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MW wg� <br /> �, `-' �"" r „.,*.r:u .°Xk.. 5.�s`'" <br /> a <br /> Mr. R.W. Conlon 2021150-4150 <br /> October 9, 1990 Page 6 <br /> o Development of the monitoring wells by removing fine sediment from the well and sand <br /> pack. <br /> 0 Collection and laboratory analyses of groundwater from tate l i monitoring wells. Samples <br /> were analyzed for TPH-G, BTEX, organic lead and 1,2-dibromoethane. Select samples <br /> were also analyzed for TPH-D and TOG. <br /> D Professional surveying of well head elevations for vertical and horizontal control. <br /> o Gauging of monitcring wells to determine groundwater elevations for the construction of <br /> a potentiometric surface map. <br /> 0 Removal of separate-phase petroleum from MW-1 and transferring it to a temporary 650- <br /> gallon storage tank. <br /> o Conducting a well location survey o,all private,commercial and municipal wells within a <br /> half-mile radius of the site using information available from the California Department of <br /> Water Resources. <br /> o Preparing this environmentLI investigation status report presenting the findings to date. <br /> 3.1 SOIL EXCAVATION SAMPLING <br /> Two pump islands were removed for the remodeling of the station,and composite soil samples <br /> were collected from beneath each pump Island location. Samples were analyzed for TPH-G and TPH-D. <br /> Hydrocarbon concentrations in soil sampled from beneath pump Island number 1 (composite sample A, <br /> B 10124188)were found to be below the practical quantitation levels(<PQL). Soil sampled beneath pump <br /> island number 2(composite sample C,D 10124188)was found to contain TAH-G concentrations of 5,700 <br /> parts per million (ppm). TPH-D concentrations were <PQL. The immediate area around pump island <br /> number 2 was excavated to an approximate depth of 15 feet. Five representative samples were collected <br /> from the borom and walls of the excavation on 101208 (discrete samples A, B,C, D.and E shown on <br /> Fioure 4). Samples were sealed, labeled and placed on ice in an Insulated container and delivered with <br /> the appropriate Chain-of-Custody manifest to a State-certified laboratory for analyses of BTEX and TPH-G. <br /> Results of laboratory analyses indicated that all five of these samples contained detectable concentrations <br /> of TPH-G ranging from 3 to 5,300 parts per million (ppm). <br /> 1� Gl2Otii1D14'ATER <br /> TECIiK(21 o ,I1'C. <br />