ARCHIVED REPORTS XR0006990 - Laserfiche WebLink

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elevatutti eontouts eStunated nsrn2 thy. &pili-to-water rneasurcattents Loliected on DeLember 31 1997 indicated that groundwater llow at the ,rte. was UIenerally c,nn,tstcnt with the eatrrnated flow on 5eptembLr IS 1997 (ht 1998 ( ondor personnel WCIL ort Srte to conduct quarterly groundwater monitonng Laboratory analyses of ,totindwater Samples caflected from the site monrtot WLil, Indicated that 811 X hPH-1-j and the ,eleetcd '�asolrnc orvgenates/additives were not detected at of above the labotatory reported deteetron limits to the sample eolleeted from MW-1 hthanol tertiary-butanol DIFF F-TBE and TAME were not detected at or above the laboratory reported detec.non limits rn am of the groundwater Samples DeteLtton hinits for the analyst, of the ,ampler collected from M\k and MW-'l were raised however due to relatively high c.oncenttattnns of 1\4 ]'T3[ rn the samples collee.ted front those wells (as described below) Benzene and TPH-O were not rieteLted it of above tared deteetron Iii-nits and low concentrations of IEX constituents were detected in the sample collected Irons MW-2 til 1-131_' was detected at l 10 000 µg/l to the MW-2 sample BTL X and 1-PH-G were not detected at or ahoy e the laboratorx reported detection limits in the sample collected Irorn M W-3 M I BE was detected at 1 900 rn the NIN4-3 ,ampie I PEI-C, and B I EX eonstrtuents were detected to the, sample L01lected horn MW--1 1vITBI was not detected at or above the lahoratory reported detection limit in the MW-4 i Sample No lloattng product Shec,n tit petroleum hydrocarbon odor was noted in the monitor wells Laboratory analytical results of the, gioundwater sample, for the, first quarter, 1998 monitoring event were generall} c.on,istent with historical quarterly groundwater analytical data MTBL eoncentrattons rr, samples from MV4-2 however incieas,-d by more than two orders of magnitudE during the three sampling events conducted at the site (,rotindwater elevation measurements collected at the ,rte monitor wells un March 27 1998 indlLate,d that the ave.ragc depth from the, around ,urtacc, to groundwater was approximately 5 feet the average depth to water at the. site tnereased br approxiinate,Iy I toot between DLLernber 3 1 1997 and March 27, 1998 C groundwater cle.vation contours estimated using the depth-to-water measurements wilc.cted un March 27 1998 indicated that groundwater gradient at the ,rte was generally consistent with the e,trIII ated gradient nn September 18 1997 and DCLCin bet 31 1997 In a telephone conversation on March 23, 1998, Mr Ronald Rowe of tht San Joaquin County Public Health Services/Privironm,ental Health Department (PHS/1 HD) indicated that based on his review of the report dated December 1 1 1997 (reterenced above), he was requesting that quarterly groundwater monitoring wnttnuc, at the site I'ui-thermore he iequested that a work plan be prepared for conducting quarterly surface water sampling and additional rnvestmation of the gasoline oxvgenatc/additive plume to the east of monitor well MW-2 Condor I subsequently prepared the Work Plan 4ddinonal Soil and 61 oundwater Investigation / Surface Writer Sampling dated May 27 1998 111 a faxed note dated June 1 1998 Mr Rowe approved the work plan with the stipulatson that a woil< plan addendum be prepared describing installation of additional borings to those proposed I in the work plan and grab sampling of the Merman & Helen s 'Marina drinking water source, Condor subsequently prepared the Work Plan .tddenehun dated July 9 1998 In a fax dated July 27 1998, Mr Ron Rowe approved the work plan addendum adding that both the faUhty pre-treated drinking water and the post- treatment water should be sampled and analyzed by appropriate methods On June 26 1998 a C ondot representative was on site to conduct quarterly groundwater monitoring Laboratory analyses of groundwater samples collected fiom the site monitor wells indicated that BTFX, TPH-Ci and the selected gasoline oxygenates/additives were not dLtected at or above the laboratory reported detection limits in the sample collected front MW-1 Lthanol, tertiary-butanol, DIPS, and ETBE were not detected at or above the laboratory reported detection limits in any of the groundwater samples TAME was detected in the samples collected fiom MW-2 and MW-3 M I BE was detected in the samples collected from MW-2, MW-3 and MW-4 131 EX and I-PH-(1 vete not detected at or above iaised laboratory detec,tron limits in the samples collected from MW-2 and M W-3 Relatively low wnaentrations of benzene, ethyl benzene, total xylenes, and I'PH-G were detected in the sample collected from IVIW-4 Toluene was not detected at or above a raised laboratory detection