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ar 4r <br /> A 5 5 0 C I A T E 5 I N C <br /> FREE PRODUCT REMOVAL <br /> Floating petroleum product has previously been observed in well MW2 On January 18, 2002, <br /> ATC installed a passive skimmer system in well MW2 in accordance with ATC's Workplan for <br /> Drinking Water Well Replacement, Temporary Water Source, and Free Product Skimmer <br /> Installation at Pacific Coast Recreation, 3755 Munford Avenue, Stockton, California, dated <br /> October 11, 2001 This workplan was approved by SJCEHD with minor modifications <br /> Approximately 0 25 gallons of free product has been recovered from the skimmer in well <br /> MW2 On June 25, 2002, only a slight, unmeasurable sheen was observed in well MW2 Table <br /> 3 summarizes the product thickness measurements and volume of product removed to date <br /> FILTRATION SYSTEM <br /> In May 2002, a carbon filtration system was installed to remove petroleum hydrocarbons from <br /> the water in domestic well DW Influent water samples collected from DW contained 88,000 / <br /> ppb of TPHg and 8,900 ppb of benzene Fuel oxygenates including MTBE were not detected in <br /> water samples collected from well DW ITPHg, BTEX, and fuel oxygenates were not detected in <br /> water samples from the first and second effluent ports identified as ICC Effluent and 2CC L <br /> Effluent in the filtration system It appears the filtration system 2s effective in removing <br /> petroleum products from water from well DW ¢ }� <br /> CONCLUSIONS 'h __``o' Gas J kt L1 <br /> �ylLa' � 0' <br /> Concentrations from wells MW� through MW6 and MW8 through MW10 remain consistent <br /> with the results from the previous sampling event Concentrations in wells MW1 and MW7--' <br /> decreased by one order of magnitude The direction of groundwater flow was consistent with the <br /> previous monitoring event Groundwater elevations have decreased since April 2002 <br /> RECOMMENDATIONS <br /> Based on the results of the second quarter 2002 monitoring episode, we recommend the <br /> following <br /> • Conducting the third quarter 2002 groundwater monitoring and sampling of wells MW1 <br /> through MW10 and DW and analyze samples for TPHg, BTEX, and oxygenate fuel <br /> additives <br /> • Continue to monitor well MW2 for floating free product and maintain skimmer system <br /> w\I 63931quan1yl2gr-2002 doc 4 <br />