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, S to 7-Eleven/Stockton 21 October 1988 ., The groundwater extracted from the pumping wells is treated through an air-stripping tower prior to discharge to the sanitary sewer system. Every two weeks, laboratory analyses are conducted on the influent-to and effluent-from the air-stripping tower for concentrations of BTEX and TPH-as-gasoline to verify compliance with requirements imposed by the Stockton Municipal Utilities District and the San Joaquin County Air Pollution Control District. The influent and effluent concentrations of BTEX and TPH-as-gasoline are tabulated on Table 2 in Appendix I and the laboratory results are in Appendix III. The air-stripping tower effluent samples were below the laboratory MDL for BTEX and TPH- as-gasoline during each sampling interval except for June 30, 1988 when 15 ppb TPH-as-gasoline and September 21, 1988 when 3 ppb TPH-as-gasoline were detected. on both these sampling events the effluent TPH-as-gasoline level was greater than the influent TPH-as-gasoline level, indicating that the concentrations y reported were from an external source. in addition to the BTEX and TPH-as-gasoline analyses, the air-stripping tower effluent is sampled every two weeks for total lead. The total lead results were below the laboratory MDL for each sampling event except for May 19, 1988 when o.009 ppm total lead was detected. This total %AA lead concentration is still well below the wastewater discharge requirement of 2.0 ppm. The results of the total lead analyses are tabulated on Table 3 in Appendix I and the laboratory results are in Appendix IV. Free product is not being extracted via pumping at this time. When free product is present in a monitoring well, the free product is bailed off during each site visit and is placed in an underground storage tank. The underground storage tank is -- �.��_�1'.�_I TEL'!i\f11 005",I1L'.