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1 <br /> Langston 's Market o <br />' <br /> 1561.5 Seventh Stree4 Lathrop, California DEC 15 1997 <br /> QY <br /> uarterl Groundwater S 11n ENVIRONMENTAL HEALTH <br /> 3P • g Report P PERMIT/SERVICES <br />' November, 1997 <br />' Narrative <br /> On November 25, 1997, WHF, Inc , in conjunction with HKM Environmental, Inc , <br />' conducted field measurements, well pumping and groundwater sampling on four (4) <br /> groundwater monitoring wells located at this site (Figures 1 & 2) <br />' Groundwater elevations were taken from four (4) wells prior to pumping (Table 1 & <br /> Appendix B) Monitoring wells EW-1, also referred to as MW-1, MW-2 through MW-4 <br /> were evacuated by means of a steam-cleaned, stainless steel bladder type pump During <br />' the three (3) volume pump down samples were collected to measure field pH, electrical <br /> conductivity and temperature (Table 3 & Appendix B) A minimum of three (3) well <br /> volumes were removed and the samples were collected with a steam-cleaned disposable <br />' bailer The samples were then labeled and placed in an ice chest cooled with Blue Ice® <br /> The samples and trip blank were then logged on a Chani of Custody (Appendix A) and <br /> transported to a State-certified laboratory, California Laboratory Services, Inc , in Rancho <br /> Cordova, California The analysis requested for the water samples was EPA method 602 <br />' for BTX&E and EPA method 5030/LUFT for gasoline The analytes and concentrations <br /> detected are listed in Table 2 of this report <br />' Groundwater Gradient <br /> The water level measurements from three (3) of the four (4) monitoring wells, MW-2, 3 <br />' and 4, were used to construct a groundwater gradient map and calculate the gradient <br /> (Figure 3) EW-1 was not used in the gradient calculation nor the construction of the <br /> groundwater gradient map The current gradient is 0 00047 ft/ft to the S 10°W direction <br />' Historical gradient maps are included in Appendix C <br /> t Summary ofAnalytiral Findings <br /> One well had detectable amounts of contamination this quarter (Table 2) MW-1 (EW-1) <br />' tested 3,900 Vg/1 Benzene, 2,300 µg/1 Toluene, 480 µg11 E-Benzene, 2,800 µg/1 Xylene and <br /> 9 2 mg/1 Gasoline, MW-2, MW-3 and MW4 were free of Petroleum Hydrocarbon <br /> contamination. Overall contaminant concentrations have increased since the last sampling <br /> event Past analytical data is included in Table 2 for comparison <br /> 1 - <br />