ARCHIVED REPORTS_XR0012715 - Laserfiche WebLink

Home Browse Search

_ .,-cmc+' �.,;- t -: ,d-^.a'*:� '_,•'- "' ��'"'_``� ��` _-�.r� :" ::+: }` _:t�.a �- � 3��":' o- 'cL �t' ""`��s P mg/kg),toluene(0.001 I to 0.0051 mrAg),and xylcnes(0.0016 to 0.160 mgA.g)were detected. 2.4 SAMPLING AND ANALYSIS OF GROUND WATER 714 wells were developed on 15 November 1988 by purging with clean PVC bailers. After purging,the wells w°err sampled with clean teflon bailers, samples of ground water from each well%tre cmpdcd into two 40 W VOA vials;the vials went capped with w1len lined seals. The samples were labelled and plaid on ice for storage and transportadon. The samples were shipped under chain-of-custody to Pace I.aboiatories for analysis by EPA method 8015 for TPI I and 13TE&X. The results of these analyses are included as Table 4. C Pttrolcurn hydrocarbons weer not dttected In the ground water at monitoring well MW 1, the apparently upgradient well. The ground water at each of the other writs contained detectable eonccnaadons of petroleum hydrocarbont The highest concentrations were measured in the wells closest to the backfilled excavadon.MW3 and MW4. The ground water at MW3 contains 9.3 rngll.TPH with 2.7 mg/1.benzene.0.360 mg1L-3luene,2.8 in /L ethylbtnzene;and 2.0 mg/L xylenes. The concentrations of petroleum hydrocarbons dissolved in the ground water appear to declinc in monitoring wells I►fi'V2,MWS.and MW6 that is with distance away from the backfilled excavation. 2.$ GAUGING 711E DEPTH TO WATER The depths to ground water were gauged on 15 November 1988 prior to purging the wells. The dcp4►s to ground water w ere:gauged with an Oil Rccovcr/System optical interface probe, No free product was found. The depths ranged frorn 35.86:to 36.72 fat from the tops of easing(Table S). The elevadons of the tops of casing went established with a level and stadia rod. The elevations were mfemwed to the base of a fixe hydrant at the intersection of 1.srding Way and EI Dorado Street;this ckv3don was initially asstnrs d in the field to be 9023 fest,as indicatod ore a blucline of surface irnptovemcnts at the clv v. ti station. The acarol elCaff n ittdicafW on the U.S.0,S.Stockton WestCalit=ix 7.5 ._.------ — --- ----- - --------— - minutc quadrangle twp(Figure 1)is 14 feet=L The elevations for tho top of Smond water on Table S and Figure 12 wxm calculated asstrxrartg art elevation of 14 feet ta:1 for the t°tf==point. fi