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SS No. 6348 , Tracy <br /> PIER, 1/31/92 <br /> of the PVC pipe and to the ground surface to an accuracy of <br /> 0 . 01 feet vertically by Triple "E" Engineering of Tracy, <br /> ' California, a licensed surveyor. Table 1 lists the surveyed <br /> elevations , as well as the measured depths to ground water <br /> on July 15, 1991. Ground water was determined to flow in the <br /> N20W direction with a gradient of 0. 0024 on that date. <br /> The wells were developed on July 12 , 1991. Prior to <br /> beginning development the wells were checked for depth to the <br /> water table using an electronic sounder and for presence of <br /> free product using tape paste. No free product or odor was <br /> noted in any of the wells. The wells were then developed with <br /> ' a surface pump until the evacuated water was clear . <br /> Well development data are attached as Appendix B. <br /> Prior to sampling on July 15, 1991, the wells were <br /> checked for depth to water and for the presence of free <br /> product or odor; no odor or free product was noted in any of <br /> the wells. Field parameters of temperature, pH, and electrical <br /> ' conductivity were measured. These data are reported in <br /> Appendix B. Confirmation samples were collected on August 15, <br /> and an additional sample from MW-4 was collected on September <br /> 12 . <br /> Once the field parameters were observed to stabilize <br /> and a minimum of four casing volumes had been purged , <br /> groundwater samples were collected using a Teflon bailer. The <br /> samples were poured into 40-milliliter volatile organic <br /> analysis (VOA) vials and polypropylene bottles, and capped with <br />' Teflon-lined screw caps. The sample bottles were then labeled <br /> and placed in a cooler with ice until they were delivered to <br /> ChromaLab in San Ramon , California . Chain-of-custody <br /> documentation accompanied the samples to the laboratory. <br /> All water discharged from the wells during <br /> development and purging was stored in DOT-approved drums <br /> pending laboratory results to determine proper disposal. <br /> ANALYTICAL RESULTS <br />' Soil samples collected from the twelve boreholes and <br /> soil and groundwater samples collected from the four monitoring <br /> wells were analyzed for Total Petroleum Hydrocarbons as <br /> Gasoline (TPH-G) using EPA Methods 5030 and modified 8015, for <br /> Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) using EPA <br /> Method 8020 , for Total Petroleum Hydrocarbons as Diesel (TPH-D) <br />' using Method 3550, for total lead, and for oil and grease. <br /> -5- <br />