The Northwest Pipe and Casing site is an NPL site located on the eastern edge of Portland, in the town of Clackamas, Clackamas County, Oregon. The 53-acre site was home to a pipe-treating operation from 1956 to 1985, during which time volatile organic compounds (VOCs), polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were released into the soil and groundwater. The site was eventually listed on the National Priorities List (NPL) on October 1992, and remedial activities were performed between August 2001 and September 2004. A groundwater remedy emplaced during the Remedial Action was later found not to be functioning properly. Furthermore, DNAPL was found in one of the site groundwater monitoring wells, and coal tar bodies were also discovered in subsurface soils. Due to the discovery of coal tar bodies and DNAPL, the EPA Region 10 Remedial Program requested assistance from the EPA Removal Program in order to remove the source of soil contamination so that a new groundwater remedy could be implemented.
Removal site activities began on August 12, 2009. However, site work was halted in November 2009 due to an unexpected increase in costs as well as delays from the onset of significant precipitation towards the end of the removal schedule. It was anticipated that removal activities would re-start in the Spring or Summer of 2010.
On June 1, 2010, EPA, the ERRS and START contractors re-mobilized to the site and set up equipment and command posts in order to resume removal work, which consisted of trucking contaminated, stockplied soil to a RCRA Subtitle D municipal landfill near The Dalles, Oregon. From June 3 through June 11, 2010, a total of 230 truck loads of contaminated soil (6,933.7 tons) was transported to the lWASCO landfill. ERRS transferred contaminated soils from the stockpile to contracted dump truck haulers using an excavator. START monitored potential emissions from transfer work, including air monitoring for volatile organic compounds, carbon monoxide, hydrogen sulfide, explosive vapors, breathable oxygen, and total particulates. ERRS kept dust and particulates low by regularly spraying water on site roads.
For further site history, please previous site POLREPS.
Site activities, such as trucking of stockpiled contaminated soil and air monitoring continued on June 14, 2010. Also on this date, trucking of contaminated soil to the landfill was completed, with a total of 262 truck loads and 8,126.23 tons of soil transported offsite and disposed of during this 2010 removal action. The total amount of soil transported and disposed for the entire removal action (2009-2010) was 787 truck loads and 24,797.58 tons.
As planned, installation of a new semi-permeable cap over Excavation Area No. 1 (EA1) also began on June 14. However, a small portion of EA1 could not be addressed or have the semi-permeable cap installed, as Oregon Iron Works (OIW) had laid down a large, packed, gravel equipment laydown yard adjacent to, and overlapping the top of EA1. The laydown years overlapped EA1 by several feet from the east to the west, and the entire length of EA1 north to south. ERRS began work on the remaining EA1 area by excavating the previously installed cap and removing over 4 feet of material. A 6-inch sand base was then laid down, which was next overlain by overlapping and sealed sheets of a semi-permeable, 12-mil geomembrane material. This material was in turn overlain by two feet of silty clay, and finally two feet of the previously removed soil cap material. The slope of the semi-permeable cap (geomembrane material and overlying silty clay) was 1.5% to the south. The final surface area dimensions of the installed semi-permeable cap were 110' by 80'.
On June 16-17, ERRS worked to re-grade and re-dress all previous work areas and roads from work completed in 2009 and 2010 in order to restore the site soil cap. ERRS filled in and smoothed out the base of the now removed soil stockpile area, as well as other low areas and ruts. Fill material included site cap soils that OIW had previously excavated during their construction activites. ERRS also overseeded and watered all graded and restored areas with a mix of northwest grass seed.
Also during this week, OIW began construction of its test track facilities by laying down rail ballast along the planned rail route. EPA coordinated daily work efforts with OIW and their contractors in order to efficiently accomplish site removal goals.
On June 17, 2010, START collected three composite confirmation soil samples from the base of the stockpile area to determine if any cross-contamination from the stockpile to surficial soils occurred, even though a liner membrane was emplaced below the stockpile. Samples were sent to EPA CLP labs for VOCs, SVOCs, metals, mercury, PCB, and TPH analysis.
None. EPA, START, and ERRS contractors demobilized from the site on June 23, 2010.
Further site activities will remain under oversight of the EPA Remedial Program in conjunction with ODEQ, the Clackamas County Development Agency, and OIW.
Continued rain during this action continued to add additional water weight to the soil stockpile, which resulted in significantly increased transportation and disposal costs.
The site is being re-used by OIW, who plans to construct an electric rail car manufacturing and test track facility.
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