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 sediment 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 Lake 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 Road, 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. Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 3 of 21 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 wastewater treatment 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 pollutants. 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. Former Columbia American Plating Site DEQ Source Control Decision January 21, 2014 Page 4 of 21 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.