Cleanup Action Plan Sternco Property Renton, Washington
Prepared for Zelman Renton, LLC
May 12, 1997 J-4735
CONTENTS
Page
1.0 EXECUTIVE SUMMARY 2.0 PROJECT BACKGROUND 2.1 Organization of CAP 2.2 Property Description 2.3 Proposed Property Redevelopment 2.4 Site History 3.0 SUMMARY OF SITE CHARACTERIZATION DATA 3.1 Site Geology and Groundwater 3.2 Contaminants of Concern by Area 3.3 Site Ranking Summary 4.0 CLEANUP ACTION EVALUATION 4.1 Regulatory Cleanup Levels and Points of Compliance 4.2 Preferred Cleanup Action 4.3 Other Alternative Cleanup Actions 5.0 JUSTIFICATION FOR SELECTING THE CLEANUP ACTION 6.0 PLANNED SCHEDULE AND RESTORATION TIME FRAME 7.0 REFERENCES
CAP-1 CAP-3 CAP-3 CAP-3 CAP-3 CAP-4 CAP-5 CAP-6 CAP-6 CAP-8 CAP-9 CAP-9 CAP-10 CAP-13 CAP-13 CAP-14 CAP-14
TABLES
CAP-1 Areas and Chemicals of Concern CAP-2 Remedial Alternatives CAP-16 CAP-17
FIGURES
CAP-1 CAP-2 CAP-3 CAP-4 CAP-5 Vicinity Map Operational Areas Map Extent of Areas of Concern Preferred Remedial Alternative Map Preliminary Schedule
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CONTENTS (Continued) APPENDIX A APPLICABLE STATE AND FEDERAL LAWS AND CLEANUP CRITERIA TABLES
A-1 A-2 A-3 A-4 Applicable Laws and Regulations Regulatory Cleanup Criteria for Detected Constituents in Soil and Debris Regulatory Cleanup Criteria for Detected Constituents in Groundwater Regulatory Cleanup Criteria for Detected Constituents in Sediments
Page
A-2 A-3 A-5 A-6
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1.0 EXECUTIVE SUMMARY
This cleanup action plan (CAP) selects the remedial alternatives for the Sternco property (Figure CAP-1). This CAP is based on the reports detailed in Section 3.0, including the final Supplemental Remedial Investigation (SRI) and final Supplemental Feasibility Study (SFS) conducted by Hart Crowser, and the Remedial Investigation Feasibility Study (RI/FS) conducted by SEACOR in 1991. This CAP will be incorporated into a prospective purchaser agreement (PPA) between the Washington State Department of Ecology (Ecology) and Zelman Renton LLC (Zelman). Environmental issues addressed in this CAP were assessed in the SRI and the RI/FS. The primary site environmental concerns are related to metals recycling activities which occurred at the site between the mid-1960s and the mid-1980s (Figure CAP-2). These activities caused releases of PCBs, lead and other metals, and TPH to site soils and groundwater (Figure CAP-3 and Table CAP-1). Consistent with the primary environmental issues of concern noted by Ecology, this CAP addresses the remediation of roughly 60,000 cubic yards of auto and wire shredder fluff debris in the Auto Fluff and Wire Fluff areas (Figure CAP-3). Fluff debris in both areas contains elevated concentrations of PCBs, and debris in the Auto Fluff Area contains elevated concentrations of lead. Soils in the Transformer Area containing PCBs are another focus of remediation. Other remedial areas and associated environmental issues addressed by this CAP include the following:
Auto Storage Area. Total lead in soil; Aluminum Dross Area. Total lead in dross fill; Drainage Ditch Area. Total lead in soils of the ditch; South Area. TPH in soil; and Sediment in Springbrook Creek. Total lead and HPAHs in sediment.
The locations of these areas are identified on Figure CAP-3. Moderately elevated metals (Cu, Pb, and Zn) and PCB concentrations in some groundwater monitoring wells were also identified as being of concern. Remedial options for each site area of concern were evaluated in the SFS. The selected cleanup alternative for each site area protects human health and the
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environment, meets regulatory cleanup criteria, and addresses related remedial action objectives. As a basis for evaluating and selecting remedial alternatives, media-specific cleanup criteria described in the CAP were derived from the Washington State Model Toxics Control Act (MTCA - Chapter 173-340 WAC) and other applicable state and federal regulations. The proposed cleanup actions provide source control for contaminated soil and debris material originating from historical operations. The selected remedial alternatives involve off-site disposal and/or on-site containment, and are summarized below. Selected remedial options and alternatives are listed for site areas in Table CAP-2.
The selected remedial alternative for the waste piles in the Auto Fluff and Wire Fluff Areas involves stabilizing fluff debris for off-site landfill disposal. This alternative includes an option to place the material on site following stabilization and an option to recycle non-ferrous metal. The selected remedial alternative for the Transformer Area soil which may exceed the MTCA Method C risk-based industrial soil cleanup level for PCB is off-site disposal at a landfill, either landfill as appropriate. The selected remedial alternative for the Drainage Ditch soils which exceed the MTCA Method A industrial soil cleanup level for lead is off-site disposal. The selected remedial alternative for the Aluminum Dross Area and for Auto Storage Area soils which exceed the MTCA Method A industrial cleanup level for lead is containment with soil cover. The selected remedial alternative for the South Area soils which exceed the cleanup level for TPH determined using the Ecology Interim TPH Policy (January 1997) is off-site disposal. The selected remedial alternative for sediments in Springbrook Creek which exceed the interim guidance for cleanup of contaminated freshwater sediment is excavation and upland on-site placement.
The selected cleanup actions will achieve applicable cleanup levels at the points of compliance, and is consistent with the planned property development and longterm usage.
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2.0 PROJECT BACKGROUND
This CAP identifies the Site-specific cleanup standards and summarizes the anticipated cleanup action and monitoring efforts for remediation of the property. This CAP will be implemented through Zelman’s application for a PPA with Ecology. The proposed remediation activities will be completed pursuant to this agreement, as set forth in a MTCA Consent Decree.
2.1 Organization of CAP
Following descriptions of the property setting, the proposed property redevelopment, and site history in Section 2.0, the remainder of this CAP presents the following sections:
3.0 - SUMMARY OF SITE CHARACTERIZATION DATA; 4.0 - CLEANUP ACTION EVALUATION; 5.0 - JUSTIFICATION FOR SELECTING THE CLEANUP ACTION; 6.0 - PLANNED SCHEDULE AND RESTORATION TIME FRAME; and 7.0 - REFERENCES.
Referenced site figures and tables are located at the end of the CAP. CAP appendices provide additional descriptions of applicable state and federal laws.
2.2 Property Description
The Sternco property (Site) is located in Renton, Washington, and consists of approximately 45 acres (Figure CAP-1). The property is bounded by SW 43rd Street to the south and Oaksdale Avenue SW to the east. The Site consists of the former Sternco Renton and Sternco Industrial Renton properties. The Sternco Renton property consisted of the northernmost 12 acres of the property, while the Sternco Industrial Renton property occupied the southern 33 acres as shown on the inset map on Figure CAP-1.
2.3 Proposed Property Redevelopment
The Site is zoned by the City of Renton as Medium Industrial (IM) and is designated as Employment Area-Valley in the City’s Comprehensive Plan. Zelman will redevelop the Site consistent with existing zoning, the City’s comprehensive plan, and with market conditions. The City of Renton is actively participating in the development planning. Zelman is exploring the possibilities of developing commercial and/or industrial uses for the Site.
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2.4 Site History
Information regarding the historical uses of the Site was obtained through interviews with members of the Sternoff family, an inspection of historical aerial photographs, and a reconnaissance of the property. The following summary of the Site's historical uses is primarily based on the Sternco Remedial Investigation (RI) and Feasibility Study (FS) prepared by SEACOR in May 1991. The SEACOR RI/FS presents additional detail for the historical activities summarized herein. Locations of the Site operational areas discussed are identified on Figure CAP-2. The historical summary focuses on metals recycling activities which began in the 1960s and continued until the mid-1980s. Releases of chemical constituents related to these activities are addressed in the cleanup action evaluation discussed in a subsequent section of the CAP. Potential environmental concerns associated with earlier activities, dating from the 1930s, are limited based on available historical and site characterization data. Environmental issues from later uses include fuel spills reportedly resulting from diesel fueling at the warehouse on the former Sternco Renton property. This warehouse was used by Bellevue Roofing in the early 1990s. Metals Recycling-1967 to 1985 The Sternoff family purchased the property in the early 1960s. Between approximately 1967 and 1985, the Sternoff Metals Corporation (SMC) used the site to recycle scrap metal and electrical equipment from various sources. Recycled products consisted primarily of automobiles, electrical wire, storage tanks, and transformers. SMC shredded automobiles and wire prior to the separation and recovery of metallic components. SMC’s recycling operation also included the temporary storage of used drums, which were reportedly steamcleaned prior to their arrival at the property. Auto recycling commenced at the property in 1968. During full operation, SMC reportedly processed between 300 and 400 cars per day. SMC deposited the fluff (or non-magnetic material) generated in this process in the area south of the auto shredder (Figure CAP-2). As a consequence, the auto fluff pile located on the property currently occupies an area located on both the Sternco Renton and the Sternco Industrial Renton properties. Interviews further revealed that SMC used auto fluff to fill low-lying areas and bring portions of the property to grade. A concrete and steel powerhouse needed to support a metals shear was built in 1969, along with a shop building that housed a 5-ton bridge crane. By 1972, SMC had apparently constructed a warehouse building. All of these structures were
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located on the Sternco Renton property in the northern portion of the Site (Figure CAP-2). SMC conducted transformer recycling on the Sternco Renton property (Figure CAP-2) starting in approximately 1974. Wire shredding and recycling operations commenced on a portion of the Sternco Industrial Renton property, north of Springbrook Creek, starting in approximately 1973. A 1974 aerial photograph indicates that a ditch located to the east of the wire shredding facility was used as an outlet for surface drainage. A 1977 aerial photograph and information obtained from the Sternoff family indicate that aluminum dross was deposited along an access road located on the Sternco Industrial Renton property north of Springbrook Creek. SMC’s recycling operations continued until the mid-1980s. Wire shredding and wire recycling operations terminated in approximately 1982. Other recycling operations, including auto recycling, continued until approximately 1985.
3.0 SUMMARY OF SITE CHARACTERIZATION DATA
This section summarizes results of the RI and SRI of existing soil and groundwater data for the environmental issues to be addressed in this CAP. It describes contaminants of concern for affected media and operational areas on the property, and Ecology’s MTCA Site Ranking data. This summary is based on information from the SEACOR RI/FS from May 1991, the final SRI, and several previous site assessment efforts including:
Earth Consultants, Inc. - Preliminary Evaluation (May 1987); and Fluor Daniels GTI - Auto Fluff Area Soil and Fluff Sample Analysis Results (November 1996) and Groundwater Monitoring Data (October 1996).
These assessment efforts included the collection of soil, waste, sediment, and groundwater samples for chemical analyses to determine the nature and extent of site contamination. The overall quality of the data for the Site is good. Several data gaps were addressed in the final SRI. The final SRI should be consulted for additional detail.
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The following summary also references existing figures and tables from the SEACOR RI and FS documents when appropriate. These documents should be consulted as necessary.
3.1 Site Geology and Groundwater
The Site geology is critical to an understanding of the environmental issues to be addressed. Site geology is characterized by alluvial deposits of interbedded sands, clays, and silts associated with the Green River Valley floodplain. Fill, primarily in the northern parcel, occurs to depths of up to 4 feet. The primary surface water feature on the Site is Springbrook Creek, which flows from the southwest to the northeast corners of the property. The creek appears to drain the entire Site, with the exception of the adjacent man-made wetland area that intrudes into the northwest corner of the property. Shallow groundwater is encountered at depths of 1 to 13 feet below the ground surface, and generally flows toward Springbrook Creek. The shallow groundwater is mounded in the northwest corner of the property as a result of the waste piles and adjacent wetlands. Regional groundwater flows north-northeast under confined conditions in deeper aquifers beneath the Site. This confined condition significantly limits the potential contamination of such deeper aquifers.
3.2 Contaminants of Concern by Area
Table CAP-1 summarizes contaminants of concern for soil and debris material areas evaluated in this CAP. These areas are identified on Figure CAP-3. Corresponding site operational areas are identified on Figure CAP-2. Contaminants of concern were identified based on applicable regulatory cleanup levels for affected media, as discussed in Section 4.0 - Cleanup Action Evaluation and in Appendix A. The primary areas of environmental concern are associated with roughly 60,000 cubic yards of shredder fluff debris in the Auto Fluff and Wire Fluff Areas and PCB-affected soils in the Transformer Area (Figure CAP-2 and Figure CAP-3). PCB, total lead, and TCLP-leachable lead in these areas contributed significantly to the overall Ecology Site Hazard Assessment and ranking score. Auto Fluff Area The total quantity of auto fluff is estimated at approximately 55,000 cubic yards, or about 42,000 tons. The auto fluff, the underlying soils, and the interstitial water were sampled and analyzed for a range of volatile and semivolatile organic
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compounds, phenols, total metals, extraction procedure toxicity (EP Tox) metals, toxicity characteristic leaching procedure (TCLP) for metals, and for fish bioassay. Contaminants of concern with concentrations exceeding the cleanup standard included total lead and possibly PCBs in the auto fluff. TCLP-leachable lead in some samples of the auto fluff exceeds the 5 mg/L criteria for designation of the material as Dangerous Waste under state regulations (Chapter 173-303090). Wire Fluff Area The total quantity of wire fluff is estimated at 4,500 cubic yards or 2,000 tons. SEACOR analyzed the wire fluff and underlying soils for semivolatile organic compounds, PCBs, total metals, and EP Tox metals. The contaminant of concern identified in the Wire Fluff Area was PCBs with concentrations potentially greater than the MTCA Method C Industrial soil cleanup level. Transformer Area Soil samples were analyzed for PCBs, total metals, TCLP metals, TPH, and selected volatile and semivolatile organic compounds. MTCA Method C Industrial soil cleanup levels for PCBs were potentially exceeded in soils within the area. The highest concentration of PCB was exceeded near the central portion of the area to a depth of about 3 feet below grade. Total lead also exceeded MTCA screening criteria at a number of locations, and TPH exceeded the TPH Interim Policy-based criteria. Other Site Areas The SRI evaluated a number of other Site areas with known or suspected releases of chemical constituents. Aluminum Dross Area. Investigations documented an aluminum dross/fill layer ranging from 2 to 3.5 feet in thickness beneath a thin layer of soil in this area of the Site. SEACOR and HC collected and analyzed twenty dross area samples for total synthetic precipitation leaching procedure (SPLP), and TCLP metals. With the exception of total lead, the sample analyses met screening level concentrations. Auto Storage Area. Investigations collected soil samples from this area and competed analyses for total metals, TPH, and PCBs. Total lead exceeded the MTCA screening criteria.
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South Area. Investigations collected soil samples to address areas of potential concern and to determine background soil concentrations. TPH concentrations in soil were above Ecology TPH Interim Policy-based criteria at heating oil AST and UST locations and a fuel drum storage area. Drainage Ditches. Investigations collected samples from six locations and completed analyses for total metals. Detected lead concentrations were above the MTCA Method A industrial soil cleanup level. Springbrook Creek. Sediment samples from Springbrook Creek were submitted for total metals, semivolatiles, PCBs, and volatiles analyses. Exceedences of interim guidance criteria for freshwater sediments were noted for total lead, cadmium, copper, zinc, and HPAHs in limited areas near the mouth of the two ditches. Groundwater Quality. Groundwater quality data were obtained from several rounds of well sampling and analysis. Laboratory testing included analyses of a wide spectrum of chemical constituents including total and dissolved metals, PCBs, and volatile and semivolatile compounds. Detected metal constituents which exceeded applicable regulatory screening criteria included copper, lead, and zinc. PCBs and Bis(2-ethylhexyl) phthalate are additional contaminants of concern. The presence of these compounds in groundwater is the result of contaminant releases from overlying soil and proximity to the auto fluff pile.
3.3 Site Ranking Summary
Ecology identified confirmed or suspected contaminant exposure pathways via air, groundwater, and surface water at the site, and completed a MTCA Site Ranking based on these data. Contaminants primarily include the following: (1) base-acid-neutral (BNA) and phenolic compounds associated with the automobile and wire shredder fluff and related operations; (2) PCBs originating from the transformer building; and (3) aluminum dross. Other confirmed or suspected compounds include priority pollutant metals such as arsenic, cadmium, lead, and mercury in soil, as well as polycyclic aromatic hydrocarbons (PAHs). The King County Health Department completed a site hazard assessment in April 1996. Using this information and data from previous investigations, Ecology further evaluated the Site and assigned it an overall priority ranking of 1. This ranking was primarily the result of the presence of arsenic, cadmium, lead, mercury, and PCBs in uncontained and exposed waste piles and surface soils. Surface water, air, and groundwater pathways received relatively high cumulative scores given the toxicity of the constituents of concern, migration potential, possible targets and receptors, and documented releases.
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4.0 CLEANUP ACTION EVALUATION
Remedial technologies and alternatives were identified for each Site operational area. Evaluations of these technologies and alternatives are presented in the SFS. The SFS assembled and selected preferred cleanup alternatives for the areas of concern on the property based on comparison of a number of remedial options. The selected alternatives address remedial action objectives for the Site by providing adequate protection for human health and the environment, and by meeting regulatory cleanup levels at the points of compliance. Together, the preferred cleanup alternatives comprise the proposed cleanup action for the Site. The following section discusses the regulatory points of compliance and preferred remedial alternatives for each site area. Other cleanup alternatives evaluated in the SFS are also briefly summarized.
4.1 Regulatory Cleanup Levels and Points of Compliance
Regulatory cleanup levels for contaminants of concern and other detected constituents are listed in Appendix A. As a general screening method for identifying contaminants of concern and points of compliance, Hart Crowser identified appropriate cleanup levels from the MTCA and other state and federal regulations as follows:
Soil and Debris Material. MTCA Method A/C Cleanup Levels (WAC 173340-740 and -745), State Dangerous Waste Regulations (Chapter 173-303 WAC), and Ecology’s TPH Interim Policy Criteria for Method C Industrial/Commercial Land Use; Groundwater. MTCA Method B Surface Water Cleanup Levels (WAC 173340-730), State Surface Water Quality Standards (Chapter 173-201A), MTCA Groundwater Cleanup Levels (WAC 173-340-720), and Federal Drinking Water Standards; and Sediment. Summary of Guidelines for Contaminated Freshwater Sediments (March 1995).
Applicable state and federal regulations are listed in Table A-1 in Appendix A along with the rationale for their inclusion. Tables A-2 through A-4 present the media-specific cleanup criteria used to evaluate remedial needs for the various areas of the property. These regulatory criteria were, in turn, used to evaluate
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various remedial alternatives, to identify handling and disposal considerations, and to select a preferred option for this CAP. Points of Compliance The selected cleanup action is aimed at providing source control for contaminated soil and debris material derived from historical operations at the Sternco property. Cleanup levels for contaminants of concern in these media were developed primarily using MTCA Method C levels, given the status of the property as an industrial/commercial site. For total lead, the MTCA Method A criteria for industrial soil is used. Planned site development would maintain industrial/commercial usage, with limited potential for direct contact or other disturbance of these materials following remedial activities. The point of compliance for soil and debris material is the surface soil throughout the property and/or at the groundwater table. Groundwater cleanup standards are based on the assumption that the area groundwater is extremely unlikely to be used as a future source of drinking water. Contact with property groundwater during site development is also unlikely but could occur on a short-term basis if deeper excavations are completed. For these reasons, groundwater cleanup standards were based on state surface water or MTCA Method B criteria. The point of compliance for groundwater is the interface with surface water receptors, including Springbrook Creek, the on-site wetlands areas, and off-site surface water bodies. The point of compliance for sediments is the underlying creek bottom, in accordance with state Sediment Quality Standards.
4.2 Preferred Cleanup Action
Cleanup alternatives considered in the SFS are listed in Table CAP-2. Site remedial areas are identified on Figure CAP-4. Remedial alternatives selected for the preferred cleanup action generally involve on-site containment and management or off-site disposal of affected soil, debris, and sediment during planned site development. The selected remedial alternatives represent the most practicable approach to protect human health and the environmental, and meet regulatory criteria and other remedial objectives. To assure that both protection of human health and the environment is achieved, institutional control measures will be undertaken to limit or prohibit activities that may interfere with the integrity of the cleanup action. These measures involve physical and legal/administrative mechanisms to control future activity on the property. Physical measures limit activity on the Site that could result in exposure
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by employing the use of fences and signs, or soil/asphalt cover. Legal/administrative mechanisms limit use and ensure maintenance of the physical measures. The restriction of Site uses include: restricting use of the property for industrial or commercial purposes or other specific land uses, restricting activities which would disturb soil covers, and restricting the use of groundwater. Maintenance activity mechanisms include: inspection and maintenance of caps and monitoring wells. Institutional controls appropriate for the Site will be described in a restrictive covenant on the property. Auto Fluff Area The preferred remedial alternative for the Auto Fluff Area is stabilization of the auto fluff with off-site disposal of the stabilized material. An option under consideration is the on-site placement of the stabilized material as fill. The preferred cleanup action will meet the remedial action objectives through ex situ stabilization of fluff debris. The remedy will provide for either off-site or on-site disposal. Solidification testing indicates that the stabilized material can exhibit suitable compressive strength for on-site backfilling consistent with site redevelopment. The stabilized fluff debris, therefore may be used as on-site backfill (Option 1). The stabilization option will be further evaluated consistent with future development plans for the Site. Non-ferrous metal recovery treatability testing indicates that metal recovery is feasible, and non-ferrous metals may be separated and recovered from the fluff debris prior to stabilization (Option 2). The non-ferrous metal recovery option will be further evaluated considering the economic return related to the implementation of recycling activities, and the influence of applicable regulations. Wire Fluff Area The preferred remedial action for the Wire Fluff is ex situ stabilization of fluff debris followed by off-site disposal of stabilized material. Transformer Area The preferred alternative listed in Table CAP-2 for the transformer area is to excavate soils with PCB concentrations greater than the MTCA Method C riskbased industrial soil cleanup level for off-site disposal as TSCA-regulated waste at a RCRA-approved disposal facility. Auto Storage Area
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The preferred alternative for soils in the Auto Storage Area which exceed the MTCA Method A Industrial cleanup levels for lead is in situ management through containment in the form of a soil cover. Aluminum Dross Area The preferred alternative for the Aluminum Dross Area is to manage the soils which exceed the MTCA Method A Industrial cleanup levels for lead in situ through containment in the form of a soil cover.
Drainage Ditch Area The preferred alternative for soil which exceeds the MTCA Method A Industrial cleanup levels for lead in this area is to excavate and dispose of the soils off site in a MFS landfill. South Area The preferred alternative for the South Area is to excavate TPH- affected soils above the Interim TPH Policy-based cleanup level, for off-site disposal. Sediment in Springbrook Creek The preferred alternative for the sediment is to excavate the lead-affected sediments which exceed the Freshwater criteria for metals and place the soil on site. Groundwater Monitoring Groundwater monitoring will be performed in areas of the site where cleanup actions result in either the removal of or containment of Site contaminants. Groundwater in locations from which contaminants are removed will be monitored quarterly for one year. Groundwater in locations where contaminants are covered will be monitored quarterly for one year, and semi-annually for an additional four years. Groundwater monitoring frequency and/or duration may be reduced if it is deemed appropriate by Ecology. Further groundwater monitoring may be required if an exceedence of the surface water quality standards is identified. Remedial action or additional groundwater monitoring will be implemented if the groundwater monitoring results indicate a consistent exceedence of applicable criteria. Groundwater monitoring analyses of remediation units will be performed for the constituents identified in the SRI as exceeding the cleanup level.
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4.3 Other Alternative Cleanup Actions
The SFS and FS screened a number of other alternatives against the MTCA screening criteria (WAC 173-340-360). Various alternatives were considered for the different Site remediation areas based on the effectiveness of the technology in achieving the threshold requirements (protection of human health and the environment, and compliance with the applicable cleanup standards). Alternatives which achieved the threshold criteria but had a high cost relative to the level of environmental protection achieved were not carried forward in the evaluation. The alternatives reviewed in the SFS and FS are listed in Table CAP-2. The preferred alternatives for the largest area of concern on the Site (Auto Fluff Area) include technologies which detoxify the contaminated media. These technologies are highly preferred by Ecology (WAC 173-340-360).
5.0 JUSTIFICATION FOR SELECTING THE CLEANUP ACTION
The selected site cleanup action complies with applicable MTCA and related regulatory threshold requirements. These requirements include:
Protection of human health and the environment; Compliance with applicable state and federal laws and regulations; and Compliance monitoring provisions.
The Site cleanup action will protect human health and the environment using a number of source management and control measures. The primary environmental risk associated with the project is direct exposure to contaminated soil, debris, and ditch and creek sediments during site development and in the future. Cleanup efforts will excavate and stabilize these materials as needed, and as appropriate for the contaminants of concern. These materials may also be used as permanent on-site fill. The prevention of human contact with affected media or other disturbance will be provided with soil covers. Where on-site management is not feasible based on results of on-going treatability studies or development plans, affected soils, debris, and sediment would be shipped for disposal at suitable off-site landfills. In addition to groundwater, other potential contaminant receptors include Springbrook Creek, the wetlands areas, and off-site surface water bodies. Source control measures described above for contaminated soil, debris, and sediment will effectively prevent potential future releases to these receptors. Also, Site groundwater is not currently used as a drinking water resource, and it is
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extremely unlikely to be used for drinking water in the future, given the availability of municipal water in the area. Other cleanup alternatives considered involved additional off-site disposal of solid waste which would be removed from the Site. While these measures would effectively prevent exposure to contaminated materials, they provide no additional benefit with regard to risk reduction. Associated costs are also not commensurate with the exposure reduction which would be achieved relative to on-site management. In addition to limiting potential exposure to human health and the environment, the preferred cleanup action will effectively achieve remedial action objectives and compliance with applicable state and federal cleanup levels. These cleanup levels will be achieved at the points of compliance upon completion of the cleanup action during planned site development. Verification sampling and analysis will assess the effectiveness of remedial measures, and postconstruction monitoring (including groundwater sampling and analysis) will continue to be conducted in accordance with an approved monitoring plan. Institutional controls will also be established in the form of a restrictive covenant to prohibit Site activities which could disturb the isolation of fill materials, or otherwise create potential exposure pathways.
6.0 PLANNED SCHEDULE AND RESTORATION TIME FRAME
A Preliminary Schedule for the Site cleanup is presented on Figure CAP-5.
7.0 REFERENCES
Earth Consultants, Inc., 1987. Preliminary Evaluation. Ecology, 1997. Washington State Department of Ecology, Toxics Cleanup Program, Interim Interpretive and Policy Statement, Cleanup of Total Petroleum Hydrocarbons (TPH), Ecology Publication No. ECY97-600, January 1997. Fluor-Daniels GTI, 199a. Groundwater Monitoring Data. Fluor-Daniels GTI, 199b. Auto Fluff Area Soil and Fluff Sample Analysis Results. Hart Crowser, 1997. Final Supplemental Remedial Investigation (SRI)/ Final Supplemental Feasibility Study (SFS), Sternco Property, Renton, Washington, May 12, 1997. Page CAP-14
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SEACOR, 1991. Remedial Investigation Report, Sternco Renton and Sternco Industrial Renton Sites, SW 43rd Street and Oaksdale Avenue SW, Renton, Washington. May 3, 1991. SEACOR, 1991. Feasibility Study, Sternco Renton and Sternco Industrial Renton Sites, May 13, 1991.
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Table CAP-1 - Contaminants of Concern for Affected Media in Site Operational Areas
OPERATION AREAS Auto Fluff Area Wetlands West of Fluff Area
MATRIX Waste Soil Surface water Sediment Waste Soil Surface water Sediment Soil Soil Waste Soil Soil Sediment Surface Water
CHEMICALS OF CONCERN PCBs, Total and TCLP Lead None None None PCBs PCBs None None PCBs, TPH, and Total Lead Total Lead Total Lead None Total Lead Total Lead, Cadmium, Copper, Zinc, HPAHs None TPH
Wire Fluff Area Wetlands West of Fluff Area
Transformer Area Auto Storage Area Aluminum Dross Area
Drainage Ditches Springbrook Creek Area
South Area
Soil
Groundwater
Groundwater
Cu, Pb, Zn, PCBs, Bis(2 ethylhexyl)phthalate
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Table CAP-2
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APPENDIX A APPLICABLE STATE AND FEDERAL LAWS AND CLEANUP CRITERIA
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APPENDIX A APPLICABLE STATE AND FEDERAL LAWS AND CLEANUP CRITERIA
The preferred cleanup alternatives for each Site area will comply with applicable local, state, and federal laws and regulations. The Washington State Model Toxics Control Act (MTCA - Chapter 173-340 WAC) represents the primary regulation that establishes cleanup levels and other requirements for the Site. Cleanup standards developed under the MTCA must also meet the statutory requirement to be least as stringent as other applicable state and federal laws. The laws and associated regulations applicable to cleanup standards developed for the Site are listed in Table A-1, along with the rationale for inclusion. Applicable cleanup concentrations for detected Site constituents, and the associated regulatory are listed in Tables A-2 through A-4.
Table A-1 - Applicable Laws and Regulations
Law or Regulation Soil and Debris Material Federal Toxic Substances Control Act (TSCA 15USC 2601; 40 CFR Part 761) State Model Toxics Control Act - (MTCA Chapter 70.105D RCW and Chapter 173340 WAC) Rationale
Disposal of Soil with PCB concentrations exceeding 50 parts per million. Fluff debris and soil contaminant concentrations exceeding Method C Industrial cleanup levels. Fluff debris and soil lead concentrations exceeding Method A Industrial cleanup levels Fluff debris contaminant concentrations exceeding Toxic Characteristic threshold criteria.
State Hazardous Waste Management Act (RCW 70.105) and State Dangerous Waste Regulations (Chapter 173-303 WAC) State Environmental Protection Policy Act (WAC 97-11-800) Ecology TPH Interim Policy for Method C Commercial Criteria Use Local City of Renton Municipal Code (4-10) Puget Sound Air Polllution Control Authority City of Renton Wetland Ordinance #4346
Grading in Excess of 500 Cubic Yards Soil with TPH concentrations exceeding Interim Policy Criteria for Direct Contact Mining or Grading in excess of 500 Cubic Yards Remedial activities associated with dust and chemical emmissions. Regulated activities, such as filling and removal of vegetation, within wetlands and their required standard buffer zones.
Groundwater Federal Clean Water Act ( 33 USC 1251) and Ambient Water Quality Criteria (Section 304 and 40 CFR part 131) State MTCA (Chapter 70.105D RCW and Chapter 173-340 WAC)
Groundwater constituent concentrations for which no surface water cleanup levels exist, and which exceed drinking water MCLs more restrictive than MTCA Method B Groundwater cleanup criteria. Groundwater contaminant concentrations for which no surface water cleanup levels exist, and which exceed Method B groundwater cleanup criteria more restrictive than federal drinking water MCLs. Groundwater contaminant concentrations which exceed Surface Water Quality Standards more restrictive than MTCA Method B surface water cleanup levels.
Water Pollution Control Act (RCW 90.48) and Surface Water Quality Standards (Chapter 173-201A) Sediment Federal Cleanwater Act (33 U.S.C. 1344) Section 404 (U.S. Army Corps of Engineers) State Water Pollution Control Act (RCW 90.48) and Sediment Quality Standards (Chapter 173-204) Shoreline Management Act (RCW 90.58)
The Corp makes the final determination as to whether an area meets the wetland definition and would be subject to regulation under the Corps program. Sediments with contaminant concentrations exceeding marine sediment quality standards. Construction valued at greater than $2,500 within 200 feet of the shoreline.
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Table A-2 - Regulatory Cleanup Criteria for Detected Constituents in Soil and Debris
Constituent/CAS Number Total Metals in mg/kg Antimony 1,400/128 MTCA Method C Industrial/Commercial (WAC 173-340-745) Arsenic 7440-38-2 Beryllium 7440-41-7 Cadmium 7440-43-9 Chromium 7440-47-3 Copper 7440-50-8 Lead 7439-92-1 Mercury 7439-97-6
(1) (1)
Cleanup Level
Regulation
217/66.7 30.5/9.3 3,500/320 17,500/1,600 130,000/11,800 1,000 1,050/96 MTCA Method A (WAC 173-340-745) MTCA Method C Industrial/Commercial (WAC 173-340-745)
Nickel 7440-02-0 Selenium 7782-49-2 Thallium 7440-28-0 Zinc 7440-66-6 TCLP Metals in mg/L Barium 7440-39-3 Cadmium 7440-43-9 Lead 7439-92-1 EP Tox Metals in mg/L
70,000/6,400 17,500/1,600 245/22.4 1,050,000/9,600 State Dangerous Waste Regulations (WAC 173-303-090) 100 1 5 Older analytical method, not currently used. State Dangerous Waste TCLP Criteria (WAC 173-303-090) presented for comparative purposes.
Barium 7440-39-3 Chromium 7440-47-3 Copper 7440-50-8 Lead 7439-92-1 Nickel 7440-02-0 Zinc 7440-66-6
100 5 NE 5 NE NE
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Table A-2 - Continued Constituent/CAS Number PCBs in mg/kg VOCs in mg/kg
Ethylbenzene 100-41-4 Tetrachloroethylene 127-18-4 Toluene 108-88-3 Xylenes 1330-20-7
(1)
Cleanup Level
65
Sheet 2 of 2 Regulation
MTCA Method C Industrial (WAC 173-340-745) MTCA Method C Industrial (WAC 173-340-745)
(1)
350,000 5 700,000 7,000,000 MTCA Method C Industrial/ Commercial (WAC 173-340-745)
SVOCs in mg/kg
4-Methyl-2-Pentanone 108-10-1 4-Methylphenol 106-214-5 Anthracene 120-12-7 Benzo(a)Anthracene 56-55-3 Benzo(k)Fluoranthene 207-08-9 Bis(2-ethylhexyl)Phthalate 117-817 Butylbenzylphthalate 85-63-7 Chrysene 218-01-7 Diethylphthalate 84-66-2 Di-N-Butylphthalate 84-74-2 Di-N-Octylphthalate 117-84-0 Fluoranthene 206-44-0 Fluorene 86-73-7 Phenol 108-95-2 Pyrene 129-00-0
(1) (1) (1) (1)
280,000/25,600 17,500/1,600 1,050,000/96,000 18/5.48 18/5.48 9,370/2,860 700,000/64,000 18/5.48 2,800,000/256,000 350,000/32,000 70,000/6,400 140,000/12,800 140,000/12,800 2,100,000/192,000 105,000/9,600 10,000 Ecology Interim TPH Policy Derived
TPH
Bolded entries indicate regulatory cleanup level exceedences. PCBs: Polychlorinated Biphenyls VOCs: Volatile Organic Compounds SVOCs: Semivolatile Organic Compounds TPH: Total Petroleum Hydrocarbons
1)
: Carcinogenic compound
Table A-3 - Regulatory Cleanup Criteria for Detected Constituents in Groundwater Constituent Cleanup Level Regulation
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Constituent Dissolved Metals in mg/L
Arsenic Barium Cadmium Chromium Copper Lead Mercury Nickel Zinc 7440-38-2 7440-39-3 7440-43-9 7440-47-3 7440-50-8 7439-92-1 7439-97-6 7440-02-0 7440-66-6
Cleanup Level
0.19 NE 0.00106 0.011 0.01106
(1) (1)
Regulation
State Surface Water Quality Standards State Surface Water Quality Standards State Surface Water Quality Standards State Surface Water Quality Standards State Surface Water Quality Standards State Surface Water Quality Standards State Surface Water Quality Standards State Surface Water Standards State Surface Water Quality Standards State Surface Water Quality Standards
0.00247
(1)
0.000012 0.162 0.061
(1)
(1)
PCBs in mg/L SVOCs in g/L
2,4-Dimethylphenol 605-67-9 2-Methylphenol 95-48-7 4-Methylphenol 106-44-5 Benzyl Alcohol 100-51-6 Bis(2Ethylhexyl)Phthalate 117-81-7 Di-N-Butylphthalate 84-74-2
0.000014
553 800 806 4,800 3.56
MTCA Method B Surface Water MTCA Method B Groundwater
MTCA Method B Surface Water
2,910
MTCA Method B Surface Water Method B Groundwater Method B Surface Water
Di-N-Octylphthalate 320 117-84-2 Phenol 108-95-2 1,110,000 Bolded entries indicate regulatory cleanup level exceedences. NE: Not Established PCBs: Polychlorinated Biphenyls SVOCs: Semivolatile Organic Compounds (1) Based on a Site-specific hardness of 110 mg/L.
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Table A-4 - Regulatory Cleanup Criteria for Detected Constituents in Sediments
Constituent Total Metals in mg/kg Arsenic 2 Cadmium 9 Chromium 5 Copper 8 Lead 1 Mercury 6 Nickel 0 Zinc 6 VOCs in mg/kg Xylenes 7 PCB HPAHs in mg/kg Benzo (a) anthracene Benzo (a) pyrene Benzo (b) fluoranthene Benzo (k) fluoranthene Total Benzofluoranthenes Benzo (g,h,i) perylene Chrysene Dibenz (a,h) anthracene Fluoranthene Indeno (1,2,3-cd) pyrene Pyrene LPAHs in mg/kg 2-Methylnapthalene Acenaphthylene Acenapthene NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE .385 .782 NE NE NE NE .862 NE 2.355 NE .875 NE NE 227 1330-20NE NE 7440-66820 540 315 7440-0275 61 35.9 7439-972 1 0.49 7439-92250 170 91.3 7440-50110 86 197 7440-47110 100 90 7440-4310 3 3.53 7440-3833 17 17 Persaud, 1993 SLC
(1)
EC & MOE, 1992 SEN
(2)
EC, 1994 PEL
(3)
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Anthracene Fluorene Phenanthrene
NE NE NE
NE NE NE
NE NE .515
Table A-4 - Regulatory Cleanup Criteria for Detected Constituents in Sediments (Con’t)
Constituent HPAHs in mg/kg OC Benzo (a) anthracene Benzo (a) pyrene Benzo (b) fluoranthene Benzo (k) fluoranthene Total Benzofluoranthenes Benzo (g,h,i) perylene Chrysene Dibenz (a,h) anthracene Fluoranthene Indeno (1,2,3-cd) pyrene Pyrene LPAHs in mg/kg OC 2-Methylnapthalene Acenaphthylene Acenapthene Anthracene Fluorene Phenanthrene Total PAHs in mg/kg OC NE: Not Established
(1)
Persaud, 1993 SLC
(1)
EC & MOE, 1992 SEN
(2)
EC, 1994 PEL
(3)
1.480 1.440 NE 1.340 NE .320 .460 .130 1.020 .320 .850 NE NE NE .370 .160 .950 10.000
.050 .070 NE NE NE NE .080 NE .200 NE .100 NE NE NE NE NE .080 NE
NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE NE
Persaud, 1993. Guidelines for the Protection and Management of Aquatic Sediment Quality in Ontario EC & MOE, 1997. Interim Criteria for the Evaluation of Sediments of the St Laurence River SEN-Toxic EC, 1994. Interim Sediment Quality Assessment Values (Draft).
SEL-Severe Effect Level.
(2)
Effect Level.
(3)
PEL - Probable Effects Level. OC - Indicates concentration was adjusted using the total organic carbon content in the sample.
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