RI/FS Report
Taylor Lumber and Treating Superfund Site Feasibility Study
Volume IV
Prepared for U.S. Environmental Protection Agency
WA No. 225-RICO-10F1/RAC V Contract No. 68-W6-0025
July 2004
Revised December 2004
CVO\043650001
CVO\043650001 Contents
Section Page
1 Introduction ...... 1-1 1.1 Purpose of Report...... 1-1 1.2 Report Organization...... 1-1 1.3 Background Information ...... 1-1 1.3.1 Site Description ...... 1-1 1.3.2 Property History ...... 1-2 1.4 Results from the RI Report and Baseline Risk Assessment ...... 1-4 1.4.1 On-property Surface Soil Outside Barrier Wall...... 1-5 1.4.2 Soil Storage Cells ...... 1-6 1.4.3 Off-property Ditch Soil ...... 1-6 1.4.4 Residential Soil...... 1-7 1.4.5 River/Creek Sediment...... 1-7 1.4.6 Contaminated Media Inside Barrier Wall ...... 1-8 1.4.7 Groundwater Outside the Barrier Wall...... 1-9 1.4.8 Surface Water ...... 1-10 1.4.9 Air ...... 1-11 1.5 Summary...... 1-11
2 Remedial Action Objectives ...... 2-1 2.1 ARARs...... 2-1 2.1.1 Chemical-specific ARARs...... 2-2 2.1.2 Location-specific ARARs...... 2-4 2.1.3 Action-specific ARARs...... 2-5 2.1.4 Summary of Risk–Based Criteria and ARARs...... 2-8 2.2 Remedial Action Objectives and Target Areas...... 2-8 2.2.1 Soil Outside the Barrier Wall ...... 2-8 2.2.2 Groundwater Outside the Barrier Wall...... 2-11 2.2.3 Contaminated Media Inside the Barrier Wall...... 2-12 2.3 General Response Actions...... 2-12
3 Identification and Screening of Technologies ...... 3-1 3.1 Presumptive Remedies ...... 3-1 3.2 Screening Process...... 3-2 3.3 Soil Outside the Barrier Wall ...... 3-2 3.3.1 Institutional Controls ...... 3-2 3.3.2 Containment...... 3-3 3.3.3 Removal ...... 3-4 3.3.4 Treatment...... 3-4 3.3.5 Disposal...... 3-7 3.4 Groundwater Outside the Barrier Wall...... 3-7 3.4.1 Institutional Controls ...... 3-7
CVO\043650001 III CONTENTS, CONTINUED
Section Page 3.4.2 Containment / Removal ...... 3-8 3.4.3 Treatment ...... 3-8 3.5 Contaminated Media Inside the Barrier Wall ...... 3-10 3.5.1 Institutional Controls...... 3-10 3.5.2 Containment ...... 3-11 3.5.3 Removal...... 3-12 3.5.4 Treatment ...... 3-15 3.5.5 Disposal ...... 3-17 3.6 Summary of Retained Technologies...... 3-17
4 Assembly of Remedial Alternatives ...... 4-1 4.1 Soil Outside the Barrier Wall (SO) ...... 4-1 4.2 Groundwater Outside the Barrier Wall (GW)...... 4-2 4.3 Contaminated Media Inside the Barrier Wall (BW) ...... 4-2
5 Detailed Analysis of Alternatives ...... 5-1 5.1 Evaluation Criteria...... 5-1 5.1.1 Overall Protection of Human Health and the Environment...... 5-1 5.1.2 Compliance with ARARs...... 5-2 5.1.3 Long-Term Effectiveness and Permanence ...... 5-2 5.1.4 Reduction of Toxicity, Mobility, and Volume through Treatment ...... 5-2 5.1.5 Short-Term Effectiveness ...... 5-2 5.1.6 Implementability...... 5-2 5.1.7 Cost...... 5-3 5.2 Evaluation of Alternatives ...... 5-3 5.2.1 Soil Outside the Barrier Wall (SO) ...... 5-3 5.2.2 Groundwater Outside the Barrier Wall (GW)...... 5-7 5.2.3 Inside the Barrier Wall (BW)...... 5-9 5.2.4 Summary ...... 5-12 6 References ...... 6-1
Appendixes A Probabilistic Risk Assessment B West Facility Soil and Off-property Ditch Hot Spot and Non-Hot Spot Exceedance Maps C Cost Estimates D MW-24s Installation and August 2004 Groundwater Sampling E Residential Soil Removal Action
IV CVO\043650001 CONTENTS, CONTINUED
Section Page
Tables 1-1 Soil Risk Summary 2-1 Summary of Chemical-Specific ARARs 2-2 Risk-based Soil COC Action Levels and Remediation Goals 2-3 Quantity Estimates for Each Cleanup Unit 3-1 Screening of Remediation Technologies 3-2 Summary of Retained Technologies 4-1 Screening of Treatment Options for Soil Target Areas 4-2 Alternatives for Soil Outside the Barrier Wall (SO) 5-1 Evaluation of Alternatives for Soil Outside of the Barrier Wall (SO) 5-2 Evaluation of Alternatives for Groundwater Outside of the Barrier Wall (GW) 5-3 Evaluation of Alternatives for All Media inside of the Barrier Wall (BW)
Figures 1-1 Facility 2-1 Soil Target Areas Outside the Barrier Wall 2-2 Approximate Area of Residential Remediation 2-3 Pentachlorophenol Concentrations (µg/L) Aug/Sept 2002
CVO\043650001 V Acronyms and Abbreviations
AC asphalt concrete ACZA ammoniacal copper zinc arsenate AOC area of contamination ARAR Applicable or relevant and appropriate requirement CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulations COC contaminant of concern COPC contaminant of potential concern CWA Clean Water Act DNAPL dense nonaqueous phase liquid DOT Department of Transportation DUS dynamic underground stripping Eco Ecological E&E Ecology and Environment, Inc. EF East Facility ELCR excess lifetime cancer risk EPA United States Environmental Protection Agency ESA Endangered Species Act FS Feasibility Study ft Feet GAC granular activated carbon HI hazard index HH human health HPO hydrolysis/pyrolysis/oxidation IA Integrated Assessment ISCO in situ chemical oxidation
CVO\043650001 VII LIST OF ACRONYMS AND ABBREVIATIONS, CONTINUED
LDR land disposal restriction LNAPL light nonaqueous phase liquid µg/L micrograms per liter MCL maximum contaminant level MCLG maximum contaminant level goal MFA Maul, Foster, and Alongi, Inc. mg/kg milligrams per kilogram mg/L milligrams per liter MW monitor well NAPL nonaqueous phase liquid ng/kg nanograms per kilogram NCP National Contingency Plan NHPA National Historic Preservation Act NPDES National Pollutant Discharge Elimination System NPL National Priorities List O&M operations and maintenance OAR Oregon Administrative Rule ODFW Oregon Department of Fish and Wildlife ODEQ Oregon Department of Environmental Quality ORS Oregon Revised Statutes OU operable unit PAH polycyclic aromatic hydrocarbon PCP Pentachlorophenol PPE personal protective equipment PRB permeable reactive barrier PRG preliminary remediation goal PS Treated Pole Storage Area RA Removal Action or risk assessment
VIII CVO\043650001 LIST OF ACRONYMS AND ABBREVIATIONS, CONTINUED
RAO remedial action objective RBC Risk-based concentration RCRA Resource Conservation and Recovery Act RI Remedial Investigation Report RI/FS Remedial Investigation and Feasibility Study redox oxidation/reduction SARA Superfund Amendment and Reauthorization Act SDWA Safe Drinking Water Act SEAR surfactant enhanced aquifer restoration SVOC semivolatile organic compound TCDD 2,3,7,8-tetrachlorodibenzo-p-dioxin TCLP toxicity characteristic leaching procedure TEQ toxic equivalency quotient TLT Taylor Lumber and Treating, Inc. TSD treatment, storage or disposal UCL upper confidence limit UTS universal treatment standard WF West Facility WP White Pole Storage Area WQC water quality criteria
µg Microgram 95UCL 95 percent upper confidence limit
CVO\043650001 IX
SECTION 1 Introduction
1.1 Purpose of Report This report is submitted to the U.S. Environmental Protection Agency (EPA) in partial fulfillment of the requirements set forth in the Statement of Work [SOW] for a Remedial Investigation/Feasibility Study [RI/FS] for the Taylor Lumber and Treating [TLT] Superfund Site, Oregon, Work Assignment [WA] No. 225-RICO-10F1, Revision #3, April 1, 2002. The Feasibility Study report is described under Tasks 11 and 12 of the SOW. EPA will use the FS in combination with the RI report to aid in development of the Record of Decision (ROD) for the site.
1.2 Report Organization This report is organized into five sections:
• Section 1, Introduction. Provides background information and summarizes the results of the RI and Baseline Risk Assessment (RA) reports. Describes the media and locations at TLT that will be considered for remediation.
• Section 2, Remedial Action Objectives. Presents the federal and state applicable or relevant and appropriate requirements (ARARs) that are considered in developing the remedial action objectives (RAOs) for TLT. Defines the RAOs for each cleanup unit, describes the general response actions, and estimates the extent of areas to be remediated.
• Section 3, Identification and Screening of Technologies. Identifies and screens the remedial technologies potentially applicable for each cleanup unit.
• Section 4, Assembly of Remedial Alternatives. Assembles the technologies retained from the screening described in Section 3 into remedial action alternatives to be considered for each cleanup unit.
• Section 5, Detailed Analysis of Alternatives. Provides detailed evaluation and comparison of alternatives.
1.3 Background Information
1.3.1 Site Description The TLT site is a former wood treating facility and lumber mill located approximately 1 mile west of Sheridan, Oregon. The properties formerly held by TLT, Inc., together occupied approximately 234 acres situated on the lower east slope of the Coast Range within the South Yamhill River Valley.
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Approximately one-quarter of the property was used as a wood treating facility, one-quarter was used as a sawmill and planing facility, and the remainder was either vacant or used as agricultural land. Wood treating operations occurred on the industrial portion of the facility west of Rock Creek Road, referred to as the West Facility. Covering approximately 40 acres, this area contains the former Treatment Plant area, White Pole Storage area, Treated Pole Storage area, Contaminated Soil Storage area, and Truck Shop area (Figure 1-1). Portions of the West Facility lie within 150 feet of the South Yamhill River and Rock Creek. The East Facility refers to approximately 40 acres of industrial property east of Rock Creek Road, and includes the former Main Office, Sawmill, Planning Mill, End Painting, and Moe’s Mountain (wood debris pile) areas. Land use in the vicinity of the TLT property includes light industrial, residential, and agricultural zoning. There are 128 homes within a 1-mile radius of the property. The former TLT property and vicinity probably will continue to be used for industrial, agricultural, and residential purposes. The West Facility is primarily covered with gravel, asphalt, buildings and stored lumber and poles. There is little permanent habitat for plants or wildlife and less than 5 percent of the area supports vegetation (predominantly grasses, weeds, and aquatic vegetation in ditches). In the East Facility, the property is relatively less paved and bears more vegetation, particularly east of the Planing Mill and End Painting facility, and Moe’s Mountain. The South Yamhill River and Rock Creek (to the south and east of the facility, respectively) provide riparian habitat for plants and wildlife. The areas investigated under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) RI include all of the East and West facilities and adjacent areas that may have been impacted by activities at the property.
1.3.2 Property History Sawmill operations began at TLT in the East Facility in 1946. Wood treating began in the West Facility in 1966, in an area that was formerly used as a drive-in-movie theater. Operations continued uninterrupted at both facilities until 2001. TLT owned the property east of the Sawmill area from 1985 until 1998, when they sold it to Sheridan Forest Products. TLT filed for bankruptcy and was placed on the EPA’s National Priorities List (NPL) in June 2001. All operations at TLT ceased in July 2001. Three companies currently own portions of the former TLT property. Pacific Wood Preserving of Oregon purchased the West Facility, with the exception of the Truck Shop area, and began wood treating operations in June 2002, using primarily copper naphthalene. Squire Investments, Inc., owns the portion of the East Facility south of the railroad tracks, and builds cedar gazebos and patio furniture. “Dee” Industrial owns the remainder of the former TLT holdings, and is currently dismantling buildings and clearing the East Facility north of the railroad tracks. The large portion of property north of the West Facility remains in agriculture. A portion of property south of Highway 18B is currently being developed for residential use.
Facility Operational History Treatment of Douglas fir logs for utility poles and pilings was the predominant activity at TLT. The facility produced approximately 2,500 treated poles per month. Wood-treating
1-2 CVO\043650001 1. INTRODUCTION
chemicals included creosote, pentachlorophenol (PCP)-enriched P-9 base oil, and Chemonite. Water-based fire retardant (a mixture of ammonium sulfate, boric acid, sodium dichromate and zinc chloride) was used until 1967 and Wolman salts (sodium fluoride, sodium arsenate, sodium chromate and dinitrophenol) until 1972. Chemonite (a 3 percent water-based solution containing arsenic acid, copper salts, zinc and ammonia) was used between 1982 and 1996.
Property Investigation History Contamination at the TLT property was mainly associated with wood treating activities. Drips or releases from aboveground storage tanks, drip pads, and tank farms in the Treatment Plant and Treated Pole Storage areas, and storage of contaminated soil from property activities represented the primary sources of contamination at the property. A number of investigations and actions occurred at TLT between the first groundwater sampling event in 1988 and the Removal Action in 2000, including:
• 1988 National Pollutant Discharge Elimination System (NPDES) Phase I Groundwater Investigation
• 1988 NPL Preliminary Assessment and Site Inspection
• 1990 NPL Listing Site Inspection
• 1991 Resource Conservation and Recovery Act (RCRA) Retort Area Characterization and Soil Removal
• 1994 RCRA Former Vault Closure
• 1994 RCRA Facility Assessment
• 1995 RCRA Interim Corrective Measures Study
• 1997 Phase I RCRA Facility Investigation
• Emergency Response: February 26, 1999
• Emergency Response: September 10, 1999
• 1999 Integrated Assessment
• 1999 Groundwater Characterization Report
• 2000 Stormwater Treatment System Phase 1 and Phase 2
• 2000 Removal Action
• 2002 Phase 1 Remedial Investigation (Phase 1 RI)
• 2002 Phase 2 Remedial Investigation and Groundwater Monitoring
• 2004 Baseline Risk Assessment (RA)
• 2004 Remedial Investigation Report (RI Report)
CVO\043650001 1-3 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
Based on the results from the Integrated Assessment (IA) and the Groundwater Characterization Report, the Removal Action (RA) defined areas that posed an imminent and substantial danger to public health or welfare or the environment, and implemented measures to address that danger. The measures included paving part of the Treated Pole Storage area, removing areas of high arsenic concentration from the roadside ditches, and installing a bentonite slurry wall (barrier wall) to contain nonaqueous phase liquids (NAPL) present beneath the Treatment Plant area. The ground surface enclosed by the barrier wall was paved, and a groundwater extraction system constructed within the barrier wall to maintain an inward hydraulic gradient. Contaminated soil from various existing stockpiles, in addition to soil resulting from RA activities, was consolidated and moved to the newly constructed soil storage cells located northwest of the Treatment Plant. When TLT was listed as a Superfund site in 2001, EPA contracted with CH2M HILL to complete an RI/FS for the site. The Phase 1 RI evaluated the nature and extent of contamination at TLT based on existing data. Specific objectives included preparing a database for the site, conducting a screening risk assessment, and identifying additional data necessary to complete the RI/FS. Phase 2 Investigation and Groundwater Monitoring addressed the needs identified in the Phase I RI. Soil and sediment sampling was conducted, additional wells were installed, and groundwater monitoring was conducted quarterly for 1 year. The RI report evaluated the nature and extent of contamination at TLT based on existing data and on results from the Phase 2 Investigation. The baseline RA estimated the potential risk posed by TLT under the assumption of no remedial action for current and reasonable expected future conditions.
1.4 Results from the RI Report and Baseline Risk Assessment The RI report and baseline RA divided the site by medium and by location or exposure area (on-property soil, off-property ditch soil, etc.), and characterized the contaminant nature and extent, and risk for each medium or location. In the RI report, contaminant concentrations were screened against industrial, residential, or tapwater Region 9 Preliminary Remediation Goals (PRGs); freshwater aquatic, or aquatic sediment screening values (SVs) were also used to identify areas of potential concern. Total equivalent quotient (TEQ) concentrations were used in place of individual dioxins/furans (herein referred to simply as dioxin or dioxins) congeners concentrations to evaluate contaminant levels. Arsenic concentrations in soil on- and off-property frequently exceeded the PRGs [residential PRG is 0.389 milligrams per kilogram (mg/kg), industrial PRG is 1.59 mg/kg], suggesting that arsenic levels in native soil are relatively high. A statistical analysis of available arsenic data estimated that background arsenic concentrations in the vicinity of TLT range up to 12 mg/kg. Therefore, arsenic concentrations in excess of 12 mg/kg are considered site-related contamination, while concentrations at or below 12 mg/kg are considered to be within background range. The human health RA calculated excess lifetime cancer risk (ELCR) values and a non-cancer hazard index (HI) for each exposure area. The regulatory risk target thresholds were 1 x 10-6
1-4 CVO\043650001 1. INTRODUCTION
(ELCR) and a HI of 1. Exposure areas that exceeded these risks are of potential concern. For the ecological RA, a hazard quotient (HQ) or an HI exceeding 1 indicated an ecological concern. A brief summary of findings for each medium or location follows. A summary of the exposure point concentrations and calculated risks for on-property and off-property soils are presented in Table 1-1. In Section 2, these results are used to define target areas and their cleanup objectives.
1.4.1 On-property Surface Soil Outside Barrier Wall In the West Facility outside the barrier wall, arsenic and dioxins in the soil are the primary risk contributors. The samples termed “surface soil” were all samples that included soil from the surface to a maximum depth of 2 feet. Depending on the study and the type of sample, a surface soil sample might have included material from the upper 6 inches, 1 foot, or 2 feet of soil column. The RI presents a discussion of the vertical distribution of contamination. Briefly, of all the samples collected at depth (2 feet and below) in the West Facility (100 for arsenic and 47 for dioxins), exceedances of PRGs or background concentrations occurred only at one location outside of the barrier wall (at BG-01 in the White Pole Storage area). Refer to Figure 4-3 of the RI for sample locations and comparisons to PRGs. Media within the barrier wall are contaminated at depth and are considered separately in Section 1.4.6. Subsurface soil will not be considered further in this document for soil outside of the barrier wall. Surface soil in the northwest corner of the Treated Pole Storage area was paved over in 2000 because of arsenic levels in excess of 300 mg/kg. Although current risk of exposure to this area has been controlled, contamination still exists and could present a future risk if the cover is not maintained or is removed. Unpaved surface soil that exceeds 100 times the PRGs for arsenic and/or dioxin TEQ occurs along the northeast boundary of the Treated Pole Storage area (near the Dryer), and near the periphery of the paved area in the northwest region of the Treated Pole Storage area. Arsenic and dioxins TEQ exceedances also co-occur along the southern boundary of the White Pole Storage area. Results from the baseline RA indicate that the calculated ELCR for industrial workers currently exceeds 1 x 10-6 at all locations in the West Facility. Current risks were based on data from unpaved soil. However, the risk from the Truck Shop area is attributable to arsenic levels that exceed the PRGs but are within background range. The ELCR for industrial workers exceeds 1 x 10-4 in the Treated Pole, Treatment Plant, and White Pole Storage areas. Risk from the White Pole Storage area was driven by the maximum detected concentrations for arsenic and dioxin TEQ in the exposure area, which occurred at sample AP-03. This location is currently under the soil storage cells. If this sample were eliminated, the risk in the White Pole Storage area would be below 1 x 10-4. HI for noncancer effects is less than one across the site. The risk to the standard industrial workers was greater than the risk to trench workers in all cases. The ELCR for trench workers exceeded 1 x 10-4 in the Treated Pole and Treatment Plant areas. Risk to trench workers was calculated by means of both surface and subsurface soil data. Because most of the soil contamination is located within the surface (0-2 feet), remediating the surface soil would mitigate risk to trench workers. However, in areas where
CVO\043650001 1-5 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY contaminated soil is paved, installing trenches through the pavement could expose workers to contaminated soil. This risk will be minimized by establishing institutional controls that require appropriate precautions during any subsurface construction. Therefore, the trench worker exposure scenario and subsurface soil are not considered further in this document. The baseline RA identified 11 sample locations in the West Facility that might provide suitable ecological habitat. All of these samples were located in the ditches along the Truck Shop and railroad tracks in the northern portion of the facility. At these locations, copper and zinc were identified as potential risk contributors in addition to dioxins and arsenic. The ecological risk associated with these areas is addressed in this FS. In the East Facility, elevated concentrations of arsenic and dioxins were observed in a few of the soil samples. However, EPA has determined that the East Facility is not a part of the Superfund site, and has referred this area to the Oregon Department of Environmental Quality (ODEQ) for possible follow-up action. The East Facility is not addressed further in the FS.
1.4.2 Soil Storage Cells The soil storage cells located in the northwest corner of the property are composed of three separate stockpiles of soil from different locations and, based on their various histories, are considered to be listed hazardous waste (F032, F034, F035). The total volume of the three cells is approximately 19,200 cubic yards (yd3). Contaminant levels in the soil storage cells are generally variable; data from Cell No. 2 show minimal contamination, while Cell No. 1 and Cell No. 3 have sporadic low-level contamination. The arsenic levels (11 to 28 mg/kg) are only slightly above background, and dioxin levels are generally low. Based on the toxicity characteristic leaching procedure (TCLP) data, the material in the soil storage cells would not be considered a characteristic hazardous waste. Application of the contained-in policy could eliminate the hazardous listing for soil in Cells No. 1 and No. 2, but, based on available data, not for soil in Cell No. 3. Dioxin concentrations that exceed 10 times the Universal Treatment Standard (UTS) of 0.001 mg/kg were detected in samples collected from Cell No. 3. Primary contributors to human health risk detected in soil samples from the soil storage cells included dioxins, arsenic, polycyclic aromatic hydrocarbons (PAHs), and PCP. Based on limited available data, the combined ELCR for the on-property worker scenario is below 1 x 10-4, and the HI is less than 1. The soil storage cells were not considered suitable ecological habitat.
1.4.3 Off-property Ditch Soil Ditches along Rock Creek Road and Highway 18B were sampled in 1999, 2002, and 2003. For sample locations, refer to Figure 4-5 of the RI Report. Arsenic and dioxins are the primary contaminants in these soils, although copper and zinc levels are also of concern with respect to small terrestrial species. Arsenic and dioxin levels were detected above the background range and the PRGs in the ditch along the west side of Rock Creek Road, in the gully between the highway and South Yamhill River, in the ditch south of the White Pole Storage area, and at the confluence of the ditch with Rock Creek (RS-11).
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In the baseline RA, the off-property ditches were considered as a single exposure area. Arsenic and dioxins were the primary contributors to human health risk, and the ELCR for a recreational exposure scenario was above 1 x 10-4 for this exposure area, exceeding the target risk threshold. The HI was less than 1. The ditches support some plant and wildlife species that are tolerant of anthropogenic disturbance, and were considered an ecological exposure area in the ecological RA. Copper, zinc, and total dioxins were identified as chemicals of ecological concern (COECs) to avian and mammalian wildlife. A risk-based concentration of 6.7 nanograms per kilogram (ng/kg) dioxin TEQ (see Table 1-1), using the lowest observable adverse effects level (LOAEL) for deer mice, is considered the target threshold for this exposure area. The deer mouse is more susceptible than other wildlife because of its small foraging area, relatively high intake per unit body weight, and the fraction of soil incidentally ingested during cleaning and foraging activities. Although the risks from copper and zinc are anticipated to be marginal to low, dioxins pose a risk that significantly exceeds the target risk threshold. The ecological HI for total dioxins exceeded 1 for all endpoint species.1 The individual ditch segments that exceed risk thresholds are described in Section 2.
1.4.4 Residential Soil Surface soil samples were collected from nearby residential yards in 1999 and 2002. For sample locations refer to Figures 4-6 and 4-7 of the RI report. Because the contaminants are derived from airborne sources, and dioxins are strongly sorbed to soil, contamination is considered to be limited to the surface soil (approximately 0 to 1 ft bgs). TEQ concentrations above PRGs were observed in soil from the five residences closest to the Treatment Plant. Risk analysis completed by ODEQ demonstrated that individual dioxin concentrations exceed the target risk thresholds at the residence located directly across Rock Creek Road from the Treatment Plant (22150 SW Rock Creek Road). The results from ODEQ’s probabilistic risk assessment are presented in Appendix A.
1.4.5 River/Creek Sediment In 1999, before RA activities began, sediment samples were collected from the South Yamhill River and Rock Creek and analyzed for semivolatile organic compounds (SVOCs), metals, and dioxins. During the Phase 2 Investigation, additional samples were collected and analyzed for metals, SVOCs, and dioxins. For sample locations, refer to Figures 4-6 and 4-7 of the RI report. In general, concentrations of contaminants in the South Yamhill River sediment samples collected from locations downstream of the Rock Creek Road ditch outfall were similar to concentrations observed upstream. However, arsenic was an exception in 1999. In that year, the arsenic concentration in sediment was 60 mg/kg at YR-14, just below the outfall. However, in 2002, three samples collected in the vicinity of YR-14 showed arsenic concentrations in the background range (less than 12 to approximately 14 mg/kg). Similarly, elevated arsenic concentrations were measured in Rock Creek sediment collected near the
1 It should be noted that when calculating the HQs for each of the dioxin/furan congeners, the exposure point concentrations (EPCs) defaulted to the maximum detected concentrations for all congeners except one, where the 95% UCL was used.
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RR crossing in 1999, but concentrations in sediment collected from this area in 2002 were in the background range. The improvement in site-related contaminant concentrations is consistent with the benefits of prior remedial actions and recent changes in property operations. Furthermore, future remedial actions related to this FS will eliminate remaining source areas and potential pathways for contaminants to migrate to the South Yamhill River and Rock Creek. The risk analysis was conducted using the maximum concentrations observed during the two sampling events. The ELCRs for sediment in the South Yamhill River and Rock Creek were 5 x 10-6 and 3 x 10-5, respectively, based on a recreational/tribal user scenario. Arsenic measured in 1999 was the primary risk driver in both cases. During the most recent sediment sampling event (2002), arsenic, copper, and nickel slightly exceeded the most conservative freshwater sediment screening values in at least one sample in Rock Creek and the South Yamhill River. Considering the low magnitude of exceedances, the fact that concentrations were similar in samples collected both upstream and downstream of the site, and that concentrations observed in 2002 are lower than those observed at similar locations in 1999, current risks to benthic invertebrates in the river and creek are believed to be low. As a result, sediment in the South Yamhill River and Rock Creek is not addressed further in this document.
1.4.6 Contaminated Media Inside Barrier Wall Inside the barrier wall, most contamination is associated with a zone of dense non-aqueous- phase liquid (DNAPL) that has been observed from 6 to 20 feet bgs, with the bulk of the DNAPL pooled on a lower confining unit (siltstone). Refer to Figure 4-9 of the RI report for a graphic of the DNAPL extent. Associated with the DNAPL is contaminated soil and a plume of contaminated groundwater. Soil, groundwater, and DNAPL samples were collected during the IA from the area now enclosed by the barrier wall (see Figure 1-1). Summarized in the RI report, results indicated sporadic high levels of arsenic, dioxins, PCP and PAHs in the surface and subsurface soils and contaminated groundwater, and DNAPL with high contaminant concentrations. The contaminants vary somewhat among media:
• DNAPL – PAHs and PCP • Soil – dioxins, PAHs, PCP, and arsenic • Groundwater – dioxins, arsenic, PCP, and benzo(a)pyrene (BaP) One of the primary goals of the 2002 field investigation was to confirm that the barrier wall and groundwater extraction system is containing the DNAPL and contaminated groundwater. An additional monitor well was installed and sampled just north of the wall, and existing wells south of the wall were sampled and probed for DNAPL. Data indicate that the system is effectively containing DNAPL and groundwater, and that the underlying siltstone is a competent aquitard and confining layer (refer to Section 4.5.1 of the RI report). For groundwater inside the barrier wall, the primary contributors to human health risk (residential exposure scenario) are dioxins, arsenic, BaP, and PCP. Total ELCR ranged from 2 x 10-5 to 2 x 10-2; the ELCR for groundwater sampled from 7 of the 10 wells inside the barrier wall exceeded 1 x 10-4. The HI for eight of the wells was greater than 1, and ranged
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up to 118; primary contributors to non-cancer risk included manganese and phenolic compounds. PCP concentrations exceeded the maximum contaminant level (MCL) of 1.0 micrograms per liter (µg/L) in seven wells, with concentrations ranging from 2.3 to 3,500 µg/L. Only traces of DNAPL were observed in the monitor wells inside the barrier wall during the quarterly sampling in 2002. However, the presence of DNAPL was confirmed when the original 2-inch polyvinyl chloride (PVC) well at MW-101S was overdrilled and replaced with a 4-inch stainless steel well. Based on this and earlier observations, the volume of DNAPL contained within the barrier wall was estimated to be approximately 250,000 gallons, affecting about 12,900 cubic yards of soil.
1.4.7 Groundwater Outside the Barrier Wall DNAPL is in direct contact with groundwater beneath the Treatment Plant area and is considered to be the primary source of downgradient contamination. The soil-bentonite barrier wall was completed in October 2000 to contain the DNAPL and source contaminants; however, residual contamination exists outside this wall. Refer to Figure 4-10 of the RI report for a graphic of the extent of residual contamination. Groundwater data collected during the IA in 1999 represent conditions before installation of the wall. Between February 2002 and May 2003, groundwater samples were collected from monitor wells outside the barrier wall during at least four quarterly events. Seven new wells were installed outside the barrier wall in July 2002, and were sampled during the subsequent groundwater monitoring events. The following conclusions were drawn from the monitoring data and presented in the RI Report:
• Arsenic occurs naturally in the groundwater. Arsenic concentrations in downgradient wells are similar to upgradient wells, and no concentration trends with time are evident.
• Dioxins have been observed in groundwater outside of the barrier wall at levels well below the MCL. The concentrations at individual wells were highly variable between sample events, ranging over four orders of magnitude. At the low concentrations measured (part per trillion range) reproducibility is difficult to achieve. Dioxins are generally not a concern in groundwater because their solubility in water is very low and they have a high affinity for particulates. Although they preferentially adsorb to organic particulates, they will adsorb to mineral surfaces in an aquifer with minimum organic carbon because of their extremely hydrophobic nature.
• Installation of the barrier wall cut off the PCP-contaminated groundwater plume from its source. PCP-contaminated groundwater exists outside the barrier wall, with the highest concentrations occurring in the stagnant zone immediately downgradient from the wall and decreasing rapidly further downgradient. PCP concentrations outside the wall did not change substantively between May 2002 and May 2003. Primary contributors to human health risk in groundwater outside the barrier wall were PCP, arsenic, and dioxins, and the total ELCR ranged from 6 x 10-6 (MW-18S) to 6 x 10-4 (MW-15S). HI ranged from less than 1 to 5.1; the primary contributor to non-cancer risk was manganese. As explained above, arsenic concentrations appeared to be within the back- ground range, and sporadic detections of dioxins are not a major concern because they
CVO\043650001 1-9 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY rarely migrate in groundwater. However, remediation of groundwater containing elevated levels of PCP to protect off-property groundwater and surface water will be considered, and this remediation will also address co-contaminants if present. The ecological RA evaluated COPC levels in groundwater wells located nearest to potential exposure areas in Rock Creek and the South Yamhill River with respect to the potential risk to aquatic and hyporheic organisms. Copper, lead, manganese, iron, barium, and pentachlorophenol in groundwater slightly exceeded available federal water quality criteria (WQC). Exceedances were small and occurred at few well locations. The ecological RA concluded that because the factors of exceedance of surface water benchmarks in shallow groundwater (without consideration of attenuating processes) were low, the associated risk to aquatic and hyporheic organisms using Rock Creek and the South Yamhill River is believed to be low.
1.4.8 Surface Water Surface water samples were collected in 1999 from 10 upstream and downstream locations in the South Yamhill River, and 2 Rock Creek locations. While DDT, barium, and mercury concentrations were above WQC protective of aquatic organisms (primarily upstream of the site), no site-related contaminants exceeded screening values in any of the 1999 samples. The 1999 data indicate that surface waters in the river and creek are not significantly affected by TLT, despite the fact that these data were collected prior to the RA activities. Assuming that conditions have improved following removal actions, additional surface water data were not collected during the Phase 2 Investigation in 2002. The ecological RA considered consumption of surface water by terrestrial wildlife as part of the total intake. The results indicate that risk from ingestion of surface water by wildlife is insignificant. To provide a screening estimate of potential risk to anglers2 who might consume fish taken from the South Yamhill River or Rock Creek, surface water concentrations were compared to the WQC for human health protection. Although no exceedances were observed in Rock Creek, concentrations of mercury, dioxins, and 4,4’-DDT were above their respective WQC in the South Yamhill River. Mercury and DDT are not considered site-related contaminants. The single dioxin exceedance was detected in a sample collected approximately 1.5 miles downstream from TLT. WQC assume a default national fish consumption rate of 17.5 grams per day (g/d). Ingestion rates as high as 175 g/d (CRITFC, 1994) have been reported for the 95 percent upper confidence level (UCL) for tribal exposure scenarios in the Columbia River Basin. Using the 95 percent UCL fish consumption rate from the CRITFC data, bis(2- ethylhexyl)phthalate and methylene chloride in addition to mercury, dioxins, and 4,4-DDT would exceed the WQC for human health protection. However, these compounds, with the exception of dioxin, are not related to site activities. The potential cumulative ELCR from all carcinogenic COPCs for surface water in the South Yamhill River (current and future recreational and tribal users) was 2 x 10-7, which is less than the lower regulatory target risk threshold of 1 x 10-6. No carcinogenic constituents were
2 Includes recreational, tribal, and other fish consumers.
1-10 CVO\043650001 1. INTRODUCTION
detected in Rock Creek. The potential non-cancer HIs for the South Yamhill River and Rock Creek were less than the non-cancer threshold value of 1.0. Based on the current conditions at the property and on results from the baseline RA, surface water at TLT is not addressed further in the FS.
1.4.9 Air Air samples were collected from seven on-property and off-property locations on seven consecutive days in 1999. Arsenic, PCP, and individual PAHs were detected at multiple locations and days at levels that exceeded their respective ambient air PRGs. These exceedances are believed to represent a “worst case scenario” for the air in the vicinity of TLT. Since that time, large portions of the Treatment Plant and Treated Pole Storage areas have been paved, and the current wood treating process no longer uses chemicals that contain arsenic or PCP. The 1999 air data were not used in the baseline RA. For the inhalation route of exposure in the human health RA, modeling was performed to estimate constituent concentrations in air from particulate or vapor emissions from soil. The Superfund Program is responsible for contamination from historical releases, i.e. from TLT, and not for emissions from current operations. Remediating the surface soil and minimizing the re-entrainment of contaminated dust into the air will protect ambient air from historical contamination present at TLT. For this reason, air, as a specific medium is not addressed further in this study.
1.5 Summary Based on the results from the RI report and the baseline RA, the following media will be considered for remediation in the FS:
• West Facility surface soil • Soil storage cells • Residential soil • Off-property ditch soil • Contaminated media inside the barrier wall • Groundwater outside the barrier wall As explained in Section 1.4, the East Facility, South Yamhill River and Rock Creek sediment, surface waters in the South Yamhill River and Rock Creek, and ambient air in the vicinity of TLT will not be considered for remediation and are not addressed further in the FS.
CVO\043650001 1-11 TABLE 1-1 Summary of Human Health and Ecological Risk in Soil Taylor Lumber and Treating Feasibility Study
Human Health Cumulative COCs Scenario Exposure Area ELCR HI Constituents % Contribution EPC Basis Current on-property worker (exposed West Facility Area 2.8 x 10-3 0.73 TEQ 98% max detect surface soil) Future on-property worker (exposed Treated Pole Storage and 1.0 x 10-3 0.91 TEQ 90% 95% UCL surface soil and soil under pavement) Treatment Plant Areas arsenic 9% 95% UCL White Pole Storage Area 1.2 x 10-4 0.65 TEQ 56% max detect arsenic 36% max detect PAHs 6% 95% UCL Truck Shop Area 2.8 x 10-5 0.55 arsenic 88% max detect PAHs 8% max detect Soil Storage Cells 6.5 x 10-5 0.52 TEQ 64% max detect arsenic 20% 95% UCL PAHs 7% 95% UCL PCP 9% 95% UCL Current and future on-property worker East Facility 8.2 x 10-5 0.45 TEQ 60% max detect (surface soil) arsenic 37% 95% UCL PAHs 1% max detect Current and future residential (surface RES-031 1.9 x 10-4 1.23 TEQ 81% max detect soil) arsenic 18% 95% UCL Current and future off-property Off-property ditches 1.7 x 10-4 0.63 TEQ 89% max detect recreational (surface soil) arsenic 10% 95% UCL
Ecological LOAEL HQ =1 Scenario Ecological Endpoint COEC HI or HQ RBC Surface soil (ecological habitat) Deer mouse TEQ 476 0.00673 ug/kg American robin Zinc 2.5 85.6 mg/kg Deer mouse Copper 3.6 38.6 mg/kg
Notes: 1For residential soil, a risk based concentration for dioxin was calculated by DEQ using probabilistic exposure factors and equations. See Appendix A. ELCR = Cumulative excess lifetime cancer risk. Estimated from all exposure routes, and all carcinogens present HI = Hazard index. Relative potential for noncancer effects posed by exposure to multiple chemical. (HI =1 is highest level considered protective.) EPC = Exposure point concentration. Either the maximum concentration detected in a given area, or the 95% UCL. TEQ = Total equivalency quotient. Combined relative toxicity of all dioxin/furans congeners present. RBC = Risk based concentration. Contaminant concentrations that correspond to acceptable risk levels. COEC = Chemical of ecological concern HQ = Hazard quotient. Relative potential for noncancer effects posed by exposure to single chemical. (HQ =1 is highest level considered protective.)
CVO\043650002
SECTION 2 Remedial Action Objectives
Development of RAOs for sites on the NPL is based on criteria set forth in the Code of Federal Regulations: 40 CFR 300.430(e)(2)(i). This rule states that remediation goals shall be established based on acceptable exposure levels that are protective of human health and the environment. In establishing cleanup requirements that are protective of human health, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP) used risk-based criteria. For carcinogens, acceptable exposure levels are equivalent to contaminant concentrations corresponding to an upper bound ELCR to an individual of between 1 x 10-6 and 1 x 10-4. For systemic (non-carcinogenic) toxicants, acceptable exposure levels represent concentrations to which the human population, including sensitive subgroups, may be exposed without adverse effects during a lifetime or part of a lifetime, incorporating an adequate margin of safety. The upper bound concentrations for these compounds occur at a HI of 1. In addition to complying with the NCP risk-based criteria, CERCLA sites must attain, or justify the waiver of, any federal or more stringent state environmental standards, requirements, criteria, or limitations that are determined to be applicable or relevant and appropriate [CERCLA §121(d)]. ARARs must be identified and considered in the development of RAOs for NPL sites. This section discusses the following:
• Federal and Oregon state regulations that are potentially applicable or relevant and appropriate
• Specific ARARs that will be used to develop RAOs for the TLT site
• RAOs for each cleanup unit
• General response actions
• Extent and volume of each cleanup unit
2.1 ARARs This section identifies potential ARARs from the universe of regulations, requirements, and guidance that might be pertinent to actions to be taken at TLT, and includes an initial assessment of whether the potential ARARs would be applicable or relevant and appropriate, based on known site conditions and potential soil and groundwater response actions. Final determination of site ARARs will be presented in the ROD.
• Applicable requirements under federal or state law are those that specifically address the situation at a CERCLA site and meet the legal prerequisites for application.
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• Relevant and appropriate requirements, while not strictly applicable, address problems or situations sufficiently similar to the site’s circumstances and are well-suited to the conditions of the site. To be considered an ARAR, a requirement must also be:
• Substantive, not procedural or administrative • Promulgated Therefore, for on-property activities, only the substantive provisions of requirements are considered ARARs. Off-property activities must comply with both substantive and administrative requirements. Policy and guidance issued by federal or state governments are not legally binding and are not ARARs; however, such advisories or guidance may be useful and are “to be considered” (TBC) for on-property actions, in the absence of ARARs. TBCs are intended to complement the use of ARARs and may be used to establish RA objectives in circumstances for which ARARs do not exist. State requirements must meet additional criteria. To qualify as a state ARAR under the NCP, the requirement must be:
• More stringent than federal requirements • Identified by the state in a timely manner • Consistently applied Federal and State of Oregon ARARs generally fall into one of three categories: (1) chemical- specific, (2) location-specific, or (3) action-specific. A summary of the potential federal and state ARARs at TLT is provided in the following subsections.
2.1.1 Chemical-specific ARARs Chemical-specific ARARs include federal and state requirements that regulate contaminants found in or discharged to the environment. These laws generally place limits on the concentration of chemicals that can be discharged to, or are present in, the environment. Separate chemical-specific ARARs are applicable to different types of media (e.g., soil, groundwater, surface water, sediment, air). In general, if a chemical is subject to more than one requirement, the more stringent one is applied.
Federal Safe Drinking Water Act (40 CFR 141) The federal Safe Drinking Water Act (SDWA) protects public health by establishing primary and secondary drinking water standards for public and community water supplies. The primary drinking water standards address toxicity and are called Maximum Contaminant Levels (MCLs) and Maximum Contaminant Level Goals (MCLGs). MCLs are designed to be attainable technically, while MCLGs are set at levels that would result in no known adverse health effects regardless of technical feasibility. CERCLA mandates that both the MCLs and the MCLGs be considered as potentially relevant and appropriate ARARs at sites where groundwater and surface water are potential sources of drinking water. However, it is the EPA’s policy to consider MCLGs as potential ARARs for the cleanup of groundwater or surface water that are current or potential sources of drinking water only when the MCLG is established at a level above zero.
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The SDWA is a relevant and appropriate ARAR at TLT. Although the groundwater quality and yield from the siltstone at TLT are not adequate for public water supply, water from the alluvial aquifer has been, and is currently, used for domestic purposes. The City of Sheridan’s municipal water supply currently extends to Rock Creek Road, but for residences west of Rock Creek Road this aquifer represents the primary domestic water source. Also, groundwater and surface water runoff from TLT flow to the South Yamhill River, which is a primary drinking water source for the City of Sheridan.
Clean Water Act (40 CFR 122) EPA has established federal WQC under the Clean Water Act (40 CFR 122). WQC are set for human health protection and for protection of aquatic life. CERCLA [40 CFR 300.121(d)] requires WQC be attained if relevant and appropriate to the circumstances of the site. Federal WQC form the basis of Oregon water quality standards. WQC are relevant and appropriate at TLT because there are discharges from the site to the South Yamhill River and Rock Creek where aquatic organisms are present. Stormwater discharges from the site are currently controlled by a National Pollutant Discharge Elimination System (NPDES) permit, Permit Number: 101267, Expiration Date: 01/31/2000.
Clean Air Act (40 CFR 50) The Clean Air Act (CAA; 40 CFR 50) regulates emissions of fugitive dust, emissions from air pollutant sources, and establishes national ambient air quality standards and national emission standards for hazardous air pollutants. The CAA would be applicable to treatment systems employed at TLT that involve recovery of a vapor phase or thermal desorption of site-related constituents. The CAA is also applicable to activities that might generate dust, such as excavation. In addition, the Oregon General Emission Standards for Particulate Matter (OAR 340-208-0100 through -0210) are applicable to visible emissions and nuisance conditions that may be generated by the construction of the selected remedy. Dust generated from earthwork or other disturbance of on-property soils must meet nuisance standards for fugitive emissions.
Oregon Environmental Cleanup Rules Oregon Environmental Cleanup Rules (OAR 340-122) are applicable and/or potentially relevant and appropriate for the establishment of cleanup levels and selection of remedial actions for soil at TLT. OAR 340-122-040(2) requires that hazardous substance remedial actions achieve one of four standards: (1) acceptable risk levels, (2) generic soil numeric cleanup levels, (3) remedy-specific cleanup levels provided by ODEQ as part of an approved generic remedy, or (4) background levels in areas where hazardous substances occur naturally. Descriptions of Oregon’s risk-based cleanup rules follow. Protectiveness The ODEQ cleanup rules require that all remedies be protective of human health and the environment, as demonstrated through a risk assessment. OAR 340-122-115 defines protective with the use of “acceptable risk” at the following levels:
CVO\043650001 2-3 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
• 1 x 10-6 for individual carcinogens • 1 x 10-5 for multiple carcinogens, and • HI of 1 for non-carcinogens Remedial actions are required for areas where hazardous substances occur at concentrations that exceed these acceptable risk levels. According to the ODEQ rules, however, institutional or engineering controls may be considered appropriate remedial actions, and treatment or removal are not necessarily required. The ODEQ protectiveness requirement is more stringent than the federal standard, which defines the acceptable risk range between 1 x 10-6 and 1 x 10-4. Hot Spot Rule The Oregon Hazardous Substance Remedial Action Rules requires consideration of treatment of hot spots to the extent feasible (OAR 340-122-0040). Oregon defines hot spots in OAR 340-122-0115 as follows:
• For groundwater or surface water, hazardous substances having a significant adverse effect on beneficial uses of water or waters to which the hazardous substances would be reasonably likely to migrate and for which treatment is reasonable likely to restore or protect such beneficial uses within a reasonable time, as determined in the FS.
• For other media (for example, soil, debris, sediment, and sludges), if hazardous substances present a risk to human health or the environment exceeding the acceptable risk level, the extent to which the hazardous substances:
− Are present in concentrations exceeding risk-based concentrations (generally, an ELCR of 1 x 10-4 or a HI of 10 for non-carcinogens),
− Are reasonable likely to migrate to such an extent that a hot spot would be created, or
− Are not reliably contained, as determined in the FS The factors to be considered for hot spot determination are similar to the remedy selection factors identified in the NCP [40 CFR 300.430(e)]. However, ODEQ rules apply a higher cost threshold for hot spot treatment, and federal rules do not make this distinction. A strong preference for treatment is required for hot spots. The Oregon environmental cleanup rules are considered applicable.
2.1.2 Location-specific ARARs Location-specific ARARs relate to the site’s geographic location relative to certain unique areas, and may limit the scope of an action (e.g., location of pumping wells or treatment areas) or place constraints on how it is implemented (e.g., limited action during migratory or nesting periods).
Floodplain The TLT site is not located within or adjacent to a designated wetland, critical habitat, wilderness, wildlife refuge, wild and scenic river, coastal zone, or navigable waters of the
2-4 CVO\043650001 2. REMEDIAL ACTION OBJECTIVES
United States or the state. However, the site is located within the 100-year floodplain of the South Yamhill River. The river provides habitat for threatened and/or endangered anadromous fish species, and the Confederated Tribes of the Grande Ronde have stated that the site is located in an area where Native American cultural resources/artifacts could be present. Encroachments in floodways and floodplains are regulated under state and federal programs, including Executive Order 11988, entitled Floodplain Management (40 CFR 6 Appendix A). Generally, these programs enforce floodplain protection standards through a permit process. Under CERCLA, the permitting aspects would not be ARARs, but conformance with substantive floodplain protection standards would be applicable for response actions that alter or result in construction (such as an on-property landfill) within a floodplain.
Endangered Species Act The federal and state Endangered Species Act (ESA), 50 CFR 450, and ORS 496.012 require protection for certain plant and animal species and their habitat. The South Yamhill River is a migratory corridor for several anadromous fish species, including Coho salmon and steelhead. Winter-run steelhead (Onchorynchus mykiss) are listed as federally threatened and as a state sensitive-critical species for the Upper Willamette River, which includes tributaries such as the South Yamhill River. Any response actions that could affect a protected species or its habitat would require prior consultation with U.S. Fish and Wildlife Service (USFWS) and Oregon Department of Fish and Wildlife (ODFW). Section 106 of the National Historic Preservation Act (NHPA) of 1966 (36 CFR 800) requires federal agencies to take into consideration the effects of federal undertakings on properties that are listed in or are eligible for listing in, the National Register of Historic Places. In order to determine the presence or absence of cultural resources within the locale, and whether the NHPA regulations apply, an archaeological survey may be required prior to any construction or excavation projects.
2.1.3 Action-specific ARARs Action-specific ARARs regulate the specific type of action or technology under consideration, and management of regulated materials. The potential federal and state action-specific ARARs for the remedial actions being considered for TLT are discussed in the following sections.
Oregon Solid Waste Management Rules Oregon Solid Waste Management Rules (OAR 340-093 through -097) are applicable to the treatment and disposal of solid waste from the TLT site. Section 340-093-0170 is applicable to the disposal of cleanup materials contaminated with hazardous substances, such as petroleum-contaminated soil. Such material must be disposed only in landfills meeting the RCRA Subpart D licensing standards and that have been authorized by ODEQ to receive this type of material. Section 340-093-0190 is applicable to the disposal of special wastes, including construction and demolition debris and oil wastes.
CVO\043650001 2-5 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
RCRA Requirements for Hazardous Wastes Federal regulations promulgated under RCRA, and corresponding state law, provide standards for the management and disposal of solid and hazardous waste. These regulations are applicable to remedial action activities that generate waste and treatment residuals. Hazardous waste regulations 40 CFR Parts 260 to 268 and OAR 340-100 to 340-106 establish procedures for identifying, handling, storing, transporting, and disposing of hazardous waste. Both substantive and the administrative aspects of these requirements are applicable if, as part of the remedial action, hazardous wastes are managed and transported off- property. The soil in the soil storage cells at TLT is considered a hazardous waste because it contained a listed waste (F032, F034, F035) before it was stockpiled in the cells in 2000. In addition, some soil at the property could exhibit a toxicity characteristic according to the TCLP. Processing and consolidation of on-property soil is not considered waste generation, but RCRA hazardous waste regulations would be applicable if the soil were to be transported off-property, treated on-property, or managed on-property on a permanent basis (i.e., landfill). Substantive RCRA closure standards for land disposal units may be ARARs for remedial actions that involve closure of waste in place, or for remedial actions that involve excavation of areas of concern and disposal in a new on-property landfill. The closure standards apply if the waste is a regulated waste and either:
• The waste was initially treated, stored, or disposed of after the effective date of the particular RCRA requirement, or
• The remedial activity constitutes disposal as defined by RCRA
RCRA Landfill Closure Requirements RCRA regulations that address closure and post-closure care of landfills (40 CFR 265.310) are potentially applicable for capping at CERCLA sites, and might be relevant and appropriate for the area inside the barrier wall at TLT. The RCRA closure performance standard [40 CFR 265.111(a),(b)] requires that a site be closed to minimize the need for further maintenance, and controls, minimizes, or eliminates, to the extent necessary to protect human health and the environment, post-closure escape of hazardous constituents to the ground or surface waters or to the atmosphere. In addition, closure and post-closure care of landfills (40 CFR 265.310) requires that the final cover minimize the migration of liquids and have a permeability less than or equal to the permeability of any bottom liner or natural subsoils present. Although the current asphalt cap is not impermeable, it does prevent direct exposure to site contaminants, prevents surface soil contaminants from being transported via stormwater runoff into surface water, and prevents formation and entrainment of dust. The asphalt cap also reduces leaching of contaminants into groundwater caused by infiltration.
2-6 CVO\043650001 2. REMEDIAL ACTION OBJECTIVES
RCRA Land Disposal Restrictions The State of Oregon has adopted the RCRA Land Disposal Restrictions (LDRs) (40 CFR Part 268), which are ARARs for off-property treatment and disposal of soils classified as a hazardous waste. Waste sent off-property will comply with the Oregon RCRA rules pertaining to the generation, transportation, treatment, storage, and disposal of hazardous waste. RCRA LDRs are intended to ensure that hazardous wastes are treated prior to land disposal. The LDRs are associated with a list of treatment standards that are primarily technology-based (i.e., as opposed to risk-based standards). According to RCRA, the LDRs are triggered once a waste is “placed” in a land disposal unit (usually a landfill), or moved into or between different RCRA units or areas of contamination (AOCs). These stipulations are significant at TLT because EPA designated the West Facility as an AOC during the RA in 2000 (see Figure 3-2 of the Removal Action Report). (If necessary, EPA will extend the AOC to include the ditches next to the facility.) EPA interprets that placement into a disposal unit occurs when wastes are:
• Consolidated from different AOCs into a single AOC,
• Moved outside of an AOC (for treatment or storage, for example) and returned to the same or a different AOC, or
• Excavated from an AOC, placed in a separate unit, such as an incinerator or tank that is within the AOC, and redeposited into the same AOC Placement does not occur, and LDRs are not applicable, when wastes are:
• Treated in situ,
• Capped in place,
• Consolidated within the AOC, or
• Processed within the AOC (but not in a separate unit, such as a tank) to improve its structural stability (e.g., for capping or to support heavy machinery) If placement on-property or off-property does not occur, the LDRs are not applicable to the Superfund action. In cases where LDRs are applicable, soil that already meets the treatment standards, referred to as universal treatment standards (UTSs) (40 CFR 268.40) or soil alternative UTSs (40 CFR 268.49), can be disposed of in a permitted Subtitle C facility without treatment. Otherwise, it must be treated prior to disposal to reduce hazardous constituent concentrations until the treatment standards are met. To be disposed of in a Subtitle D landfill, soil must meet applicable standards (site-specific health-based levels) and receive a “no-longer contained-in determination” (be de-listed) by EPA.
Department of Transportation Requirements for Transport of Hazardous Waste Transportation of hazardous materials is regulated by 49 CFR Parts 171 to 177. Requirements for transporting hazardous materials include classification, proper packaging, proper labeling and placarding, inspection, proper loading and unloading techniques, and required training. These requirements apply to contaminated soils or other remediation wastes that are considered hazardous wastes and shipped off-property.
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Oregon Well Construction and Abandonment Standards Oregon Well Construction and Abandonment Standards (OAR 690-210 and 690-022) are applicable to the construction and abandonment of wells constructed for any purpose. These rules will be applicable to any extraction or monitoring wells installed at the site.
2.1.4 Summary of Risk–Based Criteria and ARARs Location-specific ARARs that constrain the location or timing of certain activities will be considered during the remedial design. Action-specific ARARs affect remedial design and waste disposal decisions. In general, the NCP risk-based criteria and chemical-specific ARARs are used to determine remediation action levels and cleanup goals. Table 2-1 summarizes the chemical-specific ARARs applicable at TLT, and notes the differences between the various EPA and ODEQ requirements.
2.2 Remedial Action Objectives and Target Areas In this section, remedial action objectives (RAOs) are developed for the different types of contaminated media and exposure areas at TLT. The RAOs define the general expectations of a remedial action, and are based on the NCP’s requirement for the protection of human health and on chemical-specific ARARs. Since TLT has numerous types of contaminated media and exposure scenarios, the contaminated media at TLT were grouped into the following three cleanup units:
• Soil outside the barrier wall – consists of West Facility surface soil, soil storage cells, off-property ditch soil, and residential soil.
• Groundwater outside the barrier wall – the dissolved groundwater plume outside of the barrier wall.
• Contaminated media inside the barrier wall – includes soil, DNAPL, and groundwater. For each cleanup unit, threshold concentrations (potential action levels) were established that triggered consideration of all, or a portion, of that unit as a remedial action target area. The determination of target areas is important for media quantity estimates to be used in the evaluation of technologies and alternatives later in this feasibility study. Finally, this section presents remedial goals for the contaminants of concern (COCs) within each target area. COCs are the primary risk contributors as determined by the baseline RA. The remediation goals, also referred to as cleanup levels, represent the expected residual contaminant levels following a successful remedial action.
2.2.1 Soil Outside the Barrier Wall This cleanup unit includes four different types of soil that will be considered individually:
• West Facility surface soil • Soil storage cells • Off-property ditch soil • Residential soil Generally, the RAOs for this cleanup unit include:
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• Preventing human exposure through direct contact (ingestion, inhalation, or dermal) of surface or near-surface soil contamination that exceeds protective levels
• Minimizing contaminant migration via wind or water erosion
• Minimizing risk to wildlife and plant species in areas providing suitable habitat Results from the baseline RA clearly show that arsenic and dioxins are the primary COCs for soil outside the barrier wall (see Table 1-1). In a few cases other COCs were identified by the baseline RA; however, their relative contribution to risk was much less than arsenic or dioxins and occurrences were often co-located with arsenic or dioxins. Therefore, in most cases, arsenic and dioxins will be used to define the remedial action target areas for soil outside of the barrier wall.
Target Areas Remedial action target areas will be defined based on ODEQ and EPA action levels. Hot spots are distinguished from non-hot spots to allow for flexibility in the assembly and selection of remedial alternatives. When applicable, the hot spot target areas will incorporate areas of unacceptable ecological risk, which are defined here as locations that exceed both LOAEL-based concentrations for most susceptible species and the observed off- property background levels for metals. Confirmation sampling will be used to ensure that remedial goals are met for all relevant contaminants within each target area. Table 2-2 summarizes the action levels and remedial goals for arsenic and dioxins, along with the risk-based concentrations (RBCs) corresponding to other ARARs. ODEQ requires action at 1 x 10-6 risk or background; however, action in this case does not necessarily require treatment or removal. EPA requires action at 1 x 10-4 risk, which corresponds to ODEQ’s hot spot level; ODEQ has a strong preference for treatment of hot spots. The action level for ecological areas is defined by an RBC corresponding to an HQ = 1 for the most susceptible species, but not below the observed off-property background levels for metals. The remedial goals set the standards to which contaminant levels will be reduced if a remedial action is undertaken. The remedial goals protective of all ARARs are generally lower than the action levels. The remediation goals for each target area were chosen based on the most protective RBC or the site-specific background concentration, if the background level exceeded the most protective risk-based criteria. The baseline RA indicated that, in addition to dioxins, copper and zinc pose a potential risk to wildlife (not reflected in Table 2-2). The LOAEL-based concentrations were 38.6 and 85.6 mg/kg for copper and zinc, respectively, with the most susceptible species being the deer mouse for dioxins and copper and the American robin for zinc. These concentrations are low, relative to copper and zinc concentrations measured at off-property locations near TLT. To determine a more realistic action level for these metals, background levels were estimated. The residential data set was used to calculate the 95 percent upper confidence limits (95UCLs).3 Data from the off-property ditches were not used in this calculation, because many of these ditches are believed to have been affected by site operations. The
3 All residential soil samples with the prefixes RES- or SO- were used in this calculation. Refer to Appendix A-5 in the RI report for a listing of the samples and concentrations.
CVO\043650001 2-9 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
95UCLs for copper and zinc were determined to be 87 and 545 mg/kg, respectively. For both copper and zinc, these estimated background levels will be used for the remedial action levels and the remedial goals in areas of ecological habitat both on- and off-property.
West Facility Surface Soil For the surface soil in the West Facility, Figures B-1 and B-2 show the individual samples that exceed the arsenic and dioxins hot spot and non-hot spot levels, respectively. Figure B-1 also shows locations (for available ecological habitat) where dioxin TEQ exceeded the LOAEL-based concentrations for the most susceptible species and where copper or zinc exceeded the observed off-property background levels. Ditches along the railroad tracks bordering the site to the north were considered ecological habitat in the baseline RA; copper and zinc exceedances have been observed in segments of these ditches. Hot spot and non-hot spot target areas were defined by grouping contiguous areas where exceedances occurred. Straight lines were used as area boundaries in order to maintain geometric simplicity for later volumetric calculations. Professional judgment and the relative proximity and concentration of non-exceedances were used to establish the location of the hot spot area boundaries. The resulting target areas are shown in Figure 2-1. As Figure 2-1 shows, the samples that exceed non-hot spot levels cover a much larger area than those that exceed hot spot levels. The resulting difference in affected soil volume will influence the technologies selected for the hot spot and non-hot spot remedial alternatives based on implementability. The Assembly of Alternatives, Section 4, provides further explanation. Hot spot areas include 4.4 acres in the Treated Pole Storage area, 0.4 acre in the southern corner of the Treatment Plant area, 0.9 acre along the southern boundary of the White Pole Storage area, and 0.1 acre in the ditches that border the property to the north. Also hot spots, the areas beneath the pavement in the Treatment Plant and Treated Pole Storage areas are considered separately. The remaining area, consisting of about 30 acres, is considered as a non-hot spot. Quantity estimates for the target areas are summarized in Table 2-3.
Soil Storage Cells Samples obtained from the soil storage cells exceed the non-hot spot levels but not the hot spot levels (see Section 4.2.2 and Appendix A-2 of the RI report), and this material is considered as part of the non-hot spot target area in this study (see Figure 2-1). However, the soil storage cells were constructed as temporary containment for the contaminated soil generated in the RA; permanent solutions for this material will be considered in this FS. Quantity estimates for the target area are provided in Table 2-3. The remediation goals in the soil storage cells for arsenic and dioxins are similar to those for surface soil in the West Facility. Although not shown in Table 2-2, PCP is considered a COC for the soil storage cells in the baseline RA. The remediation goal for PCP is 9 mg/kg, which corresponds to the ELCR of 1 x 10-6 for the industrial worker scenario.
Off-property Ditch Soil For the off-property ditch segments along Rock Creek Road and Highway 18B, Figures B-3 and B-4 show the individual samples that exceed the arsenic and dioxins hot spot and non-
2-10 CVO\043650001 2. REMEDIAL ACTION OBJECTIVES
hot spot levels, respectively. Off-property ditches were considered ecological habitat. Ditch locations where dioxin TEQ exceeds the LOAEL-based concentrations for the most susceptible species, and copper or zinc exceeds the estimated background levels, are shown in Figure B-3. Of the 22 ditch samples with available ecological habitat, 15 exceeded the estimated background levels for copper and zinc. The formation of off-property ditch target areas was simplified by grouping all of the areas with exceedances shown in Figures B-3 and B-4 into a single hot spot target area (see Figure 2-1), as opposed to separate hot spot/ecological and non-hot target areas. Although this approach is conservative, it will greatly simplify the ditch remediation effort and the overall volume of soil generated will remain very small compared to the other sources of hot spot soil on-property in the West Facility. The remediation goals for the off-property ditches will be driven by the most protective criteria, which are the LOAEL-based concentrations for dioxins and the background concentrations for copper and zinc in ecological areas, and the non-hot spot level for dioxins in areas without ecological habitat. The remediation goal for arsenic is the estimated background concentration in all off-property ditch locations.
Residential Soil Based on the results of the Probabilistic Risk Assessment conducted by ODEQ, 22150 SW Rock Creek Road is the only residence with unacceptable risk for dioxins as defined by ODEQ. This is also the only residence where arsenic exceeds the estimated background level (14 versus 12 mg/kg). The cleanup goal for dioxins is 9.5 ng/kg based on individual congeners expressed as 2,3,7,8-TCDD. This residence underwent a removal action by EPA in November of 2004. Details of the removal action are provided in Appendix E. The extent of the property included in the action is shown in Figure 2-2. Additional sampling of the portion of the residential property to the south of the recent removal action will be conducted in 2005 and evaluated in a separate memorandum. Residential soil will not be considered further in this report.
2.2.2 Groundwater Outside the Barrier Wall The RAOs for this cleanup unit are:
• Preventing human exposure to groundwater with contaminant concentrations in excess of federal drinking water standards (MCLs)
• Preventing adverse impacts to adjacent surface water PCP is the primary COC for groundwater. The MCL for PCP is 1.0 µg/L, and the WQC for protection of aquatic life is 15 µg/L.4 This cleanup unit includes all the groundwater outside the barrier wall that exceeds the MCL for PCP (Figure 2-3). Assuming that this groundwater will not be used for drinking, the primary goal of any remedial action, if necessary, will be to prevent PCP concentrations exceeding 1 µg/L from migrating to the river. For cost estimating, it is assumed that the remediation will focus on PCP; however, any contaminants co-occurring with PCP will also be treated. The remedial
4 The baseline RA also included a comparison to the WQC for the protection of humans consuming fish. A RBC of 2.7 µg/L corresponds to a 1 x 10-4 cancer risk at an ingestion rate of 175 g/day.
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action will focus on the area outside the barrier wall greater than 100 times the MCL. The areas of lower contamination will be addressed indirectly as a result of focus on the higher concentration zone.
2.2.3 Contaminated Media Inside the Barrier Wall This cleanup unit, which includes the contaminated soil, groundwater, and DNAPL inside the barrier wall, is considered a single target area. Contaminant levels in all media exceed the hot spot RBCs; therefore, the unit will be addressed as a hot spot. In 1999, a barrier wall and cap were installed in the Treatment Plant area to achieve two objectives: protect workers and prevent contaminated groundwater and DNAPL from migrating off the property. Presently, the RAOs for this cleanup unit are:
• Preventing human exposure to contamination in groundwater, soil, or DNAPL that exceeds protective levels
• Preventing migration of contaminated groundwater that exceeds drinking water standards
• Preventing migration of DNAPL beyond the barrier wall A barrier wall and cap have been installed to contain the contamination in this area. In addition to enhancing the existing containment methods, removal and treatment will be considered for this unit.
2.3 General Response Actions Remedial alternatives will be designed to meet the RAO s for each cleanup unit. General response actions represent broad groups of actions that typically encompass a number of different remedial technologies, and form the basis for the remedial alternatives. General response actions include the following actions as specified in the NCP:
• No action – required as a baseline for comparison to other actions. • Institutional controls – administrative controls that provide protection against exposure by advising current and prospective property users about existing contamination. • Containment – used to limit the migration of contaminants, and prevent site workers, visitors, trespassers, and wildlife from exposure to them. • Removal – the physical removal of contaminants from the area of interest. Contaminants must be subsequently treated or disposed of before the risk of exposure is considered prevented. • Treatment – a permanent and substantial elimination or reduction in the toxicity, mobility, or volume of hazardous substances with the use of in situ or ex situ remedial technologies. • Disposal – removal of contaminants from the site for subsequent treatment and/or disposal at another location.
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Not all general response actions are applicable to each of the exposure media. Although the “no action” response will not satisfy any of the RAOs, it must be considered in the development of alternatives as a baseline response action.
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TABLE 2-1 Summary of Chemical-Specific ARARs Taylor Lumber and Treating Feasibility Study
Agency ARAR Media Constituents1 Criteria Notes
ODEQ Oregon Non- Soil Dioxins ELCR ≥ 1 x 10-6 ODEQ acceptable risk Hot Spot Rule, (individual (individual dioxin limit – requires remedial “Bright Line” congeners), congeners) or arsenic action, but not necessarily arsenic ≥ background treatment or removal Based on individual (EPA defines acceptable carcinogens. risk between 1 x 10-6 to 1 x 10-4)
ODEQ, Oregon Hot Soil TEQ, arsenic ELCR ≥ 1 x 10-4 Action is required above EPA Spot Rule, Based on multiple 1 x 10-4 for both ODEQ EPA Exposure carcinogens. and EPA. Limit
EPA Ecological Off-property TEQ, copper, HQ = 1 Unacceptable ecological Acceptable Ditches zinc LOAEL-based risk level – requires Risk Threshold concentration for action. most susceptible species.
EPA Safe Drinking Groundwater PCP MCL Requires action if water is Water Act (1 ppb for PCP) used for drinking. 1A more extensive list of constituents exists within the barrier wall. However, the entire area within the barrier wall will be addressed as a Hot Spot target area.
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TABLE 2-2 Risk-based Action Levels and Remediation Goals for Arsenic and Dioxin in Soil Taylor Lumber and Treating Feasibility Study
Arsenic Dioxin TEQ Notes (mg/kg) (ng/kg)
On-property Soil (including soil storage cells) Background 12 -- ODEQ arsenic non-hot spot action level / remediation goal Trench Worker RBC 1 x 10-4 1810 18100 Trench Worker RBC 1 x 10-5 181 1810 Trench Worker RBC 1 x 10-6 18.1 181 Industrial RBC 1 x 10-4 159 1590 Hot spot / EPA action level Industrial RBC 1 x 10-5 15.9 159 1Industrial RBC 1 x 10-6 1.59 315.9 ODEQ dioxin HH non-hot spot action level / remediation goal 5LOAEL-based concentration -- 6.7 EPA dioxin ECO action level / ECO remediation corresponding to HQ =1 goal Off-property Ditch Soil Background 12 -- ODEQ arsenic non-hot spot action level / remediation goal Recreational RBC 1 x 10-4 359 3590 Hot spot / EPA action level Recreational RBC 1 x 10-5 35.9 359 Recreational RBC 1 x 10-6 3.59 335.9 Dioxin HH non-hot spot action level / remediation goal 5LOAEL-based concentration -- 6.7 EPA dioxin ECO action level / ECO remediation corresponding to HQ =1 goal Residential Soil Background 12 -- ODEQ arsenic non-hot spot action level / remediation goal Residential RBC 1 x 10-4 38.9 389 Hot spot / EPA action level Residential RBC 1 x 10-5 3.89 38.9 2Residential RBC 1 x 10-6 0.389 3,49.5 Dioxin non-hot spot level / remediation goal Notes: 1Same as EPA Region 9 Industrial PRG 2Same as EPA Region 9 Residential PRG 3Based on individual congeners expressed as 2,3,7,8-TCDD 4Risk-based concentration determined by ODEQ’s Probabilistic Risk Assessment (See Appendix A) 5For deer mouse
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TABLE 2-3 Quantity Estimates for Each Cleanup Unit Taylor Lumber and Treating Feasibility Study
Description Quantity
Soil Outside of the Barrier Wall (SO)
Soil (West Facility) Hot spot = 5.8 acres (7.8 acres including the soil under existing AC cap in NW corner of Treated Pole Storage Area2)
Non-hot spot = 33.8 acres
Off-property Ditch Soil 3,850 feet
1Soil Storage Cells 19,100 yd3 (Cell 1 = 5,800 yd3, Cell 2 = 8,000 yd3, Cell 3 = 5,300 yd3)
Groundwater Outside the Barrier Wall (GW)
Area where PCP exceeds the MCL of 1 ppb 9 acres (17.5 million gallons)
Area where PCP exceeds 100 times MCL of 100 ppb 1.6 acres (3.0 million gallons)
Contaminated Media Inside the Barrier Wall (BW)
2Area contained within the barrier wall 4.6 acres
3Area within barrier wall not under existing structures 3.5 acres
4Volume of soil contained within the barrier wall 126,000 yd3
4Volume of water contained within the barrier wall 6,800,000 gallons
4Area of soil believed to be impacted by DNAPL *2.0 acres
4Volume of soil believed to be impacted by DNAPL *13,000 yd3
4Estimated volume of DNAPL 250,000 gallons
*E&E (1999) estimated the area and volume of DNAPL-impacted soil to be 2.9 acres and 18,500 yd3, respectively. However, these estimates have been revised based on recent observations and groundwater concentrations (RI Report). References: 1RI Report Section 4.2.2 2RA Report (E&E, 2000) Figure 3-3 3Assumed to be 75 percent of total area within the barrier wall 4RI Report Section 4.4
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SECTION 3 Identification and Screening of Technologies
In this section, remedial technologies are identified and screened for use in developing remedial alternatives for the three cleanup units defined in Section 2:
• Soil outside the barrier wall • Groundwater outside the barrier wall • Contaminated media inside the barrier wall For each cleanup unit, applicable technologies are discussed under the relevant general response actions, and summarized in Table 3-1. The no action response is not considered in the identification and screening of technologies, but will be considered in the development of alternatives. Technologies currently in place are included in the discussion.
3.1 Presumptive Remedies EPA has developed guidance for the selection of presumptive remedial technologies that have proven successful in past remedial actions. The purpose of these documents is to streamline the FS process and reduce the costs and time required for remedy selection. Presumptive remedies are expected to be used at all appropriate sites except under unusual, site-specific circumstances. Specific guidance is available for selecting remedies for soils, sediments, and sludges at wood treater sites that are contaminated primarily with creosote, pentachlorophenol, and/or chromated copper arsenate (U.S. EPA, 1995). The presumptive remedies outlined in the guidance include:
• Bioremediation • Thermal desorption • Incineration • Immobilization The wood treater guidance does not specifically address DNAPL and groundwater remedies. Presumptive remedy guidance for DNAPL remedial technologies is not currently available, and EPA acknowledges that removal of DNAPLs from the subsurface is difficult and often not practicable. However, partial DNAPL removal can be achieved by some of the presumptive remedies listed above. General presumptive remedy guidance for the treatment of extracted groundwater for dissolved organics and metals is available (U.S. EPA, 1996), but will not be included in this screening because it is assumed that the existing stormwater treatment system at TLT will handle groundwater treatment. The treatment works contains oil-water separation, sedimentation, filtration, and granular activated carbon systems, and is capable of removing all groundwater COCs both inside and outside of the barrier wall.
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3.2 Screening Process A list of potentially feasible remedial technologies was developed for TLT and evaluated against the following screening criteria:
• Effectiveness – the likelihood of the technology to meet RAOs.
• Implementability – the technical and logistical feasibility of applying the technology.
• Cost – the relative capital and operations and maintenance (O&M) expenses of a technology.
• Preexisting remedy – the presence of currently operational remedies was used to rapidly screen out technologies that did not offer significant advantages over those in place. Technologies considered for each cleanup unit are grouped by general response action in the following sections. A description of each technology is included with the screening results. Technologies retained through this process are assembled into remedial action alternatives for the site in Section 4.
3.3 Soil Outside the Barrier Wall The soil outside of the barrier wall includes:
• West Facility surface soil (hot spots and non-hot spots, addressed separately) • Off-property ditch soil • Soil storage cells
Two remedial actions have already been implemented outside the barrier wall that will affect the current remedial technology screening process: installation of an asphalt cap in the northwest corner of the Treated Pole Storage area and installation of a stormwater collection and treatment system. Potentially applicable technologies for remediation of surface soil outside of the barrier wall are summarized in Table 3-1 and discussed in the following subsections.
3.3.1 Institutional Controls Institutional controls consist of administrative policies that provide a level of protection against exposure and advise current and prospective property users about the existing contamination. Monitoring is considered an institutional control, and is necessary to ensure that potential risks to human health and the environment are controlled. Besides monitoring, the only applicable institutional control for soil outside of the barrier wall is land use restriction. For example, limitations might be imposed on the time spent in certain areas, and some type of personal protective equipment (PPE) might be required. Although this measure would reduce exposure in these areas, it cannot completely prevent access to the property (e.g., trespassing) and would not limit migration of contaminants via stormwater or wind. Institutional controls are easily implemented on industrial properties,
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but are often difficult to implement off-property. Institutional controls will be retained as a component of the overall remedial action alternatives, as appropriate.
3.3.2 Containment Gravel Capping A gravel cap serves primarily as an engineering control to prevent direct contact with contaminated surface soil. When properly constructed, it also limits contaminant migration via stormwater and wind erosion. A geotextile fabric must be used beneath the gravel layer to prevent the transport of fine soil particles to the surface through pumping action caused by the operation of heavy machinery on the gravel surface. A gravel cap does not reduce the infiltration of surface water to the underlying soil. A gravel cap is not suitable for areas of heavy traffic, which would quickly wear through the gravel layer and damage the underlying geotextile membrane. This technology is retained for future consideration.
AC Capping A 2.02-acre asphalt-concrete (AC) cap was installed in the northwest corner of the Treated Pole Storage area during the RA, to prevent exposure to surface soil with arsenic concentrations in excess of 250 mg/kg. The existing cap could be extended to encompass the contaminated surface soils remaining in the Treated Pole Storage and Treatment Plant areas, creating a single continuous cap over most of the area. An AC cap serves at least three functions:
• Reduces surface water infiltration through contaminated soil • Reduces exposure risk by preventing direct contact with contaminated soil • Reduces contaminant migration via stormwater and wind erosion The cap could be graded to slope toward existing stormwater conveyance systems. Current conveyance systems might need to be upgraded to handle the additional flow created by the large impermeable surface; however, the existing SWTS should have capacity because it was designed to handle runoff from the Treatment Plant and the Treated Pole Storage areas. A liner could be installed beneath the asphalt cap to increase resistance to infiltration. It is important that the AC cap be constructed to withstand the heavy machinery used at the property. This technology is retained for future consideration.
AC Capping With Consolidation This technology is similar to the capping of contaminated surface soils in place, except that stockpiled soils would be moved to a suitable location and then capped. RCRA LDRs would not apply to soils consolidated and capped within the AOC, as long as they originated from within the AOC (refer to Section 2.1.3). Thus, soil from the storage cells and ditches could be consolidated and capped without the need to meet LDRs. The area should be minimized to keep the contaminants within the smallest footprint possible. Assuming that 20,000 cubic yards were spread out to a depth of 1 foot, the resulting area of the capped surface would be approximately 4 acres, or twice the size of the existing cap in the Treated Pole Storage area. A thicker lift would require less area. The consolidation area must be within the AOC and could be located:
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• Over areas of existing contamination • Adjacent to the existing capped soil • On low spots, below the surrounding grade The cap should be designed to support heavy machinery and not interfere with property operations. A liner could be installed beneath the asphalt cap to increase its resistance to infiltration. Stabilization could be used in combination with consolidation to add structural strength and reduce the need for base course material such as crushed rock. This technology is retained for future consideration.
3.3.3 Removal Excavation of Soil Contaminated surface soil from the West Facility or off-property ditches could be excavated and transported to permitted treatment, storage, and disposal (TSD) facilities. Some TSD facilities offer treatment alternatives if required to meet LDRs. This technology is retained.
3.3.4 Treatment All of the treatment technologies evaluated in this section are assumed to take place on- property.
Soil Incineration Incineration generally treats organic contaminants by subjecting them to temperatures greater than 1,000°F in the presence of oxygen and a flame. During incineration, volatilization and combustion convert the organic contaminants to carbon dioxide, water, hydrogen chloride, and sulfur oxides. Incineration is among the EPA’s presumptive remedies for wood treater sites and has consistently been demonstrated to achieve performance efficiencies of 90 to 99 percent. However, incineration does not destroy metals. Metals will produce different residuals, depending on the volatility of the compounds, the presence of certain compounds (e.g., chlorine), and the incinerator operating conditions. Subsequent treatment might be required for the solid waste products for metals (e.g., immobilization). Costing approximately $400/ton, incineration of large volumes of contaminated media can be very expensive. Incineration could be performed at TLT or at a commercial facility. On-property incineration could be performed with a portable incineration unit; however, space availability, public opposition, and regulatory compliance might make this option difficult to implement. Only a limited number of commercial incineration facilities permitted to incinerate hazardous wastes exists nationwide. This technology is rejected because of high cost and lack of effectiveness for arsenic.
Soil and Solid Waste Immobilization Immobilization reduces the mobility of a contaminant by physically restricting its contact with a mobile phase (solidification) and by chemically altering or binding the contaminant (stabilization). The most common binders are cementitious materials, including Portland cement, fly ash/lime, and fly ash/kiln dust. These agents form a solid, resistant,
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aluminosilicate matrix that can occlude waste particles, bind various contaminants, and reduce the hydraulic permeability of the waste/binder mass. Immobilization is particularly suited to addressing inorganic (e.g., arsenic) contamination, and is one of EPA’s presumptive remedies for wood treater sites. Only limited full-scale performance data are available on the immobilization of PAHs and PCP, either alone or commingled with inorganic contamination. Some studies indicate that immobilization has been effective in treating soils with commingled organic and inorganic contamination with a total organic content of as much as 20 to 45 percent. Site-specific treatability studies should be conducted to determine a solidification/stabilization formulation that meets requirements for low leachability and high compressive strength. However, as indicated in the RI, the leachability of the soil contaminants at TLT appears to be very limited. Thus, further immobilization might not be of much value. However, in addition to immobilization, mixing of soil with a binding agent can greatly improve its structural compressive strength, reducing the need for imported material for use as a base course in capping alternatives. Medium to high relative costs are expected depending on the volume of soil to be treated. This technology is retained for future consideration.
Thermal Desorption Thermal desorption is a physical separation process. Wastes are heated to volatilize water and organic contaminants, which are transported via carrier gas or vacuum system to a gas treatment system. Design bed temperatures and residence times volatilize selected contaminants, but typically do not oxidize them. Thermal desorption is among the technologies considered as presumptive remedies for wood treater sites by EPA. High temperature thermal desorption heats the waste to 320 to 560°C (600 to 1,000°F) and is effective in removing SVOCs, PAHs, PCBs, and pesticides. Factors that can limit the applicability and effectiveness of the process include soil content, particle size, and abrasiveness. Thermal desorption does not destroy metals, which might require subsequent treatment such as immobilization. This technology is rejected based on cost and lack of effectiveness for arsenic.
Bioremediation Bioremediation creates a favorable environment that stimulates microorganisms to grow and use contaminants as food and energy sources. In general, this means providing oxygen, nutrients, and moisture, and controlling the temperature and pH. Sometimes microorganisms adapted for degradation of specific contaminants are applied to enhance the process. Bioremediation is among the technologies considered a presumptive remedy for wood treater sites by EPA. Bioremediation is typically implemented at low cost. Contaminants can be destroyed or transformed, and little to no residual treatment is required. However, the process can take months and it is difficult to determine whether all contaminants and hazardous byproducts have been destroyed. Ex situ treatment generally requires shorter time periods than in situ treatment, and allows greater uniformity of treatment because of the ability to homogenize,
CVO\043650001 3-5 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY screen, and continuously mix the soil. Also, byproducts can be contained in the treatment unit until nonhazardous end-products are produced. Although not all organic compounds are amenable to biodegradation, bioremediation techniques have been successfully used to remediate petroleum hydrocarbons, solvents, pesticides, wood preservatives, and other organic chemicals. Bioremediation is not yet commonly applicable for treatment of inorganic contaminants (i.e., arsenic) or dioxins. Because arsenic and dioxins are the primary COCs in this cleanup unit, bioremediation is not retained for future consideration.
Chemical Redox By transferring electrons from one compound to another, reduction/oxidation (redox) reactions chemically convert hazardous contaminants to nonhazardous or less toxic compounds that are more stable, less mobile, and/or inert. The oxidizing agents most commonly used for treatment of hazardous contaminants are potassium permanganate, ozone, hydrogen peroxide, hypochlorites, chlorine, and chlorine dioxide. The target contaminant group for chemical redox is organics. The technology can be used but might be less effective against nonhalogenated VOCs and SVOCs, fuel hydrocarbons, and pesticides. Treatability studies would be required to determine effectiveness on creosote compounds and dioxins. Factors that can limit the applicability and effectiveness of the process include:
• Incomplete oxidation or formation of intermediate contaminants can occur, depending on the contaminants and oxidizing agents used
• Cost of oxidizing agent required to treat the high contaminant concentrations is high
• Oil and grease can affect process efficiency Treatability tests should be conducted to identify parameters such as water, alkaline metals, and humus content in the soils; the presence of multiple phases; and total organic halides that could affect processing time and cost. Estimated costs range from $150 to $500 per cubic yard. This technology is rejected based on cost and uncertain effectiveness.
Soil Washing Soil washing is a technique for concentrating contaminants through separation. Most organic and inorganic contaminants tend to bind and sorb to clay, silt, and organic soil particles, which in turn stick to larger particles (i.e., sand and gravel). Washing separates the small particles from the large particles by breaking the adhesive bonds. The separated fines have a much smaller volume and are more easily disposed of. Soil washing is most suitable for soils with high sand and gravel content, where a significant volume reduction is realized once the fines are removed. Although soil washing is effective on organic contaminants and metals, it does not destroy or immobilize the contaminants. The cleaner coarse material must be analyzed for residual contamination before it can be disposed of. Wash water requires treatment before it can be discharged. The technology is rejected for future consideration because of cost and excessive handling requirements.
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3.3.5 Disposal Off-property Disposal of Soil Off-property disposal of contaminated soil requires transport to a permitted hazardous waste TSD facility and requires that UTSs be met. The UTS is 7.4 mg/kg for PCP, 0.001 mg/kg for tetrachlorodibenzodioxins (TCDDs) and tetrachlorodibenzofurans (TCDFs), 3.4 mg/kg for most PAH compounds, and 5 milligrams per liter (mg/L) TCLP arsenic. Contaminated soils that exhibit initial hazardous constituent concentrations greater than 10 times the UTS must be treated to reduce concentrations of hazardous constituent by 90 percent, or meet hazardous constituent concentrations that are 10 times the UTS, whichever is greater. The contaminated soil can be treated on-property to meet the UTS, then disposed off-property at a RCRA landfill, or it can be shipped off-property for both treatment and disposal. The primary COCs for this cleanup unit are arsenic and dioxins, both of which are costly to treat. Approximate disposal costs for various off-property treatment and/or land disposal options are as follows:
• Off-property treatment by incineration and disposal [arsenic < 50 parts per million (ppm)] – $375/ton
• Off-property treatment by incineration and disposal in a secured metals landfill (arsenic ≥ 50 ppm) – $405/ton This cost includes transportation and disposal charges, but does not include excavating the soil and loading it onto railroad cars. Offsite disposal is retained for further consideration as a treatment technology because it affords the greatest degree of protectiveness and achieves RAOs in the shortest timeframe.
3.4 Groundwater Outside the Barrier Wall Construction of the bentonite-slurry wall in 2000 created a barrier to horizontal groundwater flow in the alluvial water-bearing zone (WBZ), resulting in a groundwater mound upgradient of the barrier and a groundwater stagnation zone immediately downgradient (refer to Section 3 of the RI report). PCP contamination, believed to have been cut off from the DNAPL source when the barrier wall was installed, has been observed at relatively high concentrations in the stagnation zone. Although minimal PCP is migrating off-property, and concentrations appear to be at steady state, there is a potential for contamination to move toward the river. The only COC identified in the RI and baseline RA for groundwater outside of the barrier wall was PCP. Potentially applicable technologies for remediation of groundwater outside of the barrier wall are summarized in Table 3-1 and discussed in the following subsections.
3.4.1 Institutional Controls Institutional controls consist of administrative policies that provide a level of protection against exposure and advise current and prospective property users about the existing contamination. Groundwater monitoring is considered an institutional control, and is necessary to ensure that potential risks to human health and the environment are controlled.
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Besides monitoring, the only applicable institutional control for groundwater is restricting pumping. Although this measure would reduce risk by controlling exposure to contaminated groundwater, it would not affect contaminant transport off-property. Institutional controls will be retained as a component of the overall remedial action alternatives, as appropriate.
3.4.2 Containment / Removal Extraction Wells The use of extraction wells for the containment and removal of contaminated groundwater is a proven technology that could be readily implemented at TLT. With this technology, groundwater within the capture zone of an extraction well or group of wells is pumped to the surface for subsequent treatment or disposal. Extraction wells also provide hydraulic containment to prevent migration of contaminated groundwater to the South Yamhill River. During extraction of groundwater from outside of the barrier wall at TLT, it would be important to maintain a fairly low extraction rate, sufficient to prevent migration to the river but not enough to disrupt the gradient inside the barrier wall. This technology is retained because it is compatible with existing actions and would provide a high degree of protectiveness at a low capital cost.
3.4.3 Treatment In situ Bioremediation General characteristics of bioremediation are described in Section 3.3.4. Although PCP has been shown to biologically degrade in groundwater under the right conditions, treatability studies would be required to determine the potential for degradation at TLT. Studies during the 2002 Removal Action indicated that soil removed from inside the barrier wall did not have sufficient PCP degrading capability. Therefore it is unlikely that a suitable PCP degrading microbial population would exist outside of the barrier wall. Even if a suitable microbial population were present, supplementary substrate and oxygen would have to be delivered to the subsurface. Injection of these constituents upgradient of the plume would drive contaminants in the direction of the river. Although bioremediation is a presumptive remedy for soils, sediments, and sludges at wood treater sites, this guidance is not directly applicable to groundwater remediation. Because it has a low probability of success for PCP, and because of the site’s proximity to the river, in situ bioremediation is rejected from further consideration.
In situ Oxidation Chemical oxidation (redox) is described in Section 3.3.4. In situ chemical oxidation has the potential to destroy PCP outside of the barrier wall. However, uniform delivery of chemicals would be difficult to obtain, and the injected liquid might drive contaminants to the river; therefore, this technology is rejected.
Permeable Reactive Barrier Subsurface permeable reactive barriers (PRBs) consist of reactive material placed in the subsurface where a plume of contaminated groundwater must move through it as it flows,
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typically under its natural gradient (creating a passive treatment system). PRBs are capable of remediating a number of contaminants to drinking water MCLs. Once installed, PRBs are likely to have extremely low, if any, O&M costs for at least 5 to 10 years. The majority of PRBs currently in use employ iron metal, Fe(0) as the reactive medium for converting contaminants to non-toxic or immobile species. Iron metal has the ability to reductively dehalogenate hydrocarbons and reductively precipitate metals. Granular activated carbon (GAC) has been used successfully as a sorbent material in a number of PRB applications. Numerous other materials, including biologically reactive barriers, are still in the experimental stage. PRBs are typically built in one of two basic configurations. The funnel-and-gate PRB, which uses impermeable walls (sheet pilings, slurry walls, etc.) as a “funnel” to direct the contaminant plume to a “gate” containing the reactive medium; and the continuous PRB, which completely transects the plume flow path with the reactive medium. Little information is available on the use of PRBs for the treatment of PCP. However, it is presently believed that the use of Fe(0) as a reactive material is a poor choice for PCP remediation (U.S. EPA, 1998). It is expected that GAC would be effective at PCP removal, and the life expectancy of the GAC, given the relatively low concentrations and lack of other organics to compete for sorption sites, would be high. The relative costs of implementing a PRB at TLT are expected to be moderate, primarily because of the large capture area required. At least 400 feet of wall would need to be installed between the barrier wall on both the south and east sides of the site boundary. The technology is retained for further consideration.
Stormwater Treatment System A stormwater treatment system that treats both metals and organics was completed in 2000, and is currently in place and operating. The system was designed to handle runoff from the Treatment Plant and Treated Pole Storage areas during a 25-year, 24-hour storm event. Furthermore, the design assumed that the entire 21.2-acre drainage area within the Treatment Plant and Treated Pole Storage areas would eventually be paved. At present, about 7 acres are paved within the drainage area. The system is capable of operating continuously with a stormwater input of 250 gallons per minute (gpm), but can handle intermittent inputs as high as 3,625 gpm produced by the design storm. Although it is not currently permitted to do so, the system is well-suited to treat a limited amount of water from other process streams in addition to stormwater runoff. For example, the combined extraction rate from the four extraction wells within the barrier wall was less than 2.0 gpm throughout 2002, which if plumbed into the system would represent less than 1 percent of its continuous capability. The primary components of the system include:
• Conveyance System. Collects water from the drainage areas and transports it to the oil- water separators at the southeastern corner of the Treatment Plant. It is designed to have sufficient capacity to handle the additional flow from the Treated Pole Storage area should the area be paved in the future. • Oil-Water Separation and Wet Well System. Has a dual purpose: to prevent NAPL from leaving the property via stormwater and to protect the stormwater treatment
CVO\043650001 3-9 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
system from hydrocarbons that could foul the GAC. There is a 24-inch bypass line to the wet well should the separator become backed up or the flow exceed 2,200 gpm. The wet well houses two float- activated centrifugal pumps, which typically turn on and off automatically. • Storage System. Consists of an aboveground, 500,000-gallon, open-top tank, which serves as a holding reservoir for the sedimentation system. If the capacity is exceeded, the water is bypassed to the outfall without treatment. • Sedimentation System. Consists of two transfer pumps, two chemical mix tanks, four cone-bottom sedimentation tanks, and a sludge handling system. It is designed to remove total suspended solids (TSS) and prevent fouling of treating equipment, especially the GAC filters. In the first tank, polymer is added to neutralize the charges of the suspended particles (rapid-mix). A precipitant may be added to neutralize the charges of the dissolved metals. In the second tank, a polymer is added that helps solids flocculate (slow-mix). Water then overflows into the four sedimentation tanks where the floc is allowed to settle out. • Filtration System. As water overflows the sedimentation tank, it flows into a surge tank. The surge tank has a capacity of approximately 5,800 gallons. Water is pumped from the surge tank through a series of five bag filter vessels and then through the GAC vessels. • Granular Activated Carbon System. The GAC system consists of two vessels, each capable of being filled with 20,000 pounds of GAC. Treated water is discharged from the stormwater treatment system to the South Yamhill River via the Rock Creek Ditch, near the intersection with Highway 18B. Discharge is regulated under ODEQ’s NPDES waste discharge permit No. 101267 (expired 1/31/00). This technology is retained for the treatment of extracted groundwater.
3.5 Contaminated Media Inside the Barrier Wall The barrier wall is part of an engineered system designed to contain the DNAPL and prevent it from being a source of contamination to the groundwater outside the wall. This system consists of a soil-bentonite slurry wall, an asphalt concrete cap, and groundwater extraction wells. Potentially applicable technologies for remediation of DNAPL, groundwater, and soil within the barrier wall are summarized in Table 3-1 and presented in the following subsections for each of the relevant general response actions.
3.5.1 Institutional Controls Institutional controls consist of administrative policies that provide a level of protection against exposure and advise current and prospective property users about the existing contamination. Applicable institutional controls for contamination inside the barrier wall include:
• Groundwater pumping restrictions • Land use restrictions • Monitoring
3-10 CVO\043650001 3. IDENTIFICATION AND SCREENING OF TECHNOLOGIES
Restrictions reduce the risk by controlling access to the affected area; however, such measures could not completely limit access to the property (e.g., trespassing) and would not limit off-property transport of contaminants (e.g., groundwater, stormwater, or air). Monitoring is necessary to ensure that potential risks to human health and the environment are controlled while a site remedy is being implemented. Institutional controls are easily implemented and are retained as a component of the selected alternative.
3.5.2 Containment Containment is used to limit the migration of contaminants and to prevent exposure of site workers, visitors, and trespassers to them. As part of the 2000 Removal Action, a soil- bentonite barrier wall system was installed at TLT that employs the following containment technologies:
• Hydraulic containment • Barrier walls • Capping Because a functional containment system is currently in place and is fulfilling its intended purpose, the installed features will be discussed in lieu of a general survey of the potential containment technologies.
Hydraulic Containment Four groundwater extraction wells are currently operating within the barrier wall for the purpose of hydraulic containment. The wells induce a continual inward hydraulic gradient to prevent contaminant migration beyond the barrier wall, and to ensure the structural integrity of the protective cap by lowering water levels. Each extraction well is 6 inches in diameter. The pumps were installed 6 inches above the bottom of the well and are bottom- filling; that is, they will pump continuously for as long as water fills the pump body. The combined extraction rate from the four wells was less than 2.0 gpm throughout 2002. Because surface recharge into the area within the barrier wall is very limited, it is assumed that the aquifer enclosed by the barrier wall is recharged by seepage from the underlying aquitard and from across the low permeability barrier wall.
Barrier Walls A bentonite-slurry wall was constructed as a subsurface barrier to contain DNAPL and contaminated groundwater and to redirect the natural flow of groundwater around the highly contaminated area within. The barrier wall is approximately 3 feet thick and extends vertically to depths between 14 and 20 feet to the underlying siltstone. It is keyed 2 feet into the siltstone and has a permeability of less than or equal to 2.8 x 10-4 feet per day (ft/d) [1 x 10-7 centimeters per second (cm/s)]. A barrier wall is considered to be a permanent remedy, and under favorable conditions can serve its intended purpose for hundreds of years. However, numerous environmental and anthropogenic effects could cause the wall to fail partially or in full before the DNAPL contained within it has attenuated to negligible levels.
CVO\043650001 3-11 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
Capping An AC cap was constructed over the area enclosed by the barrier wall to minimize infiltration of surface or stormwater. The cap also eliminates direct exposure risk by preventing contact with contaminated soil, and controls contaminant erosion and transport via stormwater and wind. The cap was graded to slope toward existing stormwater collection systems. The present cap consists of a 2-inch-thick base course and a 2-inch-thick wearing course and is considered temporary. To make the current containment system permanent, the cap must be rebuilt to support greater traffic loads and to conform to the specifications of a RCRA landfill cover (refer to Section 2.1.3).
3.5.3 Removal Extraction Wells The use of extraction wells for the removal of contaminated groundwater and NAPL is a proven technology, and could be readily implemented at TLT. With this technology, groundwater and/or NAPL within the capture zone of an extraction well, or group of wells, is pumped to the surface for subsequent treatment or disposal. Treatment of these waste streams is discussed in subsequent sections. Groundwater Extraction The extraction of groundwater by itself for the purpose of contaminant mass removal is not an effective technology within the barrier wall, because of the large DNAPL source (estimated at about 250,000 gallons, RI report), the low solubilities of most DNAPL constituents, and the limited supply of recharge within the barrier wall. Modeling estimates indicate that if groundwater containing DNAPL constituents at solubility limits were continually extracted at the maximum sustainable rate from within the barrier wall without supplemental injection (1.6 gpm, as observed in the RA), it would take over 1,500 years before all creosote constituents were below current tapwater PRG levels (see Appendix E-3 of the RI report). This estimate assumes that the only losses of DNAPL occur through dissolution into the aqueous phase. If injection wells were used to increase the total extraction rate to 100 gpm, it would still require nearly 200 years to obtain tapwater PRG levels, assuming that the theoretical solubility limits of the constituents were maintained in the extracted water at all times. Because of the extended timeframe, this technology is rejected. DNAPL Extraction Extraction wells designed for DNAPL removal pump fluids from the bottom of the well to the surface. DNAPL recovery is slow in most cases and pumping typically occurs intermittently, but it is possible to remove large quantities of contaminant mass from the subsurface with this method. However, residual (immobile) DNAPL will remain in the subsurface and continue to act as a source of groundwater contamination for a very long time. For example, even if 90 percent of the DNAPL were removed initially by direct extraction (50 to 60 percent removal is optimistic in practice), removal of remaining contaminants via groundwater extraction would require between 60 years, given an extraction rate of 100 gpm, and 500 years, at 1.63 gpm, to achieve tapwater PRGs. Because of the extended timeframe and expected high costs
3-12 CVO\043650001 3. IDENTIFICATION AND SCREENING OF TECHNOLOGIES
associated with long-term operation of a DNAPL extraction system, this technology is rejected from further consideration.
Interceptor Trenches After extraction wells, trenches are the most widely used method of recovering contaminants. Interceptor trenches (also referred to as drains) can be very effective and can be installed with widely available construction equipment. The hydraulic capture zone for a trench is large compared to a well array, and O&M costs are proportionally lower. A trench typically is installed in an excavation down to the top of the first continuous confining layer. A perforated pipe is placed in the bottom of the trench and then backfilled with gravel. The sumps located at the end of the trench, and/or at intermittent points between, are pumped to draw groundwater and mobile NAPL toward the trench for removal. Trench systems are most effective when NAPL pools are located near the ground surface and when the distribution of the pool is controlled by physical boundaries. Standard construction equipment, either a backhoe or continuous excavation, is commonly used to dig the trench. Backhoes capable of digging a trench up to 5.5 meters (18 feet) deep are readily available in most locations. Extended-reach hydraulic excavators can reach depths approaching 15.2 meters (50 feet), with widths of 0.9 to 1.5 meters (3 to 5 feet). Interceptor trenches are effective only at capturing mobile DNAPL. Little to no DNAPL has been recovered in the monitor wells in the vicinity of the DNAPL pool since the IA in 1999 (RI report, Section 4.4.1). The lack of DNAPL in nearby wells indicates that the DNAPL pool is not mobile and therefore would not be expected flow into an interceptor trench. Even if a significant portion of the DNAPL pool were mobile and could be captured by a trench, the remaining immobile portion would remain in place and continue to act as a source for a very long time (see prior discussion on DNAPL extraction wells). Furthermore, trenching within the barrier wall at TLT would require the removal of large amounts of contaminated soil that would require treatment and disposal. The area near the DNAPL pool has the greatest density of existing structures and is at the center of current wood treating activity, and trench installation would likely require moving or demolishing many of the existing structures. Because of these complications, this technology is not retained.
Excavation and Disposal This technology would involve the complete removal of the contaminated volume within the barrier wall and would entail:
• Moving or demolishing the treatment facility • Lowering the water table • Excavating the soil • Treating and disposing of the soil, groundwater, and DNAPL • Backfilling with clean material The total mass of soil contained within the barrier wall is approximately 182,000 tons, assuming a bulk density of 1.43 tons/yd3. The costs associated with the disposal of such a large quantity of soil, much of it heavily contaminated, would be very high. This, combined
CVO\043650001 3-13 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY with the costs of each of the other activities, ensures that the relative cost of this technology would be extremely high (on the order of $100M). Therefore, the technology is rejected from further consideration.
Surfactant Flushing Surfactant flushing involves injection of a surfactant solution into the subsurface to mobilize and/or solubilize DNAPL. In addition, high molecular weight polymers or foams are added to the injection water to increase its viscosity. Sweep efficiency is improved when the viscosity of the injectate is greater than the viscosity of the DNAPL, reducing “bypassing” and raising yields. Various permutations of this technology have come to be known as Surfactant Enhanced Aquifer Restoration (SEAR). Removal efficiency can be increased by an order-of-magnitude over water flushing. The mixture of groundwater and DNAPL is then removed from the ground via extraction wells or trenches and is treated above ground. A number of drawbacks make the implementation of SEAR impractical for the removal of creosote DNAPL:
• It is very difficult to separate and treat the DNAPL, surfactant, and water mixture • High concentrations of surfactant must be used (about 4 percent) • Uniform delivery of chemicals to the subsurface is problematic • The associated relative costs are very high This technology is not retained based on feasibility and cost.
Dynamic Underground Stripping Dynamic underground stripping (DUS) provides heat to the subsurface via steam injection or electrical resistance heating for difficult-to-remediate NAPL-contaminated sites. Contaminant destruction or removal occurs through several thermodynamic and enhanced transport mechanisms:
• Physical displacement to extraction wells by applying a driving force (steam injection only), decreasing the NAPL viscosity and capillarity
• Volatilization and extraction of residual NAPL in heated zones by increasing contaminant vapor pressures
• Dissolution of residual NAPL by increasing contaminant solubilities
• Diffusion of contaminants out of low-permeability soils by increasing diffusivities in air and water
• Degradation of contaminants by increasing degradation rates by thermophilic bacteria and/or hydrolysis/pyrolysis/oxidation (HPO) reactions Compared to conventional “pump and treat” technology, removal rates using DUS could increase by a factor of 30 or more. One potential concern is that DUS is most suitable for subsurface soils with a relatively high permeability (10-2 to 10-1 cm/s). At the TLT site, the permeability varies from 8.1 x 10-7 to 1.5 x 10-3 cm/s for the upper and lower alluvium units, respectively. However, the TLT site has
3-14 CVO\043650001 3. IDENTIFICATION AND SCREENING OF TECHNOLOGIES
a massive siltstone lower confining layer at an average depth of only 17 feet below the surface, which are advantageous characteristics. Although the TLT facility has boilers that generate steam, they do not have sufficient capacity to provide the required amount of steam for this technology. Despite the high cost associated with this technology, it is retained because of the limited options for removal of the DNAPL contamination. Pilot testing would be required to assess overall effectiveness and obtain information for design and full-scale operation.
In situ Vitrification In situ vitrification is a process that uses electrical power to heat and melt soil contaminated with organics, inorganics, and metal-bearing wastes. The molten material cools to form a hard, monolithic, chemically inert, stable glass and crystalline product that incorporates the inorganic compounds and heavy metals in the hazardous waste. The organic contaminants within the waste are vaporized or pyrolyzed and migrate to the surface of the vitrified zone where they are oxidized under a collection hood. Residual emissions are captured in an off- gas treatment system. Cost estimates for this technology range from $275 to $600 per ton of contaminated soil treated. The most significant factor influencing cost is the moisture content of the soil to be treated. High moisture content requires that large amounts of energy be used to dry out the soil before the melting process can begin, thus increasing the cost. This technology is not retained because of the extremely high cost.
3.5.4 Treatment In situ Bioremediation In situ bioremediation is the chemical degradation, in place, of organic contaminants by means of microorganisms. Biodegradation can occur either in the presence (aerobic) or absence (anaerobic) of oxygen. Aerobic biodegradation converts organic contaminants to various intermediate and final decomposition products, which can include various daughter compounds, carbon dioxide, water, humic materials, and microbial cell matter. Anaerobic biodegradation converts the contaminants to carbon dioxide, methane, and microbial cell matter. Generally, degradation rates are much higher for aerobic than anaerobic processes. Wood-treating chemicals are, by design, resistant to biological degradation, and at high concentrations are generally toxic to microorganisms. However, a number of constituents in creosote have been shown to be amenable to biodegradation. Naphthalene, for example, the most prevalent PAH in creosote, is readily susceptible to aerobic biodegradation. Unfortunately, the total mass of naphthalene present as a result of the DNAPL contamination overwhelms the potential of biodegradation to remove these constituents in a reasonable timeframe based on the oxygen demand alone. For example, based on the estimated 250,000 gallons of DNAPL resident within the barrier wall, approximately 97,000 kg of the DNAPL consists of naphthalene (Appendix E-3 of the RI report presents the chemical breakdown of the DNAPL at TLT). Stoichiometrically, for aerobic degradation, each kg of naphthalene requires 3 kg of oxygen. Therefore, continual injection of air-sparged water (9 mg/L of dissolved oxygen) at 100 gpm would be necessary
CVO\043650001 3-15 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY for over 150 years to supply the required oxygen to degrade the naphthalene alone. This assumes that all of the injected oxygen would be used directly for the degradation of naphthalene. Anaerobic degradation of naphthalene is not often considered because the rates are much slower than for the aerobic process. Although bioremediation is among the technologies considered as presumptive remedies for soils, sediments, and sludges at wood treater sites, this guidance is not directly applicable to DNAPL and groundwater remediation, and therefore is not considered as a presumptive remedy for this cleanup unit. In addition to the overwhelming oxygen demand, other constituents in the DNAPL (such as PCP) are less amenable to biodegradation, and past treatability studies in the 2000 Removal Action have shown the soil at TLT to have insufficient PCP degrading capability. For these reasons, in situ bioremediation of the contaminants present within the barrier wall is rejected from further consideration.
In situ Oxidation Chemical oxidation processes involve oxidation-reduction (redox) reactions, which either completely destroy organic compounds or convert them to smaller and typically less hazardous compounds. Recent advances in the development of this technology include systems that effectively deliver and distribute reagents into soil and groundwater so that in situ chemical oxidation (ISCO) is possible. The three most common ISCO reagents are potassium permanganate (KMnO4), hydrogen peroxide (H2O2), and ozone (O3). ISCO technology has been successfully applied to sites with trichloroethylene (TCE) and perchloroethylene (PCE) DNAPL contamination. However, very limited information is available for use on creosote-contaminated sites. Batch experiments have shown that many of the constituents in creosote are amenable to oxidation with (KMnO4). The total mass of PAHs present in the creosote DNAPL represents a very large oxidant demand. For example, as discussed in the previous section, approximately 97,000 kg of the DNAPL consists of naphthalene. Stoichiometrically, for chemical oxidation, each kg of naphthalene requires 12 kg of (KMnO4). Therefore, nearly 1,600 tons of (KMnO4) would be required to oxidize the naphthalene alone. Remediation success using ISCO is heavily dependent on the ability to deliver the oxidant to the contaminated area. Low soil permeability and heterogeneity can be problematic for ISCO systems. Because the oxidants are insoluble in NAPLs such as creosote, the oxidation rate is dependent on the rate of NAPL dissolution and mass transfer to the aqueous phase. The interphase mass transfer rate can be improved by chemical gradients created during treatment, especially if high aqueous concentrations of oxidants are used. Chemical oxidation can create enough heat to boil water. The heat can increase the solubility of DNAPL constituents, as well as possibly evaporate some of the underground chemicals. Special precautions might be required to capture and treat off-gasses. Pilot testing and monitoring during startup are required to prevent adverse effects such as development of explosive forces caused by excess buildup of pressure (below the ground surface) or permeability reduction from byproduct formation. This technology is rejected because of the large quantities of reagents required, and the difficulties likely to be encountered with implementation.
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Stormwater Treatment System A stormwater treatment system, completed in 2000, is currently in place and operating. Although the system was designed and is currently permitted for the treatment of stormwater runoff only, it can handle the treatment of contaminated groundwater and potentially some NAPL as well. The system is described in Section 3.4.3.
Evaporators An evaporator system is in place at TLT that is used to reclaim wood-treating product. At present, the evaporator system is operated on a very limited basis. Liquids that accumulate in the tank farm secondary containment and in the drip pad drains are passed through an oil-water separator and GAC unit before being stored in an open-top holding tank. The water in the holding tank is subsequently used as process water. However, if water accumulates beyond the holding capacity of the tank, it is evaporated. It costs about $500/day to run the evaporator, so its use is avoided unless absolutely necessary. Water from the four extraction wells is currently processed by this system. Steam from this process is expelled into the atmosphere through a stack. Since Pacific Wood Preserving of Oregon has assumed operation of the facility and has ceased using PCP- and creosote-based treating chemicals, it has not been cost effective to operate the evaporator system on a continual basis. The site operates under ODEQ Air Contaminant Discharge Permit No. 36-7004. If significant use of the evaporator were initiated, regular monitoring of the stack discharge would be required to ensure compliance with the permit. Depending on the treatment technologies selected and the rate of DNAPL extracted, it might become feasible to incorporate the evaporator system as part of a remedial alternative. The technology is retained.
3.5.5 Disposal If DUS is implemented, extracted DNAPL will need to be disposed of. Recycling or off- property disposal are two options considered.
DNAPL Recycling Although it is doubtful whether the extracted DNAPL would be acceptable to another wood treater, the technology will be retained pending a survey of available recipients. If a receiver is identified, the DNAPL will be collected in on-property tanks and periodically shipped off- property. This technology is retained.
Off-property Disposal of DNAPL DNAPL would be drummed and treated and disposed by a permitted TSD facility. This technology is retained.
3.6 Summary of Retained Technologies Retained remediation technologies are summarized in Table 3-2.
CVO\043650001 3-17 TABLE 3-1 Screening of Remediation Technologies Taylor Lumber and Treating Feasibility Study
General Response Media Technology Effectiveness Implementability Cost Retained Action Soil Outside Barrier Wall (SO) Institutional Soil Land use Relies on rules to limit exposure to Easy to implement on-property. Low relative cost. Yes for on-property Controls restrictions contaminated soil. Difficult to implement off-property. Long term surface soil. Not allowable by RCRA for stockpiled soil. commitment. Containment Soil Capping Reduces the likelihood of the migration of Easy to implement. A portion of the treated pole storage Moderate relative Yes. In place in one contaminated soil off-property and the area is currently capped. cost. area. possibility of exposure to contaminants. Limits leaching to groundwater. Capping (with Reduces the likelihood of the migration of Easy to implement. May be able to consolidate in an area Moderate relative Yes. Allowable to move consolidation) contaminated soil off-property and the of currently contaminated surface soil. cost. Long-term contaminated soil within possibility of exposure to contaminants. Limits commitment. the AOC. leaching to groundwater. Removal Soil Excavation Will effectively remove contaminants. Easy to implement. Moderate relative Yes. Removes risks cost. associated with contaminated soil. On-property Soil Incineration Removes nearly all organic constituents, but May require subsequent stabilization of waste material. High relative cost. No. High cost and not Treatment not effective on metals. EPA Presumptive effective on all COCs. Remedy. Immobilization / Reduces leachability of metals. Effectiveness Will require treatability study to verify effectiveness on Medium to high Yes. Possibly effective stabilization on organics at the levels observed outside the organics. relative cost. on both metals and barrier wall is likely but not certain. EPA organics. Presumptive Remedy.
Thermal desorption Removes nearly all organic constituents, but High energy demand. Will require treatability study. High relative cost. No. High cost and likely not effective on metals. EPA Presumptive to not be effective on all Remedy. COCs. Bioremediation Effectively reduces the concentrations of many Will require pilot testing. Moderate relative No. Ineffective on most organic constituents. Not effective on metals, cost. COCs. dioxins/furans and probably PCP. EPA Presumptive Remedy. Chemical oxidation Removes many organic constituents, but not Will require pilot testing. High relative cost. No. Not effective on effective on metals. metals. Soil washing Does not destroy or remove contaminants. Readily implementable. High relative cost. No. Reduction in Effective for concentrating contaminants volume does not justify through separation. the cost. Off-property Soil Off-property Removes contaminants from the site. May require treatment before disposal (depending on High relative cost. Yes. Removes risks Disposal disposal contaminant concentrations), which will be included with associated with the cost of this technology. contaminated soil.
CVO\043650002 Page 1 of 4 TABLE 3-1 Screening of Remediation Technologies Taylor Lumber and Treating Feasibility Study
General Response Media Technology Effectiveness Implementability Cost Retained Action Groundwater Outside Barrier Wall (BW) Institutional Groundwater Pumping Reduces possibility of exposure to Easy to implement. Low relative cost. Yes. Required for the Controls restrictions and contaminated groundwater. protection of human groundwater health. monitoring Containment/ Groundwater Extraction wells Reduces the likelihood of the migration of Easy to implement, but requires long term pump and treat. Low relative cost. Yes. Can Removal contaminated groundwater off-property and the reduce/remove threat to possibility of exposure to contaminants. river. Treatment Groundwater In-situ Biodegradation of dioxins/furans is highly Will require treatability and pilot testing. Moderate relative No. PCP and dioxin bioremediation unlikely. Previous studies have shown the soil cost. biodegradation potential to have insufficient PCP degrading potential. is low.
In-situ oxidation May be effective for treating dioxins/furans and Proper distribution of the chemicals is difficult. Can Moderate relative No. Due to distribution PCP. potentially drive contaminants to the river. cost. difficulties
Permeable reactive Poor effectiveness expected using Fe(0) as Fairly easy to implement, and potentially requires little Moderate relative Yes. barrier reactive media. Other media have not been O&M. Treatability studies would be required to prove cost. widely applied and success is doubtful. effectiveness. Stormwater Effective in removing all contaminants. Wastewater treatment system preexisting for surface Low relative cost. Yes. In place. treatment system runoff. Will require permitting for treatment of extracted groundwater.
CVO\043650002 Page 2 of 4 TABLE 3-1 Screening of Remediation Technologies Taylor Lumber and Treating Feasibility Study
General Response Media Technology Effectiveness Implementability Cost Retained Action Contaminated Media Inside Barrier Wall (BW) -- Groundwater, DNAPL, Soil Institutional Groundwater Pumping Reduces possibility of exposure to Easy to implement. Low relative cost. Yes. Required for the Controls restrictions and contaminated groundwater. Long-term protection of human groundwater commitment. health. monitoring Soil Land use Reduces possibility of exposure to Easy to implement. Low relative cost. Yes. Required for the restrictions contaminated soil. Long-term protection of human commitment health. Containment Groundwater Hydraulic Part of the existing containment system, Currently in place. No installation Yes. In place. containment maintains an inward hydraulic gradient to cost. Long-term prevent the migration of contaminated O&M groundwater beyond the barrier wall. commitment. DNAPL and Barrier walls Part of the existing containment system, Currently in place. No installation Yes. In place. groundwater prevents DNAPL migration and minimizes cost. Long-term migration of contaminated groundwater O&M beyond the barrier wall. commitment. Soil Capping Part of the existing containment system, A cap is in place but is insufficient to handle current loads. Moderate relative Yes. In place, but minimizes infiltration of surface runoff into the The cap must be upgraded or replaced with a permanent cost. Long-term requires upgrade. contained unit. cap. O&M commitment. Removal Groundwater Extraction wells Will not be effective unless DNAPL is also Easy to implement, but will require extraction wells and Low relative cost. No. Cannot effectively removed water treatment. Long-term O&M clean up groundwater commitment. alone.
DNAPL Extraction wells Even if DNAPL can be extracted, significant Difficult to implement, will probably require enhancements Moderate to high No. Due to high cost quantities will remain uncaptured, regardless and multiple wells, also DNAPL/groundwater separation relative cost. and remaining residual of method. and treatment. Long-term O&M product. commitment
DNAPL and Interceptor Effectiveness uncertain. Can be more effective Installation would generate large quantities of High relative cost. No. Uncertain groundwater trenches than vertical wells for removing DNAPL and contaminated soil and require demolition of many of the Long-term O&M effectiveness, disruptive contaminated groundwater. existing structures. commitment and high cost.
DNAPL, soil, Excavation and Will effectively remove contaminants in a short Will generate a very large volume of soil, groundwater, and Very high relative No. Excessive cost. and disposal time period. DNAPL for disposal. Would require removal of existing cost. groundwater structures.
CVO\043650002 Page 3 of 4 TABLE 3-1 Screening of Remediation Technologies Taylor Lumber and Treating Feasibility Study
General Response Media Technology Effectiveness Implementability Cost Retained Action Contaminated Media Inside Barrier Wall (BW) con't -- Groundwater, DNAPL, Soil Removal, con't. DNAPL, soil, Surfactant flushing Effectiveness uncertain. May overcome the Aggressive flushing will require injection to prevent High relative cost. No. High cost and and solubility limitation of groundwater extraction dewatering within the barrier wall. Solvent/contaminant difficult to implement. groundwater alone. separation is difficult. Will require treatability/pilot testing.
Dynamic Has proven effective at rapidly removing > Requires significant infrastructure including: an injection High relative cost. Yes. Can potentially Underground 95% of contaminants from subsurface. and extraction well network, heat sources, blowers, and a remove nearly all of Stripping Effective on DNAPL and contaminated soil and wastewater treatment system. Will require pilot testing for contamination. groundwater. optimization. In-situ vitrification Can effectively remove organics and contain Difficult to implement and numerous containment features Very high relative No. High cost and metal contaminants. Requires treatment of are preexisting at the site. cost. difficult to implement. offgas. Treatment Groundwater In-situ May be effective for treating some organic The large DNAPL pool creates an enormous oxygen Moderate relative No. Unrealistic within bioremediation contaminants. Previous studies have shown demand. Concentrations may be sufficiently high to be cost. the barrier wall due to the soil to have insufficient PCP degrading toxic to the microorganisms. DNAPL. potential. In-situ oxidation May be effective for treating some organic The large DNAPL pool creates an enormous oxidant High relative cost. No. Effectiveness and contaminants. demand. Proper distribution of the chemicals is difficult. implementability uncertain due to DNAPL.
Stormwater Effective in removing all contaminants. Wastewater treatment system preexisting for surface runoff Low relative cost. Yes. In place. treatment system . Will require permitting for treatment of extracted groundwater and DNAPL. May require additional capacity depending on selected remedy. DNAPL and Evaporators Effective for reclaiming product from mixed Evaporator system preexisting at site for the reclamation of No installation Yes. In place. May be groundwater DNAPL/water streams. product from aqueous mixture. System is energy intensive, cost. However, useful if DNAPL but cost may be balanced based on volume reduction and power utilization recovery alternative is possible reuse of reclaimed product. May require is high. considered. additional permitting. Disposal DNAPL Recycling Effective. Will require the identification of end user willing to accept Potentially no Yes. the product. cost. Off-property Effective. DNAPL will be treated and disposed Readily implementable. High relative cost. Yes. disposal of by third party.
CVO\043650002 Page 4 of 4 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
TABLE 3-2 Summary of Retained Technologies Taylor Lumber and Treating Feasibility Study
General Response Cleanup Unit Action Media Technology
Soil outside the barrier Institutional controls West Facility surface soil Land use restrictions wall (SO)
Containment West Facility surface soil Capping
West Facility surface soil, soil Capping (with consolidation) storage cells
Removal West Facility surface soil, off- Excavation property ditch soil
Treatment West Facility surface soil, off- Immobilization (on-property) property ditch soil and soil storage cells
Disposal West Facility surface soil, off- Off-property disposal (includes off- property ditch soil and soil property treatment if necessary) storage cells
Groundwater outside Institutional controls Groundwater Pumping restrictions barrier wall (GW)
Monitoring
Containment/ removal Groundwater Extraction wells
Treatment Groundwater Stormwater treatment system
Permeable Reactive Barrier
Inside barrier wall (BW) Institutional Controls Groundwater Pumping restrictions
Monitoring
Land use restrictions
Soil Land use restrictions
Containment Groundwater Hydraulic containment
DNAPL and groundwater Barrier wall
Soil Capping
Removal DNAPL, soil, and Dynamic underground stripping groundwater
Treatment Groundwater Stormwater treatment system
DNAPL and groundwater Evaporators
Disposal DNAPL Recycling
Off-property disposal
3-22 CVO\043650001
SECTION 4 Assembly of Remedial Alternatives
This section explains how the technologies retained from the screening described in Section 3 were used to develop remedial alternatives for each of the three cleanup units defined in Section 2. The assembly of alternatives is described in the following subsections. The alternatives are described in detail and evaluated in Section 5. A range of remedial action alternatives was developed for each of the three cleanup units in accordance with the NCP 40 CFR 300.430(e). The NCP requires that alternatives include:
• A no action alternative, where no further actions are considered.
• At least one alternative that involves little or no treatment but that protects human health by preventing potential exposure.
• A range of treatment alternatives that include eliminating the need for long-term facility management (including monitoring), removal and/or destruction of hazardous substances, and use of treatment to address the principal threats and reduce the toxicity, mobility, or volume of the chemicals present.
• For groundwater, development of a limited number of alternatives that attain site- specific remediation levels within different restoration time periods. CERCLA requires EPA to select remedies that use permanent solutions, alternative treatment technologies, or resource recovery to the maximum extent practicable. In cases where the hazardous constituents pose a relatively low long-term threat, or where treatment is impracticable, EPA may use engineering controls such as containment for the protection of human health and the environment [40 CFR 300.430(a)(1)(iii)(B)].
4.1 Soil Outside the Barrier Wall (SO) The SO cleanup unit contains hot spot and non-hot spot surface soil in the West Facility, off- property ditch soil, and the soil storage cells. Although not necessarily feasible for all SO target areas, the following alternatives were assembled from the technologies retained in Section 3:
• SO-1: No action • SO-2: Institutional controls • SO-3: Capping in place • SO-4: Excavation with on-property consolidation and capping • SO-5: Excavation with off-property disposal Based on the five treatment options, alternatives for the cleanup unit were developed by the following process:
CVO\043650001 4-1 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
• Step 1: Determine which treatment options will be retained for individual target areas. For each target area, the treatment options are assessed qualitatively for effectiveness, implementability, and cost (Table 4-1). For example, for off-property ditch soil, excavation with off-property disposal and excavation with on-property consolidation and capping were retained, while capping in place and institutional controls were not, because they were not considered implementable. No action was retained for all target areas because it is an NCP requirement. For the West Facility surface soil, treatment options were considered separately for hot spots and non-hot spots. Institutional controls and capping in place were retained for non-hot spots, while excavation with off-property disposal, excavation with on-property consolidation, and capping were retained for hot spots.
• Step 2: Combine the retained treatment options into alternatives that apply to the entire SO cleanup unit as a whole. The four alternatives developed for the SO cleanup unit are summarized in Table 4-2. For example, as shown in Table 4-1, excavation with off-property disposal is an option retained for all target areas, except the non-hot spot soil in the West Facility. In Table 4-2, Alternative SO-4 includes capping in place for the non-hot spot area, and excavation with off-property disposal for all remaining target areas in this cleanup unit.
4.2 Groundwater Outside the Barrier Wall (GW) For this cleanup unit, the target area is the dissolved plume outside the barrier wall that exceeds the MCL for PCP of 1 ppb. The alternatives for the contaminated groundwater were developed from the technologies retained in Section 3:
• GW-1: No action • GW-2: Institutional controls • GW-3: Pump-and-treat • GW-4: Permeable reactive barrier
4.3 Contaminated Media Inside the Barrier Wall (BW) The BW cleanup unit is defined by the area contained within the barrier wall and includes DNAPL, contaminated soil, and groundwater. In order to meet the RAOs for this cleanup unit, the alternatives developed from the technologies retained in Section 3 are:
• BW-1: No action
• BW-2: Existing components with cap removal and heavy-duty replacement (concrete with liner)
• BW-3: Existing components with cap repair and heavy-duty overlay (concrete with liner)
• BW-4: Existing components with cap repair and heavy-duty overlay (asphalt without liner)
• BW-5: Dynamic underground stripping
4-2 CVO\043650001 TABLE 4-1 Screening of Treatment Options for Soil Target Areas Taylor Lumber and Treating Feasibility Study
Description Meets Objectives Implementable Relative Cost Retained West Facility Surface Soil Hot Spot Non-Hot Spot Hot Spot Non-Hot Spot Hot Spot Non-Hot Spot Hot Spot Non-Hot Spot No Action No No Yes Yes None None Yes1 Yes1 Institutional Controls No Yes Yes Yes Low Low No Yes Excavation with Off-property Disposal Yes Yes Yes Yes Very high Excessive Yes No Excavation with On-property Consolidation Yes Yes Yes No2 High Very high Yes No and Capping Capping In Place Yes Yes Yes Yes High High Yes Yes Ditch Soil No Action No Yes None Yes1 Institutional Controls No No3 Low No Excavation with Off-property Disposal Yes Yes Very high Yes Excavation with On-property Consolidation Yes Yes High Yes and Capping Capping In Place Yes No4 High No Soil Storage Cells No Action No Yes None Yes1 Institutional Controls Yes Yes Low No5 Excavation with Off-property Disposal Yes Yes Very High Yes Excavation with On-property Consolidation Yes Yes High Yes and Capping Capping In Place NA NA NA No
Notes: 1 NCP requires consideration of a No Action alternative 2 Excessive volume to consolidate on-property. 3 Institutional controls are not applicable/enforceable for off-property soil 4 A cap could not be installed in the ditches without excavation to lay a suitable sub-grade. 5 Not allowable under RCRA.
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TABLE 4-2 Alternatives for Soil Outside the Barrier Wall (SO) Taylor Lumber and Treating Feasibility Study
Alternative Description Target Area
SO-1 No action All
SO-2 Institutional controls West Facility non-hot spot soil
Excavation with consolidation, stabilization West Facility hot spot soil, off- and capping in Treated Pole Storage Area, property ditch soil and soil storage institutional controls cells
SO-3 Capping in place, institutional controls West Facility non-hot spot soil
Excavation with consolidation, stabilization West Facility hot spot soil, off- and capping in Treated Pole Storage Area, property ditch soil and soil storage institutional controls cells
SO-4 Capping in-place, institutional controls West Facility non-hot spot soil
Excavation with off-property disposal West Facility hot spot soil, off- property ditch soil, soil storage cells
4-4 CVO\043650001
SECTION 5 Detailed Analysis of Alternatives
In this section, the alternatives developed in the previous section are described in more detail and evaluated to provide a basis for selecting a remedy. Section 5.1 discusses the criteria used to evaluate the alternatives, and Section 5.2 contains descriptions and evaluations of the alternatives for each of the three cleanup units.
5.1 Evaluation Criteria According to the EPA’s Guidance for Conducting Remedial Investigations and Feasibility Studies under CERCLA, OSWER Directive 9355.3-01 (U.S. EPA, 1988), nine evaluation criteria must be considered in order to address CERCLA requirements:
• Overall protection of human health and the environment • Compliance with ARARs • Long-term effectiveness and permanence • Reduction of toxicity, mobility, and volume through treatment • Short-term effectiveness • Implementability • Cost • State acceptance • Community acceptance The first two criteria are threshold criteria and must be achieved by alternatives at a minimum, and the next five are considered primary balancing criteria. These first seven criteria form the basis of the detailed evaluation of alternatives. The last two criteria, state and community acceptance, are modifying criteria, and are not discussed in this section. EPA will address them following public comment on the RI/FS. The threshold and primary balancing criteria are briefly described in the following subsections.
5.1.1 Overall Protection of Human Health and the Environment Overall protection of human health and the environment is one of two threshold criteria that the selected alternative must satisfy. The discussion of effectiveness in the initial screening of technologies generally addressed this criterion. The following factors will be considered as each alternative is evaluated for this criterion:
• Comparison of baseline human health risk estimates with regulatory risk criteria
• Comparison of ecological risk estimates with regulatory risk criteria
• Evaluation of exposure pathways for human and ecological receptors following implementation of the remedial alternative
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5.1.2 Compliance with ARARs Compliance with ARARs is the second of the threshold criteria. A discussion of ARARs was presented in Section 2. The following factors will be considered as each alternative is evaluated for this criterion:
• Compliance with location-specific ARARs • Compliance with chemical-specific ARARs • Compliance with action-specific ARARs
5.1.3 Long-Term Effectiveness and Permanence The evaluation of long-term effectiveness and permanence focuses on the technical effectiveness and reliability of the remedies. The following factors will be considered as each alternative is evaluated for this criterion:
• Magnitude of estimated residual risk • Adequacy and reliability of controls
5.1.4 Reduction of Toxicity, Mobility, and Volume through Treatment This criterion addresses the statutory preference for selecting remedial actions that employ treatment technologies that permanently and significantly reduce toxicity, mobility, or volume of waste materials, and thereby reduce the principal threats at a site. The following factors will be considered as each alternative is evaluated for this criterion:
• Treatment processes used and materials treated • Amount of waste material destroyed or treated • Degree of expected reduction in toxicity, mobility, or volume • Degree to which treatment is irreversible • Type and quantity of residuals remaining after treatment
5.1.5 Short-Term Effectiveness The potential effects on human health and the environment during construction and implementation of each alternative are evaluated under short-term effectiveness. The period of evaluation includes the construction and startup period, and the duration of operation until the RAOs are achieved. The following factors will be considered as each alternative is evaluated for this criterion:
• Protection of community during remedial actions • Protection of workers during remedial actions • Environmental impacts • Time to completion
5.1.6 Implementability The evaluation of implementability includes the technical and administrative feasibility of implementing each alternative, as well as the availability of services and materials required for implementation. The following factors will be considered as each alternative is evaluated for this criterion:
5-2 CVO\043650001 5. DETAILED ANALYSIS OF ALTERNATIVES
• Ability to construct, operate, and monitor the technology
• Reliability of the technology
• Ease of undertaking additional remedial action, if necessary
• Ability to coordinate with and obtain approvals from other agencies
• Availability of equipment, specialists, technologies, off-property treatment, storage or disposal services, and capacity
5.1.7 Cost The estimated cost of each remedial option is expressed as present value (PV). The PV includes capital expenditures for implementation of the remedial action, and annual O&M costs incurred during the lifetime of the remedial action. The PV costs assume a discount rate of 7 percent over a 30-year operation period. Note that the 30-year O&M period is assumed for evaluation purposes only, the actual O&M period could be much longer in some cases. Total costs are expressed over a plus 50 to minus 30 percent range.
5.2 Evaluation of Alternatives The remedial alternatives for each of the three cleanup units are described and evaluated in the following subsections. The primary assumptions used to develop the alternatives are listed in each of the descriptions. Presented in Appendix C, cost analysis tables for each of the alternatives contain more detailed assumptions. Tables 5-1 through 5-3 present an overall evaluation of how each of the alternatives meets the seven criteria.
5.2.1 Soil Outside the Barrier Wall (SO) This cleanup unit includes: West Facility hot spot and non-hot spot surface soil, off-property ditch soil, and soil storage cells.
Alternative SO-1: No Action
Alternative Summary
Description Applies To
No action All target areas
The no action alternative is required as a baseline for comparison to other alternatives. Under this alternative, all target areas for the soil cleanup unit would be left as is, without O&M. This alternative requires no action and has no associated costs. It is readily implementable but is not protective of human health or the environment, and does not comply with ARARS.
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Alternative SO-2: Capping for Hot Spot Areas with Institutional Controls for Non-Hot Spot Areas
Alternative Summary
Description Applies To
Institutional controls West Facility non-hot spot soil
Excavation with consolidation, stabilization West Facility hot spot soil, off-property ditch soil and capping in Treated Pole Storage area, and soil storage cells institutional controls
This alternative caps the hot spot soils in place that are in the Treated Pole Storage area, where the bulk of the contaminated surface soil exists in the West Facility. The remaining hot spot surface soil in the West Facility, along with the off-property ditch soil and soil from the storage cells, will be excavated and mixed with a stabilizing agent (assumed to be Portland cement) and used as the structural base course for the cap. The new capped area will surround and extend the current cap in the Treated Pole Storage area. Institutional controls restricting trenching and ensuring cap maintenance will be established. This alternative employs institutional controls to limit exposure to the non-hot spot surface soil in the West Facility. Possible controls include restricting access, requiring personal protective equipment when digging in the area, and restricting use of material removed from the area. Quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• Excavation of West Facility hot spot surface soil will be to depth of 1 foot.
• Ditch excavation will be 1 foot deep by 3 feet wide.
• The cap will consist of a 2-inch base course and a 2-inch top course (both asphalt) over a 24-inch consolidation base consisting of stabilized soil and/or crushed rock. This design is similar to that of the existing cap in the Pole Storage area. Given the 24-inch consolidation base, the paved area will cover about 7.7 acres, which is approximately the entire Pole Storage area.
• For O&M purposes it is assumed that 25 percent of the cap will require replacement every 5 years.
• O&M time frame of 30 years The evaluation for this alternative is summarized in Table 5-1. The total expected cost is approximately $2.6M (with a plus 50 to minus 30 percent range between $1.8M to $3.9M). Capping the hot spot areas in the West Facility and excavating and capping soil from the ditches and storage cells will prevent exposure to contaminated soil, and will prevent the migration of contaminants through surface water transport and windborne erosion, thus assuring protection of human health and the environment. Future exposure to contaminated soil or development of ecological habitat in the consolidated/capped area will be prevented by institutional controls. Capping is readily implementable and will have a low impact on workers and the public during construction. While stabilization will reduce contaminant
5-4 CVO\043650001 5. DETAILED ANALYSIS OF ALTERNATIVES
mobility, overall volume of affected media will increase. Also, the long-term effectiveness relies on continued O&M of the cap, and institutional controls. Exposure to non-hot spot soil in the West Facility will be minimized via institutional controls, but it will not be eliminated and there will always be some risk to workers and trespassers. Also, contaminants will be subject to wind and water erosion and may migrate off-property as a result.
Alternative SO-3: Capping Hot Spot and Non-Hot Spot Areas
Alternative Summary
Description Applies To
Capping in place, institutional controls West Facility non-hot spot soil
Excavation with consolidation, stabilization West Facility hot spot soil, off-property ditch soil and capping in Treated Pole Storage area, and, soil storage cells institutional controls
This alternative consolidates and caps West Facility hot spot soil, off-property ditch soil and soil from the storage cells in the Pole Storage area, as in SO-2. Institutional controls restricting trenching and ensuring cap maintenance will be employed. This alternative differs from SO-2 in that it caps non-hot spot West Facility surface soil with gravel. A geotextile liner system will underlay the gravel to prevent fine soil particles from moving to the surface and becoming exposed to wind and water erosion. Future exposure to contaminated soil or potential development of ecological habitat in the capped areas will be prevented by institutional controls. Quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• Excavation of West Facility hot spot surface soil will be to depth of 1 foot.
• Ditch excavation will be 1 foot deep by 3 feet wide.
• The cap will consist of a 2-inch base course and a 2-inch top course (both asphalt) over a 24-inch consolidation base consisting of stabilized soil and/or crushed rock. This design is similar to that of the existing cap in the Pole Storage area. Given the 24-inch consolidation base, the paved area will cover about 7.7 acres, which is approximately the entire PS area.
• The cap over the non-hot spot West Facility soil will consist of a 12-inch gravel cap over a geotextile liner.
• For both the asphalt and gravel caps, it is assumed that 25 percent of the cap area will require replacement every 5 years.
• O&M time frame of 30 years The evaluation for this alternative is summarized in Table 5-1. The total expected cost of this alternative is approximately $8. 7M (with a plus 50 to minus 30 percent range between $6.
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1M to $13.0M). As for Alternative SO-2, capping the hot spot soils in the West Facility as well as contaminated soils from the ditches and storage cells will assure the protection of human health and the environment. This alternative also caps the non-hot spot soil areas in the West Facility, thereby preventing exposure to workers or trespassers and limiting the migration of contaminants from these areas. Costs of this measure must be weighed against the effectiveness and long-term benefits that it might incur.
Alternative SO-4: Excavation and Off-property Disposal
Alternative Summary
Description Applies To
Capping in-place, institutional controls West Facility non-hot spot soil
Excavation with off-property disposal West Facility hot spot soil, off-property ditch soil, soil storage cells
This alternative considers excavation with off-property disposal for all soil in this cleanup unit except for the non-hot spot areas in the West Facility. The contaminated soils (arsenic > 250 mg/kg) under the existing 2.02-acre AC cap in the Treated Pole Storage area will be excavated and disposed of as well. The cap and base course will be disposed of separately as nonhazardous waste. The non-hot spot surface soil will be capped with a gravel/geotextile liner system, as in SO-3. For this FS, it is assumed that all excavated soil will require treatment prior to final disposal. Treatment will be handled by the disposal facility, and costs are included in the total. Excavated areas will be backfilled with clean soil from a local source. The TLT site is serviced by a railroad spur, and it is assumed that all soil would be loaded directly into rail cars upon excavation and transported to the disposal facility. Quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• Excavation of hot spot surface soil in the West Facility will be to a depth of 1 foot.
• Ditch excavation will be 1 foot deep by 3 feet wide.
• The cap over the non-hot spot West Facility soil will consist of a 12-inch gravel cap over a geotextile liner.
• For O&M purposes it is assumed that 25 percent of the gravel cap area will require replacement every 5 years.
• O&M time frame of 30 years. The evaluation for this alternative is summarized in Table 5-1. The total expected cost is approximately $26. 7M (with a plus 50 to minus 30 percent range between $18. 7M to $40.0M).
5-6 CVO\043650001 5. DETAILED ANALYSIS OF ALTERNATIVES
Risk from all hot spot areas in the West Facility, contaminated ditches, and soil storage cells will be completely removed. For non-hot spot areas in the West Facility, protectiveness of human health and the environment is achieved by containment, along with institutional controls. The alternative is readily implementable and will have a low impact on property workers and the public during construction. The reduction of toxicity, mobility, and volume will be obtained through off-property treatment. Long-term effectiveness will be high because the high-risk soils outside the barrier wall are removed. Containment and institutional controls can effectively manage the risk from non-hot spot areas.
5.2.2 Groundwater Outside the Barrier Wall (GW) The target area for this cleanup unit includes the groundwater outside the barrier wall that exceeds the MCL for PCP (1 ppb).
Alternative GW-1: No Action The no action alternative is required as a baseline for comparison to other alternatives. Under this alternative, no action would be taken to remediate groundwater outside of the barrier, but monitoring would be maintained. The only technology employed for this alternative is groundwater monitoring. Under this alternative, the time until acceptable risk levels are achieved for contaminants outside the barrier wall would be on the order of hundreds of years. This alternative requires no action and has no costs other than those associated with long-term monitoring. The total expected cost of this alternative is approximately $118K (with a plus 50 to minus 30 percent range between $83K to $177K).
Alternative GW-2: Institutional Controls This alternative is similar to GW-1, with the addition of applicable institutional controls such as groundwater pumping restrictions. The evaluation for this alternative is summarized in Table 5-2. The total expected cost of this alternative is approximately $120K (with a plus 50 to minus 30 percent range between $84K to $180K). With institutional controls alone, the time until acceptable risk levels are achieved for contaminants outside the barrier wall would be on the order of hundreds of years. Institutional controls should be readily implementable and enforceable on facility property. As long as they can be maintained and contaminants do not migrate off-property, the risk would be mitigated; however, protectiveness of the river is not assured. If and when monitoring indicates a change in conditions, for example a significant increase in contaminant concentrations in the perimeter wells, then groundwater remediation might be necessary. Monitoring results that would trigger an action will be stated in the ROD/proposed plan.
Alternative GW-3: Pump-and-Treat In addition to monitoring and pumping restrictions, this alternative includes groundwater removal and treatment at the surface. The groundwater extraction also would provide hydraulic containment. It is assumed the extracted water would be treated in the existing stormwater treatment system.
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This alternative ensures that elevated levels of PCP do not migrate off-property, and thereby protects the river. Also, because the contaminant plume outside the barrier wall is small and contains a finite mass of contaminants, groundwater extraction should result in restoring the aquifer outside the barrier wall relatively quickly. It is assumed that the pump-and-treat system would focus on the portion of the outside of the barrier wall with concentrations of PCP greater than 100 µg/L (see Figure 2-3). The areas of lower contamination would be addressed indirectly as the plume is drawn toward the extraction wells. The target area quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• Six extraction wells to be installed
• Low extraction rate (0.25 gpm), sufficient to prevent migration to the river but not enough to disrupt the gradient inside the barrier wall
• Installation of four new monitor wells
• Extraction period/O&M of 30 years The evaluation for this alternative is summarized in Table 5-2. With pump and treat, the time until acceptable risk levels are achieved for contaminants outside the barrier wall should be on the order of tens of years. This alternative assumes that the extracted groundwater can be treated in the existing SWTS (given permit approval and sufficient capacity). The total cost of this alternative is expected to be approximately $492K (with a plus 50 to minus 30 percent range between $344K to $737K). The present NPDES permit would require modification for discharge of treated groundwater from the existing SWTS. ODEQ is in the process of modifying the permit to include groundwater from the current extraction wells. Depending on how the new permit is worded, addition modification to include extracted groundwater from outside of the barrier wall might be required. The alternative is readily implementable, and would have low worker and public exposure during construction.
Alternative GW-4: Permeable Reactive Barrier In addition to monitoring and pumping restrictions, this alternative employs a PRB that would treat the groundwater in situ, and does not require groundwater extraction. The target area quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• Funnel-and-gate design, with 400 feet of soil-bentonite slurry wall and three gates • The reactive medium is GAC, which would require replacement every 5 years • Installation of four new monitor wells • Extraction period/O&M of 30 years Under this alternative, groundwater would flow passively through the treatment vaults that intercept organic contaminants, preventing PCP migration and protecting the river. The local hydraulic gradient would be important to the success of this alternative. Not only does the flow rate through the wall control the rate of cleanup, but a sufficient gradient is required to assure that groundwater is driven through the gates rather than backing up and
5-8 CVO\043650001 5. DETAILED ANALYSIS OF ALTERNATIVES
flowing around the barrier. Because the groundwater velocity is very low immediately downgradient of the barrier wall, the time until acceptable risk levels are achieved could vary from tens to hundreds of years. Successful implementation would require significant groundwater modeling and favorable hydrogeologic conditions. The total cost of the alternative is approximately $944K (with a plus 50 to minus 30 percent range between $660K to $1,415K), and the evaluation is summarized in Table 5-2.
5.2.3 Inside the Barrier Wall (BW) The target area for this cleanup unit includes all contaminated media inside the barrier wall, including DNAPL, groundwater, and soil.
Alternative BW-1: No Action The no action alternative is required as a baseline for comparison to other alternatives. Under this alternative, the area within the barrier wall system would be abandoned indefinitely. Following abandonment, some of the preexisting remedies might continue to serve at least a portion of their intended purpose (i.e., barrier wall and cap), while others would not be used (i.e., extraction wells). Under this alternative, the time until acceptable risk levels are achieved for contaminants within the barrier wall (and the elimination of risk to the river) would be on the order of thousands of years. There are no costs associated with this alternative.
Alternative BW-2: Existing Components with Cap Removal and Heavy-duty Replacement (Concrete with Liner) This alternative uses the containment measures, including the barrier wall and extraction wells, and replaces the temporary asphalt cover with a permanent cap. The current level of O&M would continue, and institutional controls would be employed to maintain the system into the future. The permanent cap would require less periodic maintenance than the existing cover. Installed in 2000, the existing cap has incurred significant damage from the heavy equipment used by PWP in certain areas. The slow, heavy loads and the torques applied from stopping and starting and turning are extremely demanding on the surface. The existing cap consists of 4 inches of asphalt over a 12-inch crushed rock base. To upgrade this cap, the existing cap and subgrade would be removed. A new base course would be installed and compacted, followed by a PVC liner between layers of geotextile fabric, and capped with concrete. The liner might be required to conform to RCRA standards, as explained in Section 2.1.3. Concrete was chosen instead of asphalt because hot asphalt would probably damage the liner when placed over it. The quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• 6-inch crushed rock base course, 30 mil PVC liner, and 12-inch unreinforced concrete cap • Periodic joint reseal every 5 years • Use of existing SWTS for treatment of extracted groundwater • O&M time frame of 30 years
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With this design, the final grade would be the same as the current grade. Because the cap would be made from unreinforced concrete, joints would be required about every 20 feet to allow for expansion and contraction. A reinforced concrete cap would not have the joints, but would be considerably more expensive and was not evaluated in this alternative. The evaluation for this alternative is summarized in Table 5-3. Much of this alternative is already in place, but requires an NPDES permit modification for discharge of treated groundwater from the existing SWTS (ODEQ is in the process of changing the permit to include the groundwater). The total cost of this alternative is approximately $3. 3M (with a plus 50 to minus 30 percent range between $2. 3M to $5.0M). Long-term protectiveness of human health and the environment relies on containment and institutional controls. Note that the three capping alternatives BW-2, BW-3, and BW-4 all entail O&M of the existing groundwater extraction system, SWTS, and institutional controls, which together make up most of the total expected cost (approximately $1.8M present value) over the 30- year O&M period. The total capital cost of this alternative is approximately $1.6M.
Alternative BW-3: Existing Components with Cap Repair and Heavy-duty Overlay (Concrete with Liner) This alternative is similar to BW-2, except that instead of removing the existing cap and subgrade, the temporary AC cover would be repaired and overlaid with a permanent concrete cap. As with BW-2, the current level of O&M would continue and institutional controls would be employed to maintain the system into the future, but less maintenance would be needed for the cap than is currently required. To upgrade this cap, the damaged areas would be replaced with new asphalt, a PVC liner between layers of geotextile fabric would be installed over the asphalt, and a heavy-duty concrete cap installed over the liner. The liner might be required to conform to RCRA standards as explained in Section 2.1.3. Concrete was chosen instead of asphalt because hot asphalt would probably damage the liner when placed over it. The quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• Replacement of damaged asphalt • Installation of a 30-mil PVC liner over the existing asphalt • 8-inch unreinforced concrete cap • Periodic joint reseal every 5 years • Use of existing SWTS for treatment of extracted groundwater • O&M time frame of 30 years With this design, the final grade would be about 8 inches above the current grade. This might create problems for drainage and alignment with existing structures, and could involve a number of facility modifications not accounted for in this assessment. Because the cap would be made from unreinforced concrete, joints would be required about every 20 feet to allow for expansion and contraction. A reinforced concrete cap would not have the joints, but would be considerably more expensive and was not evaluated in this alternative.
5-10 CVO\043650001 5. DETAILED ANALYSIS OF ALTERNATIVES
The evaluation for this alternative is summarized in Table 5-3. Most of this alternative is already in place, but requires a NPDES permit modification for discharge of treated groundwater from the existing SWTS (ODEQ is in the process of changing the permit to include the groundwater). The total cost of this alternative is approximately $2. 8M (with a plus 50 to minus 30 percent range between $2.0M to $4.2M). Long-term protectiveness of human health and the environment relies on containment and institutional controls. Note that the three capping alternatives, BW-2, BW-3, and BW-4, all entail O&M of the existing groundwater extraction system, SWTS, and institutional controls, which together make up most of the total expected cost (approximately $1.8M present value) over the 30- year O&M period. The total capital cost of this alternative is approximately $1.1M.
Alternative BW-4: Existing Components with Cap Repair and Heavy-duty Overlay (Impermeable Asphalt) This alternative is similar to BW-3, except that instead of a concrete overlay, an engineered asphalt overlay would be used with a permeability at or below 1 x 10-8 cm/s. This is at least an order of magnitude below the RCRA permeability standard of 1 x 10-7 cm/s. The permeability of typical asphalt is on the order of 1 x 10-5 cm/s. As with BW-2 and BW-3, the current level of O&M would continue and institutional controls would employed to maintain the system into the future, but less maintenance would be needed for the cap than is currently required. To upgrade this cap, the damaged areas would be roto-milled to a depth of 8 inches, mixed with a 5 percent concrete binder, put back in place and compacted. The new engineered asphalt cap would be installed over the new base. Together, the asphalt layer and cementatious subgrade would total 12 inches and would be sloped to the SWTS collection system. The quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• Replacement of damaged asphalt with new cementatious subgrade • 4-inch high-strength asphalt wearing course • Periodic reseal every 5 years • Use of existing SWTS for treatment of extracted groundwater • O&M time frame of 30 years With this design, the final grade would be about 4 inches above the current grade. This might create problems for drainage and alignment with existing structures, and could involve a number of modifications not accounted for in this assessment. The evaluation for this alternative is summarized in Table 5-3. An NPDES permit modification might be required for discharge of treated groundwater from the existing SWTS (ODEQ is in the process of changing the permit to include the groundwater). The total cost of this alternative is approximately $2.6M (with a plus 50 to minus 30 percent range between $1.8M to $3.9M). Long-term protectiveness of human health and the environment relies on containment and institutional controls.
CVO\043650001 5-11 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
Note that the three capping alternatives, BW-2, BW-3, and BW-4, all entail O&M of the existing groundwater extraction system, SWTS, and institutional controls, which together make up most of the total cost (approximately $1.8M present value) over the 30 year O&M period. The total capital cost of this alternative is approximately $0.8M.
Alternative BW-5: Dynamic Underground Stripping This alternative is an aggressive attempt to remove the majority of contaminants in situ over a short time period. Superheated steam is injected under pressure through an injection well network and extracted through an interwoven network of extraction wells. The technology uses a large amount of power to drive the necessary heaters and blowers. A separate wastewater and off-gas treatment system is required. Groundwater monitoring is essential for monitoring progress of the remedy. This alternative could potentially remove over 95 percent of the organic contaminants in all phases (DNAPL, soil, and groundwater) in less than 5 years, without substantially interrupting current operations at the property. It has succeeded at similar sites, but would require pilot testing. The relatively impermeable soil at depth requires a very dense network of injection and extraction wells. Additional infrastructure includes thermal monitor wells, heat sources, blowers, and a wastewater treatment system. O&M and monitoring efforts would need to be increased during operations. The quantity assumptions are presented in Table 2-3. Other assumptions used in this alternative include:
• 56 injection wells spaced 40 feet apart on 5-spot corners • 27 extraction wells spaced 40 feet apart centered within injection well pattern • 375 kW electricity requirement • 15,000 pounds per hour steam requirement • O&M time frame of 5 years The evaluation for this alternative is summarized in Table 5-3. Total cost is approximately $13.5M (with a plus 50 to minus 30 percent range between $9.5M to $20.3M). However, it would probably eliminate the reliance on containment technologies and institutional controls. Implementability is greatly controlled by favorable subsurface conditions, and possible implications with current site operations.
5.2.4 Summary Soil Outside the Barrier Wall Of the four alternatives for this cleanup unit, SO-2 is the least costly, with the exception of the no action alternative. However, this alternative relies on institutional controls to reduce exposure to the non-hot spot surface soils. Also, the cap over the hot spot soil must be maintained indefinitely to control exposure. By removing and disposing of the hot spot soil off-property, and capping the non-hot spot areas, SO-4 is the most protective alternative, best meets federal and state cleanup requirements, and is the most expensive.
5-12 CVO\043650001 5. DETAILED ANALYSIS OF ALTERNATIVES
Groundwater Outside the Barrier Wall GW-2, institutional controls with monitoring, does not actively protect the river; however, the river would not be affected if the PCP plume continues to stagnate. By extracting contaminated groundwater and treating it on-property, GW-3 reduces PCP mass and provides hydraulic containment of the groundwater plume. With an adequate system to treat the groundwater already on-property, the costs of a pump-and-treat system are considerably lower than typically observed. The permeable reactive barrier is a passive treatment system that requires little O&M. However, installation costs are considerable, and given the present hydrologic conditions downgradient of the barrier wall, it is not certain that this technology is feasible.
Inside the Barrier Wall BW-5, DUS, may succeed in removing the contaminants from inside the barrier wall; however, implementation is 4 to 5 times more costly than capping and containment, and success is not assured. Installation of a permanent cap would provide protectiveness as long as it is maintained, but contamination will remain indefinitely. The capping alternatives (BW-2, BW-3, and BW–4) all include the cost of O&M of the groundwater extraction system and the SWTS, a total O&M net present value of nearly $1.8M. BW-4 is the least expensive remedy and meets RCRA closure requirements. By building on the existing cap, BW-3 and BW-4 would raise the existing grade and require modifications for drainage, etc. A complete cap removal and replacement fulfills the RCRA requirements and would meet existing grade. However, the total cost of this alternative is 10 to 20 percent more than the other caps (45 to 118 percent based on capital cost), and workers would incur additional risk during removal activities.
CVO\043650001 5-13 TAYLOR LUMBER AND TREATING SUPERFUND SITE FEASIBILITY STUDY
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5-14 CVO\043650001 TABLE 5-1 Evaluation of Alternatives for Soil Outside of the Barrier Wall (SO) Taylor Lumber and Treating Feasibility Study
Alternative Criteria Cost
Protection of Human Health and Long-Term Effectiveness and Reduction of Toxicity, Mobility, Capital Cost O&M Cost Total PV Cost No. Target Area Description the Environment Compliance with ARARs Permanence and Volume Through Treatment Short-Term Effectiveness Implementability ($ Millions) ($ Millions) ($ Millions) SO-1 West Facility hot No action None. Potential for exposure to None. Does not meet federal and None. No improvements or controls. None. No treatment undertaken. Excellent. No remedial actions Excellent. Requires no action. 000 spot and non-hot contaminated soil remains. Not state cleanup requirements. No reduction of risk. implemented. spot, off-property protective. ditch, and stockpiled soil SO-2 Hot spot soil in PS Capping in-place, Good. Contaminants remain in-place Fair. Meets federal requirements, but Good. Continued protectiveness None. Good. Low worker exposure. Public Good. Proven, well understood, easily 1.7 0.9 2.5 institutional controls but the exposure pathways are does not meet preference for dependent upon maintenance of cap exposure and environmental impacts implemented. Will raise the grade controlled through barriers and land treatment. RCRA closure integrity and institutional controls. during construction are readily above existing elevation. use restrictions. requirements are relevant and controlled. appropriate. Cap will meet closure performance standard. West Facility hot Excavation with on-property Good. Contaminated soil is Good. Meets federal and state Excellent. Contaminants are removed Poor. Stabilization in this case is Fair. Workers exposed during mixing. Good. Proven, well understood, easily spot soil (not in PS), consolidation, stabilization transferred to PS where risk is co- cleanup requirements. Soil remains from excavated areas. predominantly intended to increase Measures would be undertaken to implemented. off-property ditch and capping managed. Risk is eliminated from the within the AOC, LDRs not triggered. structural strength. minimize public exposure and and stockpiled soil excavated areas. environmental impacts during construction. West Facility non-hot Institutional controls Fair. Contaminants remain in-place, Good. Meets federal and state Fair. Continued protectiveness None. None. No remedial actions Good. Readily implementable, but spot soil exposure is controlled by land use cleanup requirements. State allows dependent upon maintenance of implemented. requires enforcement. restrictions. institutional controls provided institutional controls. treatment is not cost effective.
SO-3 Hot spot soil in PS Capping in-place, Good. Contaminants remain in-place Fair. Meets federal requirements, but Good. Continued protectiveness None. Good. Low worker exposure. Public Good. Proven, well understood, easily 5.7 2.9 8.6 institutional controls but the exposure pathways are does not meet preference for dependent upon maintenance of cap exposure and environmental impacts implemented. Will raise the grade controlled through barriers and land treatment. RCRA closure integrity and institutional controls. during construction are readily above existing elevation. use restrictions. requirements are relevant and controlled. appropriate. Cap will meet closure performance standard. West Facility hot Excavation with on-property Good. Contaminated soil is Good. Meets federal and state Excellent. Contaminants are removed Poor. Stabilization in this case is Fair. Workers exposed during mixing. Good. Proven, well understood, easily spot soil (not in PS), consolidation, stabilization transferred to PS where risk is co- cleanup requirements. Soil remains from excavated areas. predominantly intended to increase Measures would be undertaken to implemented. off-property ditch and capping managed. Risk is eliminated from the within the AOC, LDRs not triggered. structural strength. minimize public exposure and and stockpiled soil excavated areas. environmental impacts during construction. West Facility non-hot Capping in-place, Good. Contaminants remain in-place Good. Meets federal and state Good. Continued protectiveness None. Good. Low worker exposure. Public Good. Proven, well understood, easily spot soil institutional controls but the exposure pathways are cleanup requirements. RCRA closure dependent upon maintenance of cap exposure and environmental impacts implemented. Will raise the grade controlled through barriers and land requirements are not applicable for non integrity and institutional controls. during construction are readily above existing elevation. use restrictions. hot spot areas. controlled. SO-4 West Facility hot Excavation with off-property Excellent. Removal of contaminated Excellent. Meets federal and state Excellent. Contaminants are removed Excellent. Toxicity reduced by Good. Low worker exposure. Public Good. Proven, well understood, easily 25.0 1.6 26.5 spot, off-property disposal soil reduces risk from the excavated cleanup requirements. Transporting from excavated areas. treatment off-property prior to disposal. exposure and environmental impacts implemented. ditch, and stockpiled areas. soil off-property will trigger RCRA during construction are readily soil LDRs. controlled. West Facility non-hot Capping in-place, Good. Contaminants remain in-place Good. Meets federal and state Good. Continued protectiveness None. Good. Low worker exposure. Public Good. Proven, well understood, easily spot soil institutional controls but the exposure pathways are cleanup requirements. RCRA closure dependent upon maintenance of cap exposure and environmental impacts implemented. Will raise the grade controlled through barriers and land requirements are not applicable for non integrity and institutional controls. during construction are readily above existing elevation. use restrictions. hot spot areas. controlled.
CVO\043650002 TABLE 5-2 Evaluation of Alternatives for Groundwater Outside of the Barrier Wall (GW) Taylor Lumber and Treating Feasibility Study
Alternative Criteria Cost
Protection of Human Health and Long-Term Effectiveness and Reduction of Toxicity, Mobility, Capital Cost O&M Cost Total PV Cost No. Description the Environment Compliance with ARARs Permanence and Volume Through Treatment Short-Term Effectiveness Implementability ($ Thousands) ($ Thousands) ($ Thousands) GW-1 No action Poor. PCP concentrations would None. Does not comply with ARARs. None. Current evidence indicates None. Excellent. No actions implemented. Excellent. 0 118 118 gradually diminish over time due to that the dissolved PCP is not natural attenuation. Not protective on- migrating off-property. It is uncertain property or of the river. if degradation of PCP will occur off- property. Not effective for reducing on-property contaminant levels.
GW-2 Institutional controls Poor. PCP concentrations would Poor. Will not reduce concentrations Poor. Current evidence indicates that None. Excellent. No exposure to workers. Good. 0 120 120 gradually diminish over time due to on-property. Beneficial use not the dissolved PCP is not migrating off- natural attenuation. on-property risk restored. property. It is uncertain if degradation is managed through pumping of PCP will occur off-property. Not restrictions. Not protective of the river. effective for reducing on-property contaminant levels.
GW-3 Pump-and-treat Good. Protective both on-property Good. Can potentially reduce the Good. MCLs may be achieved on the Good. Toxicity, mobility, and volume Good. Low worker exposure. Public Excellent. Readily implementable. 165 327 492 and of the river. on-property PCP levels below MCLs over time. order of tens of years. The typical are all reduced. exposure and environmental impacts Uses well understood and proven groundwater concentrations would be However, beneficial use cannot be long-term management issues of are minimal. technologies. reduced. The extraction wells would fully restored on-property due to pump-and-treat are greatly reduced prevent the flow of contaminated DNAPL contained within the existing by the presence of the on-property groundwater off-property. barrier wall. SWTS.
GW-4 Permeable reactive barrier Fair. Protective of the river. If the Fair. Will not reduce concentrations Good. Requires very little O&M. Not Fair. The PRB reduces PCP Fair. Moderate worker exposure. Fair. Requires sufficient hydraulic 641 302 944 contaminated groundwater began to on-property. However, beneficial use effective for reducing on-property concentrations in groundwater as it Public exposure and environmental gradient to maintain flow through move off-property, the PRB would cannot be fully restored on-property contaminant levels. flows through. The source remains in impacts during construction are gates. Will require groundwater intercept and reduce the due to DNAPL contained within the tact. readily controlled. modeling. Groundwater may build up contaminants to acceptable levels existing barrier wall. and flow around the barrier. before flowing off-property.
CVO\043650002 TABLE 5-3 Evaluation of Alternatives for All Media inside of the Barrier Wall (BW) Taylor Lumber and Treating Feasibility Study
Alternative Criteria Cost Reduction of Toxicity, Protection of Human Health and Long-Term Effectiveness and Mobility, and Volume Capital Cost O&M Cost Total PV Cost No. Description the Environment Compliance with ARARs Permanence Through Treatment Short-Term Effectiveness Implementability ($ Millions) ($ Millions) ($ Millions) BW-1 No action Poor. Exposure will increase over None. Does not comply with ARARs. Poor. Some of the preexisting None. Excellent. No action Excellent. Requires no action. 0.0 0.0 0.0 time as components degrade. No remedies may continue to serve at implemented. measures to prevent inadvertent least a portion of their intended exposure to subsurface soil, and purpose (i.e., barrier wall and cap), groundwater. while others will be rendered useless (i.e., extraction wells). Effectiveness will degrade over time.
BW-2 Existing Components with Good. Reduces risk by containment Good. Meets most federal and state Good. On-property continued None. Fair. Moderate worker Good. Many components are in 1.6 1.8 3.3 Cap Removal and Heavy- of contaminated soil and land use requirements. Use of liner meets protectiveness dependent upon exposure. Public exposure and place. Maintains current grade duty Replacement restrictions. Contaminants remain in- RCRA closure requirements. Does continued O&M of system environmental impacts are (Concrete with Liner) place but the exposure pathways are not restore beneficial use of components and institutional controls. minimal. eliminated. groundwater beneath cap.
BW-3 Existing Components with Good. Reduces risk by containment Good. Meets most federal and state Good. On-property continued None. Good. Low worker exposure. Fair. Most components are in 1.1 1.8 2.8 Cap Repair and Heavy- of contaminated soil and land use requirements. Use of liner meets protectiveness dependent upon Public exposure and place. Will raise the existing Duty Overlay (Concrete restrictions. Contaminants remain in- RCRA closure requirements. Does continued O&M of system environmental impacts are grade which may not align with with Liner) place but the exposure pathways are not restore beneficial use of components and institutional controls. minimal. existing structures and require eliminated. groundwater beneath cap. drainage modifications.
BW-4 Existing Components with Good. Reduces risk by containment Good. Meets most federal and state Good. On-property continued None. Good. Low worker exposure. Fair. Most components are in 0.8 1.8 2.6 Cap Repair and Heavy- of contaminated soil and land use requirements. Use of liner meets protectiveness dependent upon Public exposure and place. Will raise the existing Duty Overlay (Imperm. restrictions. Contaminants remain in- RCRA closure requirements. Does continued O&M of system environmental impacts are grade which may not align with Asphalt) place but the exposure pathways are not restore beneficial use of components and institutional controls. minimal. existing structures and require eliminated. groundwater beneath cap. drainage modifications.
BW-5 Dynamic Underground Excellent. Could potentially remove Excellent. Meets all federal and state Excellent. Most contaminants are Excellent. Reduces toxicity, Poor. High potential of worker Poor. Success is greatly 5.3 8.2 13.5 Stripping all phases of contaminants from the ARARs including potentially restoring removed from within the barrier wall. mobility, and volume in a exposure during startup and controlled by favorable subsurface. beneficial use of groundwater. short time. operation. Public exposure and subsurface conditions. Will environmental impacts during have impact on current site construction are readily operations. controlled, but extra precautions need to be taken during operation.
CVO\043650002
SECTION 6 References
CRITFC (Columbia River Inter-Tribal Fish Commission). 1994. A fish consumption survey of the Umatilla, Nez Perce, Yakima, and Warm Springs Tribes of the Columbia River Basin. CRITFC Technical Report No. 94-3. Portland, Oregon. U.S. EPA. 1988. Guidance for Conducting Remedial Investigations and Feasibility Studies under CERCLA. EPA/540/G-89/004, OSWER Directive 9355.3-01. (Section 6.2.3.7 of the document has now been superseded by: A Guide to Developing and Documenting Cost Estimates during the Feasibility Study (July, 2000). OSWER 9355.0-75. Office of Solid Waste and Emergency Response, U.S. Environmental Protection Agency, Washington, D.C. U.S. EPA. 1995. Presumptive Remedies for Soils, Sediments, and Sludges at Wood Treater Sites. EPA/540/R-95/148. OSWER 9200.5-162. NTIS PB95-963410. Office of Solid Waste and Emergency Response, U.S. Environmental Protection Agency, Washington, D.C. U.S. EPA. 1996. Presumptive Response Strategy and Ex-Situ Treatment Technologies for Contaminated Ground Water at CERCLA Sites. EPA 540-R-96-023. OSWER 9283.1-12. NTIS PB96-963508. Office of Solid Waste and Emergency Response, U.S. Environmental Protection Agency, Washington, D.C. U.S. EPA. 1998. Permeable Reactive Barrier Technologies for Contaminant Remediation. EPA/600/R-98/125. Office of Research and Development, Office of Solid Waste and Emergency Response, U.S. Environmental Protection Agency, Washington, D.C.
CVO\043650001 6-1
APPENDIX A Probabilistic Risk Assessment
CVO\043650001 State of Oregon Department of Environmental Quality Memorandum
TO: Taylor Lumber Project File
FROM: Angie Obery (DEQ Toxicologist, Western Region)
DATE: May 7, 2004
SUBJECT: Dioxin Risk Based Concentration
This memorandum summarizes procedures used to develop a risk based concentration (RBC) for dioxin in residential soils near the Taylor Lumber Superfund Site. Because Oregon’s Revised Cleanup Law (ORS 465.315(2)(a); formerly HB 3352) allows for the conduct of probabilistic risk assessments, a soil risk-based concentration (RBC) for dioxin (2,3,7,8-TCDD) was established using probabilistic exposure factors and equations. The assumptions and model applied for the dioxin RBC were originally developed for the Generic Remedies for Soils Contaminated with Polychlorinated Biphenyls (PCBs) (DEQ 1997). Slight modifications were made to the model to adapt it to dioxins instead of PCBs and incorporated site-specific demographics into the exposures. A detailed explanation of the model is explained in the DEQ PCB Generic Remedy (DEQ 1997), Appendix B.
Overview of the Probabilistic Risk Assessment Model
For a probabilistic assessment, the models draw from a distribution of exposures to a population of exposed (and non-exposed) receptors. As requested, the model was run for residential receptors to develop a residential RBC. Each iteration represents a statistical model of one person drawn from this population, using the following process:
1. Drawing the body weight (from a distribution of body weights) for one random person in a residential population; 2. Calculating the skin area, daily inhalation rate, and other exposure factors for that person; 3. Estimating the doses received by that person for each pathway and lifestage; 4. Summing the doses received by that person for each pathway over all lifestages; 5. Estimating the risk posed to that person by the dose received from each pathway; 6. Returning to Step 1 and repeating the process for the next person in the population.
CVO\043650020 Page 1 of 4 Consistent with the Generic PCB Remedy model, the soil dioxin RBC was calculated using Crystal Ball™ v 4.0a (Decisioneering, Inc., Denver, CO) and Latin Hypercube sampling. The model ran for 10,000 iterations representing a sample of 10,000 individuals (each with different, randomly selected, characteristics) from the population of individuals defined by the chosen probability distributions. Because of the correlations and dependencies among body weight, skin area, daily inhalation rate, and other factors, the simulations were designed to maintain these dependencies.
Exposure Routes
An exposure route is the way a chemical or physical agent comes in contact with a receptor (i.e., by ingestion, inhalation, dermal contact, etc.). The following suite of exposure routes were considered to be complete when calculating the Taylor Lumber dioxin RBC:
• INGESTION / CONSUMPTION • Incidental ingestion of contaminated soil • Consumption of homegrown vegetables • DERMAL CONTACT • Dermal contact with contaminated soil • INHALATION • Inhalation of particulates (fugitive dust)
Table 1 lists typical exposure routes and identifies those included in the calculations for the residential soil dioxin soil RBC.
Modifications of the PCB Generic Remedy Model
Several chemical-specific parameters were changed in the model to adapt it from PCBs to dioxins. These include ingestion and inhalation slope factors, volatilization factor, dermal absorption factor, Henry’s law constant, Kow, and Koc. The dioxin RBC was calculated using slope factors for 2,3,7,8 TCDD. Exposure concentrations for each dioxin congener in soil can then be multiplied by toxicity equivalent factors and compared against the soil dioxin RBC.
The PCB generic remedy risk-based concentration considered the ingestion exposure route to be adequately protective for inhalation exposures to fugitive dusts and therefore not considered. However, the spreadsheet was changed to account for inhalation of fugitive dusts and not for inhalation of vapors since dioxins are not volatile and can be bound to soil particles. Intake equations and parameter values for inhalation of particulates were applied from DEQ’s Guidance for Use of Probabilistic Analysis in Human Health Risk Assessments (DEQ 1998).
CVO\043650020 Page 2 of 4 In addition to accounting for particulate risk, the exposure duration distribution was changed in the model from exponential to uniform. An exponential distribution results in a high probability that a resident will live in a home for a short period of time (<4 years) and a very low probability that a resident will live in a home for a long period of time (>4 years). Demographic information provided by Michael Niemet of CH2MHill on April 22 and 23, 2004 indicated that residents in the local area tend to live in their homes for short and long periods. Thus, local area demographics do not appear to match national housing statistics. To account for short and long- term exposure durations, the distribution was changed to a uniform distribution which allows the equal possibility of an exposure from 2 to 30 years. Changing this distribution lowered the RBC from 16 ppt to 9.5 ppt.
Results
For residents exposed to dioxins in soil, the recommended dioxin RBC (based on 2,3,7,8-TCDD toxicity) is 9.5E-06 mg/kg or 9.5 ppt. This value was compared against the 2,3,7,8-TCDD toxicity equivalent quotients (TEQs) for individual dioxin/furan congeners along with the total 2,3,7,8- TCDD TEQ. Individual congener risks were compared against DEQ’s 1 x 10-6 acceptable risk level for individual chemicals and total dioxin risks were compared against DEQ’s 1 x 10-5 acceptable risk level for multiple chemicals. Table 2 presents the individual risk and total risks. The results indicate that dioxin levels are acceptable for sample locations RES-01, RES-02, RES- 04, RES-05, and SO-03 to SO-14. Individual congeners were unacceptable at sample locations SO-01, SO-02, and RES-03 and total dioxin risk were unacceptable at sample locations SO-02 and RES-03. Note that SO-01 was collected from the roof drip line of RES-01.
References
DEQ (1997) Generic Remedies for Soils Contaminated with Polychlorinated Biphenyls (PCBs). Department of Environmental Quality, Portland, Oregon. December 1997.
DEQ (1998) Guidance for Use of Probabilistic Analysis in Human Health Exposure Assessments. Department of Environmental Quality, Portland, Oregon. January 1998, Updated November 1998. (Interim Final).
CVO\043650020 Page 3 of 4 Table 1 Exposure Routes Considered in the Calculation of Dioxin Risk-Based Concentration EXPOSURE ROUTE Residential INGESTION / CONSUMPTION Incidental ingestion of soil - adults Incidental ingestion of soil - juveniles, children Consumption of homegrown produce - adults Consumption of homegrown produce - juveniles, children Consumption of homegrown meat/milk/eggs – adults P Consumption of homegrown meat/milk/eggs - juveniles, P children Consumption of water - adults Consumption of water - juveniles, children Consumption of home caught fish - adults Consumption of home caught fish - juveniles, children DERMAL CONTACT Dermal contact with soil - adults Dermal contact with soil - juveniles, children Dermal contact with water - adults Dermal contact with water - juveniles, children INHALATION Inhalation of fugitive dust - adults Inhalation of fugitive dust - juveniles, children Inhalation of volatiles - adults P Inhalation of volatiles - juveniles, children P ECOLOGICAL Chronically exposed ecological receptors Any threatened or endangered species and/or their habitat
Exposure route included in calculation of the RBC P Exposure route judged to make minor contribution to total exposure, excluded from calculation of RBC Exposure route incomplete
CVO\043650020 Page 4 of 4 TABLE 2 Individual and Total Risks Based on Probablistic Risk Assessment Preliminary Remediation Goal Soil-Offsite (Residential) Taylor Lumber and Treating Superfund Site, Feasibility Study
Location ID: RES-01 RES-02 RES-03 RES-04 RES-05 SO-03 SO-04 SO-05 SO-06 SO-07 SO-08 SO-09 SO-10 SO-11 SO-12 SO-13 SO-14
RES-01 SO-01 RES-03 SO-02 Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Individual Analyte Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk Risk 1,2,3,4,6,7,8-HpCDD 3.E-07 3.E-06 1.E-06 2.E-05 4.E-06 1.E-06 1.E-06 7.E-07 2.E-07 4.E-07 3.E-07 2.E-08 5.E-07 9.E-09 8.E-08 2.E-07 3.E-09 6.E-08 2.E-07 1,2,3,4,7,8-HxCDD 4.E-08 3.E-07 2.E-07 5.E-06 7.E-07 2.E-07 1.E-07 1.E-07 2.E-08 0 0 0 6.E-08 0 2.E-08 0 0 0 2.E-08 1,2,3,6,7,8-HxCDD 2.E-07 1.E-06 5.E-07 2.E-05 2.E-06 6.E-07 7.E-07 4.E-07 5.E-08 2.E-07 1.E-07 8.E-09 2.E-07 0 6.E-08 0 0 1.E-08 7.E-08 1,2,3,7,8,9-HxCDD 1.E-07 4.E-07 4.E-07 1.E-05 1.E-06 5.E-07 3.E-07 2.E-07 3.E-08 1.E-07 0 0 2.E-07 0 0 4.E-08 0 1.E-08 3.E-08 1,2,3,7,8-PeCDD 3.E-07 0 8.E-07 1.E-05 4.E-06 1.E-06 7.E-07 6.E-07 0 3.E-07 0 0 2.E-07 0 1.E-07 6.E-08 0 0 9.E-08 2,3,7,8-TCDD 6.E-08 0 1.E-07 2.E-06 3.E-07 2.E-07 1.E-07 000000000000 OCDD 2.E-08 3.E-07 3.E-07 9.E-07 2.E-07 9.E-08 8.E-08 5.E-08 1.E-08 4.E-08 2.E-08 0 3.E-08 8.E-10 5.E-09 2.E-08 3.E-10 7.E-09 2.E-08 1,2,3,4,6,7,8-HpCDF 4.E-08 3.E-07 1.E-07 2.E-06 4.E-07 2.E-07 1.E-07 7.E-08 2.E-08 4.E-08 9.E-08 1.E-09 6.E-08 1.E-09 3.E-08 3.E-08 0 1.E-08 2.E-08 1,2,3,4,7,8,9-HpCDF 2.E-09 0 5.E-09 3.E-07 2.E-08 9.E-09 5.E-09 5.E-09 0 2.E-09 00000009.E-10 0 1,2,3,4,7,8-HxCDF 1.E-07 0 9.E-08 3.E-06 1.E-06 1.E-07 1.E-07 000000000000 1,2,3,6,7,8-HxCDF 5.E-08 0 4.E-08 3.E-06 0 7.E-08 6.E-08 000001.E-08 000000 1,2,3,7,8,9-HxCDF 0 0 0 1.E-07 5.E-08 0 0 1.E-08 00000000000 1,2,3,7,8-PeCDF 7.E-09 0 0 3.E-07 0 0 0 2.E-08 0000001.E-08 0000 2,3,4,6,7,8-HxCDF 7.E-08 0 8.E-08 2.E-06 0 1.E-07 1.E-07 000002.E-08 0 7.E-08 0000 2,3,4,7,8-PeCDF 3.E-07 0 1.E-07 2.E-06 3.E-07 1.E-07 2.E-07 1.E-07 0000002.E-07 0000 2,3,7,8-TCDF 3.E-08 0 2.E-08 9.E-08 2.E-08 1.E-08 1.E-08 4.E-08 8.E-09 2.E-08 0 1.E-08 6.E-08 0 1.E-07 0 0 7.E-09 6.E-09 OCDF 6.E-10 2.E-08 1.E-09 3.E-08 9.E-09 4.E-09 1.E-09 2.E-09 4.E-10 8.E-10 2.E-09 2.E-11 2.E-09 2.E-11 3.E-10 1.E-09 0 7.E-10 7.E-10 Total Risk 2.E-06 6.E-06 4.E-06 8.E-05 2.E-05 5.E-06 4.E-06 2.E-06 3.E-07 1.E-06 6.E-07 4.E-08 1.E-06 1.E-08 8.E-07 4.E-07 4.E-09 1.E-07 4.E-07
Notes: Nondetects were not included in risk calculations and are represented by a zero in the table. "RES" samples are composite samples "SO" samples are from roof drip-lines Bolded/Italic values are above residential risk values. 2,3,7,8 TCDD PRG = 9.5E-06 mg/kg
CVO\043650021
APPENDIX B West Facility Soil and Off-property Ditch Hot Spot and Non-Hot Spot Exceedance Maps
CVO\043650001
APPENDIX C Cost Estimates
CVO\043650001 TABLE C-1 Cost Estimates for Retained Remedial Alternatives -- Soil Outside the Barrier Wall (SO) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
SO-1 No Action O&M time frame 30 yr There are no capital costs associated with this alternative There are no operations and maintenance costs associated with this alternative APR 7% Includes: Total Cost $ - 30% Below$ - 50% Above$ -
SO-2 Capping Hot Spot PS Soil In- Soil in Cell 1 5,800 yd3 1) PS Area Grading and Clearing $ 293,228 1) Institutional Controls $ 2,068 Place Using Stabilized Hot Spot Soil in Cell 2 8,000 yd3 a) Remove existing vegetation and debris estimate per yd2 (w/ disposal) $ 3 36,653$ 109,960 a) Legal and clerical fees Lump sum$ 5,000 1$ 167 $ 2,068 Surface and Ditch Soil Outside Soil in Cell 3 5,300 yd3 b) Grading estimate per yd2 $ 5 36,653$ 183,267 of PS Area - Institutional Linear feet of ditch 3,850 ft 2) Periodic 1/4 Replacement Event $ 863,783 Controls for Non-Hot Spot Soil Ditch depth of removal 24 in 2) Excavation and Consolidation $ 165,274 a) 1/4 replacement Estimate 1/4 of initial cost$ 417,655 5$ 69,609 $ 863,783 Ditch width of removal 3 ft a) Ditch soil per yd3 $ 7.44 856$ 6,365 Includes: Ditch soil volume 856 yd3 b) Surface soil per yd3 $ 7.44 2,259$ 16,804 Total O&M PV$ 865,851 Existing asphalt cap in TP area Hot spot surface area 6,776 yd2 c) Storage cells per yd3 $ 7.44 19,100$ 142,104 Excavation of contaminated soil Surface depth of removal 12 in outside of the PS Area Surface soil volume 2,259 yd3 3) Installation in PS Area $ 756,544 Excavation of cont. ditch soil Consolidation depth 24 in a) Stabilize, spread and compact per yd3 $ 20.00 22,214$ 444,284 Cells 1, 2, and 3 Vol. increase due to stabil. 10% b) Base asphalt course (installed) per yd2 $ 3.70 36,653$ 135,618 Treatment by stabilization Consolidation area req'd. 36,653 yd2 c) Top asphalt course (installed) per yd2 $ 4.41 36,653$ 161,642 Consolidation in the PS Area Contaminated area in PS 21,333 yd2 d) Drainage repair or installation Lump sum$ 15,000 1$ 15,000 with asphalt cap Available area in PS 37,333 yd2 Land use restrictions Asphalt cap top course 2 in 4) Fill Excavated Areas to Grade $ 72,475 Asphalt cap base course 2 in a) Fill material installation per yd2 $ 9.22 6,776$ 62,475 Assumed soil bulk density 1.4 ton/yd3 b) Drainage repair or installation Lump sum$ 10,000 1$ 10,000 Repair period 5 yr O&M time frame 30 yr 5) Surveying and Testing $ 24,700 APR 7% a) Surveying Lump sum$ 5,500 1$ 5,500 b) Geotech testing (design and construction) per test$ 1,600 12$ 19,200
6) Engineering Services $ 358,399 a) Health and Safety Lump sum$ 4,100 1$ 4,100 b) Reporting 2% Capital costs 2%$ 1,312,220 $ 26,244 c) Design 5% Capital costs 5%$ 1,312,220 $ 65,611 d) Construction Management 10% Capital costs 10%$ 1,312,220 $ 131,222 e) Services During Construction 10% Capital costs 10%$ 1,312,220 $ 131,222 Total Cost $ 2,536,471 30% Below$ 1,775,530 Total Capital Cost$ 1,670,620 50% Above$ 3,804,706
CVO\043650003 Page 1 of 3 TABLE C-1 Cost Estimates for Retained Remedial Alternatives -- Soil Outside the Barrier Wall (SO) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
SO-3 Capping Hot Spot PS Soil In- Soil in Cell 1 5,800 yd3 1) PS Area Grading and Clearing $ 293,228 1) Institutional Controls $ 2,068 Place Using Stabilized Hot Spot Soil in Cell 2 8,000 yd3 a) Remove existing vegetation and debris estimate per yd2 (w/ disposal) $ 3 36,653$ 109,960 a) Legal and clerical fees Lump sum$ 5,000 1$ 167 $ 2,068 Surface and Ditch Soil Outside Soil in Cell 3 5,300 yd3 b) Grading estimate per yd2 $ 5 36,653$ 183,267 of PS Area - Capping Non-Hot Linear feet of ditch 3,850 ft 2) Periodic 1/4 Replacement Event $ 2,938,294 Spot Soil In-Place Ditch depth of removal 24 in 2) Excavation and Consolidation $ 165,274 a) 1/4 replacement Estimate 1/4 of initial cost$ 1,420,719 5$ 236,787 $ 2,938,294 Ditch width of removal 3 ft a) Ditch soil per yd3 $ 7.44 856$ 6,365 Includes: Ditch soil volume 856 yd3 b) Surface soil per yd3 $ 7.44 2,259$ 16,804 Total O&M PV$ 2,940,362 Existing asphalt cap in TP area Hot spot surface area 6,776 yd2 c) Storage cells per yd3 $ 7.44 19,100$ 142,104 Excavation of contaminated soil Surface depth of removal 12 in outside of the PS Area Surface soil volume 2,259 yd3 3) Installation in PS Area $ 756,544 Excavation of cont. ditch soil Consolidation depth 24 in a) Stabilize, spread and compact per yd3 $ 20.00 22,214$ 444,284 Cells 1, 2, and 3 Vol. increase due to stabil. 10% b) Base asphalt course (installed) per yd2 $ 3.70 36,653$ 135,618 Treatment by stabilization Consolidation area req'd. 36,653 yd2 c) Top asphalt course (installed) per yd2 $ 4.41 36,653$ 161,642 Consolidation in the PS Area Contaminated area in PS 21,333 yd2 d) Drainage repair or installation Lump sum$ 15,000 1$ 15,000 with asphalt cap Available area in PS 37,333 yd2 Capping non-hot spot soil in-placeAsphalt cap top course 2 in 4) Fill Excavated Areas to Grade $ 72,475 with gravel cap Asphalt cap base course 2 in a) Fill material installation per yd2 $ 9.22 6,776$ 62,475 Land use restrictions Assumed soil bulk density 1.4 ton/yd3 b) Drainage repair or installation Lump sum$ 10,000 1$ 10,000 Non-hot spot surface area 163,593 yd2 Depth of gravel cap 12 in 5) Non-hot spot capping $ 3,159,257 Repair period 5 yr a) Remove existing vegetation and debris estimate per yd2 (w/ disposal) $ 3 163,593$ 490,779 O&M time frame 30 yr b) Grading estimate per yd2 $ 5 163,593$ 817,965 APR 7% c) Geotextile (installed) per yd2 $ 2 163,593$ 327,186 d) Gravel course (installed) per yd2 $ 9.22 163,593$ 1,508,327 e) Drainage repair or installation Lump sum$ 15,000 1$ 15,000
6) Surveying and Testing $ 24,700 a) Surveying Lump sum$ 5,500 1$ 5,500 b) Geotech testing (design and construction) per test$ 1,600 12$ 19,200
7) Engineering Services $ 1,211,399 a) Health and Safety Lump sum$ 4,100 1$ 4,100 b) Reporting 2% Capital costs 2%$ 4,471,478 $ 89,430 c) Design 5% Capital costs 5%$ 4,471,478 $ 223,574 d) Construction Management 10% Capital costs 10%$ 4,471,478 $ 447,148 e) Services During Construction 10% Capital costs 10%$ 4,471,478 $ 447,148 Total Cost $ 8,623,239 30% Below$ 6,036,267 Total Capital Cost$ 5,682,877 50% Above$ 12,934,858
CVO\043650003 Page 2 of 3 TABLE C-1 Cost Estimates for Retained Remedial Alternatives -- Soil Outside the Barrier Wall (SO) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
SO-4 Excavation of Contaminated Soil in Cell 1 5,800 yd3 1) Removal & Loading Into Gondola Cars $ 680,344 1) Institutional Controls $ 2,068 Hot Spot Surface and Ditch Soil Soil in Cell 2 8,000 yd3 a) Remove existing cap (incl. haul) per yd2 $ 44.80 9,777$ 438,010 a) Legal and clerical fees Lump sum$ 5,000 1$ 167 $ 2,068 w/ Offsite Treatment and Soil in Cell 3 5,300 yd3 b) Remove existing soil and load per yd3 $ 7.44 12,616$ 93,866 Disposal - Capping Non-Hot Linear feet of ditch 3,850 ft c) Remove soil from cells and load per yd3 $ 7.44 19,100$ 142,104 2) Periodic 1/4 Replacement Event $ 1,633,473 Spot Soil In-Place Ditch depth of removal 24 in d) Remove existing ditch soil and load per yd3 $ 7.44 856$ 6,365 a) 1/4 replacement Estimate 1/4 of initial cost$ 789,814 5$ 131,636 $ 1,633,473 Ditch width of removal 3 ft Includes: Ditch soil volume 856 yd3 3) Soil Treatment and Disposal $ 19,513,914 Total O&M PV$ 1,635,541 Excavation of contaminated Existing cap area 9,777 yd2 a) Transport, treatment, and disposal per ton (high As >= 50 ppm)$ 405 23,423$ 9,486,414 surface and ditch soil and Existing asphalt thickness 4 in b) Transport, treatment, and disposal per ton (low As < 50 ppm)$ 375 26,740$ 10,027,500 soil under cap in TP area Existing base 24 in T&D of Storage Cells 1, 2, and 3 Surface area 28,072 yd2 4) Fill Excavated Areas to Grade $ 358,968 Offsite treatment and disposal Surface depth of removal 12 in a) Fill material installation per yd2 $ 9.22 37,849$ 348,968 Capping non-hot spot soil in-placeSoil volume 12,616 yd3 b) Drainage repair or installation per yd2 $ 10,000 1$ 10,000 with gravel cap Assumed soil bulk density 1.4 ton/yd3 Non-hot spot surface area 163,593 yd2 5) Non-hot spot capping $ 3,159,257 Depth of gravel cap 12 in a) Remove existing vegetation and debris estimate per yd2 (w/ disposal) $ 3 163,593$ 490,779 Repair period 5 yr b) Grading estimate per yd2 $ 5 163,593$ 817,965 O&M time frame 30 yr c) Geotextile (installed) per yd2 $ 2 163,593$ 327,186 APR 7% d) Gravel course (installed) per yd2 $ 9.22 163,593$ 1,508,327 e) Drainage repair or installation Lump sum$ 15,000 1$ 15,000
6) Surveying and Testing $ 3,500 a) Surveying Lump sum$ 3,500 1$ 3,500
7) Engineering Services $ 1,138,659 a) Health and Safety Lump sum$ 4,100 1$ 4,100 b) Reporting 2% Capital costs (less T&D) 2%$ 4,202,070 $ 84,041 c) Design 5% Capital costs (less T&D) 5%$ 4,202,070 $ 210,103 d) Construction Management 10% Capital costs (less T&D) 10%$ 4,202,070 $ 420,207 e) Services During Construction 10% Capital costs (less T&D) 10%$ 4,202,070 $ 420,207 Total Cost $ 26,490,184 30% Below$ 18,543,129 Total Capital Cost$ 24,854,643 50% Above$ 39,735,276
CVO\043650003 Page 3 of 3 TABLE C-2 Cost Estimates for Retained Remedial Alternatives -- Groundwater Outside the Barrier Wall (GW) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
GW-1 No Action Number of monitor wells 16 There are no capital costs associated with this alternative 1) Annual Groundwater Monitoring $ 117,886 O&M time frame 30 yr a) Monitoring plan 10 hr mid level engineer$ 750 30$ 750 $ 9,307 Includes: APR 7% b) Fieldwork 10 hr field tech$ 850 30$ 850 $ 10,548 GW monitoring c) Analytical PCP/PAH-SIM (OLC03.2) @ $400 e $ 6,400 30$ 6,400 $ 79,418 d) Reporting 20 hr mid level engineer$ 1,500 30$ 1,500 $ 18,614
Total O&M PV$ 117,886
Total Cost $ 117,886 30% Below$ 82,520 50% Above$ 176,829
GW-2 Institutional Controls Number of monitor wells 16 There are no capital costs associated with this alternative 1) Annual Groundwater Monitoring $ 117,886 O&M time frame 30 yr a) Monitoring plan 10 hr mid level engineer$ 750 30$ 750 $ 9,307 Includes: APR 7% b) Fieldwork 10 hr field tech$ 850 30$ 850 $ 10,548 GW pumping restrictions c) Analytical PCP/PAH-SIM (OLC03.2) @ $400 e $ 6,400 30$ 6,400 $ 79,418 GW monitoring d) Reporting 20 hr mid level engineer$ 1,500 30$ 1,500 $ 18,614
2) Institutional Controls $ 2,068 a) Legal and clerical fees$ 5,000 1$ 167 $ 2,068
Total O&M PV$ 119,954
Total Cost $ 119,954 30% Below$ 83,968 50% Above$ 179,931
CVO\043650003 Page 1 of 3 TABLE C-2 Cost Estimates for Retained Remedial Alternatives -- Groundwater Outside the Barrier Wall (GW) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
GW-3 Pump-and-Treat Existing monitor wells 16 1) Preparation $ 3,650 1) Annual Groundwater Monitoring $ 192,340 New monitor wells 4 a) Mobilize equipment and personnel Lump sum$ 3,650 1$ 3,650 a) Monitoring plan 20 hr mid level engineer$ 1,500 30$ 1,500 $ 18,614 Includes: New extraction wells 6 b) Fieldwork 40 hr mid level engineer$ 3,000 30$ 3,000 $ 37,227 New extraction wells Expected output per well 0.25 gpm 2) Install New Monitor Wells $ 12,000 c) Analytical PCP/PAH-SIM (OLC03.2) @ $400 e $ 8,000 30$ 8,000 $ 99,272 New monitor wells O&M time frame 30 yr a) Well components 2", 20 ft deep PVC well$ 1,500 4$ 6,000 d) Reporting 40 hr mid level engineer$ 3,000 30$ 3,000 $ 37,227 Existing SWTS APR 7% b) Vaults, bollards, etc. per well$ 1,000 4$ 4,000 GW pumping restrictions c) Well development per well$ 500 4$ 2,000 2) Institutional Controls $ 2,068 GW monitoring a) Legal and clerical fees Lump sum$ 5,000 1$ 167 $ 2,068 3) Install New Extraction Wells $ 63,000 a) Well components 6", 20 ft deep PVC well$ 4,000 6$ 24,000 3) Annual Maintenance $ 49,636 b) Piping and fittings HDPE pipes$ 1,000 6$ 6,000 a) Labor 40 hr mid level engineer$ 3,000 30$ 3,000 $ 37,227 c) Misc. vaults, flowmeters, etc. per well$ 4,000 6$ 24,000 b) Supplies$ 1,000 30$ 1,000 $ 12,409 d) Well development per well$ 500 6$ 3,000 e) Extraction pumps Pumps $ 1,000 6$ 6,000 4) O&M Workplan and Manual 60 hr mid level engineer$ 4,500 1$ 150 $ 1,861 $ 1,861
4) Treatment System $ 25,000 5) Additional Costs to the SWTS $ 24,811 a) Activated carbon filter Use existing SWTS$ - $ - a) Electricity fraction of total @ 14,550,000 gpy$ 211 30$ 211 $ 2,622 b) Holding tank and secondary containment Use existing SWTS$ - $ - b) Carbon fraction of total @ 14,550,000 gpy$ 813 30$ 813 $ 10,086 c) Route to SWTS Lump sum$ 25,000 1$ 25,000 c) Labor fraction of total @ 14,550,000 gpy$ 975 30$ 975 $ 12,103
5) Completion $ 20,000 6) Annual Reporting $ 55,841 a) Disposal of generated wastes Lump sum$ 10,000 1$ 10,000 a) Effectiveness assessment report 60 hr mid level engineer$ 4,500 30$ 4,500 $ 55,841 b) Site cleanup Lump sum$ 5,000 1$ 5,000 c) Demob equipment and personnel Lump sum$ 5,000 1$ 5,000 Total O&M PV$ 326,558
6) Surveying and Testing $ 5,000 a) Surveying Lump sum$ 5,000 1$ 5,000
7) Engineering Services $ 36,376 a) Health and Safety Lump sum$ 1,640 1$ 1,640 b) Reporting 2% Capital costs 2%$ 128,650 $ 2,573 c) Design 5% Capital costs 5%$ 128,650 $ 6,433 d) Construction Management 10% Capital costs 10%$ 128,650 $ 12,865 e) Services During Construction 10% Capital costs 10%$ 128,650 $ 12,865 Total Cost $ 491,583 30% Below$ 344,108 Total Capital Cost$ 165,026 50% Above$ 737,375
CVO\043650003 Page 2 of 3 TABLE C-2 Cost Estimates for Retained Remedial Alternatives -- Groundwater Outside the Barrier Wall (GW) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
GW-4 Permeable Reactive Barrier Existing monitor wells 16 1) Preparation $ 56,000 1) Annual Groundwater Monitoring $ 192,340 New monitor wells 4 a) Mobilize equipment and personnel Lump sum$ 6,000 1$ 6,000 a) Monitoring plan 20 hr mid level engineer$ 1,500 30$ 1,500 $ 18,614 Includes: Length of slurry wall 400 ft b) Move utilities, structures and debris Lump sum$ 50,000 1$ 50,000 b) Fieldwork 40 hr mid level engineer$ 3,000 30$ 3,000 $ 37,227 Funnel and gate PRB Depth of protective cap 30 in c) Analytical PCP/PAH-SIM (OLC03.2) @ $400 e $ 8,000 30$ 8,000 $ 99,272 GAC reactive media Width of protective cap 9 ft 2) Install New Monitor Wells $ 12,000 d) Reporting 40 hr mid level engineer$ 3,000 30$ 3,000 $ 37,227 New monitor wells Number of gate vaults 3 a) Well components 2", 20 ft deep PVC well$ 1,500 4$ 6,000 GW pumping restrictions Vault depth 17 ft b) Vaults, fittings, etc. per well$ 1,000 4$ 4,000 2) Institutional Controls $ 2,068 GW monitoring Vault x-sect. area 16 ft c) Well development per well$ 500 4$ 2,000 a) Legal and clerical fees Lump sum$ 5,000 1$ 167 $ 2,068 Vault GAC fill depth 6 ft2 GAC bulk density 33 lb/ft3 3) PRB Installation $ 196,083 3) Media Changeout $ 50,241 GAC changeout interval 3 yr a) GW Modeling Mid level engineer$ 120 150$ 18,000 a) GAC removal and disposal per event @ $0.74/lb$ 7,033 9$ 2,110 $ 26,182 O&M time frame 30 yr b) Gate vaults (installed) 20 feet deep$ 20,000 3$ 60,000 b) GAC installation per event$ 6,463 9$ 1,939 $ 24,059 APR 7% c) GAC installed per lb$ 0.68 9,504$ 6,463 d) Slurry wall (installed) per ft$ 250 400$ 100,000 4) O&M Workplan and Manual 60 hr mid level engineer$ 4,500 1$ 150 $ 1,861 $ 1,861 e) Protective cap (installed) per yd2 (incl. geotextile) $ 29.05 400$ 11,620 5) Annual Reporting $ 55,841 4) Completion $ 219,481 a) Effectiveness assessment report 60 hr mid level engineer$ 4,500 30$ 4,500 $ 55,841 a) Disposal of generated wastes per yd3 $ 200 1,007$ 201,481 b) Site cleanup Lump sum$ 10,000 1$ 10,000 Total O&M PV$ 302,351 c) Demob equipment and personnel Lump sum$ 8,000 1$ 8,000
5) Surveying and Testing $ 20,000 a) Surveying Lump sum$ 20,000 1$ 20,000
6) Engineering Services $ 137,602 a) Health and Safety Lump sum$ 1,640 1$ 1,640 b) Reporting 2% Capital costs 2%$ 503,564 $ 10,071 c) Design 5% Capital costs 5%$ 503,564 $ 25,178 d) Construction Management 10% Capital costs 10%$ 503,564 $ 50,356 e) Services During Construction 10% Capital costs 10%$ 503,564 $ 50,356 Total Cost $ 943,517 30% Below$ 660,462 Total Capital Cost$ 641,167 50% Above$ 1,415,276
CVO\043650003 Page 3 of 3 TABLE C-3 Cost Estimates for Retained Remedial Alternatives -- Inside the Barrier Wall (BW) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
BW-1 No Action O&M time frame 30 yr There are no capital costs associated with this alternative There are no operations and maintenance costs associated with this alternative APR 7%
Total Cost $ - 30% Below$ - 50% Above$ -
BW-2 Existing Components Target area 16,940 yd2 1) Site Grading and Clearing $ 172,429 1) O&M Reseal Event $ 10,858 with Cap Removal and Reseal period 15 yr a) Remove existing asphalt (incl. haul) per yd2 $ 6.40 16,940$ 108,416 a) Reseal work Lump sum$ 20,000 1$ 667 $ 8,273 Heavy-Duty Replacement Crushed rock base 6 in b) Bring to depth & stockpile per yd3 (2X cost for haz mat) $ 7.44 6,588$ 49,013 b) Engineering services 20% Capital, design, procurement and oversight$ 4,000 1$ 133 $ 1,655 (Concrete with liner) Concrete cap 12 in c) Drainage repair or installation Lump sum$ 15,000 1$ 15,000 c) Effectiveness assessment report 30 hr mid level engineer$ 2,250 1$ 75 $ 931 Existing asphalt thickness 4 in Includes: O&M time frame 30 yr 2) Installation $ 1,037,321 3) GW Extraction System $ 1,188,563 Existing hyd. cont. system APR 7% a) Crushed rock and clean fill (installed) per yd2 $ 4.61 16,940$ 78,093 a) Labor 1 person @ $20/h halftime$ 20,160 30$ 20,160 $ 250,166 Existing barrier wall b) 30 mil PVC liner and geotextile (installed) per yd2 $ 6 16,940$ 101,640 b) Boiler, compr, evaporator, etc. Power, chemicals, and maintenance$ 71,622 30$ 71,622 $ 888,760 Concrete cap replacement c) Concrete w/ sealed joints (installed) per yd2 $ 50.63 16,940$ 857,588 c) Annual permitting $ 4,000 30$ 4,000 $ 49,636 Existing SWTS GW pumping restrictions 3) Surveying and Testing $ 24,700 4) Stormwater Treatment System $ 571,560 Land use restrictions a) Surveying Lump sum$ 5,500 1$ 5,500 a) Electricity $325/mo$ 3,900 30$ 3,900 $ 48,395 b) Geotech testing (design and construction) per test$ 1,600 12$ 19,200 b) Carbon 20,000 lbs/yr @ $0.75/lb$ 15,000 30$ 15,000 $ 186,136 c) Chemicals and maintenance Average @ $1200/mo + $300/mo labor$ 18,000 30$ 18,000 $ 223,363 4) Engineering Services $ 337,401 d) Monthly & quarterly NPDES mon. Analytical and labor$ 9,160 30$ 9,160 $ 113,667 a) Health and Safety Lump sum$ 4,100 1$ 4,100 b) Reporting 2% Capital costs 2%$ 1,234,450 $ 24,689 5) Institutional Controls $ 2,068 c) Design 5% Capital costs 5%$ 1,234,450 $ 61,722 a) Legal and clerical fees$ 5,000 1$ 167 $ 2,068 d) Construction management 10% Capital costs 10%$ 1,234,450 $ 123,445 e) Services during construction 10% Capital costs 10%$ 1,234,450 $ 123,445 Total O&M PV$ 1,773,049
Total Capital Cost$ 1,571,851 Total Cost $ 3,344,901 30% Below$ 2,341,431 50% Above$ 5,017,351
BW-3 Existing Components Target area 16,940 yd2 1) Asphalt Repair $ 68,205 1) O&M Reseal Event $ 10,858 with Cap Repair and Reseal period 15 yr a) Remove damaged asphalt (incl. haul) per yd2 $ 6.40 4,235$ 27,104 a) Reseal work Lump sum$ 20,000 1$ 667 $ 8,273 Heavy-Duty Overlay Broken asphalt 25 % b) Subgrade repair and compact per yd2 $ 2.31 4,235$ 9,762 b) Engineering services 20% Capital, design, procurement and oversight$ 4,000 1$ 133 $ 1,655 (Concrete with liner) Concrete thickness 8 in c) Asphalt course (installed) per yd2 $ 7.40 4,235$ 31,339 c) Effectiveness assessment report 30 hr mid level engineer$ 2,250 1$ 75 $ 931 Existing asphalt thickness 4 in Includes: O&M time frame 30 yr 2) Installation $ 738,365 3) GW Extraction System $ 1,188,563 Existing hyd. cont. system APR 7% a) 30 mil PVC liner and geotextile (installed) per yd2 $ 6 16,940$ 101,640 a) Labor 1 person @ $20/h halftime$ 20,160 30$ 20,160 $ 250,166 Existing barrier wall b) Concrete w/ sealed joints (installed) per yd2 $ 33.75 16,940$ 571,725 b) Boiler, compr, evaporator, etc. Power, chemicals, and maintenance$ 71,622 30$ 71,622 $ 888,760 PVC liner c) Modifications due to grade change Lump sum$ 50,000 1$ 50,000 c) Annual permitting $ 4,000 30$ 4,000 $ 49,636 Concrete cap overlay d) Drainage repair or installation Lump sum$ 15,000 1$ 15,000 Existing SWTS 4) Stormwater Treatment System $ 571,560 GW pumping restrictions 3) Surveying and Testing $ 24,700 a) Electricity $325/mo$ 3,900 30$ 3,900 $ 48,395 Land use restrictions a) Surveying Lump sum$ 5,500 1$ 5,500 b) Carbon 20,000 lbs/yr @ $0.75/lb$ 15,000 30$ 15,000 $ 186,136 b) Geotech testing (design and construction) per test$ 1,600 12$ 19,200 c) Chemicals and maintenance Average @ $1200/mo + $300/mo labor$ 18,000 30$ 18,000 $ 223,363 d) Monthly & quarterly NPDES mon. Analytical and labor$ 9,160 30$ 9,160 $ 113,667 4) Engineering Services $ 228,543 a) Health and Safety Lump sum$ 4,100 1$ 4,100 5) Institutional Controls $ 2,068 b) Reporting 2% Capital costs 2%$ 831,270 $ 16,625 a) Legal and clerical fees$ 5,000 1$ 167 $ 2,068 c) Design 5% Capital costs 5%$ 831,270 $ 41,563 d) Construction management 10% Capital costs 10%$ 831,270 $ 83,127 Total O&M PV$ 1,773,049 e) Services during construction 10% Capital costs 10%$ 831,270 $ 83,127 Total Cost $ 2,832,862 Total Capital Cost$ 1,059,812 30% Below$ 1,983,003 50% Above$ 4,249,293
CVO\043650003 Page 1 of 3 TABLE C-3 Cost Estimates for Retained Remedial Alternatives -- Inside the Barrier Wall (BW) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
BW-4 Existing Components Target area 16,940 yd2 1) Asphalt Repair $ 23,777 1) O&M Reseal Event $ 42,625 with Cap Repair and Reseal period 5 yr a) Rubblize and rebind damaged asphalt per acre$ 27,174 0.88$ 23,777 a) Fog seal Lump sum$ 15,300 5$ 2,550 $ 31,643 Heavy-Duty Overlay Broken asphalt 25 % b) Engineering services 20% Capital, design, procurement and oversight$ 3,060 5$ 510 $ 6,329 (Imperm. Asphalt) High density asphalt 4 in 2) Installation $ 520,000 c) Effectiveness assessment report 30 hr mid level engineer$ 2,250 5$ 375 $ 4,653 Existing asphalt thickness 4 in a) Impermeable asphalt course (installed) per acre$ 130,000 3.50$ 455,000 Includes: O&M time frame 30 yr b) Modifications due to grade change Lump sum$ 50,000 1$ 50,000 3) GW Extraction System $ 1,188,563 Existing hyd. cont. system APR 7% c) Drainage repair or installation Lump sum$ 15,000 1$ 15,000 a) Labor 1 person @ $20/h halftime$ 20,160 30$ 20,160 $ 250,166 Existing barrier wall b) Boiler, compr, evaporator, etc. Power, chemicals, and maintenance$ 71,622 30$ 71,622 $ 888,760 Asphalt cap overlay 3) Surveying and Testing $ 24,700 c) Annual permitting $ 4,000 30$ 4,000 $ 49,636 Existing SWTS a) Surveying Lump sum$ 5,500 1$ 5,500 GW pumping restrictions b) Geotech testing (design and construction) per test$ 1,600 12$ 19,200 4) Stormwater Treatment System $ 571,560 Land use restrictions a) Electricity $325/mo$ 3,900 30$ 3,900 $ 48,395 4) Engineering Services $ 223,287 b) Carbon 20,000 lbs/yr @ $0.75/lb$ 15,000 30$ 15,000 $ 186,136 a) Health and Safety Lump sum$ 4,100 1$ 4,100 c) Chemicals and maintenance Average @ $1200/mo + $300/mo labor$ 18,000 30$ 18,000 $ 223,363 b) Reporting 2% Capital costs 2%$ 568,477 $ 11,370 d) Monthly & quarterly NPDES mon. Analytical and labor$ 9,160 30$ 9,160 $ 113,667 c) Design 5% Capital costs 5%$ 831,270 $ 41,563 d) Construction management 10% Capital costs 10%$ 831,270 $ 83,127 5) Institutional Controls $ 2,068 e) Services during construction 10% Capital costs 10%$ 831,270 $ 83,127 a) Legal and clerical fees$ 5,000 1$ 167 $ 2,068
Total Capital Cost$ 791,764 Total O&M PV$ 1,804,816
Total Cost $ 2,596,581 30% Below$ 1,817,606 50% Above$ 3,894,871
CVO\043650003 Page 2 of 3 TABLE C-3 Cost Estimates for Retained Remedial Alternatives -- Inside the Barrier Wall (BW) Taylor Lumber and Treating Superfund Site, Feasibility Study
Remedial Alternative Description Design Criteria Capital Costs Operation and Maintenance Costs Description Specifications Rate Qty Cost Description Specifications Rate Qty Cost/yr O&M PV
BW-5 DUS Target area 87,000 ft2 1) Preparation $ 367,500 1) System Operation and Maintenance $ 1,556,927 Target volume 13,000 yd3 a) Mobilize field crew 2 field personnel, 30 days$ 250 60$ 15,000 a) System operator Lead operator$ 84 2,080$ 174,720 $ 716,386 Includes: Depth to siltstone 17 ft b) Equip: drill rig, backhoe, decon materials$ 15,000 1$ 15,000 b) System technician 2 field crew, 3 days$ 50 2,080$ 104,000 $ 426,421 Thermal desorption system O&M time frame 5 yr c) Overdrill & abandon site wells$ 2,500 15$ 37,500 c) Engineering oversight As required$ 86 500$ 43,000 $ 176,308 APR 7% d) Site preparation Lump sum$ 300,000 1$ 300,000 d) Hydrogeologist oversight As required$ 86 500$ 43,000 $ 176,308 e) Maintenance Per year$ 15,000 1$ 15,000 $ 61,503 2) Injection System $ 656,480 a) Well installation (4" dia.) 40' centers on 5 spot corners$ 3,500 56$ 196,000 2) O&M Workplan and Manual $ 33,827 b) Steam piping and insulation (4") per ft$ 65 3,360$ 218,400 a) Document preparation 110 hr mid level engineer$ 8,250 1$ 8,250 $ 33,827 c) Air piping and insulation (1") per ft$ 18 3,360$ 60,480 d) Valving & well connection$ 1,000 56$ 56,000 3) Disposal Costs $ 1,878,257 e) Pipe supports$ 225 336$ 75,600 a) Bulk liquids, 2K to 12K BTU incin. Assumes 30,000 gallons of product/year$ 1.32 347,037$ 458,089 $ 1,878,257 f) Misc. concrete, testing, etc. Lump sum$ 50,000 1$ 50,000 4) Power and Chemicals $ 4,429,558 3) Extraction System $ 450,610 a) Electricity charge Total load 375 kW$ 0.08 3,285,000$ 259,187 $ 1,062,716 a) Well installation (6" dia.) On 40' centers$ 5,000 27$ 135,000 b) Natural gas b) GW extraction pump$ 3,500 27$ 94,500 Boiler Assumes 24 months operation$ 1 1,606,321$ 1,606,321 $ 2,904,258 c) Water piping and insulation (1") per ft$ 18 1,620$ 29,160 Oxidizer$ 1 76,212$ 76,212 $ 312,484 d) Valving & well connection$ 1,500 27$ 40,500 c) Removal/Regen of Spent Carbon <2K to 10K lb$ 0.28 4,000$ 1,120 $ 4,592 e) Pipe supports$ 225 162$ 36,450 d) Carbon change outs 12 per year$ 1,120 12$ 13,440 $ 55,107 f) Misc. concrete, testing, etc. Lump sum$ 25,000 1$ 25,000 e) Boiler feedwater chemicals Assumes 24 months operation$ 50,000.00 1$ 50,000 $ 90,401 g) Air compressor$ 45,000 2$ 90,000 5) Annual Reporting $ 337,241 4) Vapor Extraction System $ 352,845 a) Effectiveness assessment report 30 hr mid level engineer$ 2,250 1$ 2,250 $ 9,225 a) Liquid ring vacuum pump Lump sum$ 250,000 1$ 250,000 b) Quarterly monitoring report Lump sum$ 5,000 4$ 20,000 $ 82,004 b) Vapor water separator included$ - $ - c) Quarterly sampling Lump sum$ 15,000 4$ 60,000 $ 246,012 c) Vapor knockout tank included$ - $ - d) Condenser$ 39,520 1$ 39,520 Total O&M PV$ 8,235,810 e) Cooling tower w/pumps$ 63,325 1$ 63,325
5) Air Treatment Equipment $ 166,460 a) Rengerative thermal oxidation unit$ 166,460 1$ 166,460
6) Water Treatment Equipment $ 363,500 a) Equalization tank (double wall)$ 40,000 1$ 40,000 b) Dissolved air floatation unit$ 190,000 1$ 190,000 c) Product tank$ 12,500 1$ 12,500 d) Carbon adsorption unit$ 46,000 1$ 46,000 e) Discharge piping$ 50 1,500$ 75,000
7) Boiler $ 875,000 a) Steam boiler Rental unit$ 25,000 24$ 600,000 b) Feed water treatment system$ 100,000 1$ 100,000 c) Natural gas connection$ 50 3,500$ 175,000
8) Monitoring & Control $ 613,130 a) Thermal monitoring wells$ 1,500 83$ 124,500 b) Thermal sensors$ 145 332$ 48,140 c) Vapor flow monitoring$ 5,500 28$ 154,000 d) Instrumentation & controls 10% equipment cost$ 286,490 1$ 286,490
9) Completion $ 265,000 a) Waste disposal$ 250,000 1$ 250,000 b) Site cleanup$ 5,000 1$ 5,000 c) Demob equipment and personnel$ 10,000 1$ 10,000
10) Surveying and Testing $ 24,700 a) Surveying Lump sum$ 5,500 1$ 5,500 b) Geotech testing (design and construction) per test$ 1,600 12$ 19,200
11) Engineering Services $ 1,134,511 a) Health and Safety Lump sum$ 18,000 1$ 18,000 b) Reporting 2% Capital costs 2%$ 4,135,225 $ 82,704 c) Design 5% Capital costs 5%$ 4,135,225 $ 206,761 d) Construction Management 10% Capital costs 10%$ 4,135,225 $ 413,522 e) Services During Construction 10% Capital costs 10%$ 4,135,225 $ 413,522 Total Cost$ 13,505,545 30% Below$ 9,453,881 Total Capital Cost$ 5,269,735 50% Above$ 20,258,317
CVO\043650003 Page 3 of 3
APPENDIX D MW-24s Installation
CVO\043650001
TECHNICAL MEMORANDUM
Field Report on MW-24S Installation and Sampling
PREPARED FOR: Robin Strauss PREPARED BY: Michael Niemet DATE: August 16, 2004
Work completed thus far related to the MW-24S Installation and Sampling effort included:
Friday, August 6th
• Flush-mount MW-9S • Grub and clear for MW-24S
Monday, August 9th
• Check location of RS-11 • Water levels (except MW-24S) • Sample some wells
Tuesday, August 10th
• Install MW-24S • Sample some wells
Wednesday, August 11th
• Attempt to develop MW-24S • Sample remaining wells (except MW-24S and MW-10S) Low groundwater levels prevented sampling of MW-24S and MW-10S. Also, MW-24S could not be developed at this time. It is recommended that MW-24S not be developed until groundwater levels rise to above the top of the screen, in order to ensure that the full length of the screen interval is properly developed. The reason for the lack of available groundwater at MW-24S and MW-10S is probably due to the time of year (late summer) and the unseasonably dry spring and summer. Another possibility is that the siltstone may be relatively elevated in the vicinity of MW-24S and MW-10S, causing the groundwater to flow around the siltstone mound, particularly when groundwater levels are low. It is recommended that the siltstone contour map, developed as part of the Groundwater Characterization (2000, LM), be updated to include the data obtained by the installation of new monitor wells in 2002 and 2004. It is important to note that before the water level and geological data for MW-24S can be used for mapping purposes, the well needs to be accurately surveyed (top of casing, ground elevation, northing and easting).
CVO/FIELD REPORT.DOC 1 184362.FS.01
PROJECT NUMBER WELL NUMBER 165241.FI.01 MW-24S SHEET 1 OF 1
MONITORING WELL RECORD DRAWING & CONSTRUCTION LOG
PROJECT NAME: Taylor Lumber LOCATION : Sheridan, OR ELEV, NGVD (Top of Well Casing): 205.49
FIELD OBSERVERS: B.Collom START DATE: 08/10/2004 SURFACE ELEV, NGVD: 203.08
DRILLING METHOD: Hollow Stem Auger FINISH DATE: 08/10/2004 NORTHING: 7735.89
DRILLING CONTRACTOR : GeoTech Explorations EASTING: 9666.04
Top Cap WELL CONSTRUCTION MATERIALS
Protective Surface Casing 3.3 ft BOREHOLE DIA(S) 10 INCHES TO: 14.5 FT BGS INCHES TO: FT BGS 3.1 ft INCHES TO: FT BGS Ground Surface 1.0 ft Surface Seal PROTECTIVE CASING TYPE Steel PROTECTIVE CASING DIAMETER 6" w/steel lid WELL CASING TYPE PVC DIAMETER 2" COUPLING TYPE Flush threads Bentonite Seal SCREEN TYPE PVC DIAMETER 2" SLOT SIZE 0.010" SCREEN LENGTH 5' TOP CAP TYPE Slip PVC END CAP/PLUG TYPE 0.5' PVC pointed Well Casing CENTRALIZER TYPE N/A CENTRALIZER LOCATION(S) N/A
Bentonite Seal FILTER PACK TYPE Silica Sand 6.5 ft GRADUATION 10/20
8.5 ft SEALS (S) SURFACE Concrete
Filter Pack ANNULAR Baroid holeplug bentonite 3/8" chips BACKFILL N/A
MATERIAL TYPE
Well Screen 10/20 silica sand-50 lb 8 bags 3/8" bentonite chips-50 lb 3 bags concrete steel protective casing 1 ea.
PROJECT NUMBER BORING NUMBER 165241.FI.01 MW-24S SHEET 1 OF 1
SOIL BORING LOG
PROJECT NAME : Taylor Lumber LOCATION : Sheridan, OR LOGGER: B.Collom START DATE: 8/10/04 10:05 DRILLING METHOD: HSA CME 850 Trackermount w/140lb slide hammer + 2" splitspoon FINISH DATE: 8/10/04 11:45 DRILLING CONTRACTOR : GeoTech Explorations WATER LEVELS: Water @ ~13'
SAMPLE STANDARD SOIL DESCRIPTION COMMENTS PENETRATION TEST SOIL NAME, USCS GROUP SYMBOL, COLOR, DEPTH OF CASING, DRILLING RATE RESULTS MOISTURE CONTENT, RELATIVE DENSITY, DRILLING FLUID LOSS 6"-6"-6" OR CONSISTENCY, SOIL STRUCTURE, TESTS AND INSTRUMENTATION ND TYPE RECOVERY (FT) DEPTH BELOW SURFACE (FT) NUMBER A INTERVAL (N) MINERALOGY. 9:00-on site, met driller + mob on site @ MW24s. _ _ 10:05-begin augering w/10" OD augers. BZ Headspace = 0 ppm, Downhole = 0 ppm. _ _ 10:20-driving splitspoon for sample #1. _ 1 3.5-4.0'-Silt w/Sand + Clay (ML). Med.brown _ 5-7-6 BZ =0 ppm, Downhole = 0 ppm. SS 0.5' w/orange + black mottles, low plasticity, 70% fines, _ 30% sand-sand is fine to v.fine, dry, med.stiff, some _ organics, rootholes, 0 ppm. 5 ___ __ 10:40-driving sampler for sample #2. Top 0.2' as above, grading to Silty Clay w/Sand BZ= 0 ppm, Downhole = 0 ppm. 2 @~5.9' to 6.5'(CL). 80% fines, 20% sand, med.yellow _ 0.7' 5-8-10 _ SS brown w/orange + black mottles, stiff, few organics, dry sand is fine to v.fine, 0 ppm. _ _ 10:55-driving sampler for #3. 7.8-8.3' as above, abrupt change to Sandy Gravel BZ = 0 ppm, Downhole = 0 ppm. _ 3 w/Silt(GC) at 8.3', fines >10%, sand 30%, gravel 60%, _ 12-16-25 light brown to med.brown w/black orange + white SS 1.2' _ mottles, gravel is 1/2" to 3/4", subrounded, sand is _ fine to med.dry, 0 ppm. 11:15-driving sampler for #4. 10 ___ As above, higher gravel content(GC), fines <10%, __ BZ = 0 ppm, Downhole = 0 ppm. sand 20%, gravel 70%, gravel 1/2" to 2", rounded, 4 11:30-Siltstone @ ~13.5'. _ 1.0' 18-35-32 med.brown, moist at 11', 0 ppm. _ SS 11:45-BOH @ 14.5'. prep. to install monitor well. _ 12.7' to 13.0' Sandy Clayey Silt w/Gravel(CL), _ med.red brown to dk.brown, 70% fines, 20% sand, _ 5 _ 33-49-50/3 10% gravel, sand is fine to med., gravel 1/4" 1.3' subangular, moist, loose, 13.0 to 13.5 changes _ SS _ abruptly to Gravel w/Silt(GW), med.grey brown to 15 ___ dk.grey brown, 5% fines, 45% gravel, gravel __ angular to subangular, 1/4" to 1" wet. 13.5 to _ 14.0' changes abruptly to siltstone, grey green, _ weathered, friable, no fractures, dry to moist, 0 _ ppm. _
_ _
_ _
20 ___ __ End of Boring at 14.5ft _ _
_ _
_ _
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25 ___ __
_ _
_ _
_ _
_ _
_
Table X Selected PCP Concentrations Outside Barrier Wall (µg/L) Taylor Lumber and Treating Superfund Site Time MW-1S MW-13S MW-9S MW-10S MW-15S MW-16S MW-103S PZ-102 PZ-105 1999-2000 25 U NA 24 U 26 U NA NA 5.6 25 U 82 Feb-02 6.9 0.25 0.047 U 0.099 220 10 6.4 0.37 3.5 May-02 14 0.25 0.049 U 0.13 220 15 7 0.3 8.2 Aug-02 14 2 0.046 U 0.38 250 28 12 0.34 17 Nov-02 14 2.6 0.32 U 0.18 U 210 21 4.7 0.13 4 Feb-03 6 0.32 U 0.32 U 0.32 U 130 11 5 0.23 0.77 May-03 3.3 0.56 U 0.046 U 0.13 190 11 20 0.32 2.6 Aug-04 12 0.15 0.039 U TBD 290 180 8.3 0.13 15 NA = Not Available TBD = To be determined U = Not detected. The associated numerical value represents the method reporting limit.
TECHNICAL MEMORANDUM
Taylor Mill Monitoring Well 24S
PREPARED FOR: Mike Niemet/CVO and Robin Strauss/CVO File PREPARED BY: John V. Thatcher, PLS CH2M HILL Portland Survey Group DATE: September 23, 2004
The field work was done on September 16, 2004. The field crew arrived on site at 4:45 PM, could not reach the client’s contact by phone, and therefore could not obtain the key to open the well casings and expose the measuring points of the wells (top of PVC). The horizontal and vertical components of a well survey are done using different processes and instruments. Because the horizontal work was not conducive to measuring accurate elevations due to site conditions, and because the wells could not be opened, no useful vertical information was obtained during the September 16, 2004 site visit. The approximate horizontal postion of Well 24S was measured from control set by occupying Well 20S and backsighting Well 19S, both which wells were surveyed by this office in 2002. Approximate Northing, Well 24S = 534,573. Approximate Easting, Well 24S = 7,446,032. Horizontal datum is Oregon Coordinate System of 1983, North Zone (NAD 83/91). Units are international feet.
PDX/Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\WELL 24S.DOC 1 184363 Taylor Mill Site Field Work performed on 09-25-2004 Surveyed Points
Top Steel GND Point Northing Easting MP Elev. Casing Notes Elev. Elev. MW 24S 534572.8 7446032.4 205.49 203.08 205.47 MP=PVC, GND & Steel Casing*=Concrete N. side MW 9S 534495.7 7446401.4 204.04 204.33 204.33 MP=PVC, GND & Steel Casing=Concrete N. side 1. Holding PVC elev. of 208.870 for MW 20S, a check run was made to MW 19S. Measured elev. of top of PVC of Well 19S = 210.40'. Record elev. = 210.44'. Error = 0.04'. 2. Elevations on this spreadsheet are based on holding an elevation of 208.870' for top of PVC of Well 20S.
3. Coordinate system is: "The Oregon Coordinate System of 1983, North Zone" (NAD83\91) In International Feet Elevations are based on GPS points that are described as being NGVD 29 per Dunkel drawing Coordinates of these points are available in the original "Local" system and also in the incorrectly calculated State Plane coordinates (Per Dunkel drawing) on the "other coordinates" tab, this sheet.
*Measured with the hinged lid open at the point nearest the PVC casing. The PVC casing is slightly above the rim of the steel casing.
Surveyed Wells Sept 2004.xls 1 05/31/2005 OR North Intl. Ft OR North Intl. Ft Dunkel local Dunkel local Dunkel SPC Dunkel SPC point Northing Easting Northing Easting Northing Easting gp01 535516.88 7446235.49 8682.91 9855.29 535515.81 7446220.60 gp04 534817.84 7446194.05 7983.26 9824.14 534816.77 7446179.16 gp05 535004.01 7445668.06 8161.69 9295.40 535002.94 7445653.17 gp06 535168.71 7445548.00 8324.63 9172.91 535167.64 7445533.11 gp07 535327.28 7445476.22 8482.14 9098.79 535326.21 7445461.32 gp08 535453.25 7445640.31 8610.53 9261.03 535452.18 7445625.42 gp09 535574.27 7445943.96 8736.02 9562.91 535573.20 7445929.07 gp20 535380.16 7446288.00 8546.97 9909.81 535379.09 7446273.11 mw 9s 534495.70 7446401.40 7664.21 10036.15 534494.63 7446386.51 mw 101s 535116.02 7445956.91 8277.95 9582.60 535114.95 7445942.02 mw 17s 535460.79 7445865.04 8621.38 9485.66 535459.72 7445850.15 mw 18s 535550.16 7444712.92 8693.78 8332.22 535549.09 7444698.03 mw 19s 534907.39 7445460.26 8062.01 9089.02 534906.32 7445445.37 mw 20s 534793.29 7445739.98 7952.03 9370.42 534792.22 7445725.09 mw 21s 536591.26 7447129.86 9770.47 10733.85 536590.19 7447114.97 mw 22s 535255.62 7446779.92 8429.67 10403.57 535254.55 7446765.03 mw 23s 535227.18 7447426.17 8410.75 11050.24 535226.11 7447411.28 mw 24s 534572.82 7446032.38 7735.89 9666.04 534571.75 7446017.49 pw 1 534863.58 7445962.78 8025.59 9592.19 534862.51 7445947.89 pw 2 534933.96 7446113.32 8098.19 9741.69 534932.89 7446098.43 pw03 535174.62 7446129.55 8339.10 9754.38 535173.55 7446114.66 pw04 535355.83 7445656.48 8513.34 9278.64 535354.76 7445641.59 wf01 535834.40 7446011.15 8997.14 9626.27 535833.33 7445996.25 wf02 535830.99 7446135.57 8995.56 9750.74 535829.91 7446120.68 wf03 535825.14 7446247.79 8991.36 9863.05 535824.07 7446232.90 wf04 535711.41 7446129.55 8875.89 9746.48 535710.34 7446114.66 wf05 535699.50 7446243.04 8865.65 9860.15 535698.43 7446228.15 wf06 535636.74 7445896.10 8797.78 9514.13 535635.66 7445881.21 wf07 535618.14 7446120.40 8782.48 9738.70 535617.07 7446105.51 wf08 535596.95 7446230.30 8762.91 9848.91 535595.88 7446215.41 wf09 535597.42 7446283.74 8764.17 9902.35 535596.35 7446268.85 wf10 535515.54 7445863.17 8676.10 9482.99 535514.47 7445848.28 wf11 535526.37 7446029.67 8689.38 9649.32 535525.30 7446014.78 wf12 535476.46 7446279.17 8643.14 9899.56 535475.39 7446264.28 wf13 535345.44 7446285.73 8512.21 9908.04 535344.37 7446270.83 wf14 535204.03 7446291.92 8370.90 9916.32 535202.96 7446277.03 Correct State Incorrectly converted as Plane Local Per Dunkel Coordinates Coordinates Drawing
Plan
Monitor Well MW-24S Installation and Sampling Plan
Taylor Lumber and Treating Superfund Site Sheridan, Oregon
Submitted to U.S. EPA
WA No. 225-RICO-10FI Contract No. 68-W6-0025
August 2004
Contents
Section Page
Installation and Sampling Plan ...... 1 Background ...... 1 Data Needs ...... 1 Project Organization ...... 2 New Monitor Well...... 4 Siting 4 Installation...... 4 Well Development...... 5 Survey 5 Groundwater Sampling...... 6 Sample Parameters, Containers, Preservatives and Holding Times...... 6 Decontamination of Field Equipment ...... 7 Management of Investigation-Derived Waste ...... 7 Sample Labels ...... 7 Sample Handling and Custody Requirements ...... 7 Sample Packing and Shipping...... 7 Laboratory Contacts and Addresses...... 8 Field Documentation...... 8 Anticipated Work Schedule ...... 9
Attachment A: Groundwater Sampling SOP Attachment B: Monitor Well Installation SOP Attachment C: Bore-Hole Logging SOP Attachment D: Field Parameter Monitoring SOP Attachment E: MultiRae/MiniRae Air Monitoring SOP Attachment F: Investigation-Derived Waste Management Plan Attachment G: Well Logs
CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC
Installation and Sampling Plan
Background The Taylor Lumber and Treating (TLT) Superfund Site is a lumber mill and wood treating facility located in northwest Oregon on the east slope of the coast range, near the city of Sheridan. The goal of this Monitoring Well Installation and Sampling Plan is to provide additional information on the nature and extent of groundwater contamination by PCP downgradient of the barrier wall. This report describes installation of the new monitoring well (MW-24S) and sampling from this and eight existing wells nearby.
Data Needs In October 2003, the Draft Remedial Investigation (RI) was submitted for review by the U.S. Environmental Protection Agency (EPA), Oregon Department of Environmental Quality (DEQ), National Oceanographic and Atmospheric Administration (NOAA), and the Confederated Tribes of Grande Ronde (the Tribe). Comments received illustrated the need for additional groundwater monitoring between the South Yamhill River and the dissolved PCP contamination that was identified south of the barrier wall.
• The Tribe: …The high PCP levels in MW-15S should be discussed and considered in the feasibility study process. It is possible that the PCP is currently not migrating from this area as the report describes; but it is also possible that this contamination could migrate to the South Yamhill River, especially during a heavy rainfall event or an extremely wet winter. The PCP contamination in MW-15S is an area that requires additional attention.
• EPA (Dana Davoli): …one concern is that the plume from outside the bentonite wall could be moving between these two monitoring points [MW-10S and PZ-102] (about 250 feet apart) and that it might be reaching the water at levels of concern. The area between these two points is downstream of MW15s which is the well outside the south end of the bentonite wall with the highest PCP (190 ug/L in May-03). MW15s is about 350 feet north of the river… I think it would be very useful to attempt to close this data gap, since it seems that it can be done easily and fairly cheaply (no dioxin/furan analysis).
• EPA (Martha Lentz): …To date, there has been no wells drilled and/or sampled within 100 feet of the river, which I consider to be a data gap…
• EPA (Bruce Duncan): …I agree with Martha Lentz (EPA hydrogeologist) that uncertainty remains about the potential pathway via ground water outside the slurry wall (also mentioned in the Tribal, NOAA, and ODEQ comments). This is heightened by the increase in PCP in one well outside the containment area.
CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC 1 INSTALLATION AND SAMPLING PLAN
PCP concentrations in all wells downgradient of the barrier wall are summarized in Table 1. Groundwater sampling locations are shown in Figure 1. PCP levels in groundwater are highest at the barrier wall and decrease with increasing distance from the wall.
TABLE 1 PCP Concentrations Downgradient of Barrier Wall (µg/L) Monitor Well MW-24S Installation and Sampling Plan
Time MW-9S MW-10S MW-15S MW-16S MW-20S MW-103S PZ-102 PZ-105
1999-2000 24 U 26 U NA NA NA 5.6 25 U 82
Feb 2002 0.047 U 0.099 220 10 NA 6.4 0.37 3.5
May 2002 0.049 U 0.13 220 15 NA 7.0 0.30 8.2
Aug 2002 0.046 U 0.38 250 28 0.013 J 12 0.34 17
Nov 2002 0.32 U 0.18 U 210 21 0.32 U 4.7 0.13 J 4
Feb 2003 0.32 U 0.32 U 130 11 0.32 U 5 0.23 J 0.77
May 2003 0.046 U 0.13 190 11 0.027 J 20 0.32 U 2.6
NA = Not Available J = The analyte was positively identified. The associated numerical result is an estimate. U = Not detected. The associated numerical value represents the method reporting limit.
Comments on the Draft RI suggested that the well should ideally be located within 100 feet of the river and centered directly south of the gap between MW-10S and PZ-102. However, the location of PZ-105 was incorrectly displayed on all the figures of the Draft RI, except Figures 3-5 and 3-6. PZ-105 is actually significantly further south and east than shown in most of the figures. Therefore, it makes the most sense to center the new monitor south of the gap between PZ-105 and PZ-102.
Project Organization Table 2 presents the names and responsibilities of key project personnel that will be involved in the monitoring well installation and sampling.
2 CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC INSTALLATION AND SAMPLING PLAN
TABLE 2 Project Personnel Monitor Well MW-24S Installation and Sampling Plan
Title Responsibility Name Phone
EPA Project Manager Coordinates all of the project efforts. Loren 206-553-4903 Interfaces directly with the CH2M HILL Project McPhillips/EPA Manager
CH2M HILL Project Responsible for the coordination and Robin 541-768-3520 Manager, Project QA execution of all work items associated with Strauss/CH2M Manager project planning and implementation. Liaison HILL between program-level managers and project- level team members. Identifies team members and project assignments. Manages and tracks schedule and budget. Ensures that all tasks are completed by assigned team members within schedule and budget constraints.
Project Task Manager Responsible for coordinating and Mike 541-768-3726 implementing the monitor well installation Niemet/CH2M sampling plan. Point of contact. HILL
Field Team Leader and Oversees field activities and implements the Barry 541-740-3250 Site Safety Coordinator Field Sampling Plan. Implements the Health Collom/CH2M and Safety Plan in the field. HILL
EPA Chemist/Data Responsible for coordinating analytical Laura 206-553-4323 Validation services with Contract Laboratory Program Castrilli/EPA (CLP) laboratories. Coordinates sample shipments to CLP laboratories, monitors lab turn-around-time. Reviews and validates data and generates data validation summary report.
CH2M HILL Data Responsible for preparing chain-of-custodys, Trish 409-984-0298 Manager sample bottle labels. Uses project database to Larson/CH2M produce data summary reports under direction HILL of the project manager.
CH2M HILL Project Coordinates chemistry issues for CH2M HILL. Scott 541-768-3148 Chemist Interacts with EPA Chemist on Quality Echols/CH2M Assurance Project Plan (QAPP); prepares HILL sample bottles and handles data validation issues. Prepares QAPP, point of contact for non-CLP laboratories.
PWP Site Manager Oversees site operations Bob 503-843-2122 Halderman/PWP 503-437-0199 (cell)
PWP Safety Manager Manages safety and environmental issues for Roland 503-843-2122 PWP on a region-wide basis Mueller/PWP 503-851-4075 (cell)
"Dee" Industrial Site Property owner Bob Harris/"Dee" 503-434-5525 Manager Industrial 503-784-9262 (cell)
CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC 3 INSTALLATION AND SAMPLING PLAN
New Monitor Well
Siting The new monitor well (MW-24S) will be installed off of the south shoulder of Oregon State Highway 18B, and situated between MW-9S and MW-10S such that it fills he gap between PZ-102 and PZ-105 (Figure 1). This location best meets the needs identified during review of the Draft RI. The location where the new monitor well is to be installed can be identified by first locating the Speed Zone Ahead sign on the south side of Highway 18B about 200 feet west of the intersection with Rock Creek Road. From the sign move 6 feet west (there should be a “60’→” painted in orange on the highway shoulder at this location). Measure 60 feet south from the highway centerline to find the installation location. There is a light trail that has been established through the thick blackberries to the location. The location is under some large trees shortly before the bench of land drops steeply to the river. The ODOT right-of-way extends 50 feet to the south of the highway centerline. Therefore, the location is 10 feet past of the state right-of-way on private property, and does not require a permit from the state (as confirmed by Dave Chuculate/ODOT 503-986-2876). A number of power and telecommunication lines run overhead near the highway shoulder, however, the drill rig will be far enough to the south of the lines for them not to be a concern during drilling. The property owner, Bob Harris of “Dee” Industrial must be contacted for permission to install the well prior to starting work. A utility locate must be performed prior to starting work. The drilling subcontractor will be consulted to make sure that the drill rig can access the proposed location. It is likely that excavation and/or clearing will be required before access can be achieved, and a track-mounted drill rig may be necessary. Flaggers and/or other traffic control measures will be required while moving equipment on and off of the state highway.
Installation Monitor well installation and logging will be conducted per SOPs included as Attachments B and C, respectively. A borehole will be drilled with a 10-inch outside diameter (O.D.) [6.625-inch inside diameter (I.D.)] hollow stem auger. For logging purposes, split spoon samples will be collected throughout the depth of borehole. For health and safety purposes, the borehole will be monitored for organic vapors during drilling using either a flame ionization detector (FID) or photo-ionization detector (PID). Readings will be taken at the top of the borehole, in the breathing zone of the worker closest to the borehole, and from the soil cuttings. The readings will be recorded in a field notebook. See Attachment E for specifics of PID and FID operating procedures. Note that monitoring with a combustible gas indicator (CGI) and an oxygen meter are not required at this location. If possible, drilling will proceed 1 foot into the siltstone. Based on the well logs of three nearby monitor wells (see Attachment G), siltstone can be expected to be encountered between 9 and 14 feet bgs. The well will be screened 5 feet, measured upward from the siltstone interface. The well will have a 6-inch sump to serve as a silt trap. This will require
4 CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC INSTALLATION AND SAMPLING PLAN that the bottom 6 inches of the boring be filled with bentonite chips, provided the boring is 1 foot into the siltstone. 10-20 Colorado silica will be used as the filter pack. The filter pack will extend at least 2 feet but no more than 3 feet above the top of the screen. The well risers, screens, and sumps will be 2-inch-I.D. schedule 40 polyvinyl chloride (PVC) with flush-threaded sections and 0.010-inch machine slots. The well will be an above ground completion with bollards extending 4-feet above the surface, and painted yellow. The well will be marked with the proper well identification provided by the CH2M HILL representative in addition to an OWRD well identification tag. A lock, keyed similar to other nearby monitor wells, will be supplied by the CH2M HILL representative. Drill cuttings and core materials will be containerized and labeled. Final disposal of the drum contents will depend on the groundwater test results, since contaminated groundwater is the only pathway for contamination of this soil. If groundwater sampling results are within acceptable limits, the soil will be discarded onsite. For further details see IDW Management SOP.
Well Development Development of the new monitor well will proceed following SOP (see Attachment B). The well will be developed by means of mechanical surging and overpumping using either a submersible, positive displacement, or centrifugal pump. The pump intake will be set into the screened section of the well. The discharge rate may be periodically adjusted, and the pump will be rapidly raised and lowered to create a surging action in the well. Development will continue as long as the water withdrawn continues to decrease in turbidity, or to the satisfaction of the site hydrogeologist, generally after 5 well volumes are removed or after a maximum of 2 hours, whichever comes first. Groundwater produced during development will be collected and containerized. If possible, this water will be disposed into the facility wastewater treatment system. For further details see IDW Management SOP (Attachment F).
Survey Following installation, a surveyor will be contracted to determine the following parameters for the new monitor well (MW-24S):
• Northing (TLT Local Coordinates) • Easting (TLT Local Coordinates) • Ground surface elevation (feet above mean sea level [MSL]) • Top of casing elevation (feet above MSL) The elevation of the north side of the top of the PVC casing will be determined to the nearest +/-0.01 foot. A mark in indelible ink will be placed on the casing to indicate the location that was surveyed. The horizontal location will be determined to the nearest 0.5 foot. All measurements will be referenced to the National Geodetic Vertical Datum (NGVD). The surveyor will be licensed to operate in the State of Oregon. The surveyor shall provide guidance for the conversion of local to state plane coordinates.
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Groundwater Sampling
Sample Parameters, Containers, Preservatives and Holding Times Groundwater sampling of the newly installed MW-24S, along with existing nearby monitoring wells (MW-1S, MW-9S, MW-10S, MW-13S, MW-15S, MW-16S, MW-20S, MW- 103S, PZ-102, and PZ-105), will be conducted following development of MW-24S. Sample locations are shown in Figure 1. Any future monitoring of these wells will be determined following analysis of the results for this sampling event. A total of 15 samples will be collected during sampling events. These 15 samples will include one field sample from each of the 11 monitor wells, one field duplicate, one MS, one MSD, and one equipment rinse blank. Sampling parameters are summarized below.
AUGUST 2004 Required Sample Containers, Preservation, and Holding Times Taylor Lumber and Treating
Analytical Sample Holding a b c Analyses Method Matrix Container Qty Preservative Time
Bottle Group A – send to EPA-Manchester Lab
PCP 8041 water 1-L amber glass 2 Cool 4°C 7/40 days a= Glass containers will be sealed with Teflon®-lined screw caps. b= All samples will be stored promptly at 4°C in insulated chest upon collection. c= extraction hold time/analysis hold time
AUGUST 2004 Sample Summary Taylor Lumber and Treating
Parameter Method Field Field MS/MSD Field Equipment Total Samples Duplicates Blanks Rinse Number of Blanks Samples
PCP 8041 11 1 1/1 0 1 15
Manchester (MW-24S) (MW-24S) Lab Duplicate frequency = 10% MS/SD frequency = 5 % Equipment rinse blank = 1 collected at time determined by the field crew.
For the field duplicate collect an additional sample volume from MW-24S, and for the MS/MSD collect 2 additional sample volumes from MW-24S. Therefore, altogether, 4 sample volumes will need to be collected from MW-24-S. The Field Team Leader (FTL) is responsible for ensuring proper sampling, labeling of samples, preservation, and shipment of samples to the laboratory to meet required holding times. Pre-cleaned and certified sample containers will be purchased and made available to the sampling team before sample collection. The FTL will retain all certificates of analysis for the pre-cleaned containers.
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Decontamination of Field Equipment All field meters and probes will be cleaned and rinsed with tap water and deionized water between sample locations and at the end of each sampling event. Decontamination includes a wash in an Alconox detergent solution, a rinse with tap water, and a rinse with deionized water.
Management of Investigation-Derived Waste Materials generated during the sampling event will include purged groundwater, used Teflon™ tubing, rinsate from equipment decontamination, and used PPE. Purged groundwater and rinsate will be stored in 55-gallon drums until disposal into the onsite treatment system when convenient. Used supplies and PPE will be disposed of at the facility waste disposal site. Note that these disposal procedures need to be cleared with PWP before work commences. For further details see IDW Management SOP.
Sample Labels Prior to collection of a sample the container must be properly labeled. The sample label should be attached directly to the sample container. The information that should be included on the sample label includes:
• Project name • Sample ID (same as the well ID) • Date sampled • Time sampled (in military time) • Initials of sampler(s) • Analysis for which the particular container is intended
Sample Handling and Custody Requirements Components of sample custody procedures include the use of field logbooks, sample labels, custody seals, and COC forms. Special EPA COCs and custody seals must be used and will be supplied to the field team prior to sampling. Each person involved with sample handling will be trained in COC procedures before the start of the field program. The COC form will accompany the samples during shipment from the field to the laboratory.
Sample Packing and Shipping During the field effort, Barry Collom or Mike Niemet will notify the EPA RSSC about shipments to the laboratory. Hard plastic ice chests or coolers with similar durability will be used for shipping samples. The coolers must be able to withstand a 4-foot drop onto solid concrete in the position most likely to cause damage. Double contain sample bottles in ziplock bags, grouped by sample set. Styrofoam or bubble wrap will be used as packing material to protect the samples from leakage during shipment. Coolers will be packed with ice, and double bagged in ziplock baggies. A volume of ice approximately equal to sample volume should be present in each cooler. Blue ice will not be used. After packing is complete, the cooler will be taped securely, with custody seals affixed across the top and bottom joints.
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Cooler Shipment Notes: 1. Include a temperature blank (DI water in plastic bottle) in each cooler. 2. Record the airbill on each Chain-of-Custody. 3. Mike Niemet should be listed as the contact person on the COC, not Loren McPhillips. 4. Use custody seals on the cooler. 5. Make sure return address is on the cooler so it can be returned to Corvallis. Samples will be shipped in accordance with procedures approved by the Department of Transportation for transporting hazardous substances. Please note: • The contract laboratory must be informed in advance if a Saturday shipment/analysis will be required. Manchester laboratory does not accept samples on Saturday.
• Upon shipping Mike Niemet or Barry Collom will notify Laura Castrilli (who will notify the EPA lab), as appropriate.
• Samples will be shipped priority overnight FedEx to the EPA or contracted laboratory for analysis. On the FedEx slip check “bill sender”. The Sender’s account number is 2029-5846-0. Using this number will save us approximately 70% on shipping costs. The reference number should be the full project number followed by a slash “/” then the 5 digit employee number. For example: 184362.AN.01/31952.
Laboratory Contacts and Addresses Samples will be sent to the following laboratories for analyses: Manchester Environmental Laboratory 7411 Beach Drive East Port Orchard, WA 98366 Phone 360-871-8800 FAX 360-871-8850 Attn: Karen Norton/ESAT Sample Shipment Coordinator
Field Documentation The field team will log daily activities in project-dedicated field logbooks. Notebook pages will be photocopied every day to provide a backup to the original notebook. The FTL will maintain the sampling activities notebook, which will contain the following materials:
• Instrument calibration logs • PID data sheets • Photo log • Well construction logs • Copies of field notes
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Field Records Field notes will be recorded with indelible, waterproof ink. Field books will be permanently bound and will be composed of materials suitable for use under field conditions (for instance, Rite-in-Rain™ notebooks). The exterior of each book will be labeled with the project name and number, the period in which the book was used, and the name of the primary author. Each page, thereafter, will be numbered (preprinted or entered by the user) and will have the date and author’s name in the upper right corner. Personnel will update the project notebooks daily during field activities. In addition to the investigation data, the following site activity records will be recorded in the project notebooks:
• Time of arrival and departure from the site • Project personnel and subcontractor personnel onsite • Equipment calibration records • Health and safety monitoring records • Equipment present and equipment used • Names of visitors, their associations, and purpose of visit Information recorded during a sampling event will include the sample designation (type, zone, station, and depth), sample location, sample number, equipment, procedure, names of samplers, containers used (type and quantity), preservation lot numbers, and analyses to be performed. Safety and health monitoring activities performed according to the Health and Safety Plan will be recorded in the field book.
Anticipated Work Schedule A tentative schedule for the well installation and sampling is shown in Table 3.
TABLE 3 Tentative Schedule Monitor Well MW-24S Installation and Sampling Plan
Task Tentative Schedule
Mark locations for utility check June 28, 2004
Visit with site managers to get approval on well June 28, 2004 and geoprobe locations and type of completions
Contact utility coordinating service July 6, 2004
Get approval for management of IDW August 2, 2004
Install monitor well MW-24S August 9, 2004
Develop MW-24S August 10, 2004
Sample MW-24S and other nearby wells August 11, 2004
Confirm proper IDW management August 16, 2004
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ATTACHMENT A Groundwater Sampling SOP
General Conditions Before sampling, any site conditions that may affect the quality of the sample should be documented. Weather conditions must be recorded, including temperature, wind direction, and precipitation (type and intensity). Other conditions include the presence of airborne particulate such as dust from a gravel road, or the presence of an unusual odor. The outer protective monument, well casing, and well cap will be inspected for any signs of damage. If there is evidence of damage, or if a lock is missing, this information will be recorded in the field notebook and reported to the PM. A congruent set of locks were placed on all well monuments and locking well caps in February 2002. Before each well is sampled, the headspace will be screened for the presence of organic gases using a photo ionization detector (PID) (or flame ionization detector (FID)). If organic gases are detected, the concentration will be document in the field notebook and gases will be allowed to dissipate before proceeding.
Groundwater Elevation Groundwater elevation measurements will be made no more than 72 hours before each sampling event. If a difference in pressure between the air in the casing and ambient barometric pressure is suspected (i.e., if air-tight monitoring well caps are used), at least 5 minutes will be allowed for the water level in the well casing to equilibrate prior to making the measurement. A confirmatory water level will be measured and must agree with the initial measurement by within ±0.01 foot. The depth to water to the nearest 0.01 foot from the top of casing will be measured with an electric water-level indicator. The depth to water, measurement date, and measurement time will be recorded on the Groundwater Sampling Field Data Sheet (See Attachment B) for each well. The water-level indicator will be decontaminated between wells by rinsing the probe with distilled water and shaking the probe dry or wiping it with a clean paper towel.
Well Purging A minimum of three well casing volumes will be removed prior to sampling to provide for groundwater samples that are representative of geochemical conditions in the surrounding aquifer. The wells shall be purged (pumped) using dedicated polyethylene suction tubing
CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC 1 GROUNDWATER SAMPLING SOP and a peristaltic pump. The purge water will be disposed as IDW, according to specific project methods. Water will be collected in a graduated bucket to gauge the purge rate and total purge volume. Teflon tubing dedicated to each monitor well will be used due to its relatively inert properties. The wells will be purged at a rate generally below 0.5 gpm, consistent with low- flow sampling protocols. Field parameter measurements (temperature, pH, dissolved oxygen, oxidation-reduction potential, specific conductivity, and turbidity) will be made once per well casing volume, as described below, and recorded on a Groundwater Sampling Field Data Sheet. The volume of water to be purged from each well prior to sampling will be calculated in the field and noted on the field data sheet. The DTW measured just prior to sampling is subtracted from the total depth to the bottom of the well (TD) and multiplied by 0.17 or 0.65 (for 2- and 4-inch inside diameter wells, respectively) to compute each well casing volume to be purged. If a low yielding well is encountered, the well will be bailed and allowed to recover within 80 percent of the original static water level before sampling. If a well is known to be low yielding, field parameters will be collected during the start and end of the one well casing volume removal effort. Otherwise, field parameters will be measured following the removal of the casing volume with the peristaltic, and then prior to sampling as the well is bailed.
Groundwater Sample Collection Procedures Sampling procedures include the following steps: 1. Unlock the well cap and screen the headspace using a PID for organic gases. If present, allow gases to dissipate before proceeding. Record the PID measurements. 2. Measure water level using an electronic water level probe. Record the water level. 3. Purge the well using a peristaltic pump with dedicated tubing (see previous section for purge volume calculation). Set the suction tubing intake so that it is near the top of the water column during pumping. Extract a minimum of three purge volumes from the well. Note volumes purged on the field data sheet. 4. Measure the water level and field water quality parameters (with instruments placed in a flow-through cell) after each purge volume, and record the measurements in the groundwater quality sampling diary. 5. Collect groundwater samples after field parameter readings have stabilized within 10 percent of the previous measurement, and turbidity readings are less than 5 to 15 NTU.
6. Store samples in cooler at 4 °C.
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ATTACHMENT B Monitoring Well Installation SOP
Specific boring location and depth, access for drilling equipment, and locations of surface and subsurface utilities and sources near potential drill sites will be determined independently for each additional phase of work.
Drilling Methods An outside contractor (driller) will supply and operate the proper equipment and construct monitoring wells in compliance with OWRD regulations. A CH2M HILL geologist, hydrogeologist or engineer will supervise the drilling and log the boring as describe in the Bore-Hole Logging SOP. All boreholes will be monitored for organic vapors during drilling using either a flame ionization detector (FID) or photo-ionization detector (PID) for the health and safety of drilling and support personnel and assessment of subsurface conditions. Readings will be taken at the top of the borehole, in the breathing zone of the worker closest to the borehole, and from the soil cuttings. The readings will be recorded in a field notebook. See the Multirae / Minirae Air Monitoring SOP for specifics of PID and FID operating procedures.
Guidelines for Drilling Boreholes by Hollow Stem Auger 1. The method of advancing the boring shall be in accordance with the current ASTM Designation D5784 when drilling and sampling boreholes in unconsolidated materials (i.e., for shallow well construction in the Willamette Valley). 2. The driller shall provide hollow-stem augers of sufficient size to drill holes required for installation of two-inch monitor wells. The diameter of the hollow-stem augers will be of sufficient size to permit placement of a minimum 4-inch annular space between the outside of the well casing and the borehole wall. 3. The driller shall have on hand at least two complete samplers and a sufficient number of auger lengths to complete each hollow stem auger boring to the depth indicated in the project specific scope of work. 4. The driller shall have end plug(s) available for placement at the tip of the auger flights to be used to block movement of cuttings into the lead auger. The end plug shall be specifically designed for this purpose. The use of sampling tools, drill rods, etc., not specifically designed to serve as an end plug is not acceptable. 5. Drilling additives will not be used without specific approval of the CH2M HILL representative. 6. When removing drill tools used for the borehole advancement from the borehole, the driller will be careful to avoid the creation of a potential vacuum and blowup at the bottom of the borehole. 7. All borings not completed as wells will be abandoned in accordance with OWRD regulations.
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Soil Sampling using Split-Spoon Techniques
General Description A split-spoon sampler is a steel tube, split in half lengthwise, with the halves held together by threaded collars at both ends of the tube. The split spoon can be driven into consolidated materials using a drive weight mounted on a drilling rig. A standard split-spoon sampler has a 2-inch outer diameter and 1-3/8-inch inner diameter. Standard lengths are 20 inches and 26 inches. Split-spoon soil and sediment samples are usually collected in conjunction with hollow- stem auger drilling techniques using a 140-pound drive hammer. The split spoon is attached to a metal rod and driven into the undisturbed soil ahead of the lead auger. The hammer drives the spoon into the ground, typically raised and dropped 30 inches per blow. The hardness of the soil can be determined by extrapolating the number of hammer blows that are required to advance the split spoon 6 inches into the soil.
Equipment / Materials • Appropriate PPE • Stainless steel pan or bowl • Field notebook • Utility knife with hooked blade • zip-lock bags • PID or FID (calibrated before use)
Procedures / Guidelines Record sample location (i.e., borehole ID), depth, and time and date of sampling in field notebook. Have the driller report blow count and record the value in the field notebook and/or on the well log. The driller will collect and provide the soil sample to the project team. The driller will lay the split spoon assembly on a horizontal surface or split spoon rack and remove top assembly and drive shoe from sampler. The sampling tube will be opened carefully by removing one-half of the split spoon. Split the liner (if a liner is used) with a utility knife, preferably with a hook-edge attachment. Log the soil sample according to the Bore-Hole Logging SOP. Take a representative sample of the split spoon for ionizable volatile organic material headspace analysis. Perform an ionizable volatile organic material headspace analysis on a representative sample from a split spoon sample by taking a PID or FID reading from the headspace of a zip-lock bag containing a representative sample from the split spoon. An aliquot of soil must be immediately placed into a zip-lock bag to minimize loss of VOCs. Use a consistent amount of soil volume in each zip-lock bag, making sure to leave room at the top for the headspace reading and not to compact the soil. After filling the zip-lock bag, immediately seal the bag to prevent the loss of volatiles. Allow volatilization of any compounds into the air space of the bag for 10 minutes in a warm place (>50 °F). Take the reading by breaking the zip-lock bag seal just enough to insert the probe of the PID/FID, inserting the probe, and
2 CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC MONITORING WELL INSTALLATION SOP recording the result. Discard the soil and bag according to the IDW management plan. See the organic gas monitoring SOP for specifics of PID and FID operating procedures.
Guidelines for Split-Spoon Soil Sampling with a Hollow Stem Auger 1. Where specified, the samples shall be collected with the standard split-spoon sampler by driving it with a 140-pound hammer falling 30 inches, in accordance with current ASTM Designation D1586. 2. The sampling spoon shall be a stainless steel 2-inch OD split-barrel sampler with an ID of 1-3/8 inches. Traps or retainers of the flap or spring type shall not be used while conducting the Standard Penetration Test unless authorized by the CH2M HILL representative. A retainer may be used if approved by the CH2M HILL representative to obtain a sample if the sample was lost during the first attempt. The drive shoe or the entire sampler shall be replaced if damaged in such a manner as to cause projection within the interior surface of the sampler. 3. The sampler will be dismantled and the sample removed from the sampler as requested by the CH2M HILL representative. Well/Piezometer Construction Monitor wells are to be constructed to facilitate the collection of representative samples of groundwater in accordance with individual project DQOs. Monitor well construction procedures will follow applicable OWRD laws, regulations, and guidelines, as well as industry standard practices as established in ASTM D5092-90(1995)e1 and D5787-95. Wells will be constructed using 2-inch-diameter Schedule 40 polyvinyl chloride (PVC) well screen and blank. Actual screening depths will be determined in the field. Wells will be screened with a 10-foot, 0.010 slot-size screen with a 0.5 foot sediment trap. The sump/end cap, screen, and riser assembly will be lowered through the hollow-stem auger (or temporary casing) to the proper depth or to the bottom of the boring. A filter pack of 10 x 20 clean silica sand will be placed adjacent to the entire screened interval to prevent the caving of natural material around the screen. The filter pack will extend at least 2 feet but no more than 3 feet above the top of the screen, to be confirmed by sounding with a weighted tape. The filter pack will be emplaced by carefully pouring sand down the annulus between the casing and the hollow-stem augers (or temporary casing). The augers (or temporary casing) will be pulled back as the filter pack is being emplaced such that sand is always inside the hollow-stem augers. Bentonite chips will be used to seal the annulus above the filter pack for shallow wells. Time release compressed bentonite pellets will be used to fill the annular space below the water table while regular (non-time release) bentonite chips may be used to fill the annular space above the water table. For wells completed above ground a locking monument cover will be placed over the well casing. Flush mounted wells will be housed in a protective well vault. Monuments and monitoring well vaults will be held in grout or cement, filling the top 6-12 inches of the bore hole. Wells completed above ground will need at least three visible cement filled pipes (equal to or greater than the height of the monument) to protect the well from damage, as noted in OWRD regulations.
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Guidelines for Installing Monitor Wells with a Hollow Stem Auger Installing Well Casing 1. Wells shall be constructed with materials and to the diameters and depths shown on as described in the Scope of Work. 2. Where the bottom of the piezometer/monitor well is higher than the bottom of the boring, the lower portion of the boring shall be raised by adding sand, 100 percent bentonite chips, or bentonite cement; by pumping or tremieing through a pipe placed at the bottom of the boring and withdrawing the casing to the base of the correct well depth as determined by the CH2M HILL representative. If bentonite-cement grout is used, it shall be allowed to set a minimum of 12 hours or to a suitable hardness as determined by the CH2M HILL representative before overlying sand is placed. This mixture may contain a quick setting agent to decrease the setting time. The required setting period shall depend on the type of setting agent used and must be acceptable to the CH2M HILL representative. 3. The piezometer/monitor well casing/screen and annular materials (sand, bentonite pellets, and grout) shall be installed as described in the Scope of Work. 4. Under no circumstances will casing thread lubricants, tape, pipe dope, or any other potentially contaminating or foreign substances be allowed to be used during well construction. Substitutes for any foreign substances shall only be authorized by the CH2M HILL representative. Placing Annular Materials 5. The driller will install annular materials per the well design. These materials will include the filter pack, bentonite seal, and cement grout. 6. In general, the filter pack will be placed to 2 feet above the top of the well screen as the augers or drill pipe is withdrawn. The driller shall prevent bridging of the sand between the well casing and inside the auger, and place additional sand as required. For shallow well installations, the driller may use the dry pour method for filter pack placement or as approved by the CH2M HILL representative. For wells greater than 20 feet deep, the filter pack will be placed with a tremie pipe as the augers are being withdrawn. Frequent measurements will be made using a sounding device provided by the driller, to check the elevation of the filter pack and confirm that bridging has not occurred. 7. Following filter pack tagging, a minimum 2-foot-thick layer of granular bentonite seal shall be placed above the filter pack or as determined by the CH2M HILL representative. The depth to the top of the bentonite seal shall be measured to document its thickness. For depths greater than 50 feet, the CH2M HILL representative will provide a specification for emplacement of a bentonite slurry. 8. Cement grouting will be placed from the bentonite seal to the ground surface. The grout will be allowed to cure a minimum of 24 hours before the wellhead is completed. Wellhead Completion 9. For wells 2-inches or less in diameter that are completed above ground, the driller shall provide and install an upright locking protective cover in accordance with OWRD regulations. The well casing shall be centered in a concrete pad as specified in and at least three protective guard posts will be installed at the corners of the pad, in accordance with OWRD regulations.
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10. It is assumed that all flush-mount well completions will occur in high traffic areas. The driller shall provide and install a 6-inch manhole style vault to house the flush mounted well. 11. All wellhead completions will be marked with the proper well identification provided by the CH2M HILL representative in addition to an OWRD well identification tag.
Well Development After construction, monitor wells must be developed to remove sediments in the well and filter pack. Monitoring well development procedures will follow applicable OWRD laws, regulations, and guidelines, as well as industry standard practices as established in ASTM D5521-94 and D5978-96e1. The monitoring wells will be developed after construction to remove turbidity created by the drilling and construction process. Well development will begin no sooner than 24 hours after construction is completed to allow the bentonite seal to stabilize. The development will be documented in the field notebook or on a well development form. The amount of water extracted, water levels, the turbidity, and the time of surging and pumping will be recorded. The wells will be developed by means of mechanical surging and overpumping using either a submersible, positive displacement, or centrifugal pump. The pump intake will be set into the screened section of the well. The discharge rate may be periodically adjusted, and the pump will be rapidly raised and lowered to create a surging action in the well. Development will continue as long as the water withdrawn continues to decrease in turbidity, or to the satisfaction of the site hydrogeologist, generally after 5 well volumes are removed or after a maximum of 2 hours, whichever comes first. Groundwater produced during development will be managed according to the procedure outlined in the investigation-derived waste (IDW) management plan. Decontamination for the pumps is described in the decontamination section.
CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC 5 ATTACHMENT C Bore-Hole Logging SOP
General Description This technical practice is applicable to standard soil classification and logging classification results. These details apply to using standard CH2M HILL well logs (form D1586) to record subsurface observations made during monitoring well drilling, but the soil description section (section 5.2.3) may be helpful when describing samples obtained during manual soil boring and direct push (Geoprobe) testing. This technical practice serves as a general guidance to help assure that consistent data collection methods are used. More detailed information on bore hole logging can be found in ASTM D2488, Practice for Description and Identification of Soils (Visual-Manual Procedure). Procedures / Guidelines Form D1586 is a standard CH2M HILL well log form. Following are instructions for completing the log forms in the field. Field personnel should review completed logs for accuracy, clarity, and thoroughness of detail. Heading Information
Project Number. Use a project number identifier as appropriate. Boring Number. Enter the boring or piezometer number. Number the sheets consecutively for each boring. Project. Fill in the name of the project. Location. If stationing, coordinates, mileposts, or similar project layout information is available, indicate the position of the boring to that system by using modifiers such as “approximately” or “estimated,” as appropriate. Elevation. Enter the elevation. If it is estimated from a topographic map, or if it is roughly determined by using a hand level, use the modifier “approximately.” Drilling or Excavation Contractor. Enter the name of the drilling company or excavation contractor and the city and state where the company is based. Equipment. Identify the bit size and type, drilling fluid (if used), and method of drilling (e.g., mud rotary, hollow-stem auger, casing hammer air rotary, rotosonic, etc.). Information on the drilling equipment (e.g., CME 55, Mobile B61) should also be entered. Groundwater Levels. Record the depth below ground surface at which groundwater was first encountered during drilling as well as the depth to the static water level in the borehole. Frequent groundwater measurements are recommended. If free water is not encountered during drilling, or cannot be detected because of the drilling method, this
CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\ATTACHMENT C_2.DOC 1 BORE-HOLE LOGGING SOP information should be noted. Generally, groundwater levels should be measured each morning before resuming drilling and at the completion of each boring. Record date and time of day of each groundwater level measurement. If groundwater is not stabilized, record as such. Start and Finish. Enter the dates the boring was begun and completed. Time of day may be added if several borings are performed on the same day. Logger. Enter the first initial and full last name of the logger.
Technical Data
Testing, logging, and sampling data should be recorded for the depth at which they were obtained. Depth Below Surface. Use a depth scale that is appropriate for the sample spacing and for the complexity of subsurface conditions. Sample Interval and Type of Sampler. Draw horizontal lines at the top and bottom depth of each sample interval. These lines should extend to the soil description column. For a very short sample interval, the bottom line can be lowered after the interval column to provide room for writing the information (see Figure 2-2). Enter the depth at the top and bottom of the sample interval. Number and Container. Enter the sample number and type. Number samples consecutively regardless of type. Enter a sample number, even if no material was recovered in the sampler. The type of sample can be identified by using the following: Sample Recovery. Enter the length to the nearest 0.1 foot of soil sample recovered from the sampler. There may be some wash or caved material (slough) above the sample; do not include the wash material in the measurement.
Soil Description
Soil descriptions should be precise and comprehensive without being verbose. The correct overall impression of the soil should not be distorted by excessive emphasis on insignificant details. In general, stress similarities rather than differences between consecutive samples. Soil descriptions must be recorded in the Soil Description column. The format and order for soil descriptions will be as follows: 1. Color 2. Mottles 3. Estimate of particle size percentages 4. Moisture 5. Sedimentary structure 6. Bedding 7. Basal contacts 8. Special features
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Color Soil color should be described according to the Munsell soil color chart. The color identification should be written in parentheses following the color name; for example, very dark gray (10YR, 3/2). If the soil is multiple colors, more than one color description may be used; for example, dark grayish brown (10YR, 3/2) or mottled olive brown (2.5Y, 4/3).
Mottles add definition
Estimate of Particle Size Percentages The soil group name and symbol is based on certain percentages of the various soil fractions present in the soil sample and plasticity. Estimates of the particle size percentages shall be documented in the soil description column.
Moisture The degree of moisture present in a soil sample should be defined as dry, moist, or wet. Moisture content can be estimated from the criteria listed as follows: • Dry—Absence of moisture, dusty, dry to the touch • Moist—Damp, but no visible water; additionally, the luster of the sample (i.e., whether the sample appears dull or shiny) should be noted • Wet—Visible free water, usually soil is below water table
Sedimentary Structures These structures should include features formed at the time of deposition such as bedding and grain size distribution and features formed after deposition such as bioturbation. The following terms should be used when describing sedimentary structures: • Fining Downward—Grain or particle sizes becoming progressively smaller with increasing depth. Depth interval should be recorded. • Coarsening Downward—Grain or particle sizes becoming progressively larger with depth. Depth interval should be recorded. • Bioturbated—Churned or stirred sediment by organism. • Burrowed—Tube-like or elongated disturbed trace(s) in sediment that is caused by organisms as they move through sediment.
Bedding The size of bedding should be recognized as planes of separation in sediments of the same composition and recorded in unit thickness. The thickness of the bedding should be recorded in the interval where it occurs. The following terms, modified after McKee Weir (1953), should be used when describing bedding thickness:
• Very Thickly Bedded (massive, homogenous with no visible bedding)—>1m or >39.37in. • Thickly Bedded—30 to 100 centimeters (cm) or 11.8 to 39.37 inches
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• Medium Bedded—10 to 30 cm or 3.94 to 11.8 inches. • Thinly Bedded—3 to 10 cm or 1.18 to 3.94 inches. • Very Thinly Bedded—1 to 3 cm or 0.39 to 1.18 inches. • Thickly Laminated—0.3 to 1 cm or 0.12 to 0.39 inch. • Thinly Laminated—< 0.3 cm or < 0.12 inch.
Basal Contacts Draw horizontal lines across the soil description column to indicate lithological changes in subsurface materials. Label the lines as follows to characterize the nature of these basal contacts:
• Abrupt—less than 1 inch • Clear—1 to 2.5 inches • Gradual—2.5 to 5 inches • Diffuse—greater than 5 inches • Obscure—contact not observable (between samples)
Special Features These include chemical staining and the existence of concretions or nodules. The following terms should be used when describing special features: • Oxide Staining on Joints/Slicks—Iron staining (red in color) or manganese staining (very dark brown to black in color) along joints or slickensides • Oxide Staining on Root Traces—Iron staining (red in color) or manganese (very dark brown to black in color) staining along holes formed by decomposed roots • Iron (Fe) Nodules—An irregular shaped concentration of iron (red in color) that is harder than surrounding material • Fill—Fill represents material that has been placed by man on the naturally occurring ground surface. Fill material is identified either from historical information or from the occurrence of man-made materials such as concrete, brick, glass, plastic, wood, grease, etc. Comments
Include all pertinent observations. Instruct the driller to identify any significant changes in drilling (changes in material, problems in the drilling process, etc.). Specific information might include the following:
• Date and time drilling began and ended each day • Depth and size of casing and the method of installation • Date, time, and depth of water level measurements • Depth of hole caving or heaving • Depth of change in material • Measurements made with monitoring equipment (PID) during drilling • Groundwater sample field parameter results
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ATTACHMENT D Field Parameter Monitoring SOP
General Description This SOP provides guidelines for collecting groundwater and surface water field parameters such as specific conductance, pH, oxidation-reduction potential, dissolved oxygen, and turbidity from portable, direct-reading instruments. Specific parameters to be monitored as well as the frequency of data collection will be indicated in the trip specific field instructions.
Procedures / Guidelines All equipment used for field measurements will be maintained in accordance with the manufacturer’s instructions. Routine maintenance and all equipment repairs will be documented in the site logbook. Whenever a piece of equipment fails to operate properly, the instrument either will be repaired in-house if possible, or sent out for repairs, and another instrument equivalent to the original will be substituted, if possible. Field instruments will be calibrated daily before beginning sampling activities. All field instruments will be calibrated in accordance with the manufacturer's specifications. Record calibration information in the field log book or groundwater sampling diary, including the make, model, and serial or identification number of each field instrument, as well as the readings observed during instrument calibration. Standards used to calibrate the field survey instruments will be certified. The method and frequency of calibration for the instruments used for each field activity are described in the manufacturer's instructions and summarized briefly in the table below.
Instrument Calibration Activity Frequency
Dissolved Oxygen Meter Air calibration to 100% saturation Beginning of each sampling activity
Oxidation Reduction Meter Calibrate to Zobell Solution Beginning of each sampling activity
Turbidity Meter Calibrate to standard(s) supplied by Beginning of each sampling activity manufacturer pH Meter Calibrate against standard pH solutions Beginning of each sampling activity (4.0SU, 7.0SU, 10.0SU) using 2 or 3 point calibration
Specific Conductivity Meter Check reading with a solution of known Beginning of each sampling activity conductivity (e.g., 1,000 µS/cm standard)
Field parameter measurements of groundwater help determine if water removed from a well represents in situ groundwater conditions. When collecting groundwater samples,
CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC 1 FIELD PARAMETER MONITORING SOP specific conductance, pH, oxidation-reduction potential, and dissolved oxygen measurements will be sampled in parallel, with probes measuring from an open-top overflow cell or a flow-through cell to prevent atmospheric oxygen from mixing with the sample. Turbidity measurements are made from grab samples, which are to be collected at the same time probe measurements are recorded. In general, purge water is considered to be representative of in situ groundwater conditions when field parameter readings agree to within 10% of the past set of readings, with readings taken at least one purge volume apart. All field parameter instrument probes will be decontaminated by rinsing with DI water between uses. If instrument probes become contaminated with NAPL or other substances not readily removed with a DI water rinse, field decontamination procedures for monitoring equipment will be followed to clean the instrument.
Field Measurement of Specific Conductance Specific conductance (SC) of groundwater samples is a measure of the ability of that sample to conduct electricity, given in a value corrected to a standard temperature (25 °C). The specific conductance of groundwater is directly related to the concentration of ions in solution, and may therefore be a good indicator groundwater contamination. Specific conductance meters are capable of measuring over large interval, so care must be taken to record the units of measure with the reading. The units of measure applicable to most groundwater applications are uS/cm. Since specific conductance measurements are based on a standard temperature, SC probes will have a built in temperature sensor. Most probes will include the temperature of the groundwater in the display and this value should be used when recording temperature in the log book or groundwater sampling diary.
Field Measurement of pH The pH of groundwater is a measure of the concentration of hydrogen (H+) ions in solution, or the acidity of the water. pH is presented in standard units on a log scale ranging from 0- 14, with a value of 7 indicating pure water (DI water), lower values indicating acidic groundwater conditions and higher values indicating basic groundwater conditions. pH is also a temperature dependent parameter and is presented as a value corrected to a standard temperature (25 °C). Because pH varies over such a large scale (14 orders of magnitude), the pH meter needs to be calibrated to at least two values. Generally, the meter is calibrated to a neutral value (7), and a low value (4) if acidic groundwater conditions are expected or a high value (10) if basic groundwater conditions are expected.
Field Measurement of Oxidation-Reduction Potential The oxidation-reduction potential (ORP) of groundwater is a measure of electron activity that provides an indication of the relative tendency of the natural system to be an electron donor or acceptor, giving a gross indication of the type of RedOx reactions taking place in the aquifer. ORP measurements are read as a voltage, with mV being the scale most applicable to environmental applications. The measurement may be positive or negative and the units of
2 CVO\Z:\REPORTS\184362.PR.01 PDFS TAYLOR 5-24-05\MW-24S SAMPLING PLAN 8-04.DOC FIELD PARAMETER MONITORING SOP measurement may be variable so the field technician should be careful to record the sign (+/-) and the units of measurement in the field log book or groundwater sampling diary. ORP is influenced by the amount of dissolved oxygen in the water, so measurements should be taken from a flow-through cell in order to prevent atmospheric oxygen from mixing with the sample.
Field Measurement of Dissolved Oxygen The dissolved oxygen (DO) of a groundwater sample is measured as a mass per volume, with mg/L most applicable to environmental applications. Dissolved oxygen measurements should be taken with a probe in a flow-through cell in order to prevent atmospheric oxygen from mixing with the sample.
Field Measurement of Turbidity The turbidity of a sample is a qualitative measure of the amount of suspended material present in the groundwater. Most turbidity meters measure the amount of suspended material by sending a beam of light through a sample (contained in a clear glass vial that is placed in the meter) and measuring the refracted light to determine turbidity. Turbidity is measured in Nephelometric Turbidity Units (NTUs). The most common cause for a meter to provide false readings occurs when the glass of the turbidity meter tube becomes dirty. It is important to wipe the outside of the glass vile dry with a clean paper towel before inserting it into the meter. If the inside of the vile becomes dirty use a cotton swab or similar and soap to clean the inside of the meter tube, and then rinse with potable water and finally with deionized water.
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ATTACHMENT E MultiRae / MiniRae Air Monitoring SOP
General Description This SOP provides a broad guideline for the field use of a MultiRae or MiniRae photo ionization detector (PID). The MultiRae is configured to measure volatile organic compounds (VOCs), hydrogen disulfide (H2S), lower explosive limit (LEL), oxygen (O2), and carbon dioxide (CO2). The MiniRae is configured to measure only volatile organic compounds (VOCs). For specific instructions, refer to manufacturer’s operations and maintenance manual. Equipment / Materials
• Operations manual • A MultiRae with fully charged battery pack • A cylinder of calibration gas • A regulator for the calibration gas cylinder • A short length (as short as possible) of tubing to transfer calibration gas from cylinder to MultiRae Procedures / Guidelines Only properly trained personnel shall use this instrument. For specific instructions, see operation manual. The instrument shall be calibrated at the beginning of each field day according to the manufacturer’s instructions. After calibration, a background level will be measured at the site. Background measurement will be collected away from any probable organic vapor sources, such as a vehicle exhaust pipe. Air Monitoring with the MultiRae or MiniRae (MRae) Specific guidelines and requirements for air monitoring with an MRae air monitoring device will be specified in the trip specific field instructions. MRae air monitoring data are to be recorded on a field form (e.g., a boring log) or in the field logbook. The MRae can perform four types of air monitoring. The applicability of the air monitoring technique depends on the task and will be called out in the field instructions.
• Breathing Zone Monitoring: The MultiRae can monitor the air in the breathing zone. Monitoring shall be done periodically to ensure that workers are not exposed to potentially hazardous atmospheres or circumstances. • Borehole Monitoring: The MultiRae is to be used monitor the top of a boring to check for potentially hazardous atmospheres. This technique is applicable during monitor well installation, monitor well sampling, direct push soil sampling, and some hand augering.
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• Sample Headspace Monitoring: Headspace monitoring is performed by placing a soil sample in an enclosed space for a set period and then monitoring the space above the sample. This is described in more detail in the Monitor Well Installation SOP. • Sample Screening: Sample screening is performed by placing the probe tip of the monitoring instrument near the location to be screened (e.g., a soil sample, water sample, unknown surface). The quality of the screening depends on the wind direction and distance of the monitoring instrument tip from the screened material or surface.
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ATTACHMENT F Investigation-Derived Waste Management Plan
This plan describes the investigation-derived waste (IDW) streams likely to be generated by the MW-24S installation and sampling at the Taylor Lumber and Treating (TLT) Superfund Site and explains how they will be managed and disposed. The scope of work for this project includes monitoring well installation, development and sampling. The waste streams associated with this scope of work may include:
• Personal protective equipment (Tyvek coveralls, gloves, etc.) • Disposable sampling items (bailers, tubing, tape, packing materials, etc.) • Drill cuttings and core materials • Purge water from well development and sampling • Rinse water from decontamination of field equipment. All uncontaminated solid waste (PPE or sampling materials) will be collected in a plastic garbage bag and disposed of in an onsite municipal solid waste dumpster. Contaminated items will be placed in a separate container that will be disposed of as hazardous waste with contaminated soil. Drill cuttings and core materials will be containerized and labeled. Final disposal of the drum contents will depend on the groundwater test results, since contaminated groundwater is the only pathway for contamination of this soil. If groundwater sampling results are within acceptable limits, the soil will be discarded onsite. Purge and decontamination rinse water generated from the sampling activities will be collected and containerized. If possible, this water will be disposed into the facility wastewater treatment system. Otherwise the water will be stored in drums, tested for toxicity characteristic and disposed of accordingly. Containers will be labeled using paint and/or engraved into the container(s) with the following information of the lid and side:
• Date • Location • Type of waste (e.g. soil, water, contaminated PPE, etc.). If material is known to be hazardous label as such. • Consecutive number for tracking purposes Note, do not use indelible ink markers (i.e., Sharpies) for labeling drums, as these markings will fade in the sunlight and be obscured by rust.
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ATTACHMENT G Well Logs
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