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The sampler purged groundwater volumes (a calculation was done for each well following <br /> sounding measurements) from each well using a submersible electric purge pump Between <br /> each well volume purge, conductivity, pH, and water temperature readings were obtained and <br /> noted on the attached groundwater sampling information sheets Once these readings stabilized <br /> after two consecutive purge volumes, and the well recovered to about 80% of the initial water <br /> level, aquifer water was assumed to enter the well and the sample was collected Purge water <br /> was stored on-site in drums <br /> The groundwater sample was collected with a new disposable bailer and the groundwater sample <br /> which was poured with minimum cavitation into the appropriate, laboratory prepared sample <br /> containers leaving no headspace The sample container was then immediately capped, labeled and <br /> placed in a chilled ice chest for shipment to Priority Environmental Laboratory in Milpitas, <br /> California (a State Certified Testing Lab) under chain-of-custody documentation <br /> Groundwater Contour Map and Flow Gradient <br /> Groundwater contour map was prepared for the data listed in Table 1, plotting contour's to a <br /> known project datum (see Figure 1) Water levels rose slightly with a groundwater flow <br /> direction was to the north under a calculated gradient of 0 003 <br /> Chemical Analytical Methods and Results <br /> iThree groundwater samples were analyzed using EPA Methods 5030/8015 and 602 for Total <br /> Petroleum Hydrocarbons as Gasoline (TPHG), Benzene, Toluene, Ethylbenzene and Xylene <br /> (BTEX) The chain-of-custody and a the Laboratory Analysis Results can be found in Appendix <br /> C The analytical results of the groundwater samples revealed the following (see Table 2), <br /> Table 2. Groundwater Chemical Analytical Data <br /> Well Date TPHG Benzene Toluene Ethylbenzene Xylene MBTE <br /> NoSampled -----------------------------ug/I------------------------------ <br /> T-1 1/7/88 NA 00907 ND ND ND NA <br /> T-1 3/26/92 ND ND ND ND ND NA <br /> T-1 2/18/93 ND ND ND ND ND NA <br /> T-1 6/10/93 ND ND ND ND ND NA <br /> T-1 10/11/93 ND ND ND ND ND NA <br /> T-1 3/28/96 ND ND ND ND ND NA <br /> T-1 6/27/96 ND ND ND ND ND NA <br /> T-1 9/23/96 ND ND ND ND ND NA <br /> T-1 12/19/96 ND ND ND ND ND ND <br /> T-2 1/7/88 NA ND ND ND ND NA <br /> T-2 3/26/92 ND ND ND ND ND NA <br /> T-2 2/18/93 ND ND ND ND ND NA <br /> T-2 6/10/93 ND ND ND ND ND NA <br />< < Tracy High Project No 4729 Page 2 <br />