ECSI Number: Responsible Party: Klamath County. QTime Number: Entry Date: 9/22/04 (VCP)

Transcription

1 ECSI Number: 1213 Responsible Party: Klamath County QTime Number: Entry Date: 9/22/04 (VCP) Proposed Remedial Action Staff Report - Addendum Chiloquin Forest Products Chiloquin, Klamath County, Oregon Project Manager: Katie Robertson RP Contacts: Lani Hickey Klamath County 305 Main Street Klamath Falls, OR This document is an addendum to the Proposed Remedial Action Staff Report dated November 12, A copy of the November 12, 2004 staff report is included as Attachment A and includes information on the site background, previous site investigations, and the proposed remedy. The purpose of this addendum is to address potential human health and the environment associated with dioxin and furan contamination in soil on the former Chiloquin Forest Products site in Chiloquin, Oregon. This proposed remedial action is for on-site soil only. This document presents the basis for the Oregon Department of Environmental Quality s (DEQ s) recommended remedial action for dioxin impacted soil at the former Chiloquin Forest Products site located at the west end of Blocklinger Street in Chiloquin, Oregon. This recommended remedy was selected in accordance with Oregon Revised Statutes (ORS) through and OAR Chapter 340, Division 122, Sections 010 to Remedial Action Objectives and Status In April 2005, remedial activities were performed at the site. Asbestos containing materials were removed from the boiler house, and the boiler house was demolished. Metal was recycled, and approximately 360 tons of bricks were transported to the Klamath County Landfill for re-use as road base. Approximately 360 tons of petroleum contaminated soil (PCS) and 530 tons of pentachlorophenol (penta) contaminated soil were transported to off-site landfills. As part of penta excavation activities, a relatively small amount dioxin contaminated soil was also removed. Excavations were graded or backfilled with soil from the site. Remedial action objectives (RAOs) were achieved by the removal of the boiler house and the excavation and off-site landfill disposal of PCS. For the penta removal action, the RAO was essentially met. Surface soil met the cleanup goal for direct contact by site users, including a residential scenario. Deeper soils in the southwest portion of the penta excavation exceeded the cleanup goal; however, exposure could only occur by trenching through this area. A follow-up groundwater investigation indicated that penta concentrations in groundwater do not pose a likely threat to human health or the environment.

2 Chiloquin Forest Products (former) Page 2 Confirmation samples obtained from the small dioxin excavation area indicated that remaining concentrations were still above the target cleanup goal. Removal assessment activities were performed to delineate the extent of dioxin in soil in this area. Concentrations were found to exceed the cleanup goal; however, concentrations in background samples obtained from other areas of the site were also above the cleanup goal. Because the target cleanup goal for dioxin was not achieved, the overall RAO for mitigating unacceptable risks at this site has not yet been achieved. Dioxin Delineation Two confirmation soil samples were collected from the sidewalls of the dioxin excavation and analyzed for dioxins. Results detected 4.8 nanograms per kilograms (ng/kg) and 110 ng/kg dioxins, expressed as a 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity equivalent concentration (TEQ). These results exceeded the 3.9 ng/kg cleanup goal. In June 2005, six hand-augered soil borings were completed to depths between 0.5 feet and 4.0 feet below ground surface (bgs) to delineate the extent of contamination around the dioxin excavation area. Analyses of soil samples collected from these borings detected dioxins ranging in concentration from 15 ng/kg to 194 ng/kg TCDD (TEQ) exceeding the residential EPA Region 9 Preliminary Remedial Goal (PRG) (3.9 ng/kg), with most exceeding the industrial PRG (16 ng/kg). In October 2005, surface soil sampling was conducted to further delineate the dioxin contamination near the dioxin and penta excavation areas. The surface soil samples were obtained on a 40-foot square grid pattern. Additionally, four background samples (BGND-1 through BGND-4) were collected from the east portion of the property. Dioxin was detected ranging from 1.1 ng/kg to 2,688 mg/kg, although dioxin in most samples was between 10 ng/kg and 400 ng/kg. Relatively higher concentrations are present east and southeast of the penta excavation. Two significantly high dioxin concentrations were present at A-5 (2,629 ng/kg) and H-4 (1,207 ng/kg). Assumed background samples obtained from other locations at the site had concentrations ranging from 32 ng/kg to 108 ng/kg. All these results exceed the target residential cleanup goal of 3.9 ng/kg. In May 2006, soil sampling activities were conducted to assess the source and extent of dioxin contamination on and off the site. Soil samples were collected from unassessed areas of the site, adjacent properties (including the school and residential properties), other urban areas of Chiloquin, and surrounding vicinity. Sample locations were located on public lands and were based on wind direction (north or west from March through October and from the southsoutheast from November through February. A total of 17 soil samples and one duplicate were analyzed for dioxins. Since dioxins originated from many different sources, this assessment also evaluated the source profiles for dioxin. Based on data collected to date, dioxin concentrations are highest in surface soil on the project site in the area of the former penta excavation. The dioxin profile in this area is consistent with penta. Elevated dioxin concentrations were also detected on and near the site, with congener profiles suggesting sources other than penta, such as wood burning, herbicide application, and diesel emissions. An initial screening of dioxin concentrations against conservative screening levels indicates exceedances are present, primarily on and near the site. On-site concentrations

3 Chiloquin Forest Products (former) Page 3 will be addressed as part of the overall remedial approach for dioxin contamination at the former mill property. Additional risk based evaluation of off-site results is necessary and is being performed independent of this proposed remedial action. Summary of Risk Currently, the site has unrestricted access. Reasonably likely future site uses include housing, recreation, and commercial development. The most likely potential exposure pathways would be direct contact with contaminated soils. Penta and petroleum hydrocarbons were identified as the primary Contaminates of Potential Concern (COPCs) in soil but have been addressed by the April 2005 remedial actions. Dioxins and furans have emerged as the primary COPCs remaining on the site. Remedial action objectives (RAOs) were defined to address the unacceptable risks posed by dioxins and furans in soils on the site. Unacceptable risks to human receptors were associated with direct contact with dioxin- and furan-contaminated soil by current trespassers and future residents, future occupational workers, future construction workers, future utility workers, and/or future recreational users. Cleanup Goals The cleanup goal for dioxin- and furan-contaminated soil is 3.9 ng/kg, expressed as a 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) toxicity equivalent (TEQ) concentration. This cleanup goal is the PRG for residential soil and represents a 1 x 10-6 excess cancer risk level for human exposure to individual carcinogens (dioxin congeners). A cleanup goal of 39 ng/kg as 2,3,7,8- TCDD TEQ represents a 1 x 10-5 excess cancer risk level for human residential exposure to multiple congeners. For future commercial workers at the site, the cleanup goal is 16 ng/kg. For future construction workers the cleanup goal is 130 ng/kg. These cleanup goals are based on a 1 x 10-6 excess cancer risk level for human exposure to individual congeners. Hot Spot Concentration Hot spot concentration for dioxins and furans in soil was defined as 390 ng/kg as 2,3,7,8-TCDD TEQ. This concentration represents a level that is 100 times the acceptable risk level for human exposure to each individual carcinogen, based on residential exposures. Feasibility Study/Proposed Remedy An addendum to the January 3, 2005 Analysis of Brownfield Cleanup Alternatives (ABCA) which is equivalent to a Feasibility Study was completed in September Remedial action objectives (RAO) to address the unacceptable risks posed by dioxins and furans in soils on the site were identified in the ABCA addendum and include: 1) prevent direct human contact to dioxin- and furan-contaminated soils that pose an unacceptable risk; 2) prevent migration of dioxin- and furan-contaminated soils from the site associated with wind and surface water erosion; 3) remediate hot spots of dioxin- and furan-contaminated soils to the extent feasible; 4) implementing only those alternatives that allow for redevelopment of the property to occur. In order to evaluate potential remedial actions that will address the RAOs, the following alternatives were screened:

4 Chiloquin Forest Products (former) Page 4 Alternative 1: No Action; Alternative 2: Protective Cover and Deed Restriction; Alternative 3: Hot Spot Soil Removal and Off-Site Disposal/Protective Cover; Alternative 4: Construction Worker Soil Removal and Off-Site Disposal/Protective Cover; and Alternative 5: Residential Soil Removal and Off-Site Disposal. The remedial alternatives were evaluated based on protectiveness, effectiveness, long term reliability, implementability, implementation risk, reasonableness of cost, and their ability to treat hot spots. A summary of the evaluation factors is presented on Table 1. Based on the above comparative analysis of alternatives, the cleanup alternative recommended for dioxin- and furancontaminated soils at the site is Alternative 2, the protective cover and deed restriction. The proposed remedy meets the requirements of OAR Chapter 340, Division 122, Sections 0205 to 0360; and Chapter 340, Division 122, Sections 010 to The proposed remedy was also selected in accordance with ORS through A final decision, in the form of an addendum to the January 5, 2005 Record of Decision, will be made after consideration of public comments. The site will remain listed on the Confirmed Release List and Inventory of Hazardous Substances. Tables Table 1 Balancing Factors Attachment A - Proposed Remedial Action Staff Report, November 12, 2004

5 Table 2 - Evaluation and Comparison of Alternatives Analysis of Brownfield Cleanup Alternatives Addendum Chiloquin Mill Site Restoration Project Chiloquin, Oregon Alternative Effectiveness Long-Term Reliability Implementation Implementation Risk Extent to Which Treat Hot Spots Reasonableness of Cost Notes of Significance Score Rank Alternative 1: No Action No Action does not effectively manage risk. The No Action Alternative will not reliably address the contamination or associated risk. The No Action Alternative is easily implemented. Because there are no construction or remediation activities associated with the No Action Alternative, there is no risk to workers or the public during implementation of this alternative. Does not address hot spots. This no action alternative does not achieve RAOs. Retained as baseline for comparison. Not protective. 0 4 $0 (-) (-) (-) (-) (-) (-) (-) (-) (+) (+) (+) (+) (+) (+) (+) (+) (-) (-) (-) (-) (+) (+) (+) (+) Alternative 2: Protective Cover/Deed Restriction This alternative addresses direct-contact risk as long as the cover is maintained and the deed restriction is abided by. The time to reach the RAO is estimated to be less than 6 months, including recording of the deed restriction. Although this alternative does not reduce toxicity or mobility of the contamination in the soil, the cap would prevent direct contact with residual contamination in soil (as long as the integrity of the cover is maintained). Contact with contaminated soil could arise due to water/wind erosion over time, animal burrowing, or from human activity (e.g., digging) in the area. Erosion and burrowing are addressed through proper design and maintenance. The potential for human activity is addressed through a deed restriction. available construction techniques. Administration of the deed restriction will require legal representation and recording of documents with the County. Public notification of the environmental concerns would be completed easily through posted warning signs, bulletins, or public meetings. Construction of the protective cover (placement and compaction of 27,130 cubic yards of material) completed in approximately 42 days. Construction activities associated with this alternative are minimal and there is little risk during implementation if care is taken to prevent direct contact with the source soils. The primary potential impact to the community would be dust generation during construction of the protective cover. Dust control would be used to decrease dust generation. Does not remediate hot spots. Hot spots of contamination are capped in place. Costs are reasonable; RAOs achieved through risk management. Construction of the protective cover may restrict the use of the site (approximately 16.8 acres). The constructed protective cap may affect flexibility of future site grades during site redevelopment (i.e., protective cap may hinder anticipated site use). 2 1 Alternative 3: Hot Spot Soil Removal and Off-Site Disposal/Protective Cover/Deed Restriction Alternative 4: Construction Worker Soil Removal and Off-Site Disposal/Protective Cover/Deed Restriction Alternative 5: Soil Removal to Residential Levels with Off-Site Disposal $192,500 (+) (-) (-) (-) (+) (0) (0) (-) (-) (+) (+) (+) (-) (+) (+) (+) (+) (-) (-) (-) (-) (+) (+) (+) This alternative is effective. Hot spots of soil Landfill disposal does not reduce the toxicity or removed, however, significant amount of impacted mobility of the contaminants. This alternative soils remains above residential cleanup goals otherwise has good long-term reliability because the requiring additional actions to manage risk. Disposing landfill is a controlled disposal facility that will be of the soil at a landfill will eliminate the human health required to conduct long-term maintenance risk from the soil by removing the contaminated and monitoring. Residual risk associated with source to a managed facility. The time to reach the impacted soils remains at the site, requiring RAO is estimated to be less than 6 months, including construction and maintanence of a cap to prevent recording of the deed restriction.. direct contact. available construction techniques. Transportation time and distance to the landfill is manageable (less than 360 cubic yards of contaminated material excavated and transported off-site). It is anticipated groundwater will not be encountered during excavation procedures. Addresses soil hot spots through excavation and off-site disposal in a licensed landfill facility. Hot spots addressed, however, incremental costs compared to Alternative 2 do not provide proportionate benefits of risk reduction. Additional remedial measures are needed to manage residual risk. $218,000 (+) (+) (-) (-) (+) (0) (0) (-) (-) (-) (0) (+) (-) (-) (+) (+) (+) (+) (0) (0) (-) (-) (+) (+) This alternative is effective. Disposing of the soil at a Landfill disposal does not reduce the toxicity or landfill will eliminate the human health risk from the mobility of the contaminants. This alternative soil by removing the contaminated source to a otherwise has good long-term reliability because the managed facility. While some contaminated soils are landfill is a controlled disposal facility that will be removed from the site, a significant amount of required to conduct long-term maintenance impacted soils remains above residential cleanup and monitoring. Residual risk associated with goals requiring additional actions to manage risk. The impacted soils remains at the site, requiring time to reach the RAO is estimated to be within 6 construction and maintanence of a cap to prevent months, including recording of the deed restriction. direct contact. available construction techniques. Transportation time and distance to the landfill is manageable (less than 1,480 cubic yards of contaminated material excavated and transported off-site). It is anticipated groundwater will not be encountered during excavation procedures. Addresses soil hot spots through excavation and off-site disposal in a licensed landfill facility. $311,400 (+) (+) (+) (-) (+) (0) (0) (-) (-) (-) (0) (+) (-) (-) (-) (+) (+) (+) (0) (0) (-) (-) (-) (+) This alternative is very effective. Disposing of the soil Landfill disposal does not reduce the toxicity or at a landfill will eliminate the human health risk from mobility of the contaminants. This alternative the soil by removing the contaminated source to a otherwise has good long-term reliability because the managed facility. The time to reach the RAO is landfill is a controlled disposal facility that will be estimated to be within 8 months, including recording of required to conduct long-term maintenance the deed restriction. and monitoring. Notes: 1. Costs from Table Each alternative is compared to other alternatives for each evaluation criteria and is ranked as favorable (+), equal (0), or unfavorable (-) in relation to the other alternative. Scores are summed at the right of the table for each alternative. 3. Alternative ranking considers both total score and ability to meet selection criteria (RAOs and cleanup goals), as explained in Notes of Significance. available construction techniques. Transportation time and distance to the landfill is manageable although a large amount of contaminated soils (95,250 cy) are excavated and transported off-site. It is anticipated groundwater will not be encountered during excavation procedures. This alternative poses little threat to workers or the community during construction, if personal protection is used. The primary potential impact to the community would be dust generation during excavation and spilling of soil or vehicular accidents during the transport to the landfill. Dust control would be used to decrease dust generation. Prior to departure from the site, all loose soil would be brushed from the truck or drop boxes. All trucks would be tarped to prevent incidental spilling during transport. This alternative poses little threat to workers or the community during construction, if personal protection is used. The primary potential impact to the community would be dust generation during excavation and spilling of soil or vehicular accidents during the transport to the landfill. Dust control would be used to decrease dust generation. Prior to departure from the site, all loose soil would be brushed from the truck or drop boxes. All trucks would be tarped to prevent incidental spilling during transport. This alternative poses little threat to workers or the community during construction, if personal protection is used. The primary potential impact to the community would be dust generation during excavation and spilling of soil or vehicular accidents during the transport to the landfill. Dust control would be used to decrease dust generation. Prior to departure from the site, all loose soil would be brushed from the truck or drop boxes. All trucks would be tarped to prevent incidental spilling during transport. Addresses soil hot spots through excavation and off-site disposal in a licensed landfill facility. Construction of the protective cover may restrict the use of the site (approximately 16.8 acres). The constructed protective cap may affect flexibility of future site grades during site redevelopment (i.e., protective cap may hinder anticipated site use). Hot spots addressed, however, Construction of the protective cover may restrict the incremental costs compared to use of the site (approximately 16.8 acres). The Alternatives 2 and 3 do not constructed protective cap may affect flexibility of future provide proportionate benefits of site grades during site redevelopment (i.e., protective risk reduction. Additional cap may hinder anticipated site use). remedial measures are needed to manage residual risk. Costs are not reasonable for level of risk reduction achieved. $8,773,800 (+) (+) (+) (+) (+) (+) (+) (+) (-) (-) (-) (-) (-) (-) (-) (-) (+) (+) (0) (0) (-) (-) (-) (-) F:\DATA\Jobs\DEQ\15545 Chiloquin\Tk 5 ABCA Addendum\Table2.xls

6 ATTACHMENT A Proposed Remedial Action Staff Report November 12, 2004