplying the Maximum Individual Risk within the census tract by the population r-• of the census tract. The Total Excess Cancer Burden for the 1i ' '••' affected area was calculated by adding the Excess Cancer Burdens of the 88 census tracts within the affected area. Model Results of the Health Risk Assessment The results of these calculations are as follows: The Total Maximum Individual Risk is calculated to be 9.89 x 10~ . This is the probability of any one person contracting n. cancer from a 70-year exposure to the maximum emissions from the proposed facility and is less than 1 in 1/000,000. ri The Total Excess Cancer Burden is calculated to be , 0.03142. This is the maximum probable number of additional people I in the affected area that may contract cancer from a 70-year p exposure to the maximum emissions from the proposed aeration i '.. facility. • i . The summary of the Maximum Individual Risk and Excess n x ^. /"~Y . Cancer Burden is shown in Table 3. - 20 -

TABLE 3 Results of Health Risk Assessment n Using EPA Federal Register and DHS/ARB r Unit Risk Values

Unit Risk Maximum Excess Value . Individual Cancer Contaminant

* TCE 1.3 x 10'6 b 7.09 x 10"7 0.02252 PCE 5.8 x 10"7 C 4.90 x 10"8 0.00156 Benzene 5.3 x 10"5 d 2.53 x 10"8 0.00080 Chloroform 1.0 x 10~5 e 1.95 x 10"7 ' 0.00619 r^ Methylene Chloride 4.1 x 10"6 f 1.12 x 10"8 0.00036

Total 9.89 x 10"7 0.03142

a Using year 2000 residential and employment population. b 50 FR 52424, EPA, 12/23/85. C 50 FR 52882, EPA, 12/28/85. ftReport to the Scientific Review Panel on Benzene,- ARB/DHS, 11/84, e The Air Toxics Problem in the United States: An Analysis of fi- Cancer Risks for Selected Pollutants, EPA, 5/85. f EPA-600/8-82-004FF. fr' i • • - 21 -

Acute Exposures The health risk assessment also evaluated the possibility of ill effects from short-term acute contaminant concentrations from the aeration facility emissions. The analysis concluded that the calculated maximum short-term concentration is more than 13,000 times lower than the limits for occupational exposure established by the California Administrative Code, Title 8, Section 5155. The analysis also concluded that the maximum 8-hour concentration than would occur is more than 3,000 times lower than the established limits (see Table 4}.

n •r

Ml n-

I, >w si TMU E 4

ACUTE EXPOSURES FHOM MAXIMUM SHORT-TEBM CONCENTRATIONS Of TCE AND PCE IH AIR EMISSIONS rflOM TJIE PROTOGED NORTH IIOLLYWOD-BUBfUNK AERATION rACILITT

Max. Ave. Cone, foe Period (1,2) Excursion Compound Period t 0.15 km § 0.3 km (3) Limit (4,5) PEL (4,6) TLV-TWA (7,8) TLV-STEL (7,9)

TCE 1-Hour 9.6 ppb 8.5 ppb 150,000 ppb 200,000 ppb (52.1 ug/m ) (46.2 ug/m )

8-Hour 6.8 ppb 6.0ppb 25,000 ppb 50,000 ppb (36.5 ug/m ) (32.3 ug/m )

PCB 1-Hour 1.2 ppb 1.1 200,000 ppb 200,000 ppb (8.1 ug/m ) (7.2 ug/m )

8-Hour 0.85 ppb 0.75 ppb 50,000 ppb 50,000 ppb (5.7 ug/m ) (5.0 ug/m )

NOTES:

(1) Turner, D. B. Workbook of Atmospheric Dispersion Estimates, U.S. EPA, 1970, AP-26. (2) Guidelines for Air Quality Planning and Analysis, Volume 10, Revised, EPA-450/4-77-001. (3) Distance is comparable to the 1/3 km from the child-care center to the proposed emission source as identified in the letter from DHS to SCACKD dated March 20, 1986. Maximum Average Concentrations occur 0.15 km frora source. (4) California Administrative Code, Title 8, Section 5155. (5) Excursion Limit is the maximum concentration of an airborne contaminant to which an employee may be exposed without regard to duration provided the 8-hour time-velghted average (TWA) concentration does not exceed the Permissible Exposure Limit (PEL). (6) PEL Is the maximum permitted 8-hour TWA concentration for an airborne contaminant. (7) Occupational Safety and Health Administration, General Industry Standards, 29 CFR 19.10.1000 (Code of Federal Regulations). (8) Threshold Limit Value - Time-Weighted Average (TLV-TWA) concentration is the maximum concentration for a normal 8-hour workday and 40-hour workweek, to which nearly all workers may be exposed, dally, without adverse effect. (9) Threshold Limit Value - Short Term Exposure Limit (TLV-STEL) is a TWA concentration for a 15-minute time period which should not be exceeded at any time during a workday, even if the TLV-TWA is not exceeded. K. ' ' ' : ': " IV I r Evaluation of the California Department of Health Services i ' • The Air Quality Model and Risk Assessment for this 1 ; proposed project has been evaluated and deemed adequate and p conservative by the DHS in their March 20, 1986 letter to the SCAQMD. The DHS has further concluded, in their March 28, 1986 1. letter to the LADWP, that the proposed North Hollywood-Burbank '—- Aeration Facility would not pose a "significant health exposure." ' See Appendix IS-C for these letters. r: •r; T° ft r- r- i ^ • . - 24 -

f'. Air Quality Considerations P-- At the maximum contaminant emission rates of 16 Ib./day TCE, 2.4 Ib./day PCE, and smaller amounts of other VOCs, the proposed [ f aeration facility operation will result in a maximum air contaminant P concentrations at a location about 0.5 km northwest of the facility [. of about 0.10 ppb for TCE, 0.01 ppb for PCE, and much less for P the other VOCs. The average concentration of TCE over the affected 1 area will be less than 0.005 ppb. j ... The LADWP recently conducted a random air sample at the proposed aeration facility site to identify the presence of ^ i... VOCs. The analysis of the air sample revealed that TCE, PCE, and other VOCs are now present in the air at the site. The SCAQMD has an air quality monitoring station in Burbank approximately 5 miles southeast of the proposed project site. In March 1985, the SCAQMD began taking air samples at this station for the purpose of monitoring the presence of selected toxic ambient VOCs (including TCE and PCE). Samples are taken approximately every 12 days. The SCAQMD data indicates that the ambient air concentrations range from 0.11 ppb to 2.6 ppb for TCE and 0.6 ppb to 6.9 ppb for PCE. The average ambient concentrations at the SCAQMD Burbank station are 0.46 ppb for TCE and 2.8 ppb for PCE. These Values are much higher than the maximum average 0.005 ppb of TCE, 0.0006 of PCE, and smaller concentrations of other VOCe that will be added to the affected area by the proposed aeration facility. - 25 -

.) i |: Other VOCs that are also present under ambient conditions at the Burbank station including vinyl chloride, chloroform, 1,2-dichloroethane, 1,1,1-trichloroethane, carbon tetrachloride, 1,2-dibromoethane, benzene, and toluene. Thus, the data indicates that the VOCs resulting from the proposed project are much lower than the typical amounts of VOCs that are already in the air. It- is therefore concluded that the proposed project will not result n in degradation of the air quality. fi; Health Considerations [ i| The calculated values of risk from the air quality and p, ^vrrisk assessment model based on the maximum emissions of 16 Ib./day ' CE and 2.4 Ib./day PCE are as follows: • Maximum Individual Risk: less than 1 in 1,000,000 Total Excess Cancer Burden: 0.03 for the affected area rn that includes an assumed population of over 650,000 [L As the DHS has pointed out in their review of the n model, the. actual health risk is probably lower than the n: calculated risks mentioned above for the following reasons: t\' f- - 26 -

T) j ; ". o It is not likely that there will be 650,000 in population p in the affected area since this figure assumed that both ' ' I 1 ' I- residential and working population remain in the affected H p area. It is not likely that any individual will remain within the affected area for 70 years, and much less j _ | likely that any individual will remain in the location PP of maximum concentration for 70 years. ' • '-• o The actual concentration of contaminants in the groundwater to be treated will most likely be 3 times less than the assumed 650 ppb TCE and 100 ppb PCE that f [ was the basis for specifying the air emission rates of 16 Ib./day TCE and 2.4 Ib./day PCE for the SCAQMD permit.

ft. In any event, the Total Excess Cancer Burden of 0.03 shows that the maximum probable number of people within the population of the affected area is well below one (1.0), or effectively that no one would contract cancer as a result of the proposed project. .The Maximum Individual Risk of less than 1 in 1,000,000, ft although technically finite, is so small that it is considered not f significant. For comparison, the Maximum Individual Risk from the existing average ambient air quality conditions, as measured at the SCAQMD Burbank station and other SCAQMD sampling sites in the greater Los Angeles area/ is about 400 times greater than that s~.S r*sk resulting from the maximum emissions of the proposed aeration facility. * . ' In the November 13, 1985 Federal Register, the EPA found that amounts of VOCs resulting from aeration of VOC contaminated water did not significantly increase risks from airborne contaminants (see Appendix IS-A). A detailed discussion of naturally occurring, traditional, and man-made carcinogens and the associated risks, is provided in a written testimony by Professor Bruce N. Ames and is located in Appendix IS-D. Professor'Ames has served on the Board of Directors of the National Cancer Institute (National Cancer Advisory Board) and is presently Chairman of the Department of Biochemistry at the University of California Also included in Appendix IS-D is a Detailed Summary of Specific Health Effects Considerations which discusses cancer r p I risks and toxicological and epidemiological data.

TV r

APPENDIX 10

COST ANALYSIS

r r r r l COST ANALYSIS

The costs presented in this OUFS are intended only to provide a means of comparing the relative capital, operating and maintenance costs of candidate remedial alternatives and not for the preparation of detailed cost estimates, bid documents, or process designs. Although treatment facilities involving aeration and granular activated carbon adsorption processes are now available on a modular and/or turnkey basis, the wide variation of capital and operating costs associated with these rr processes makes it difficult to standardize the costs to any degree of reliability. In addition, process design parameters, which are crucial in the development of these costs, are not standardized but are instead site-specific. Also, the ir development and application of safety factors is somewhat subjective and further impacts the reliability of cost estimates. tt Other researchers (to be noted) have compiled a I ,. considerable amount of cost data for treatment processes used in • the removal of volatile organic chemicals from water supplies. r Without exception, they too have noted the difficulty in deriving reliable cost estimates for a given treatment alternative. Much of the information provided herein has been drawn or adapted from .nL. these sources. The following information outlines the methods used in developing the costs for each of the screen alternatives n: (aeration, GAC, aeration plus GAG). A brief sensitivity analysis is also provided for the major cost parameters of each alternative, but in view of the ranges of costs involved, this it" analysis should be viewed as very approximate. For this reason, a more comprehensive treatment was not performed. All costs shown are for a facility treating 2000 gallons per minute, 168 hours per week. Treatment is assumed to provide contaminant removal down to Maximum Contaminant Level (MCL) or better. For each cost estimate, low and high estimates are given to indicate the expected range of costs for each alternative. In each of the [L alternatives discussed, the costs associated with collection, n: conveyance and discharge of the treated supply are included. r- !L ri - 2 -

Cost Details for Groundwater Extraction and Conveyance

Each of the screened alternatives requires facilities for the extraction and conveyance of groundwaters. For purposes of simplicity, these facilities, and their attendant costs, were assumed to be identifical since the method of treatment does not influence the collection aspects of the alternatives. Therefore, extraction and conveyance facilities, which include well drilling, construction and development, pumps and transmission pipeline, were considered to be fixed expenditures. The costs associated with each of these items were obtained from manufacturer's quotes and in-house (LADWP) estimates; a breakdown of the required materials and the associated costs is detailed in the following: re Estimated Cost R: Extraction Wells Drill and case to 285± feet $ 22,500 Pump and motor 7,500 ti Installation 7,500 Cost per well 37,500

' - Cost for 8 wells 300,000

IE Collecting/Inlet Line Install 6,621 feet of 12-inch steel pipe @ nc $9.83/inch/foot (paved) 781,013 Install 3,964 feet of nc 12-inch steel pipe @ $6.41/inch/foot (unpaved) 304,911

Install 50 feet of 16-inch steel pipe @ $6.40/inch/foot (unpaved) 5,120

Outlet Line

Install 460 feet of 16-inch steel pipe @ _i • $9.81/inch/foot and connect . 72,202 I- -»,-. SUBTOTAL 1,463,246 Contingencies (20%) 292,649 l.L TOTAL $1,755,895 i>. Operating and maintenance costs for these facilities are limited primarily to periodic pump maintenance and r electricity requirements. The total annual energy requirement to convey 2,000 gallons per minute of groundwater to the proposed site, assuming 80-percent pump efficiency, is summarized in the following: Energy, KW-hours Groundwater extraction (285± feet) 1,177,000 Head loss through pipeline (equivalent 11,000 feet 12-inch) 417,100 nu- . 50-foot lift to top of aeration r tower (not applicable to GAG) 206,500 Total 1,800,600 KW-hours (1,594,100 for GAG) L" Annual cost @ .$0.084/KW-hr $151,000 r- ($134,000 for GAG) i For simplicity, the annual maintenance labor cost for the extraction and conveyance facilities was included in the labor estimates derived for each alternative in Tables 2, 3, r. and 4. PL PL fi n: r- (L PL iV

I Alternative 1: Aeration Costs developed for this alternative include an r- aeration column shell 12.0 feet in diameter and 48.0 feet in height, a packing depth of approximately 20.0 feet, column pad and supporting structure, 15-hp blower and influent pump, demister, dehumidifier, and related appurtenances. Capital cost data for aeration equipment was obtained ] ' primarily from manufacturer's specifications sheets and i, consultant estimates, to which was added in-house estimates and contingency costs.

'•- CAPITAL COSTS • p~. Treatment Plant i.'-i Item Low High f-1. Column shell $ 10,000 $ 45,000 Packing media 6,500 . 9,000 Engineering 25,000 50,000 ) Blower 5,000 7,500 r Electrical 5,000 12,500 Pump 5,000 .8,000 Column Appurtenances 5,000 15,000 Site pad, valves, piping, support r structure 40,000 75,000 Landscaping, plumbing paint 15,000 25,000 Contingency 10,000 30,000 Totals $126,500 $277,000

Hi Groundwater Collection/Conveyance Facilities Equipment and Installation $1,755,895 $1,755,895 r. TOTAL CAPITAL COST: $1,882,395 $2,032,895 r " r1 ;r '[X ' - 5 - \:i Annualized Capital Cost R" Low High M- 8%, 20 years $191,700 $207,000 _.. 8%, 15 years 219,900 237,500 n... 8%, 10 years 280,500 303,000 10%, 20 years 221,100 238,800 10%, 15 years 247,500 267,300 n.; 10%, 10 years 306,400 330,800 -- 12%, 20 years 252,000 272,200 12%, 15 years ..276,400 298,500 r... 12%, 10 years 333,200 359,800 n: Annual Operating and Maintenance Costs Low High r: Pump power, 1,800,600 kW-hr $151,300. $151,300 n Blower power, 98,000 kW-hr 8,200 8,200 r: Chemicals for biofouling, - corrosion 37,000 37,000 r: Maintenance 5,000 10,000 ft Total $201,500 $206,500 rJ TOTAL ANNUAL, COST I:- Low High Annual Cost $393,200 $566,300 r, Cost, $/1000 gallons 0.374 0.539 Approximate cost: $0.46 + $0.08 per thousand gallons.

I,- r- ;,v I.• . r-

Cost Analysis for Aeration A comparison of the above cost figures with those obtained from the available literature [22,28,29,30] for pilot-plant and production facilities indicates that the range of capital, operating and maintenance expenditures for the treatment r plant alone is reasonable, especially with regard to the total cost to treat 1000 gallons (this comes out to about $0.06 to $0.10 per 1000 gallons, excluding groundwater collection/conveyance P~- costs) . The lower figure is probably too optimistic, although I, one reference [24] cites a value of only $0.03/1000 gallons. It can be seen from the above that engineering and material estimates greatly influence the annualized cost, making the r effect of the assumed interest and project life estimates small by comparison. Love et al [22] has estimated the cost of a 0.5 MGD rr aeration plant at approximately $0.20/1000 gallons; extrapolation of this data for a 2000-gpm (2.88 MGD) plan indicates a cost of about $0.05/1000 gallons. Clark et al [31] has developed a simple regression model relating the cost of treatment by aeration with such parameters as system size and air-to-water ratio. Although this model includes the costs associated with chlorination of the effluent stream, the model does demonstrate that cost is primarily a function of system capacity. For this reason, it is expected that the material costs of aeration (for the treatment plant) would dominate annualized cost, as the above figures indicate. Therefore, operational changes made after construction would presumably have little effect on the total cost of this n: alternative.

FT Alternative 2; Liquid-Phase Granular Activated Carbon Adsorption (GAG) Facilities for this alternative include two fixed contactors having a combined volume of approximately 3500 cubic feet, along with appurtenant electrical, mechanical and civil elements. Two situations — virgin carbon supply and disposal n and off-site carbon regeneration — were investigated in order to consider the possible cost savings of reusing a virgin carbon supply. Again, the costs of groundwater collection are included n for comparison purposes. ff - 7 - T(: f- Capital Costs Low j.ir-' Contactors $175,000 $220,000 1 Backwash pump . 5,000 10,000 r.^ Foundation 20,000 30,000 Transfer tank 50,000 65,000 li Electrical ' 5,000 15,000 Valves, piping 10,000 20,000 ["' Engineering 40,000 65,000 I/ Pilot study — 10,000 Contingency 20,000 58,000 [ ' Totals $325,000 $493,000

("" Groundwater Collection/Conveyance Facilities ' i . Equipment and Installation $1,755,895 $1,755,895 n TOTAL CAPITAL COST: $2,080,895 $2,248,895 Annualized Capital.Costs r: Low High 8%, 20 years $211,900 $229,000 8%, 15 years 243,100 262,700 8%, 10 years 310,100 335,200 10%, 20 years 244,400 264,200 10%, 15 years 273,600 295,700 10%, 10 years 338,700 366,000 12%, 20 years 278,600 301,100 12%, 15 years 305,500 330,200 12%, 10 years 368,300 398,000

Annual Operating and Maintenance Costs Case 1: Virgin Carbon Low High H " ' Pump power, I i" :-.,-.. 1,594,100 KW-hrs $134,000 $134,000 (""*» . Carbon . 178,500 210,000 f Disposal 100,000 126,000 | Maintenance 10,000 25,000 _] Totals $442,500 $495,000 - 8 -

Case 2: Regenerated Carbon Low High Pump power, 1,594,100 KW-hrs $134,000 $134,000 Carbon 94,500 94,500 10% make-up 9,450 9,450 Maintenance 10,000 25,000 n. Totals $247,950 $262,950 Total Annual Cost r Annual Cost $459,850 $893,000 Cost, $/1000 gallons 0.437 0.850 r Approximate cost: $0.64 + $0.21 per thousand gallons e Cost Analysis for GAC Based on the figures presented for GAC treatment using virgin carbon and regenerated carbon, it is apparent that the primary factor affecting the annualized cost of this alternative is the carbon supply. This conclusion is substantiated by the regression model for GAC developed by Clark et al [31]. The use of regenerated carbon in water treatment, however, must be : qualified on the basis of prior use: that is, a carbon that has been used to treat wastewater should not be employed in the subsequent treatment of a drinking water supply after .it has been r regenerated. The required segregation of carbon types at the regeneration plant may increase the cost of the regenerated r' carbon supply or impact its availability. However, the use of I _.. regenerated carbon appears to have significant potential for cost savings and should be considered. Hj_ Love et al [22] indicates an approximate capital cost ' •" of $0.50/1000 gallons for a 0.5 MGD GAC plant treating 1000 parts ,, per billion of TCE. This data extrapolates to about $0.35/1000 H gallons for a 2000-gpm (2.88 MGD) plant (this does not include I '- the cost of collection/conveyance) . j _. Alternative 3; Aeration Plus GAC I This alternative is considered to be identical with H . that of aeration alone with the single exception that GAC is | " added to the aeration column off-gas to prevent venting of f-**. > contaminants into the air. [r - g -

Capital Costs Low High Aeration costs $126,500 $277,000 Carbon contactors 100,000 120,000 Pilot study — 10,000 Contingency 10,000 30,000 Totals $236,500 $437,000 Groundwater Collection/Conveyance Facilities Equipment and Installation $1,755,895 $1,755,895 TOTAL CAPITAL COST: $1,992,395 $2,192,895

Annualized Capital Costs Low High 8%, 20 years $202,900 $223,400 [p"^ 8%, 15 years 232,800 256,200 8%, 10 years 296,900 326,800 i . 10%, 20 years 234,000 257,600 r 10%, 15 years 261,900 288,300 p4" 10%, 10 years 324,300 356,900 [! 12%, 20 years 266,700 293,600 12%, 15 years 292,500 322,000 r: 12%, 10 years 352,600 388,100 ,- Annual Operating and Maintenance Costs 1- Case 1: Virgin Carbon j- Low High 1 L Pump power, 1,594,100 KW-hrs $151,300 $151,300 '• Carbon 40,000 45,000 Disposal 15,000 21,000 iF Vr Energy 8,500 8,500 l Carbon handling 17,500 fi. - Maintenance 10,00— 0 15,000 n '• Totals $224,800 $258,300 f- - 10 -

Case 2: Regenerated Carbon Low Pump power, 1,594,100 KW-hrs $151,300 $151,300 Reactivation 17,000 45,000 Make-up losses 4,500 7,000 Freight 7,000 7,500 Energy 8,500 8,500 Carbon handling 17,500 Maintenance 10,000 15,000 Totals $198,300 $251,800 r Total Annual Cost ' Low Annual Cost $401,200 $646,400 Cost, $/1000 gallons 0.382 0.615 Approximate cost: $0.50 + $0.12 per thousand gallons r: Cost Analysis for Aeration Plus GAG As with the aeration alternative, the cost of this treatment process is primarily a function of engineering and materials. Again, the potential cost savings of utilizing ft reactivated carbon is an attractive feature. The GAC process is »• an adaptation of available odor-control equipment, so the range ft of cost for this aspect of the overall process should be small. Present Worth Considerations ft For the purposes of this study, each candidate treatment alternative was considered to have a 15-year service life. A present worth analysis (based on a 10% interest factor) ft of each alternative is summarized in the following: Capital Present ft Cost Worth Aeration

; Low $1,882,395 $201,500 $3,415,000 •n •> High 2,032,895 206,500 3,603,500 - 11 -

Capital O&M Present Cost. f Cost . Worth GAG (carbon not regenerated) Low 2,080/895 442,500 5,446,600 High 2,248,895 495,000 6,013,900 I: GAC (carbon regenerated) r~ Low 2,080,895 247,950 3,966,800 High 2,248,895 262,950 4,248,900 | Aeration/GAC (carbon not regenerated) t Low 1,992,395 224,800 3,702,200 High 2,192,895 258,300 4,157,500 Aeration/GAC (carbon regenerated) Low 1,992,395 198,300 3,500,700 High 2,192,895 251,800 4,108,100

Ir f fr fr f,

I - 12 -

It is clear from the above figures that although aeration is numerically the most cost-effective alternative, the recommended alternative (aeration plus GAG) is, in view of the probably uncertainties involved, essentially equivalent to the aeration-alone option with regard to project cost. This factor, combined with the obvious adverse public health implications of the aeration-alone 'alternative, further justifies the r aeration/GAC recommendation.

Sensitivity Analysis The unit costs developed from the present worth analysis are based on an influent TCE concentration of 650 parts r per billion (ppb). As concentration varies, so will the costs of treatment. The impact of concentration change on capital costs, however, may be completely different than that for operating and r maintenance costs. For example, aeration tower efficiency'is relatively independent of influent concentration, so one would expect aeration capital and operating/maintenance costs to remain relatively constant over a wide range of influent concentrations. r: However, for GAG treatment, operating and maintenance costs will vary almost proportionately with influent concentration since the r- quantity of carbon used is a function of time. The large cost associated with the groundwater extraction and conveyance system tends to overshadow the ranges of annualized capital cost of the treatment plants alone and makes an overall comparison of alternative costs with published _t . data difficult. In view of this, and considering that the '• cLCCUlTcLCaccuracyV Ooff +th* J"e1 ^ cosr*r\c4t~ rangevanrrose mam ay t r bV\*e i aas e ? higV» T rrVh » aas c ; ±4 - 20%O ft 9-, aa detaile*^£a4- = d 1- andd exhaustivexhaust: e sensitivity analysis was considered to be f unnecessary.