State of Oregon Department of Environmental Quality Memorandum

To: Rich Muza and Kristine Koch, US EPA Date: February 3, 2014

Through: Keith Johnson, NWR Cleanup and Site Assessment

From: Mark Pugh, Project Manager Alex Liverman, Portland Harbor Stormwater Coordinator

Subject: Revised Source Control Decision Former Columbia American Plating Site ECSI # 29

Responsible Party (RP): 3003 NW 35th LLC Operator: Carson Oil Company, Inc.

RP Contact: Project Consultant: Martha Sharp Chris Wohlers 3125 NE 35th Avenue Wohlers Environmental Services, Inc. Portland, Oregon 97296 7440 SW Hunziker Street, Suite C 503-224-8500 Tigard, Oregon 97223 [email protected] 503.670.1344 (telephone) 503.670.1701 (fax)

1.0 INTRODUCTION

This revised Source Control Decision (SCD) provides DEQ’s summary of a source control evaluation and source control measures that have been completed for the former Columbia American Plating site, located at 3003 NW 35th in Portland, Oregon (Figure 1). The revised SCD was prepared to address November 22, 2013 comments from the United States Environmental Protection Agency (EPA) on the draft SCD dated October 28, 2013. The evaluation was completed in accordance with the Joint Source Control Strategy (JSCS; DEQ and USEPA, 2005).

The site is located approximately 3,000 feet south of a portion of the Willamette River within the area designated by EPA as the Portland Harbor Superfund Study Area. In December 2008, 3003 NW 35th LLC and DEQ signed a Consent Judgment that required site investigation and source control measures as needed, and completion of a source control evaluation.

Based on DEQ’s preliminary evaluation of potentially complete pathways to Portland Harbor it was apparent that site stormwater discharge to the City of Portland stormwater conveyance lines, which then discharges to the Willamette River via City Outfall #18, was the primary pathway of concern at the site. Soil and groundwater at the site also were investigated. Stormwater source control measures completed by 3003 NW 35th LLC include removal of legacy from historic operations from the on-site and adjacent City of Portland storm drain lines and upgrades to the on-site stormwater system in compliance with the 2012 NPDES 1200Z Industrial Stormwater general permit that covers current operations at the site. 3003 NW 35th LLC prepared and submitted a source control evaluation report upon completion of four stormwater sampling events to assess effectiveness following implementation of the source control measures (Wohlers 2013).

The chief objectives of the stormwater source control evaluation are: A) to determine whether existing and potential stormwater contamination sources have been identified; and B) to determine whether Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 2 of 21 additional characterization or source control measures are needed at the site. These determinations generally rest upon demonstrating that site-related information provides sufficient support to make the following findings:

1. Existing and potential facility-related contaminant sources have been identified and characterized. 2. Historical and on-going contaminant sources have been removed or are being controlled to the extent feasible. 3. Performance monitoring conducted after Source Control Measures (SCMs) were implemented supports the conclusion that the SCMs are effective. 4. Adequate measures are in place to ensure source control and good stormwater management measures occur in the future.

Based on a review of the source control evaluation report and related documents, DEQ concludes that this site is not a significant ongoing source of contaminants to the Willamette River, and that source control measures implemented at the site are adequate to control potential future discharges. This determination is predicated on continued implementation of source control measures described in the facility’s stormwater pollution control plan and stormwater monitoring required by the NPDES 1200Z permit. DEQ will continue to review site monitoring and permit compliance to ensure the effectiveness of source control. A discussion of site conditions, monitoring results, source control measures, and the basis for DEQ’s SCD are presented below.

2.0 SITE DESCRIPTION AND HISTORY

2.1 Site Description

Site property is located in the Guild’s Industrial Sanctuary of northwest Portland, in the northwest corner of Section 24, Township 1 North (T1N), Range 1 East (R1E) (Figures 1 and 2). The site covers 1.25 acres and is comprised of tax lot 300 (property ID No. R117688) and Tax Lot 100 (Property ID No. R117690). Zoning is heavy industrial and unlikely to change in the future given the site’s location in the Guild’s Lake Industrial Sanctuary. Therefore, residential exposure scenarios are not applicable to the site.

The site property is bounded on the north side by Carson Oil (ECSI # 1405), on the west side by Container Management Services (aka, Myers Container Corporation; see ECSI #4784), on the east side by NW 35th Avenue, and on the south by Lake , which is unpaved. Carson Oil is the current operator at the subject site, with similar petroleum distribution-related activities occurring at both 3003 and 3125 NW 35th properties.

The site is located within a 38-acre sub-basin in the east-central portion of the Outfall #18 stormwater basin (Figure 3). Stormwater flows north in the City of Portland stormwater lines along NW 35th, with contribution from numerous other stormwater laterals and lines, and ultimately discharges into the river at outfall #18 at river mile 8.8. Overland flow of stormwater from the site to the Willamette River does not occur.

Because the site provides no ecological habitat, DEQ did not require an ecological risk assessment for terrestrial animals. The potential for ecological risk due to the site stormwater discharge to the Willamette River was evaluated as discussed below.

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2.2 Site Features

A building occupies the majority of the northern Tax Lot 100, while Tax Lot 300 is vacant (Figure 2). With the exception of landscaping in the northeast, the site is covered by pavement, buildings or other hardscape. During historical operations the southwest site area was unpaved and used for drum and equipment storage (Figure 4).

Plating operations were conducted inside on the main concrete floor of the building. A smaller office and basement area were located on the east side of the building.

2.2.1 Stormwater System

The historical storm drain line configuration and 2009 sample locations are shown on Figure 5.

During initial site development in 1958, the eastern part of the building was constructed and a single storm drain line running west to east beneath the building was installed to manage stormwater. This line was subsequently cut and plugged in the mid-1980s, likely when the building was expanded and another storm drain line, the north and south catch basins, and the sump were installed. The sump was 8 feet deep and the catch basins were 2.5 feet deep. The sump also received roof runoff. Sump water was pumped to a 4-foot deep storm drain lateral that connected to the City line in NW 35th Avenue.

The northern catch basin is located in a loading dock area and was plugged sometime prior to 1993, under orders from the City of Portland, to prevent site runoff from directly entering the City storm sewer. Accumulated stormwater in the loading dock area was then collected and treated in a former site system located along the north side of the building, before being discharged to the sanitary sewer. Treated wastewater was also reportedly pumped to the sump and ultimately discharged to the storm drain line. In the mid-1990s the southern storm drain line reportedly collapsed, causing stormwater to accumulate in low lying areas, which was collected and used in site processes or discharged to the sanitary sewer.

Upon termination of site operations in May 2003, there was no active stormwater management.

During a November 30, 2004 site visit, DEQ observed the loading dock area to be filled with an estimated volume of about 1,000 gallons of accumulated rain water. The water had a slight petroleum sheen, and a partially submerged transformer housing was observed.

The site stormwater system was upgraded in 2010 (Figure 2). The sump was abandoned and the original north catch basin was replaced. Two surface water catch basins and several onsite building roof drains collect precipitation/surface water at the subject site. Catch basins CB-S and CB-N are located on the eastern portion of the site and collect surface level water/precipitation that flows over the asphaltic site surface to discharge to the two catch basins. Roof surface precipitation is collected in three roof drains and discharges directly to the onsite oil-water separator. The two catch basins have an interior sump that allows solids to settle in the bottom of the catch basin and each catch basin is fitted with a non-woven polypropylene fabric filter with an attached oil/grease absorbent bag designed to reduce the discharge of oil and grease, suspended solids and associated .

In addition, each catch basin is equipped with a Flo-Stop valve that includes a ball valve that closes if petroleum is present in the surface water inflow stream, preventing liquid flow out of the catch basin and release of accumulated petroleum product in the event of a petroleum release.

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The two catch basins are cleaned once per year and the filters are replaced as needed based on observations associated with monthly site stormwater system inspections.

Stormwater discharged from the two catch basins and from the three roof drains enters a treatment system that initially includes a 1700-gallon capacity coalescing plate oil water separator designed to remove residual oil from the discharged water. Treated water is then discharged to a precast manhole Contech StormFilterR stormwater filtration system. The filtration system includes seven rechargeable media-filled cartridges that trap particulate matter and adsorb other pollutants such as metals, hydrocarbons and nutrients (e.g., phosphorous).

Following the treatment process described above, collected/treated water flows to a wet well equipped with a pump that transfers stormwater to a manhole with a discharge pipe to the City of Portland municipal stormwater system located in the adjacent N.W. 35th Avenue right of way. All components of the stormwater system are installed at depths of 5.5 feet or less, with the exception of the wet well, which extends to about 12 feet below ground surface (bgs). The wet well is constructed of concrete with 5-inch thick sidewalls and a 6-inch thick bottom.

2.3 Current and Historical Site Operations

The building was constructed in two phases. The original building structure was constructed in 1958 and consists of the eastern part of the building and its basement. The building was expanded in the mid 1980s to include the main plating room. The site operated as a plating facility from 1975 to 1987 as the Kirsten Corporation, and by Columbia American Plating from 1987 to 2003, when it was closed under order by the City of Portland Bureau of Fire and Rescue due to public health and safety concerns. Electroplating operations used a variety of hazardous materials, including acids, bases, various metals and metallic solutions (e.g., zinc, nickel, copper, chromium, cadmium), solvents, and oxidizers. The main plating area was primarily used for zinc plating. Kirsten Corporation reportedly conducted precious metal plating in the basement. Cyanide was used until 1991, when further discharge of potential cyanide containing water was prohibited by the City of Portland. Chlorinated solvents trichloroethene (TCE) and 1,1,1- trichloroethane (TCA) were used for degreasing/cleaning from 1987 to 1991.

Hazardous waste streams included sludges generated from cleaning and the water treatment system, spent cyanide and spent TCE and TCA, which are classified as F006 hazardous waste, F008 waste and F002 waste, respectively. Large volumes of solutions containing spent acid and caustic plating/rinse waters were treated on-site and discharged to the City of Portland sanitary sewer under permit. Over 200 drums and containers of hazardous waste and other site-related process chemicals were routinely stored at the site. Poor waste management practices were the subject of numerous enforcement actions as discussed below in Section 3.0. The site was abandoned in 2003, leaving numerous containers of waste materials, process chemicals and stormwater accumulated at the site.

In 2009, 3003 NW 35th LLC assumed ownership and began development of the site. The older southern building and basement were demolished and converted to parking space. A new concrete floor was installed in the former plating building, which was refurbished into a warehouse. All equipment from previous operations was removed by 2011. Most of the exterior area was paved and the stormwater system was upgraded.

Current operations include storage, sale and distribution of petroleum products. The outside area is used for parking for Carson Oil fleet vehicles. These activities correspond to standard industrial codes 4226- Special Warehousing and Storage and 5172-Petroleum & Products Wholesale. Up to approximately 20,000 gallons of petroleum-related products, including diesel, lube oil, diesel exhaust fluid, are stored in

Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 5 of 21 the warehouse. Truck washing operations are conducted at the site by an off-site vendor. Wash water is collected and disposed of in the sanitary sewer with approval from the City of Portland.

2.4 Site Geology and Hydrogeology

Site property is located near the southwest edge of the Portland basin, a northwest-southwest trending structural feature that contains a thick sequence of alluvial deposits overlying basalt lava flows of the Columbia River Basalt Group (CRBG) (Beeson et al., 1991; Swanson, et al., 1993). The Tualatin Mountains, which bound the northwest edge of the basin, are located approximately 0.25 miles southwest of the site.

From top to bottom, the alluvial deposits in the basin consist of Quaternary deposits (artificial fill, flood plain and channel deposits of the Willamette and Columbia rivers, and deposits from Ice Age catastrophic floods from glacial Lake Missoula), and older alluvial deposits of Pliocene to Miocene age (Troutdale Formation and Sandy River Mudstone) (Beeson et al., 1991). The Quaternary and older sedimentary deposits overlie the Miocene-age CRBG that consists of a series of flood basalt flows of varying extent, thickness, structure, magnetic polarity, and geochemistry that cover portions of western Idaho, Oregon, and Washington. In the Portland basin, the CRBG occurs at its shallowest depth near the edges of the basin and slopes toward the center of the basin where it is more than 1,600 feet below ground surface (bgs) in the Vancouver, Washington, area (Swanson et al., 1993).

The site was constructed on sand with and fill deposited as dredge spoils. Emplacement of the fill is thought to be related to development of the area in the early 1900s for the Lewis and Clark Exposition. The fill is generally brown in color and extends to a depth of 12 feet or more at the site. The fill is underlain by gray native alluvial sand that extends to at least 35 feet bgs at the site. The native sand overlies a silty unit that extends to about 50 feet bgs, the maximum exploration depth at the site. The silt likely represents ancient deposits.

Sandy unconsolidated deposits with clay or gravel interbeds generally extend to a depth of about 100 feet in the area, and are underlain by the Pleistocene Troutdale Formation, a , gravel and conglomerate unit, commonly cemented, that is an important regional water supply aquifer.

Permanent monitoring wells have not been installed at the site. Wet soil was encountered at depths of about 8 to 12 feet in the 33 borings completed by EPA in June 2003 (EPA, 2004). However, it appears that sufficient water for sampling was not available until borings reached about 15 feet bgs, presumably the depth of the saturated zone. Shallow groundwater was found between 13 and 15 feet bgs in borings advanced in August 2008, when shallow groundwater would expect to be at or near seasonal lows. Shallow groundwater monitoring in wells installed at the adjacent Carson Oil property show a seasonal range of groundwater depth varying from 8 to 11.5 feet bgs, and a groundwater flow direction to the north or northwest (e.g., Wohlers, 1999, consistent with topography, surface water patterns, and the location of the Willamette River.

3.0 REGULATORY HISTORY

In 1975, DEQ issued Air Contaminant Discharge Permit #26-2809. No major violations were noted as of 1993. The site was registered by DEQ as a Large Quantity Generator of hazardous waste (ORD068788926), and operated under a City of Portland Wastewater Discharge Permit (#413-005) for discharges to the sanitary sewer. In 1991, Columbia American Plating was fined by the City and prohibited from further cyanide discharges to the sanitary sewer.

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Repeated Resource Conservation and Recovery Act (RCRA) waste management violations throughout the 1980s resulted in DEQ enforcement action in 1990. A series of appeals resulted in a Consent Agreement under which Columbia American Plating was to remove all accumulated waste by 1993. DEQ completed a Preliminary Assessment of the site in 1993 and noted that some waste had been removed, but observed waste containers and drums still present on site, some appearing corroded and/or in poor condition.

Following closure of the facility in 2003, DEQ requested EPA assistance in evaluating and mitigating threats to human health from the voluminous hazardous waste and materials left at the site. EPA issued an action memorandum for a removal action in May 2003, and completed the removal action as discussed in Section 4.

In July 2004, DEQ’s Site Assessment Program reviewed site information following the EPA removal action and determined it was a high priority for a response action, with uncontrolled stormwater discharges a major concern.

In December 2008 DEQ entered in a Consent Judgment with 3003 NW 35th LLC as part of their purchase of the site property. Prior to the Consent Judgment 3003 NW 35th LLC completed additional investigation as summarized in Section 4.5.

The Consent Judgment Scope of Work included the following:

 Completion of a source control evaluation in accordance with EPA and DEQ’s Joint Source Control Strategy (DEQ/EPA, 2005) to include sampling and analysis of catch basin , stormwater and contents of the storm drain lines, identification and characterization of potential sources of contamination to the storm drain system, and a camera survey assessment of the presence of site-related sediment in City stormwater pipes

 Completion of source control measures to remove site-related sediment from City storm lines and/or to address stormwater runoff with the potential to adversely affect the Willamette River

 Appropriate management and disposal of concrete debris piles and concrete generated during future development

 Coating the interior floor to minimize contact by site workers

 Preparation of a groundwater risk screening memorandum to include a beneficial water use survey within the locality of facility as defined in Oregon Administrative Rule (OAR) 340-122- 0115 (35)

Details of this work are provided in Sections 7 and 8. Currently, stormwater discharges at the site are managed under a NPDES 1200Z Industrial Stormwater general permit issued by DEQ in 2007 and renewed, with significant changes in July 2012. Carson Oil was assigned coverage in August 2012 under the 2012 permit following completion of the stormwater system upgrades at the site, as documented in an updated Stormwater Pollution Control Plan included as Appendix C of the Revised Source Control Evaluation (Wohlers, 2013).

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4.0 HISTORICAL INVESTIGATIONS AND CLEANUP 4.1 Carson Oil Site Investigation-1992 Carson Oil completed environmental investigation on their property immediately north of the former plating site (Cascade Earth Sciences, LTD, 1992). Groundwater collected from temporary borings near the property line contained elevated levels of TCE (up to 240 ug/L) and total cyanide (up to 30 ug/L). Lower to non-detect levels were detected in other borings, suggesting the former plating operation was the source. 4.2 DEQ Preliminary Assessment-1993 DEQ’s Preliminary Assessment documented site operational history, the high volume of hazardous waste and material observed during a site visit, and poor waste management practices (DEQ, 1993). Due to the type and amount of waste present, DEQ requested EPA to complete an investigation to include soil and groundwater sampling. 4.3 EPA Site Inspection-1993 The scope of EPA work included advancing 10 shallow borings for collection of 17 soil samples for various analyses (Weston, 1994). Sample locations are shown on Figure 4. Groundwater samples were not collected. Soil samples were collected at depths ranging from 1 to 11 feet bgs and analyzed for volatile organic compounds (VOCs), polychlorinated biphenyls (PCBs), metals and base/neutral/acid compounds, which include polycyclic aromatic hydrocarbons (PAHs). Soil analytical results are shown on Tables 1 through 3. Generally low or non-detect concentrations were reported in the majority of samples. Elevated levels of several metals were detected, most notably cadmium in shallow soil along the north side of the property. Cadmium was detected in SB-007 at 108 mg/kg, and at 300 mg/kg in SB-008. These borings targeted the water treatment area and north catch basin, respectively. PCBs were detected in only one of thirteen samples and results were not tabulated in the report. The only detection of PCBs was Aroclor 1260 in sample SB02, collected from 1 foot bgs near the western property boundary. 4.4 EPA Removal Action and Investigation-2003 In response to a request from DEQ’s Emergency Response Program, EPA completed a removal action at the site from May 2003 to April 2004 (EPA, 2004). The objective of the removal action was to stabilize the site, remove hazardous substances and debris for off-site disposal, and evaluate the need for additional investigation. Stabilization measures included securing containers with covers and establishing a stormwater and decontamination water collection and treatment system. Building surfaces and the storm drain system were pressure-washed multiple times. Some water had to be disposed off-site as hazardous waste. A total of 1460 containers, most containing liquids, were sampled and characterized to determine disposal options. A total of 77,507 gallons of hazardous liquids and 560 cubic yards of hazardous and non- hazardous debris were removed from the site. 4.4.1 EPA Stormwater Management The poorly functioning stormwater management system at the site necessitated EPA active management and disposal of accumulated stormwater, in addition to water generated during pressure washing. A total of 33,000 gallons of water was treated and discharged to the sanitary sewer under permit from the City of Portland Bureau of Environmental Services.

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The initial 20,000 gallons of accumulated stormwater was tested and s discharged to the sanitary sewer in September 2003. EPA sampled stormwater that subsequently accumulated in the south storage area (SSA) and north storage area (NSA). Initial results showed levels of arsenic, copper, molybdenum, nick, silver, zinc and cyanide were above discharge limits for sanitary sewer disposal in the SSA, while the NSA sample concentrations were substantially lower and met discharge limits (Table 4., “SSA/Catch Basin”- 03070913 and “NSA/Catch Basin”-03070914). EPA installed pumps in the north and south catch basin areas to collect stormwater as it was generated, and conducted further testing. Due to persistent elevated levels of various metals, EPA set up a water treatment system, pressure washed all hard surfaces in the north and south areas twice, and containerized wash water . In January 2004, a water pipe burst requiring management of an additional 15,000 gallons of water that accumulated in the basement. EPA treated this water, along with water generated during previous pumping and pressure washing events, using filtration and a cation/anion exchange system utilizing flow through resin beds.

At the completion of EPA work, accumulated water in the north and south area catch basins was sampled again (Table 4, “SSA/Catch Basin”-03070923 and “NSA/Catch Basin”-03070924). Concentrations were considerably lower than initial sample results, and all were below sanitary discharge permit levels. However, most detected concentrations were above DEQ/EPA JSCS screening criteria for stormwater. Arsenic, mercury, selenium and cyanide were not detected in the second round of sampling.

4.4.2 EPA 2003 Soil and Groundwater Investigation

In July 2003, EPA completed an investigation that included advancing 33 soil borings to 15 feet bgs (Figure 6). A total of 109 soil samples and 30 groundwater samples were collected. A test pit was advanced west of the southern parking area for sample collection and to observe soil conditions and fill material. Approximately 34 soil samples generally were analyzed for cyanide, RCRA metals (inorganics), SVOCs including PAHs and bis(2-ethylhexyl)phthalate (also known as BEHP), and VOCs. Thirty groundwater samples were analyzed for RCRA metals (inorganics) and cyanide. Thirteen groundwater samples were analyzed for VOCs and SVOCs.

Groundwater and soil results for cyanide are shown on Table 5. Inorganic results for soil and groundwater are shown on Tables 6 and 7, respectively. SVOC and VOC results for soil and groundwater are shown on Table 8. It should be noted that some EPA and DEQ screening criteria for human health listed on the tables have been revised since 2003, but are considered acceptable for human health risk screening.

EPA 2003 Soil Results

The majority of detected soil concentrations were below EPA Region 9 Preliminary Remediation Goals (PRGs) in use at that time. Arsenic was detected in several samples above the PRG, but within the range of expected background concentrations in the Portland Basin (DEQ, 20131). Only one chromium concentration exceeded 2009 PRGs, the human health criteria in use at that time. The current screening criteria for total chromium are substantially higher.

Cadmium, chromium and lead were detected above the JSCS SLV in a number of samples. Mercury was above its SLV for bioaccumulation in about half samples analyzed, but most detected concentrations are consistent with the background level of 0.2 mg/kg for the Portland Basin (DEQ, 2013), and all concentrations are below the SLV based on toxicity.

1 DEQ has identified the following background metal concentrations for the Portland Basin (all in mg/kg): arsenic- 8.8; cadmium-0.63; chromium-76; copper-34; lead-79; mercury-0.23; selenium-0.71; silver-0.82; zinc-180.

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Cyanide was detected at up to 16.6 mg/kg, and below human health screening criteria. There is no SLV established for cyanide in soil.

VOCs were not detected in soil. SVOC detections were limited to soil borings BH-24, BH-28, BH-29, and BH-32, located generally in the central, east central edge, northeast corner and southern edge of the site property. PAHs were the only SVOCs detected, with the exception of one BEHP detection in the sample collected from 8-10 feet bgs at BH-28.

Of the PAHs, only benzo(a)pyrene in deep soil samples (8-10 feet) from BH-24 and BH-32, was detected above human health screening criteria. SVOC concentrations in soil are below their respective JSCS criteria. It should be noted that detection limits for BEHP were elevated above its SLV (330 ug/kg) in a number of samples, primarily borings advanced beneath or near the plating area, where elevated levels of BEHP in groundwater were observed as described below.

EPA 2003 Groundwater Results

TCE, PCE, cyanide and BEHP were the primary contaminants detected in shallow groundwater. SVOCs and metals were detected at generally low frequency and/or concentration. TCE, cyanide and BEHP results for the 2003 EPA sampling are shown on Figures 6, 7 and 8, respectively.

The highest TCE concentration of 96 ug/L was detected at BH-20, located near the northern property boundary, whereas the three samples collected in the vicinity of the former TCE tank contained less than 13 ug/L.

Cyanide was detected in seven of thirty samples collected by EPA. Detections were generally limited to the northern part of the site property. Detections are not contiguous between sample locations and do not indicate an ongoing source of cyanide or a significant cyanide plume. All detected concentrations exceed the SLV for ecological receptors (5.2 ug/L). Only two EPA samples exceed the EPA Maximum Contaminant Level (200 ug/L) and the tapwater PRG (730 ug/L). Subsequent sampling detected a higher level of cyanide near BH-20 as discussed below. These detections are not of concern given the lack of a complete exposure pathway to ecological receptors and lack of drinking water use in local groundwater.

BEHP was detected in most of the shallow groundwater samples. The highest levels occur in the southwest part of the former plating room, with a maximum detected concentration of 524 ug/L at BH-1, located near the western property boundary. BEHP detections were well above the SLV for groundwater of 2.2 ug/L. The source of the BEHP is not clear as there is no historical record of its use at the site, and it is not known to be used in the plating process. Investigations are ongoing at the drum and container processing business immediately west of the site to assess if it is a source of BEHP.

Based on available data in 2005, there did not appear to be any significant risk to human health or the environment. However, DEQ determined that additional sampling to fill data gaps in sample coverage and support a source control evaluation were needed to completely address environmental concerns at the site (DEQ, 2005). These recommendations were the basis for the work completed in 2008 and during the subsequent source control evaluation described below.

4.5 Focused Site Investigation-2008

Carson Oil completed a site investigation to better define site environmental conditions in anticipation of purchasing the site property (BB&A, 2008). The results of the investigation were used to identify a Scope of Work to be completed by 3003 NW 35th LLC under terms of the DEQ Consent Order. Sample

Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 10 of 21 locations are shown on Figure 9. Results for soil and catch basin sediment sampling are shown on Table 9. Results for water samples are shown on Table 10.

4.5.1 2008 Catch Basin Sediment and Water Sampling

Sediment from the two catch basins (samples “SDN-S” and “SDS-1”) was analyzed for Toxicity Characteristic Leaching Procedure metals, total metals, VOCs, and/or PCBs. Standing water collected from the north drain area (SDN-SW; SDNSW2) was analyzed for VOCs, dissolved metals and PCBs.

Metals in SDS-1 were detected at concentrations an order of magnitude or more above JSCS SLVs for catch basin sediments. PCBs were detected at concentrations of 0.341 mg/kg (Aroclor 1254) and 1.07 mg/kg (Aroclor 1254) in the north and south catch basin, respectively. Sediment removal and a storm line cleanout was completed as a source control measure as discussed below.

Copper (2 ug/L) and zinc (32.1 ug/L) were the only analytes detected in the standing water sample. Detected concentrations were below JCSC SLVs for surface water.

4.5.2 Plating Room Soil

Nine shallow borings were advanced to a depth of five feet beneath the former plating room for soil sample collection. Samples were analyzed for cadmium, chromium, copper, lead, silver and zinc and cyanide. Chromium, copper, lead and zinc were detected at concentrations below DEQ risk-based concentrations (RBCs) for human health (DEQ, 2012) and JSCS screening criteria, and appear consistent with naturally occurring concentrations (DEQ, 2013).

Cyanide was detected in two soil samples at low concentrations of 0.376 and 0.586 mg/kg, well below DEQ human health screening criteria.

4.5.3 Former TCE Tank Area

Two borings were advanced in the TCE tank area for soil and groundwater collection. One sample was collected near BH-20 where the highest level had been detected during the EPA investigation. Groundwater samples were collected at depth intervals of approximately 15, 30 and 50 feet to assess vertical contaminant distribution just south of the former TCE tank area.

Relatively low levels of TCE were detected (<25 ug/L) in groundwater (Figure 6). TCE was not detected in the sample from the 30 or 50 foot depth interval, indicating that TCE is limited to the uppermost shallow groundwater. A sample collected near BH-20, the EPA sample with the highest concentration (96 ug/L) had a relatively low TCE concentration of 21 ug/L, and likely reflects natural attenuation of TCE in groundwater since EPA sample collection in 2003. TCE levels exceed DEQ RBCs for drinking water, but are below other human health RBCs.

Cyanide was detected in shallow (15 feet), intermediate (34 feet) and deep groundwater samples (50 feet) near B-20, but not detected in the other two 2008 groundwater sampling locations (Figure 7). The cyanide concentration of 2,180 ug/L in shallow groundwater is this highest level detected at the site. Cyanide concentrations decreased with depth from 2,180 ug/L at 15 feet to 34 ug/L at 50 feet.

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4.6 City of Portland Storm Line Assessment and Cleanout – 2003-2010

Between 2003 and 2010, the City of Portland Bureau of Environmental Services completed sampling and cleanout of storm drain lines in the Outfall 18 Basin as part of the City Outfalls Project (BES, 2012; see ECSI #2425). This work was conducted under terms of a 2003 Intergovernmental Agreement with DEQ and included sampling City lines located on NW 35th (Figure 3). Inline solids results from City sampling are summarized on Table 11. Data collected by 3003 NW 35th LLC during their source control evaluation are included for comparison.

The concentrations of metals (especially cadmium, chromium, copper, lead and silver) and phthalates detected in on-site sediment samples were generally an order of magnitude or higher than detected in the sediment samples collected from the City storm line. Elevated levels of metals are consistent with site operations, while the source of phthalates remains unclear.

PCBs were detected at overall higher concentrations in the City samples, indicating there were likely other sources contributing PCBs in the storm lines on NW 35th Avenue.

In 2010, the City cleaned out approximately 3,000 feet of storm lines along NW 35th Avenue, including the section adjacent to the site. A sample collected to represent the segment near the site contained elevated leachable lead levels, requiring disposal as hazardous waste. The sample also contained total PCBs at 1.4 mg/kg.

A total of about 39 tons of sediment and sludge were removed and disposed. Due to the elevated lead levels, about 10 tons was disposed as hazardous waste. The remaining sediment was disposed of at the waste management facility in Hillsboro, Oregon. Approximately 20,000 gallons of water generated during the cleanout was discharged under permit to the City sanitary sewer.

Post-removal sampling showed that maximum concentrations typically decreased by an order of magnitude. The City concluded that much of the legacy contamination had been removed from both private and public storm drain lines in the area, and that no further assessment was needed in this segment of the system (BES, 2012).

5.0 POTENTIAL SOURCES AND CONTAMINANTS OF INTEREST

5.1 Potential Contaminant Sources

Given the long operational history, associated high volume of process chemicals and poor hazardous waste management practices, there are a number of potential source areas at the site. These include the interior plating room and basement, the TCE tank area, exterior waste storage areas, the former unpaved debris storage and disposal area in the southwest corner of the site, and the former waste water treatment system. Observations of a partial transformer submerged in the loading dock area and subsequent detections of PCB in the associated catch basin indicate the transformer may have been a source of PCBs.

Potential contaminant sources related to ongoing operations appear to be limited to incidental spills of various petroleum products stored in the building and drips or incidental releases from vehicles. Currently, there are no hazardous wastes generated at the site and no hazardous substances stored outside the building.

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5.2 Contaminants of Interest

The following COIs were identified for the source control evaluation: - Metals (cadmium, copper, chromium, lead, mercury, nickel, silver, and zinc) - Cyanide - PCBs - Organochlorine - VOCs - Semi-volatile organic compounds (SVOCs), including phthalate esters - PAHs

With the exception of organochlorine pesticides, COIs were based on their historical use in site processes or detections in historical samples. DEQ requested that organochlorine pesticides be included as COIs in initial catch basin and storm water sampling due to their occurrence in a number of sites in the and to assess whether site was a contributing source. Due to impairment listings of the lower Willamette River water column, DEQ’s 1200Z stormwater permits for this basin require analysis of aldrin, DDT and DDE in stormwater.

5.3 Contaminated Media

Inline solids, primarily impacted by metals, were present in the site stormwater conveyance prior to source control actions. Source control measures described below removed the majority of the material. Significant volumes of contaminated inline solids were also present in the City lines adjacent to the site along NW 35th Avenue during the initial source control evaluation in 2009, contributed by multiple properties along NW 35th and the unpaved Lake Road. The City of Portland completed additional storm line cleanout of lines along NW 35th Avenue in 2010 (BES, 2012). Under current operations, a low volume of sediment accumulates in the on-site stormwater catch basins, but is periodically removed.

Generally low level contamination is present in site soil and groundwater.

6.0 HUMAN HEALTH RISK SCREENING

In 2005, DEQ completed a screening level risk assessment, using data collected by EPA during the Site Investigation and Removal Actions described below, and identified additional work needed to address environmental concerns at the site (DEQ, 2005). Generally low or non-detect concentrations were reported in the majority of samples with only arsenic, benzo(a)pyrene, and chromium above risk-based standards for human health (Table 12). Arsenic concentrations appear consistent with expected naturally occurring concentrations (DEQ, 2013). Benzo(a)pyrene was detected in only 3 of 36 samples (8%), with only one reported concentration above risk-based criteria. Chromium exceeded its risk-based concentration in only one sample. The 90% upper confidence limit of the mean concentration for chromium site-wide was 40 mg/kg, which is well below applicable human health screening criteria and consistent with naturally occurring concentrations. Based on available data in 2005, there did not appear to be any significant risk to human health.

The only potentially significant contamination in groundwater related to human health is cyanide and TCE in groundwater near the property boundary (Figure 6, Figure 7). TCE likely originated from the TCE tank area at the site and migrated up to about 300 feet to the north based on data collected in 1992. More recent sampling indicates it has attenuated since that time. TCE levels are not above DEQ RBCs for direct contact or vapor intrusion, but are above drinking water standards.

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Cyanide concentrations also are above drinking water standards, but below other DEQ RBCs.

Due to the site’s location in the Guilds Lake Industrial Sanctuary, it is unlikely that local groundwater is or will be used as a drinking water source in this area. Thus TCE does not present a human health risk.

7.0 POTENTIALLY COMPLETE CONTAMINANT MIGRATION PATHWAYS TO THE WILLAMETTE RIVER

7.1 Stormwater

The site contributes stormwater to City of Portland storm lines that discharge at Outfall 18 into the Willamette River, making this a complete pathway. Given the distance and physical separation from the river, however, the overland flow pathway is not complete. Stormwater was the only complete pathway for transport of contaminants to the river considered in the source control investigation and this decision.

7.2 Groundwater Discharge to the Willamette River

Site-related contaminants do not appear to present a threat to the Willamette River based on the distance of about 3,000 feet to the river and generally low concentrations detected in groundwater. Since this pathway is incomplete, this low level contamination is not significant from a source control perspective and no source control measures were warranted.

7.3 Groundwater Infiltration into Storm Lines

Shallow groundwater occurs at about 12 feet bgs at the site. This is well below the on-site stormwater lines and most of the stormwater treatment system components, and the City of Portland storm drain lines in the vicinity of the site. The bottom of the wet well component of the stormwater treatment system is approximately 12 feet, and thus within the range of seasonal water table fluctuation. The wet well is constructed of concrete with 5-inch sidewalls and a 6-inch bottom. It is unlikely that significant groundwater could infiltrate this structure. In addition, the location of the stormwater system is not located near contaminant sources, and does not appear to be intersect significant groundwater contamination in the event infiltration were to occur (see figures 6, 7 and 8).

Thus groundwater infiltration into the storm drain conveyance is not considered a significant pathway of concern and no source control measures are warranted.

8.0 STORMWATER SOURCE CONTROL MEASURES

8.1 Stormwater Conveyance Assessment

On-site stormwater conveyance assessment was conducted from 2008-2009 with DEQ oversight under terms of the Consent Judgment (O’Gara, 2009). Initial mapping and camera surveys identified the storm system layout shown on Figure 5.

In August 2008, sediment and water samples were collected from the on-site catch basins. In May 2009 the north and south storm line laterals were cut near the connection with the City line in order to plug the pipe for subsequent jetting, and for grab sediment sample collection. Samples from other line segments were collected during jetting. Samples A through G represent on-site line segments shown on Figure 5.

Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 14 of 21

The north line was dry and contained minimal sediment. Significant sediment was observed and sampled in the south storm sewer connection sample. Samples also were collected from the City lines.

In addition, standing water in the loading dock area and wash water generated during on-site and off-site line jetting were analyzed.

Samples generally were analyzed for various metals (cadmium, chromium, copper, lead mercury, nickel, silver and zinc, and cyanide) VOCs (sediment only), PCBs, PAHs, and phthalate esters (sediment only).

8.1.1 On-site Stormwater Solids Sampling Results and Cleanout

Inline Solids

Sampling results for inline solids collected in May 2009 from the on-site stormwater conveyance are shown on Tables 13 through 16. High levels of metals, with the exception of mercury and cyanide, were detected in every sample. Elevated levels of phthalates also were detected. Concentrations of metals and phthalates commonly exceed their respective SLVs by ten times or more.

PCBs were detected in three of four samples analyzed, with a maximum total PCB concentration of 690 ug/kg (440 ug/kg Aroclor 1254; 250 ug/kg Aroclor 1260). This level is marginally above the toxicity SLV, but well above the bioaccumulation SLV.

PAHs were detected at relatively lower levels, with only two compounds detected above SLVs. Because only low levels of three VOCs were detected, they are not shown on data tables. Organochlorine pesticides were not detected and were not carried through as COIs for the source control evaluation, although aldrin, DDT and DDE were still analyzed in 1200Z stormwater sampling as required under permit (see section 9.3).

Overall, the concentrations were consistent with previous sampling results in 2008 and indicated removal of inline sediments was warranted.

On-site Wash Water

Sample results for water generated during the May 2009 storm line cleanout are shown on Tables 17, 18 and 19. Relatively high levels of metals and PAHs were detected. PCBs were detected above JSCS SLVs.

Line Cleanout

All on-site lines historically used to convey stormwater were jetted and cleaned with the exception of the north storm line, which was permanently plugged, dry, and contained no appreciable sediment. A total of 3,740 gallons of wash water and accumulated water in the loading dock area and 2.5 tons of solids contaminated by legacy site activities were removed from the on-site system. The inline solids were disposed off-site as F-06 listed waste from plating sludge from electroplating operations.

8.1.2 Off-site Stormwater Conveyance Sampling and Cleanout

Inline Solids

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Inline solids results for the City storm drain line in NW 35th Avenue are shown on Tables 20 through 23. Results for water generated during off-site and on-site cleanout activities are included on Tables 17, 18 and 19.

Concentrations of metals, PAHs and phthalates were substantially lower in off-site sediment compared to on-site samples, suggesting the site may have been a source for these contaminants. Up to 7,500 ug/kg total PCBs were detected in off-site sediment, compared to levels of less than 1,000 ug/kg detected in on- site sediment. This suggests that, in addition to the site, there may have been other contributions to the City line from non-site-related sources.

Because only low levels of three VOCs were detected they are not shown on data tables.

Off-Site Wash Water

Relatively high levels of metals were detected, comparable to those in on-site wash water, although chromium, lead and zinc were somewhat higher in the off-site samples. PCB levels in off-site and on-site wash water are similar. PAHS are notably lower in off-site wash water, although still above their respective SLVs.

Line Cleanout

The City of Portland storm lines in NW 35th are 24-inch diameter concrete pipes at a depth of about 5 feet. The lines were accessed for cleanout and sampling through two manholes. AAX278 is located approximately 300 feet north of the site, and AAX318 is located just south of the site near the intersection of Lake Street and NW 35th Avenue (Figure 3). The line segment between these manholes was approximately one-third filled with sediment. This hampered the camera survey and necessitated partial cleaning of the lines to complete the survey.

A total of 1,490 gallons of wash water and 4.80 tons of inline solids and were removed from the NW 35th Avenue storm line. Significant residual sediment remained in the line. In 2010 the City of Portland conducted additional line cleanouts as described in Section 4.

8.2 Ongoing Stormwater Management

Carson Oil maintains compliance with their 2012 NPDES Industrial Stormwater general permit. Stormwater monitoring and best management practices are described in the Stormwater Pollution Control Plan (Wohlers, 2012) required under the permit. Operational, structural and engineering controls summarized in the plan include:

 Interior storage of petroleum products  Twice annual site-wide sweeping  Off-site vehicle maintenance and fueling  Twice annual catch basin cleanout  Flow-stop valves in catch basins  Catch basin filters  Spill containment around paved surfaces with inlets  On-site management plans for emergency preparedness and response, and spill control and countermeasures  Oil water separator

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 Contech StormFilter®

The initial catch basin cleanout was completed in July 2012, and included sampling of catch basin sediment as described below. The second cleanout was completed in October 2013. A total of 1,928 gallons (water and accumulated sediment) were removed from the two catch basins and oil-water separator during the second cleanout. The six Contech StormFilter® filters also were cleaned and replaced. Sampling was not completed during the second cleanout.

9.0 STORMWATER SYSTEM MONITORING SUMMARY

One catch basin sediment and four stormwater sampling events were conducted. Sampling was completed in accordance with DEQ’s Guidance for Evaluating the Stormwater Pathway at Upland Sites (2010), to evaluate source control effectiveness following site cleanup and installation of the new or enhanced stormwater management system elements. In addition, separate stormwater sampling events were completed per the NPDES 1200-Z permit monitoring requirements.

Grab stormwater samples for the source control evaluation and 1200Z monitoring were collected from a concrete vault approximately 24 inches wide and 12 inches deep. The vault has an influent pipe from the storm filter and an effluent pipe discharging to the City of Portland stormwater conveyance. Water in the vault is the farthest downstream, post-treatment sample location prior to discharge to the City system.

Grab sediment samples were collected directly from the north (CB-N) and south (CB-S) catch basins.

Appendix E of DEQ’s guidance contains a tool for evaluating stormwater data. This tool was created by using contaminant concentration data from many of the stormwater and stormwater solids samples collected at Portland Harbor-area heavy industrial sites. This data is used to create a series of charts that plot rank-order samples against contaminant concentrations, and are used to identify contaminant concentrations in samples that are atypically elevated. Concentrations falling within the upper/steeper portion of the curve are an indication that uncontrolled contaminant sources may be present at the site and that additional evaluation or source control measures may be needed. Concentrations that fall on the lower/flatter portion of the curve suggest that stormwater is not being unusually impacted by contaminants at the site and, while concentrations may exceed the risk-based SLVs, they are within the range found in stormwater from active industrial sites in Portland Harbor.

A summary of the data, compared to JSCS SLVs and the typical curves tool is presented below. Analytical results are shown on Tables 24, 25, and 26 for catch basin solids, Tables 27, 28 and 29 for stormwater, and Table 30 for NPDES 1200-Z stormwater monitoring.

9.1 Catch Basin Sediment-2012

Sediment samples were collected in July 2012 from the north (CB-N) and south (CB-S) catch basins. Approximately 1 inch of sediment was observed in CB-N, with up to two inches observed in CB-S, representing sediment accumulation over approximately 1 year since the new system was installed. A petroleum odor and sheen were noted for CB-S sediment.

The most notable results of the sediment sampling are the high levels of phthalates, particularly BEHP in CB-N. The detected level of 1,300,000 ug/kg is several orders of magnitude higher than its SLV or

Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 17 of 21 previous detections in sediment samples, and much higher than concentrations found in other Portland Harbor area industrial sites (DEQ, 2010). Bis(2-ethylhexyl)phthalate is a plasticizer common in plastic containers and polyvinyl chloride piping and is commonly associated with paint, and lubricants used in petroleum products.

Current site operations are related to and similar to those on the adjacent Carson Oil property, which do not specifically include BEHP. In 2007, DEQ analyzed catch basin solids from the Carson Oil site during site discovery activities in Basin 18 (DEQ, 2008). The BEHP concentration in one of those samples also was quite high (475,000 µg/kg).

Relatively high levels of petroleum hydrocarbon (greater than 10,000 mg/kg) were reported in both catch basin samples. However, PAHs were detected at low concentrations, with only one PAH compound exceeding its SLV for sediment.

With the exception of arsenic in CB-N and cadmium in CB-S, none of the metal concentrations exceeded their respective SLVs. Arsenic and cadmium levels are in the flat part of the rank order curves, indicating that additional source control measures are not warranted.

With the exception of phthalates, all parameters analyzed were either no longer detected or found at significantly reduced concentrations than were found in the sediment removed from the lines in 2008.

9.2 Source Control Evaluation Stormwater Sampling

Organic compounds, including SVOCs (PAHs, phthalates), PCBs and petroleum hydrocarbons, generally were not detected or were detected below JSCS SLVs.

BEHP was detected in the initial source control evaluation stormwater sampling event at 2.7 ug/L, marginally above the JSCS criterion of 2 ug/L for human health based on fish consumption, but below the EPA Preliminary Remediation Goal for drinking water and other ecological SLVs. BEHP was not detected in three subsequent sampling events.

The PAHs chrysene and benzo(b)fluoranthene in the initial source control sampling event were the only organic compounds above their respective SLVs, with detected concentrations less than 10 times the SLV. Chrysene and benzo(b)fluoranthene were not detected in three subsequent sampling events.

For metals, arsenic, cadmium, copper, lead and zinc were detected at concentrations exceeding their respective SLVs in two or more sampling events. The two highest arsenic detections (2.70 ug/L; 3.50 ug/L) just slightly above the lower/flatter portion of the rank order curve of concentrations found at other heavy industrial sites in the Portland Harbor. Concentrations of other metals are well below those found at other industrial sites in the Portland Harbor area. On this basis no additional source control measures are warranted.

9.3 NPDES 1200-Z Stormwater Sampling Results 2011-2012

NPDES 1200-Z sampling results show consistently low or non-detect concentrations. At the time of this memo, four sampling events have been completed under the 2012 NPDES 1200-Z permit. In the10/30/12 and 2/22/13 sample events, analysis of Impairment Pollutants, including pesticides (aldrin, DDT, DDE), PAHs and PCBs also was required. Most contaminants were not detected. Zinc and one PAH (pyrene) were detected marginally above their respective SLVs, but below the benchmarks and reference

Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 18 of 21 concentrations of the permit, and well below the knee of the “typical” rank-order curves for Portland Harbor industries. DDT was detected in one of two samples at 0.000006 mg/L, equivalent to 0.006 ug/L, compared to its JSCS SLV of 0.00022 ug/L. There is no known source of organochlorine pesticides at the site. It is thought that area-wide organochlorine contamination is a result of air deposition from historical pesticide production facilities such as the Rhone-Poulenc site.

10.0 SUMMARY AND CONCLUSIONS

3003 NW 35th LLC completed a source control evaluation in accordance with JSCS guidance and DEQ- approved work plans. Contaminant pathways of concern are limited to stormwater discharge into the Willamette River via the City of Portland storm sewer system. DEQ concludes that legacy and any residual contamination at the site has been characterized and controlled to the extent feasible based on the following:

 The EPA Response Action removed extensive hazardous material from the site and thoroughly cleaned historical operational area surfaces.

 The site has been completed paved with the exception of a small planter strip, thus precluding mobilization of soil contaminants in stormwater, or direct contact by site workers.

 Facility-related contaminant sources have been identified and characterized. Historical site investigations have adequately characterized known contaminant releases. Camera surveys and storm line cleanouts were completed, and catch basin sediment and stormwater were analyzed during the source control evaluation for a comprehensive suite of analytes.

 Stormwater is the only complete pathway to the Willamette River at the site.

o Stormwater treatment appears effective in removing or treating contaminants to low levels as stormwater monitoring indicates that most contaminants of concern from the historical and on-going operations at the site do not exceed JSCS SLVs. On occasion some contaminants have been detected above JSCS SLVs in stormwater, but the overall contaminant levels in stormwater are well below “typical” levels found at industrial sites in the Portland Harbor Area. As such, these levels are not indicative of ongoing or uncontrolled sources of legacy contamination on the site and do not warrant additional investigation or source control measures. o Catch basin sediment testing in the existing and newly installed catch basins suggests there is an unknown source of phthalates to the onsite stormwater conveyance system. There is no indication that phthalates were ever used or generated at the site. The sediment accumulation rate and volume is low, and lack of detectable phthalates in three of four stormwater samples show that the stormwater treatment system is effective in preventing significant contamination from entering the off-site stormwater system. o On-going stormwater discharges are regulated under a NPDES 1200-Z permit that requires monitoring for most contaminants of concern, periodic catch basin cleanout and filter maintenance, and corrective actions for consistent detections above permit benchmarks. DEQ will continue to review monitoring and permit compliance to ensure that source control measures continue to be effective.

In summary, DEQ concludes that legacy contamination at the site has been adequately characterized and removed or controlled to minimize the potential for contaminants to be released through stormwater to the

Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 19 of 21 river. Residual contamination does not present a risk to human health and does not present a threat to the Willamette River though stormwater discharges or any other pathway.

For this reason, DEQ’s Cleanup Program is not requiring further site characterization, additional stormwater source control measures or any other remedial action at this time. This determination is predicated on continued implementation of source control measures described in the facility’s stormwater pollution control plan and stormwater monitoring required by the NPDES 1200Z permit. The 2012 1200Z permit requires monitoring for a broad suite of contaminants (including most of the contaminants of concern for Portland Harbor sediments) and compels improvements to best management practices, as warranted by monitoring results. DEQ will continue to review site monitoring and permit compliance to ensure the effectiveness of source control.

References:

Bergeson Boese & Associates (B-B&A; 2008), Focused Site Investigation for Completion of Prospective Purchaser Agreement, September 23, 2008.

Beeson et al., 1991, Beeson, M. H., T. L. Tolan, and I. P. Madin (1991), Geologic map of the Portland quadrangle, Multnomah and Washington Counties, Oregon, and Clark County, Washington, Oregon Department of Geology and Mineral Industries Geological Map Series GMS-75, scale 1:24,000.

Cascade Earth Sciences, LTD, 1992, Phase II Investigation at Carson Oil Main Office, April 10, 1992.

City of Portland, Bureau of Environmental Services (BES), Outfall Basin 18 Inline Solids Investigation, Technical Memorandum No. OF 18-2, City of Portland Outfall Project, ECSI No. 2425. July 2010.

City of Portland, Bureau of Environmental Services (BES), 2012, Outfall Basin 18 East-Central Subbasin Source Investigation, May 2012.

DEQ, 2003, Risk-Based Decision Making for the Remediation of Petroleum Contaminated Sites. Updated June 7, 2012.

DEQ, 2005, Memorandum to ECSI File #29, Screening Level Risk Assessment and Recommendations for Additional Work, Columbia American Plating, 3003 NW 35th Avenue, Portland, Oregon 97210. March 17, 2005.

DEQ, 2008, Re: Catch Basin Sediment Sampling Results and Findings, Carson Oil, ECSI #1405, Letter to S. Gaylord (Carson) from K. Johnson (DEQ). May 14, 2008.

DEQ, 2010, Guidance for Evaluation the Stormwater Pathway at Upland Sites. Appendix E: Tool for Evaluating Stormwater Data. Updated October 2010.

DEQ, 2013, Development of Oregon Background Metals Concentrations in Soil, Technical Report, March 2013.

EPA, 2004, Columbia American Plating Removal Action Report, Portland, Oregon. Region 10 START Team. May 2004.

O’Gara, 2009, On-Site Stormwater Sewer Cleanout Report. September 29, 2009.

Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 20 of 21

Oregon Department of Environmental Quality and United States Environmental Protection Agency, 2005, Portland Harbor Joint Source Control Strategy. December 2005. http://www.deq.state.or.us/lq/cu/nwr/PortlandHarbor/docs/JSCSFinal0512.pdf

Swanson, et al., 1993, Swanson, R.D., McFarland, W.D., Gonthier, J.B., and Wilkinson, J.M., 1993, A description of hydrogeologic units in the Portland Basin, Oregon and Washington: U.S. Geological Survey Water-Resources Investigations Report 90-4196, 56 p., scale: 1:100,000.

Washington State Department of . 1994. Natural Background Soil Metals Concentrations in Washington State, Publication 94-115. Toxics Cleanup Program. October.

Weston, 1994, Site Inspection Report, Columbia American Plating, Portland, Oregon, Doc. Control #4000-19-02-AAAP. September, 1994.

Wohlers Environmental Services, Inc., 2013, Revised Stormwater Source Control Evaluation Report, Industrial Facility, 3003 NW 35th Avenue, Portland, Oregon. April 29, 2013.

Wohlers Environmental Services, Inc., 2012, Stormwater Pollution Control Plan, Carson Oil Co., 3003 NW 35th Avenue, Portland, Multnomah Co., Oregon 97296. March 30, 2012.

Wohlers Environmental Services, Inc., 1999, Fourth Quarter '99 Groundwater Monitoring & Closure Request Report. December 1999.

Figures:

Figure 1: Site Vicinity Map Figure 2: Site Features and Surface Water Flow Map (2013) Figure 3: Basin 18 East-Central Subbasin Figure 4: Historical Features and EPA SI Sample Locations Figure 5: Stormwater Conveyance On-Site Sample Locations Figure 6: TCE in Groundwater Figure 7: Cyanide in Groundwater Figure 8: BEHP in Soil and Groundwater Figure 9: Site Plan (2008)

Tables:

Table 1. Inorganics in Soil Table 2. Volatile Organic Compounds (VOCs) in Soil Table 3 Base Neutral Acids (BNAs) in Soil Table 4. Storm Water and Treated Water Results as Compared to NPDES Permit Wastewater Discharge Limitations Table 5. Summary of Cyanide Analytical Results for Groundwater and Soil Samples Table 6. Summary of Inorganic Analytical Results for Soil Samples Table 7. Summary of Inorganic Analytical Results for Groundwater Samples Table 8. Columbia American Plating Analytical Results from June 2003 Field Event Table 9. Soil Analytical Results Table 10. Groundwater Analytical Results

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Table 11. Summary of Chemical Analytical Results, On-Site and Off-Site Storm Line Solid Samples Table 12. Contaminants of Potential Concern Table 13. On-site Metals in Sediment (mg/kg) Table 14: On-site PCBs in Sediment (ug/kg) Table 15. Phthalate Esters (ug/kg) Table 16. PAHs (ug/kg) Table 17. Metals in Water (ug/l) Table 18. PCB Aroclors in Water (ug/l) Table 19. PAHs in Water (ug/l) Table 20. Off-site Metals in Sediment (mg/kg) Table 21. Off-site Phthalate Esters in Sediment (ug/kg) Table 22. Off-Site PAHs in Sediment (ug/kg) Table 23. Off-Site PCBs in Sediment (ug/kg) Table 24. Sediment Sample Analytical Results: TPH-Dx, TPG-Gx, SVOCs & TOC Table 25. Sediment Sample Analytical Results: PCB Aroclors & PAHs Table 26. Sediment Sample Analytical Results: Total Metals and Cyanide Table 27. Stormwater Sample Analytical Results: TPH-Dx, TPG-Gx, PCB Aroclors, TOC & TSS Table 28. Stormwater Sample Analytical Results: PAHs and SVOCs Table 29. Stormwater Sample Analytical Results: Total Metals and Cyanide Table 30. NPDES 1200-Z Stormwater Results