WORK PLANS - Laserfiche WebLink

Home Browse Search

3.2 Sediment Sampling As shown in Figure 3-1, two sediment samples will be collected at two random locations (SDI and S132) in the Stockton Deep Water Channel directly underneath thearkin lot. Actual p g sediment samples will be collected in locations where potential contamination may have been deposited in the sediment. As requested by DTSC, should time permit, a maximum of two additional samples will be collected (SD3 and SD4). In any event, a minimum of two discrete samples (SDI and SD2) plus one duplicate sample will be submitted for analysis. As directed by DTSC and EPA, sediment samples will be collected approximately 4 to 8 inches below the surface of the sediments. Sediment samples will be analyzed for CLPAS semivolatile organic compounds and CLPAS metals to assist in determining the presence of wood treating components in sediments beneath the site (i.e., specifically cresols, pentachlorophenol, arsenic; and chromium VI). Because the CLP laboratory is unable to speciate chromium VI, total chromium will be assessed using CLPAS metals analysis; and if elevated levels of total chromium (� 100 mg/kg) are found in sediments, then the sample will be analyzed for chromium Vi at an outside laboratory to be determined by EPA 3.3 Wood Sampling As shown in Figures 3-I and 3-2, wood samples will be collected from four random wood piling locations (P1 through P4). The parking structure on the site consists of a framed decking system supported by wood pilings spaced approximately 20 feet apart' At least one sample will be ., collected from above the high water line (if feasible) and at Ieast-one sample within the zone of tidal fluctuations, provided the sample can be collected in a safe manner. For convenience, wood piling samples may be collected from the piers immediately adjacent to the sediment sample locations. The samples will be analyzed for CLPAS semivolatiles to determine the presence of and to measure the concentrations of cresols and pentachlorophenol (PCP) in the wood pilings. The wood pilings are being sampled primarily for cresols and PCP to determine whether they can be disposed at a Class II landfill. Forward Landfill, a Class II landfill in Stockton, California, requires the wood samples be sampled for cresols and PCP using the Toxicity Characteristic Leaching Procedure (TCLP). No Waste Extraction Test (WET) is required. Analysis of wood samples for metals or other constituents is not required for acceptance at the CIass II landfill. 3.4 Groundwater Sampling As shown in Figure 3-1, groundwater sampling will be collected at four discrete locations (GWI through GW4). Groundwater sampling locations GWI, GViW2, and GW3 will be collected at soil boring locations SBI through S133, extended to groundwater. Based on discussions with EPA and DTSC, sample locations GWI, GW2, and GW4 were selected to assist in determining the presence of hazardous substances (i.e, petroleum hydrocarbons, volatile organic compounds, and MTBE migrating onto the site from a possible upgradient, offsite source [i.e., former ARCO station]). Similarly, sample location GW3 was selected to determine the presence of hazardous substances from potential offsite sources specifically the former fertilizer facility, print shop, and gasoline service station to the south of Weber Block. nA362IM8sAMwebsap2.wp5 WEBER BLOCK (Area 9) Sampling and Analysis Plan Q Page 7