Remedial Action Report Construction Phase

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of contaminated soil left in place. All soil samples were collected and analyzed using EPA and DEQ approved methods. Soil sampling procedures are detailed in the sampling and analysis plan included in the RAP (Century West 1999a). Soil samples were assigned sample identifications which included the area designation, chronological order of the sample, and sample depth relative to street grade. For example, sample 22-18-15.0 was the eighteenth sample collected from Area 22 and was collected from a depth of 15.0 feet below street grade. Occasionally, soil samples were collected near lift hoists, drywells, underground storage tanks, or from soil piles. These samples may include characters in the sample identification (LH, DW, UST, and SP) to reflect the potential source in question. Specialty Analytical, located in Tualatin, Oregon, and Oregon Analytical Laboratory, located in Beaverton, Oregon, provided analytical laboratory services during the construction phase of the project. In general, soil samples were analyzed for total petroleum hydrocarbons-hydrocarbon identification (NWTPH-HCID) analysis with quantification using the DEQ-approved methods. Select samples with elevated petroleum hydrocarbon concentrations were also analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX) using EPA Method 8020 or 8021 and polynuclear aromatic hydrocarbons (PAH) using EPA Method 8270SIM. Select samples with gasoline contamination were additionally analyzed for total lead using EPA Methods 200.7 and 6010; and 1,2-dibromoethane (EDB) and 1,2-dichloroethane (EDC) using EPA Method 8260. Soil samples with heavy oils, including samples collected in the vicinity of used oil UST and drywell areas, were additionally analyzed for halogenated volatile organic compounds (HVOCs) using EPA Methods 8260, leachable cadmium, chromium, and lead using EPA Methods 1311 and 6010, and polychlorinated biphenyls (PCBs) using Method 8082. Laboratory reports and chain-of-custody documentation for all soil samples collected during construction phase remedial actions are provided in Appendix C. 4.~ Water Sampling During the construction phase Century West collected water samples for laboratory analysis to evaluate treatment system performance and groundwater quality in Remediated Areas 2, 6, 18, 19, 22, and 23. All water samples were collected and analyzed using EPA and DEQ approved methods. Water sampling procedures are detailed in the sampling and analysis plan included in the RAP (Century West 1999a). In general, water samples were collected from the water in an excavation (labeled Influent) or from the treated water in the discharge pipe from the treatment system (labeled Effluent). From April 12, 1999 through May 4, 1999, dewatering was performed from Sump 1 located in the former Chevron property (Figure 4). When additional excavations required dewatering on the Courthouse Square property, the sample identification included information on the general area of the excavation (i.e., southwest: SW or southeast: SE). For example, water sample SW Influent was collected from the southwest portion of the property. Construction Phase - Remedial Actions - 8- 4080600127 Courthouse Square November 9, 1999