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q <br /> r 7-Eleven/Stockton <br /> February 1989 <br /> A review of the groundwater monitoring data indicateS that <br /> I groundwater levels have gradually risen in response to seasonal <br /> precipitation. Since the September 21, 1988 monitoring, the <br /> groundwater level has risen an average of 0.73 feet in elevation <br /> beneath the site. <br /> Groundwater Gradient Maps (Figures 3, 4, and 5) depict the <br /> interpreted groundwater table conditions beneath the site. The <br /> regional groundwater-gradient direction remains to the east- <br /> southeast as reported in the past. Mounding of the groundwater <br /> surface due to a leaking water pipe at the rear of the 7--Eleven <br /> Store continues, and a:- shown on the gradient maps has apparently <br /> ,,.. become more significant. The hydraulic gradient of the <br /> i groundwater surface also remains consistent at a 0.2 percent <br /> slope. <br /> Free product has not been detected in any monitoring wells <br /> during this reporting period. However, monitoring wells (MW)-3 <br /> and MW-40 which previously contained free product, have been dry. <br /> GROUNDWATER SAMPLING AND ,ANALYSES <br /> �.a <br /> iw The groundwater monitoring wells and nearby domestic wells <br /> were sampled on four separate occasions during this reporting <br /> ,. period. The first sampling round was conducted on November 11, <br /> 1988 following re-implementation of remediation system operation. <br /> Samples were collected in accordance with GTI's SOP's 9, 10, 11, <br /> and 12 (Appendix II) . Each sample was analyzed for benzene, <br /> I ' toluene, ethylbenzene, •and xylenes (BTEX) and total petroleum <br /> hydrocarbons (TPH)-ds-gasoline by modified U.S. Environmental <br /> i Protection Agency (EPA) Methods 5030/8020/6015. The sampling <br /> schedule during this period for the wells on and near the site, <br /> was as follows: <br /> i' a. _. ,. �ai CHUI'1lril'ATF:H <br /> !! Tt:�u�na.ucv,f�c. <br />