ARCHIVED REPORTS XR0006987 - Laserfiche WebLink

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1 ' detected in th(. up,trLan) ,Lit face water sample (DDN) collected fl(1111 thL drainage ditch located Last of thL "rte None of thL crthLr H 1 l X con,trtUents or I PI-[-(, wcrL deteLted it of abovL the laboratory reportLd detection Irrnrts in this ,ample. B I I X and FPH-(i were not deteLted in any of thL three iLmainirig surface water samples ' MT13E detected at or above the laboratory repeated detection limit rn all of the surface water Samples except the Sample LOHLUed him the viLinity of the, pump Rouse in the island drainage channel (1DCW) None of the remaining selected gasohrrL oxygenates/additi%cs wcrc. detected it of above. the laboratory reported detection ' Irmrt, in an-y Of the ,urtace water samples M flak- (20 fc`�,1) Nsa, the. oniv analyte detected at or above the laboratory reported detection limits in the marina's ' pre-treated dr:nkim, water ()III) Lhlorotorm bronlodichlorotnethane and dibromochlorontethane were detected in the manna , treated drinking water at or above. the laboratory reported detection limits (at concentrations of 18 6 1 and 3 0 rLspLctrvely) ( hloroform bromodichloromethanc and dibromochlorometlnane appear to be byproduct, of tlne mat Ina , drinking water treatment ,ystem Oil December 30 1998 ( ondoi LonduLted elu.srterly groundwater and surface water monitoring at Merman & Helen s Manna locatLd at VLnce lsldnd I Lrry in Stockton, California Laboratory analytical results indicated Ithat the gasoline oxygenate MTBF was detected in samples collected from monitor wells MW-I MW-2 MW-3, and MW-4 at LoncLritratiorns of 1 3 µg/l I 1 000 µg/l 3 500 pg/l, and 1 5 µg/l respectively Iertiary-butanol was ' detected in the groundwater samples collected from monitor wells MW-2 and MW-3 at concentrations of 150 µg/1 and 130 µg/I, respectively TAML' was detected in the groundwater samples collected from monitor wells MW-2 and M W-3 at concentrations of 37 µg/I and 8 3 gg/l, respectively None of the other oxygenates/additives were detected at or above the laboratory reported detection limits in any of the groundwater samples IToluene was detected rn thL groundwater sample collected from monitor well MW-2 at a Loncentration of 1 2 µg/1 BMA c._onstiterents were detected in the groundwater sample colleLted from monitor well MW-4 at concentrations of 24 fig/l 0 4 µg/I 2 3 lig./l and ?2 pg/1 respectivLly BTF'X constituents were not detected rn the groundwater samples collected from monitor wells MW-1 and IVIW-3 I PH-G was detected in the groundwater sample colleLted from monitor well MW-4 at a corrLentration of 2 mg/1 Z PH-CJ was not detected ' in the groundwater samples collected from monitor wells MW-1, MW-2, or MW-3 Intrinsic bioremediation testing was discontinued at the site following the third quarter, 1998, monitoring event because of Inconclu,ive results and because the petroleum hydrocarbon contamination at the Site is probably of secondary concern relative to the presence of gasoline oxygenates The intrinsic bioremediation testing results for the four quarters beginning with the Fourth quarter 1997 groundwater monitoring event and ending with the third quarter 1998 groundwater monitoring event indicated that subsurface conditions at the ,rte appeared to be conducive to the aerobic and/or anaerobic breakdown of petroleurn hydrocarbons However the re,ults did not conclusively indlLate that rnttinsic bioremediation was occurring at the site No well-defined differences in the ' intrinsic bioremediation parameters were established up-gradient (MW-1) in the plume center (MW-4), and down-gradient (MW-2 and MW-3) at the site I his may be in part related to tine relatively low concentrations of petioletun hydrocarbons prLsLnt at MW-4 and the very short residence time of groundwater in the soil at the site ' Groundwatet elevation measurements collected at the site on December 30, 1998, indicated that the average depth to groundwater was approximately 4 6 feet bgs which is approximately one-half foot higher than the I average groundwater elevation measured on September 30 1998 Groundwater elevation contours for December 30 1998 indtcated that the ground«atei madient at the site x%as generally consistent with that measured on September 18, 1997 December 31, 1997, March 27, 1998, June 26, 1998, and September 30, 1998 IBTEX and TPH-G were not detected at or above the laboratory reported detection limits in any of the surface . water samples Low concentrations of MTBE (1 4 and 1 0 µg/i) were detected in the upstream surface water Isample (DUN) and the downstream surface water sample (DDS), respectively None of the remaining selected