STAFF REPORT

SELECTED REMEDIAL ACTION

For

LOG SLIP DEBARKER AREA FORMER MODOC LUMBER FALLS,

Prepared By

OREGON DEPARTMENT OF ENVIORNMENTAL QUALITY Eastern Region Cleanup Program Bend Office

May 2007

TABLE OF CONTENTS 1. INTRODUCTION ...... 1 1.1 INTRODUCTION ...... 1 1.2 SCOPE AND ROLE OF THE RECOMMENDED REMEDIAL ACTION ...... 1 2. SITE HISTORY AND DESCRIPTION ...... 2

2.1 SITE LOCATION AND LAND USE ...... 2 2.2 PHYSICAL SETTING ...... 2 2.2.1 Climate ...... 2 2.2.2 Geology and Hydrogeology ...... 2 2.3 HISTORY OF OPERATIONS ...... 3 2.4 BENEFICIAL LAND AND WATER USE DETERMINATION ...... 4 2.4.1 Future Land Use ...... 4 2.4.2 Beneficial Water Use ...... 4 3. SITE INVESTIGATIONS ...... 6

3.1 PREVIOUS MODOC PROPERTY INVESTIGATIONS ...... 6 3.2 LOG /S LIP DEBARKER ADDITIONAL INVESTIGATIONS ...... 6 3.3 NATURE AND EXTENT OF CONTAMINATION ...... 7 3.4 LOCALITY OF FACILITY DETERMINATION ...... 8 4. RISK ASSESSEMENT ...... 9 4.1.1 Conceptual Site Model ...... 9 4.1.2 Human Health Risk Screening ...... 9 4.1.3 Ecological Risk Screening ...... 10 4.2 UNCERTAINTY EVALUATION ...... 10 4.3 HOT SPOT DETERMINATION ...... 11 5. REMEDIAL ACTION OBJECTIVES ...... 12

5.1 REMEDIAL ACTION OPTIONS ...... 12 5.2 SELECTION OF ALTERNATIVES ...... 13 5.2.1 Alternative One - Engineering Controls (EC), Institutional Controls (IC), and Groundwater Monitoring ...... 14 5.2.2 Alternative Two - Groundwater Extraction, and Groundwater Monitoring ...... 14 5.3 EVALUATION OF REMEDIAL ACTION ALTERNATIVES ...... 15 6. SELECTED REMEDIAL ACTION ...... 17

6.1 DESCRIPTION OF THE SELECTED ALTERNATIVE ...... 18 6.1.1 INSTITUTIONAL CONTROLS ...... 18 6.1.2 ENGINEERING CONTROLS ...... 18 6.1.3 GROUNDWATER MONITORING ...... 18 6.1.4 CONTINGENCY PLAN ...... 18 6.2 RESIDUAL RISK ASSESSMENT ...... 18 6.3 PEER REVIEW SUMMARY ...... 19 6.4 PUBLIC NOTICE AND COMMENT ...... 19 6.5 CONCURRENCE ...... 20

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

Appendix A ...... 21 Appendix B ...... 24

Figures

Figure 2-1 ...... 25 Figure 2-2 ...... 26 Figure 3-1 ...... 27

Tables

Table 3-1...... 28 Table 4-1...... 29 Table 5-1...... 30 Table 5-2...... 31

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

1. INTRODUCTION

1.1 INTRODUCTION

This document presents the selected remedial action for soil and groundwater at the Former Modoc Lumber Site – Log Slip Debarker (LSD) area in Klamath Falls, Oregon. The remedial action has been developed in accordance with Oregon Revised Statutes (ORS) 465.200 through 465.455, and Oregon Administrative Rules (OAR) 340-122-010 through 340-122-115.

The remedial action is based on the administrative record for this site. A copy of the Administrative Record Index is attached as Appendix A. This report summarizes the more detailed information contained in the Remedial Investigation (RI) and Feasibility Study (FS) reports completed under Oregon Department of Environmental Quality (DEQ) Voluntary Cleanup Agreement between Pinecone LLC and DEQ, dated April 1, 2000.

1.2 SCOPE AND ROLE OF THE RECOMMENDED REMEDIAL ACTION

The remedial action addresses the presence of Pentachlorophenol (PCP), primarily from wood treating activities in other parts of the site that has been identified as the principal contaminant of concern (COC) in subsurface soils and groundwater at the LSD area. The remedial action consists of the following elements:

• Institutional Controls; • Engineering Controls; • Groundwater Monitoring; and • Contingency Plan.

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

2. SITE HISTORY AND DESCRIPTION

2.1 SITE LOCATION AND LAND USE

The Modoc Lumber (Modoc) site is located along the northeast shore of , in Klamath Falls, Klamath County, Oregon (Figure 2-1). The subject property consists of an irregularly shaped parcel covering approximately 120 acres. The site is generally bounded by Klamath Ave. to the north, 4 th Street to the east, Lake Ewauna to the west and the City’s wastewater treatment plant to the south. The property is located within Township38 S, Range 09 E, Section 32. The LSD area is currently tax lot DA 801.

2.2 PHYSICAL SETTING

2.2.1 Climate

Klamath Falls receives approximately 20 inches of precipitation annually with approximately 30 percent occurring as snowfall. The majority of the precipitation falls between October and May. The temperature varies considerably as the area is a high desert climate. Freezing morning temperatures can be encountered throughout the year and summer temperatures can reach into the mid-90 °F range.

2.2.2 Geology and Hydrogeology

The site is located immediately south of the downtown business area on relatively flat land adjacent to Lake Ewauna, a hydraulically controlled portion of the in the Upper Klamath watershed. The approximate ground elevation of the site is approximately 4,100 feet above mean sea level. Surface water runoff from the subject property flows directly to Lake Ewauna, or is conveyed to the lake via four separate storm drain systems for the area.

The area consists primarily of volcanic terrain characterized by Basin-and-Range type faulting. The rocks consist of consolidated volcanic rock, semi-consolidated volcanic ash and sediments derived largely from volcanic rocks. These rock units range from Tertiary to late Quaternary in age. Typical of the Basin and Range Geologic Province, northwest trending normal faults initiated in the Pliocene are common throughout the region. The Klamath Falls area is part of an anticline that has

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon subsequently been dropped due to normal faulting to form the present graben (Peterson and McIntyre, 1970).

The USDA, NRCS Soil Survey of Klamath County, Oregon, Southern Part (1985) identifies the majority of the site as being Teeters silt loam. This soil type is characterized as being very deep, poorly drained soils that formed in diatomaceous sediment. These strongly alkaline soils usually have a silt loam surface layer and are frequently inundated with water.

Previous field investigations conducted in the shallow subsurface indicate that the subject property is underlain by silts, silty sands, and fine silty gravel (Kennedy/Jenks 1997, EMS 2006). Some areas contain composted wood and bark. These surficial soils are underlain by Pleistocene-age sedimentary rock.

Shallow groundwater has been encountered at depths as shallow as 0.5 foot below ground surface (bgs) in areas near the lake, and at depths of up to 12 feet bgs at the northeast corner of the Modoc property. Groundwater beneath the subject property was initially assumed to flow southwest, toward Lake Ewauna (Kennedy/Jenks, 1997). The installation of monitoring wells in 2003 indicate that shallow groundwater beneath the site migrates generally away from Lake Ewauna except in the northernmost portion of the site (near Klamath Ave. and Fourth St.). This is primarily caused by regulating the level of the Lake Ewauna reservoir, using the Keno Dam, located about five river miles south of the site.

The most prolific water bearing unit in the basin is the Tertiary lower basalt unit, consisting of basalt flows interbedded with tuff and flow breccia (Newcomb and Hart, 1958). These units are overlain by sedimentary deposits of the Yonna Formation which typically have very low yields and form a confining layer for the deeper volcanic rock units. Overlying these deposits is Quaternary age alluvial deposits consisting of alluvium, lake deposits and interbedded layers of basalt, tuff and pumice. Wells completed in this aquifer, known as the sedimentary aquifer unit by Illian (1970), generally have low yields that are suitable only for domestic uses.

2.3 HISTORY OF OPERATIONS

The Modoc Lumber Company manufactured wood products from approximately 1947 to 1994. The Ewauna Box Company operated a mill on the southern portion of the Modoc facility prior to Modoc’s operation. The City of Klamath Falls is the current owner of the property previously used as the Ewauna Box Company. Other prior wood product facilities that operated on portions of the Modoc facility include Ellingson Timber Company and Big Lakes Box Company. When the mill was closed in 1994, operations included saw mills, dry kilns, a re-saw mill, and a wood fuel pellet mill. Support facilities included log decks planers, storage sheds, a machine shop, a truck repair shop, a

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon boiler room, parts storage and offices. A wood waste landfill located south of the waste water treatment plant was also present.

The LSD area was specifically utilized to receive and debark green logs and facilitate transfer of debarked logs to other on-site areas for processing.

Between 1995 and 2000, all of the structures associated with Modoc Lumber’s operation were demolished or removed, inclusive of concrete foundations. The site is in the process of being redeveloped into a mixed use riverfront development, including commercial, light industrial and residential uses.

2.4 Beneficial Land and Water Use Determination

2.4.1 Future Land Use

The former Modoc property, including the LSD Area, was previously zoned industrial. The property is located within the Klamath Falls city limits, and is currently in the process of being redeveloped for mixed use, including commercial, light industrial, and urban residential uses. The City-owned wastewater treatment plant, located directly south of the LSD Area, is zoned for industrial purposes. Property to the east of the Modoc property is zoned for low to medium density commercial uses. It is likely that the LSD Area will be redeveloped for commercial or industrial uses, given its proximity to the City’s wastewater treatment plant and other nearby industrial uses.

2.4.2 Beneficial Water Use

Beneficial uses were evaluated for the shallow water-bearing zone considering current uses and the following factors listed in OAR 340-122-080(3)(f)(F):

• Historical land and water uses • Anticipated future land and water uses • Concerns of community and nearby property owners • Regional and local development patterns • Regional and local population projections • Availability of alternate water sources

There were 33 water well logs on record with the Oregon Water Resources Department (WRD) for the western half of Section 33 and the eastern half of Section 32. The wells range from 150 feet to over 2000 feet in depth. The majority of the wells are used for thermal heating of buildings or re- injection of thermal water. Four wells are used for industrial purposes, three wells are marked for

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon domestic purposes (at 275 feet or greater depth), two wells for irrigation, and one well is a community water supply well drilled to over 800 feet depth. This well is part of the Conger well field, located up-gradient of the site in the northwest quarter of Section 32. There was also one well used for dewatering at the City wastewater treatment plant; the depth of this well is 39 feet. The site and surrounding properties are within the City of Klamath Falls and would be serviced by the City’s municipal water system. Due to the apparent horizontal direction of the nearest well and the vertical distance and lithology to the next (deeper) water-bearing zone, it is unlikely that the impacted shallow aquifer will adversely affect those beneficial uses.

The shallow groundwater generally flows away from Lake Ewauna, as described in Section 2.2.2, and presented in Figure 2-2. Therefore, it does not appear that the shallow groundwater is likely to migrate under the currently regulated conditions towards Lake Ewuana. However, if dewatering of the aquifer occurs related to construction of foundations, groundwater may be discharged to surface water via storm drains or other conveyances. In addition, the shallow depth of the groundwater suggests that shallow groundwater may recharge surface water other than Lake Ewauna, primarily drainages in the area. Therefore, the likely current and future beneficial use of the shallow aquifer is recharge to surface water.

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

3. SITE INVESTIGATIONS

3.1 Previous Modoc Property Investigations

Previous work at the Modoc property for underground storage tanks (USTs) resulted in several no- further action (NFA) determinations by DEQ in 1991 and 2000. Later, while in DEQ’s Voluntary Cleanup Program the Modoc property received final remedial action decisions for multiple sources and operable units in 2001 and again in 2004 (DEQ 2001, 2004). Table 3-1 provides a summary of the multiple areas and operable units of the Modoc facility that have received assessments, investigations, and final decisions.

Several of the investigation activities (Pond Saw, Filing Room, Dry Lumber Building, Dry Kilns, Burner, AST Area, and the Shed) were eliminated from further action because concentrations of potential contaminants of concern were below acceptable levels or were not statistically different from local background samples.

Some of the areas underwent interim removal actions measures (IRAMs) consisting of soil excavation and a combination of groundwater monitoring to reduce contaminant concentrations. Further assessment determined that the constituents of concern are at acceptable levels for the Sawmill Area, Planar Resaw Area, Mill Storm Drain D & E, and the West Shop Area.

An IRAM was also performed at the LSD area, which resulted in approximately 21 cubic yards of contaminated soil and water being removed and disposed of as FO32 listed waste at a hazardous waste landfill.

Following the 2004 Remedial Action decision by DEQ, it was determined that the LSD area and the near shore sediment adjacent to LSD and Truck Shop /Steam Cleaner Areas required additional investigation and assessment to achieve closure.

3.2 Log/Slip Debarker Additional Investigations

As discussed above, the LSD area required additional investigation work and included several rounds of exploratory boring and installation of monitoring wells. The reports providing the details of the previous investigations include:

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

• Phase 4 Soil and Groundwater Investigation Report (SECOR, March 2001); • Phase 5 Soil and Groundwater Investigation Report (GeoEngineers, June 2003); • Phase 6 Remedial Investigation Report (GeoEngineers, October 2004); • Phase 7 Site Closure Activities Report (EMS, March 2005); • Phase 8 Site Closure Activities Report (EMS, October 2005); and • Phase 9 Site Closure Activities Report (EMS, April 2006).

The LSD area consisted of a sawmill, two debarkers, a log slip and a sorter. The additional sampling detected several poly-aromatic hydrocarbons (PAHs) and PCP. PCP was detected at 31.5 to 70.6 micrograms per kilogram (ug/kg) in soil. Only one PAH, benzo(a)pyrene at 83.5 ug/kg exceeded the USEPA Region IX Preliminary Remediation Goals (PRGs). Groundwater samples detected several PAHs with 3 compounds (benzo(a)pyrene, benzo(b)fluoranthene, and ideno(1,2,3- cd)pyrene) exceeding the PRGs, and PCP (0.852 to 1,590 ug/l) exceeding the PRGs.

Due to the proximity of the LSD Area to Lake Ewauna, there was concern that the lake sediments may have been impacted by site conditions. Sediment sampling was conducted in 2003, 2005, and 2006 to assess the presence of contaminants in near-shore and offshore sediments. No PCP was detected above a reporting limit of 0.1 mg/kg.

The sediment samples did contain several detections of PAHs (both carcinogenic and non- carcinogenic) and metals at levels that exceed the DEQ Screening Level Values (SLVs) for freshwater sediment. Lead was the only metal that exceeded the sediment SLV adjacent to the adjacent Truck Shop/Steam Clean Area. Based on the exceedances of SLVs, DEQ requested subsequent bioassay testing of sediments. The bioassay testing performed indicated none or limited toxicity of sediments.

Further, the investigation of nearby City storm outfalls have indicated that the detections of lead and other metals may be related to storm water collection and runoff from another area of the City. And DEQ believes that the presence of PAHs in Lake Ewauna may need additional investigation. Regardless, additional work regarding the Lake Ewauna sediments is recommended in conjunction with other regional study efforts.

3.3 Nature and Extent of Contamination

Historical use of the LSD area of the site was to debark, cut and sort logs. There is no documentation of PCP use associated with the former buildings or operations in the LSD Area. Extensive soil and shallow groundwater sampling has been conducted in the LSD Area to determine the nature and extent of the PCP (SECOR, 2001, GeoEngineers, 2003, and 2004, EMS, 2005a, 2005b, and 2006a). Elevated concentrations of PCP exist in groundwater in a well defined portion

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon of the LSD Area, centered around LSDMW-1. No soil containing PCP has been identified to date. The results of these investigations indicate that the majority of the PCP impacts are detected in the shallow groundwater samples rather than soil samples. Given the shallow nature of the groundwater, it may be difficult to distinguish the two media apart. The primary contaminant of concern (COC) for the LSD area is PCP, with concentrations ranging up to 45 mg/L in the shallow groundwater.

PCP use reportedly occurred in an adjacent area called the PCP Dip Trench (PDT) Area, about 500 feet north of the LSD Area. The PDT Area was investigated by SECOR (2001) and found to have detectable PCP in two out of sixteen shallow soil samples, and one out of six groundwater samples.

Dioxin/furans can be assumed to be present since they are commonly considered an impurity in the manufacture of PCP. Based on sample results in the PCP Dip Trench (PDT) Area, soil samples containing PCP and heavy oil range hydrocarbons also contained 2,3,7,8-tetrachlorodibenzo-p- dioxin (2,3,7,8-TCDD) at a toxicity equivalency factor (TEF) of 11.7 nanograms (ng)/kg. The DEQ Risk Based Concentrations (RBCs) for 2,3,7,8-TCDD in soil range from 10 ng/kg for urban residential exposure, 17 ng/kg for occupational exposure, 130 ng/kg for construction exposure, and 3,700 ng/kg for an excavation worker exposure (DEQ 2007b). The maximum detected PCP soil concentration in the PDT Area was 0.704 mg/kg, but no PCP has been detected in soil sampling at the LSD. Based on the results in the PDT Area, it is likely that the LSD Area may also contain dioxins/furans, but would likely be within an acceptable risk range based on DEQ’s RBCs and specific risk scenarios.

3.4 Locality of Facility Determination

Extensive soil and shallow groundwater sampling has been conducted in the LSD Area to determine the nature and extent of the PCP (SECOR, 2001, GeoEngineers, 2003, and 2004, EMS, 2005a, 2005b, and 2006a). Elevated concentrations of PCP exist in a well defined and limited in extent portion of the LSD Area, centered near well LSDMW-1 (Figure 3-1).

No soil containing PCP has been identified to date. However, it may be very difficult to distinguish whether the shallow soils, the shallow groundwater or both are impacted. Nonetheless, the groundwater sampling data identifies a limited, well defined area of impacted shallow soil/groundwater that is being considered the Locality of the Facility (LOF).

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

4. RISK ASSESSEMENT

4.1.1 Conceptual Site Model

The sources, effected media, pathways, and receptors were chosen based on current and likely future land use scenarios for the areas within the LOF. The sources include spills, leaks overfills. The secondary sources include surface and subsurface soils. The exposure media include soil gas, surface and subsurface soils, particulates and shallow groundwater. The exposure routes include inhalation of particulates, ingestion, dermal contact, inhalation of volatile compounds and direct contact with dissolved phase or separate phase product.

4.1.2 Human Health Risk Screening

The contaminant concentrations for each environmental medium were compared with conservative risk-based screening level values to determine which media and contaminants posed potential risk to human health. If detected concentrations of chemicals in a particular medium did not exceed the screening levels, then that medium was eliminated as a medium of potential concern and was not evaluated further. Chemicals and pathways that exceeded the screening levels were considered to pose an unacceptable risk and required further action.

The risk screening tool used to evaluate concentrations at the site was DEQ’s RBCs for Individual Chemicals table (revision March 20, 2007). Urban residential, occupational, construction worker, and excavation worker scenarios were applied to the site.

For soils, the soil ingestion, dermal contact, and inhalation exposure pathway was found likely to be complete for pentachlorophenol and dioxins/furans. The generic RBCs for these constituents, exposure pathway and receptor scenarios are presented in Table 4-1. For the groundwater pathway, either an excavation or construction worker may be exposed to the shallow groundwater. The generic RBCs for the same constituents, exposure pathway and receptor scenarios are also presented in Table 4-1.

Using these generic RBCs, the maximum detection of 45 mg/l in shallow groundwater for PCP, and given the likely future uses of the land and shallow groundwater, it appears that the only exposure

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon pathway receptor scenario that is being exceeded in the LOF is the excavation/construction worker exposed to the shallow groundwater.

4.1.3 Ecological Risk Screening

An ecological risk assessment has not been completed for the site, although soil and sediment samples have been screened against Oregon DEQ’s SLVs for Ecological Exposure to freshwater sediment and terrestrial mammals to determine if there is a likely risk.

Sediment sampling was conducted adjacent to the LSD Area to assess the presence of PCP in shoreline sediments. No PCP was detected above a reporting limit of 0.1 mg/kg. The near shore sediments contained several PAHs (both carcinogenic and non-carcinogenic) at levels that exceed the DEQ SLVs for freshwater sediment. Lead was the only metal that exceeded the sediment SLV adjacent to the adjacent Truck Shop/Steam Clean Area. Subsequent bioassay testing have indicated no toxicity of sediments.

Additionally, most PAHs with the exception of pyrene, are not considered biaoccumulative (DEQ 2007). Therefore, given the absence of demonstrated toxicity, the limited spatial extent of impacted sediment, the absence of bioaccumulation potential for most of the COCs, the available evidence does not suggest a potential for unacceptable ecological risks. However, DEQ believes that the presence of PAHs in Lake Ewauna may need additional investigation. Regardless, additional work regarding the Lake Ewauna sediments is recommended in conjunction with other regional study efforts.

PAHs and metals are expected to persist in sediments and remain adsorbed to fine grained particulates. Degradation processes are not expected to reduce concentrations in sediments to any appreciable degree in a reasonable timeframe. While, metals and PAHs have not been identified as COCs for the site they remain a potential concern for the Lake Ewauna sediments.

Based on the relatively small size of the LOF, DEQ believes that any significant use of this site by terrestrial mammals is unlikely, especially given future development plans, which will also result in diminished available viable habitat. Notwithstanding, the likelihood of site access, it should also be noted that OAR 340-112-0115 and DEQ risk assessment policy for non-threatened and endangered species is to protect the species population, not every individual organism.

4.2 Uncertainty Evaluation

This section discusses the uncertainty in the risk estimates for both the groundwater and soil exposures and of sediment in Lake Ewauna.

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

Given future development plans for the site, including proposed extensive paving, building construction, importing of fill and landscaping, the likelihood of urban residential or occupational exposure to soil within the LOF is low. Timely development of the site will reduce many potential exposure pathways and access restrictions will prevent exposure until that timeframe, while the soil management and contingency plans proposed for the site will address management and future uncertainties for the construction and excavation worker scenarios.

There has been no identified ecological risks at the LSD Area; although the potential for a groundwater flow reversal, while slim, may eventually discharge contaminated groundwater to surface water and sediments in Lake Ewauna. Additional data and investigation may be warranted in the future to further evaluate possible sediment issues in Lake Ewauna, especially as related to anthropogenic sources.

4.3 HOT SPOT DETERMINATION

As specified in OAR 340-122-080(7), an evaluation was conducted to identify hot spots of contamination in media other than water. OAR 340-122-115(31)(b) defines as hot spots media other than water where hazardous substances are present in concentrations greater than:

• 100 times the acceptable risk level for human exposure to each individual carcinogen; • 10 times the acceptable risk level for human exposure to each individual non-carcinogen; or • 10 times the acceptable risk level for exposure of individual ecological receptors or population of ecological receptors to each individual hazardous substance.

A hot spot may also be identified where hazardous substances are reasonably likely to migrate to such an extent that they have a significant adverse effect on beneficial uses of groundwater or surface water. Since no soil hot spot acceptable risk guidelines are exceeded based on the soil RBCs, available data, and considering the applicable exposure pathways, a hot spot of contamination in soil is not likely to be present at the site.

A groundwater hot spot is defined by concentrations in groundwater that have a significant adverse effect on a beneficial use of the shallow groundwater. Since the beneficial use of the shallow groundwater is possible recharge to nearby surface waters and no surface water or sediment samples have contained PCP or exceeded SLVs, there does not appear to be a groundwater hot spot present at the site.

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

5. REMEDIAL ACTION OBJECTIVES

Acceptable risk levels, as defined in OAR 340-122-115(1) through (6), and remedial action objectives were developed based on the identified beneficial uses, exposure pathways and the risk assessment. Site-specific remedial action objectives (RAOs) were developed for soil and groundwater for the purpose of achieving protection of human health, ecological receptors, and beneficial uses, as required by OAR 340-122-040 (PBS 2007). The RAOs for the site are as follows:

• Prevent exposure to shallow groundwater (and soil in contact with the groundwater) containing PCP and dioxins/furans that exceed the generic RBCs for the exposure of groundwater to excavation and construction workers; and • Verify that residual concentrations of PCP in groundwater are stable and decreasing over time.

5.1 REMEDIAL ACTION OPTIONS

To demonstrate that the RAOs are met to the maximum extent practicable, each remedial alternative was evaluated to assess its protectiveness based on the standards in OAR 340-122-040. These standards are:

• Ability of remedial action to protect present and future public health, safety, and welfare;

• Ability of remedial action to achieve acceptable risk levels specified in OAR 340-122-115;

• Ability of the remedial action to prevent or minimize future releases and migration of hazardous substances in the environment;

• Requirements for long term monitoring, operation, maintenance and review; and

• Feasibility of the remedial actions is evaluated by balancing remedy selection factors contained in OAR 340-122-090(3) and (4). These balancing factors are:

1. Effectiveness and timeframe of remedial action to achieve protection through eliminating or managing risk.

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

2. Long term reliability - reliability of remedial action to eliminate or manage risk and associated uncertainties (for this focused feasibility study, long-term reliability is based on compatibility with likely final remedies).

3. Implementability - ease or difficulty of implementing remedial action, considering technical, mechanical, and regulatory requirements.

4. Implementation risk - potential impacts to workers, the community, and the environment during implementation.

5. Reasonableness of cost - includes capital costs, operations and maintenance, periodic review, and net present value of remedial action.

5.2 SELECTION OF ALTERNATIVES

Several remedial action technologies were considered for the site as a means of achieving the site RAOs including:

• Engineering controls – i.e. capping to limit access to shallow groundwater;

• Institutional controls – deed restriction to limit uses of shallow soil and shallow groundwater within the LOF;

• Shallow groundwater monitoring;

• Treatment of groundwater using pump and treat techniques; and

• Treatment of soils using excavation and offsite disposal.

In-situ biological and chemical treatments were considered, however the ability of oxidation compounds or other enhancement of biological degradation compounds to reduce the concentration of PCP has had limited success at other sites with similar contaminants. In addition, these types of treatment will not likely reduce the toxicity of dioxins/furans commonly associated with PCP. The technologies that appeared to be viable alternatives were assembled into likely remedial action alternatives and evaluated based on the five balancing criteria identified in section 5.0 and further outlined in the feasibility study. Two alternatives were determined to be feasible for the site:

• Alternative 1 - Engineering Controls (EC), Institutional Controls (IC), and Groundwater Monitoring; and

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

• Alternative 2 - Groundwater Extraction, and Groundwater Monitoring.

Each of the alternatives includes shallow groundwater monitoring to verify that residual concentrations of PCP in the limited area of groundwater impact are stable and/or decreasing over time. A “No Action” alternative was not included because it does not meet the RAOs for the site.

5.2.1 Alternative One - Engineering Controls (EC), Institutional Controls (IC), and Groundwater Monitoring

This alternative would employ an engineered cap (engineering controls; EC) and place restrictions on use of the shallow subsurface soils and shallow groundwater (institutional controls; IC) in locations that exceed the RAOs to manage the risk at the site. The IC would include use restrictions and a soil management plan to be implemented when disturbing the capped area or the shallow soils. These restrictions would be recorded with the deed of the legal property that contains the impacted soil, through an Easement and Equitable Servitude agreed to by DEQ and the current property owner. The site would remain on the DEQ’s Confirmed Release List and Inventory. Groundwater monitoring would be required to document that residual groundwater concentrations are stable and/or decreasing over time. This remedy relies on the stability of the residual contamination that has likely resided within this area for more than the 15-plus years since this part of the site was actively used. It is likely that natural degradation of the PCP is occurring, but its rate and effectiveness are difficult to estimate.

5.2.2 Alternative Two - Groundwater Extraction, and Groundwater Monitoring

Alternative Two includes the extraction and treatment of contaminated groundwater using granular activated carbon. The goal of this treatment process is to reduce the RBC, thereby avoiding the use of any engineering or institutional controls. A trench or large diameter holes will be used to place pumps and extract groundwater. The water would be treated with granular activated carbon and re- injected into a trench on site downgradient of the impacted area. Soil excavated from the trenches or boreholes would also serve as source reduction, since it is likely that the soil in contact with the shallow groundwater contains residual PCP. This excavated soil would have to be managed as a hazardous waste. Groundwater monitoring, to document whether residual groundwater concentrations are stable or decreasing over time, would also be implemented as part of this remedial action alternative.

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Log Slip Debarker Area Staff Report Former Modoc Lumber Site Klamath Falls, Oregon

5.3 EVALUATION OF REMEDIAL ACTION ALTERNATIVES

The two remedial action alternatives described above, were evaluated for their feasibility based on the five balancing factors identified in OAR-340-122-090 (3) and (4): effectiveness, long-term reliability, implementability, implementation risk and reasonableness of cost (Table 5-1). The alternatives were also evaluated to insure that each one was considered protective of current and future human health and the environment as defined in OAR 340-122-040. In addition, OAR 340- 122-090 (4)(c) requires the feasibility study to evaluate the extent to which a remedial actions treats a hot spot of contamination. The extent to which treatment is feasible must include the application of a higher cost threshold for evaluating the cost of treating hot spots of contamination. Since a hot spot of contamination was not identified at the site, the evaluation does not include the extent to which a remedial action alternative treats a hot spot.

• The soil excavation and offsite disposal portion of Alternative #2 is a very effective technique to eliminate the risk in a short time frame using physical removal and transport to a permitted facility. Groundwater extraction is less effective, because the technology relies on extracting contaminated water that may be difficult to completely remove. It is likely that groundwater extraction may not reduce the contamination to acceptable levels before reaching its technical practicality limit. It is very possible that Alternative #2 may also require use restrictions being contemplated as part of Alternative #1 to restore protective conditions. Use of Engineering and Institutional Controls (EC/IC, Alternative #1) to manage risk is an effective way to prevent having a completed exposure pathway to the contamination. Overall, Alternative #1 is considered more effective than Alternative #2.

• The limited soil excavation and groundwater extraction alternative were considered to have the highest long-term reliability because of the permanence of removing contaminant mass from the site. Alternative #1 is slightly less reliable than Alternative #2 because the contaminated material is being managed onsite and relies on risk management tools, which must be maintained over the long term. Alternative #1 is therefore slightly less reliable than Alternative #2 because it may not be able to eliminate or reduce the contaminants to the degree that limited excavation can permanently remove the contaminants.

• EC/IC and excavation/offsite disposal alternatives rank relatively high for implementability. EC (i.e. capping) is a proven technique to eliminate an exposure pathway. ICs have been recorded at this site and others in Klamath County with residual contamination. Excavation/off-site disposal and groundwater extraction is a readily available and proven technology. Both alternatives were given the same score for this category, and are considered approximately equal for the implementability criteria.

• EC and IC ranks the highest for the implementation risk criteria because there is minimal to no exposure to the contaminated media. Extraction and excavation/offsite disposal has a

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higher short-term risk, and therefore ranks lower for this criteria because of the potential exposures to remediation workers. Given the relatively sparse population and large size of properties in the immediate vicinity of the site, there should not be any increased risk to neighbors by implementing either of these remedies. Alternative #1 was given a higher score for this category since this alternative is less intrusive.

• Both remedies include installation of two monitoring wells and long term groundwater monitoring. Alternative #1 is the least costly alternative ($63,405) because it relies on risk management tools (i.e. capping of shallow soils and recording deed restrictions, groundwater monitoring) to achieve protectiveness. Alternative #2 is estimated to be significantly more costly ($275,259) and it may eventually require engineering and/or institutional controls to be protective. Alternative #1 was given a higher score based on the alternative being more cost effective. A summary of the cost evaluation is shown in Table 5-2.

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6. SELECTED REMEDIAL ACTION

Both alternatives can be considered protective as designed and implemented, but achieve protection through different mechanisms. Alternative #1 uses risk management tools to monitor and control exposure to the residual contamination. Alternative #2 actively removes contaminant mass so that risk management tools would not be needed if the RAOs were achieved. In comparing the balancing criteria for each alternative, Alternative #1 is considerably less expensive, slightly more effective and has a lower implementation risk than Alternative #2. Alternative #1 has slightly less reliability because instead of removing the impacted media it relies on risk management tools to prevent exposures to the affected area. Both alternatives ranked equally for implementability. Overall, Alternative #1 ranks higher than Alternative #2 using the balancing criteria. Therefore, Alternative #1 is selected as the remedial action for this site.

This remedial action alternative is recommended as a protective and reasonable method to achieve the RAOs, and can be conducted in a manner that is protective of human health and the environment. Since the area of impact is well defined and of limited extent, and the beneficial use of the shallow groundwater is limited by a relatively small LOF, the use of engineering and institutional controls with groundwater monitoring is expected to achieve a high degree of long-term permanence. Additionally, the future site redevelopment is at a stage where the recommended remedial action can be incorporated into its design to achieve the maximum effectiveness and protection. The property owner plans to create a separate tax lot for the LOF when this portion of the former Modoc Lumber facility is platted for redevelopment.

Because of uncertainties associated with the successful implementation of this recommended remedial alternative, a periodic monitoring, review and contingency plan will be developed that will evaluate the performance of the remedy, and allow for changes that may affect the ability of the remedy to meet the RAOs. The objective of the periodic monitoring, review and contingency plan will be to maintain the overall protectiveness of the selected remedy.

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6.1 DESCRIPTION OF THE SELECTED ALTERNATIVE

6.1.1 INSTITUTIONAL CONTROLS

An Easement and Equitable Servitude (E&ES) will be placed on the parcels listed above to limit future land use to industrial/commercial uses, and prohibit water well installations without prior DEQ approval. In addition, the E&ES will require an approved soil management plan be in place prior to conducting any excavation on the parcel.

6.1.2 ENGINEERING CONTROLS

Areas that require an impermeable cap to prevent direct contact with impacted soils and prevent on site soils from migrating off the parcel. An interim gravel cap will serve to isolate the shallow impacted soils. As redevelopment of the parcel occurs areas that are not covered with concrete or asphalt will need to be covered with a geotech fabric and a sufficient amount of soil/fill cover.

6.1.3 GROUNDWATER MONITORING

Groundwater monitoring of the shallow groundwater will be conducted using existing wells to ensure residual soil contamination is not transferring to the shallow groundwater and migrating beyond the known area of impact. A groundwater monitoring plan will be developed to determine if further removal is needed or if the contingency plan needs to be implemented.

6.1.4 CONTINGENCY PLAN

A Contingency Plan will be developed to permit various improvements to the remedial alternative in order to maintain protective conditions at the site and achieve the RAOs developed for the site.

6.2 RESIDUAL RISK ASSESSMENT

OAR 340-122-084(4)(c) requires a residual risk evaluation of the recommended alternative that demonstrates that the standards specified in OAR 340-122-040 will be met, namely:

• Assure protection of present and future public health, safety, and welfare, and the environment

• Achieve acceptable risk levels

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• For designated hot spots of contamination, evaluate whether treatment is reasonably likely to restore or protect a beneficial use within a reasonable time

• Prevent or minimize future releases and migration of hazardous substances in the environment

As a result of future site work, the following potential exposure risks remain:

• Possible ingestion, dermal contact, or inhalation of remaining soil and shallow groundwater due to elevated concentrations of PCP for possible occupational receptors and construction workers.

The Contingency Plan will be used to address potential future issues identified at the site, while the Soil and Sediment Management Plan will be used to manage and dispose of any contaminated material.

6.3 PEER REVIEW SUMMARY

Technical documents produced during the investigation of the LSD area site have been reviewed by a technical team at DEQ. The team consists of the project manager/hydrogeologist, and a toxicologist. The team unanimously supports the selected remedial action.

6.4 PUBLIC NOTICE AND COMMENT

The public notice and comment (PNC) period for the recommended remedial action at the Former Modoc Lumber site occurred during the month of April. The PNC was placed in the Oregon Secretary of State’s Bulletin and in the Klamath Falls Herald and News. There was one written comment received by DEQ from the Oregon Department of State Lands (DSL) (Appendix B). The comment was primarily focused on remedial investigations and actions related to the continued interest in Lake Ewauna sediments. As has been previously discussed, the investigation of Lake Ewauna sediments is an ongoing issue and does not necessarily reflect DEQ’s remedial action decision for the LSD area. As such, the Staff Report for the LSD area has been approved by DEQ.

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6.5 CONCURRENCE

State of Oregon, Department of Environmental Quality

By: ______Date: ______Joni Hammond Administrator, Eastern Region

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Appendix A

ADMINISTRATIVE RECORD INDEX Log Slip Debarker Area Former Modoc Lumber Facility Klamath Falls, Oregon

The Administrative Record consists of the documents on which the recommended remedial action for the site is based. The primary documents used in evaluating remedial action alternatives for the LSD Area, Former Modoc Lumber site are listed below. Additional background and supporting information can be found in the Modoc project file located at DEQ Eastern Region Office, 300 SE Reed Market Road, Bend, Oregon.

SITE-SPECIFIC DOCUMENTS

Century West Engineering, Geoprobe Investigation, Modoc Lumber Company, Klamath Falls, OR, July, 1998.

EMS, 2005a, Phase 7 Site Closure Activities Report, Former Modoc Lumber Facility, March 2005.

EMS, 2005b, Phase 8 Site Closure Activities Report, Former Modoc Lumber Facility, October 2005.

EMS, 2006a, Phase 9 Site Closure Activities Report, Former Modoc Lumber Facility, April 2006.

EMS, 2006b, Focused Feasibility Study, Former Log Slip/Debarker Area, Former Modoc Lumber Facility, Klamath Falls, OR, October 2006.

GeoEngineers, Phase V Soil and Groundwater Investigation Report, Former Modoc Lumber Facility, Klamath Falls, OR, July, 2003.

GeoEngineers, Phase VI Remedial Investigation Report, Former Modoc Lumber Facility, Klamath Falls, OR, October, 2003.

GeoEngineers, Third Quarter Groundwater Monitoring and MSD-C Excavation Report, Former Modoc Lumber Facility, Klamath Falls, OR, January, 2004.

GeoEngineers, Fourth Quarter Groundwater Monitoring and Other Activities Report, Former Modoc Lumber Facility, Klamath Falls, OR, April, 2004.

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Illian, J.R., 1970, Interim Report on the Ground Water in the , Oregon: Salem, Oregon State Engineer.

Kennedy Jenks Consultants, Level I Environmental Site Assessment Report, Modoc Lumber Company Property, Klamath Falls, OR, Prepared for Rural Development Initiatives, Inc., February, 1997.

Kennedy Jenks Consultants, Level II Investigation Report, Modoc Lumber Company Property, Klamath Falls, OR, Prepared for Rural Development Initiatives, Inc., October, 1997.

Newcomb R.C., and Hart, D.H., 1958, Preliminary Report on the Ground Water Resources of the Klamath River Basin, Oregon: U.S. Geological Survey Open File Report(unnumbered).

Oregon DEQ Voluntary Agreement for Remedial Investigation / Feasibility Study, April 1, 2000.

Oregon DEQ File Review, Former Modoc Lumber Site, Klamath Falls, OR, May 31, 2000.

Oregon DEQ, Staff Report for Remedial Action, Timber Mill Shores (Amerititle Parcel), August 2, 2001.

Oregon DEQ, Staff Report for Remedial Action, Tax lots AC 701, CA 1401, DA 800 and 801, and 32DB 100, and Section 33 tax lot CC 500, August 2004

Oregon DEQ, 2006, Focused Feasibility Study, Former Log Slip / Debarker Area, Former Modoc Lumber Facility, Letter to Pinecone, LLC, October 23, 2006.

Oregon DEQ, 2007. Guidelines for assessing bioaccumulative chemicals of concern in sediment. Oregon Department of Environmental Quality, Environmental Cleanup Program. January 31, 2007.

Oregon DEQ, 2007b. Risk-Based Concentrations for Individual Chemicals. Oregon Department of Environmental Quality, Environmental Cleanup Program. Revision March 20, 2007.

PBS, 2006, Response to Comments on Focused Feasibility Study, Former Log Slip/Debarker Area, Former Modoc Lumber Facility, Letter to DEQ, November 22, 2006.

PBS, 2007, Revised Focused Feasibility Study, Former Log Slip/Debarker Area, Former Modoc Lumber Facility, January 2007.

Peterson, N.V., and McIntyre, J.R. 1970, The Reconnaissance Geology and Mineral Resources of Eastern Klamath County and Western Lake County, Oregon: Oregon DOGAMI Bulletin 66.

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SECOR, Phase III Soil and Groundwater Investigation, Former Modoc Lumber Facility, Klamath Falls, OR, January, 2001.

SECOR, Phase IV Soil and Groundwater Investigation, Former Modoc Lumber Facility, Klamath Falls, OR, February, 2001.

USDA, NRCS, 1985, Joint Publication, Soil Survey of Klamath County, Oregon, Southern Part.

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Appendix B

PUBLIC COMMENT and DEQ RESPONSE

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Figure 2-1

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Figure 3-2

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Figure 3-1

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Table 3-1

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Table 4-1

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Table 5-1

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Table 5-2

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