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Canepa's Car Wash 248 E Park Street, Stockton, California aka: 642 N. Hunter Street Phase H Site Characterization and July 2, 1994 Quarterly Groundwater Report(May 1994) Page: 7 5.0 Groundwater Conditions ICahfornra and Federal Governments have mandated that virtually ail groundwater is beneficial for current or future use, unless it can be demonstrated that no beneficial use is Iknown This aquifer is considered to be of beneficial use and as a result, must be protected from contamination Those identified uses include agriculture and industrial, as well as potential use for animal or human consumption I The present water table was encountered between 50 and 52 feet below ground level in the borings Water level data during well development and sampling show the depth to water between 46 and 48 feet below ground level (Table 4) The analyses from the December 14, 1993 sampling event (MW-1, 2, 3) showed BTEX and Gasoline contammmatmon in all of the monitoring wells (Table 2, Appendix B) After the additional monitoring wells were installed, a quarterly groundwater sampling event was conducted on May 25, 1994 Contamination of BTEX and Gasoline was detected in all wells, MW-1 through 7 (Figure 12, Table 2, Appendix B) 6.0 Conclusions and Recommendations The three bonngs (B-1, 2 & 3) drilled and sampled as Phase I of the investigation, disclosed contamination of a significant nature extending down to the water table, and that ' the lateral limits of soil contamination had not been defined Phase II borings and monitoring wells were proposed and approved Three borings (B4, 5 & 6) were dnlled and sampled Three monitoring wells were also drilled and sampled for soil and groundwater contamination Soil contamination was found in all the borings except B4, and in all the groundwater samples IAdditional "step-out" Phase II wells were proposed and approved Four additional monitoring wells (MW-4, 5, 6 & 7) were installed to further define the groundwater gradient and to help define the groundwater contanunation plume MW-4 was the only off-site well, and was drilled (with written permission) in the parking area of Standard Rent-A-Car The Phase II drilling did define the lateral limits of soil contamination to the northeast, northwest and southwest Additional data may be needed to west, east and south The lateral limits of groundwater contamination were not defined with any of the monitoring