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`• - Martin Thorpe . � 16 October 1987 1 WEISS ASS OCL4TES. was detected at S. s Ppb in MW-I. fSoluble lead con ray of ns ranged below -detection 'xn -2._ -= -. -_ - - to 3 ppb_yin MW-1. One ppb�Iead was detected in MW3 . - - G4/FID analysis of the development water composite sample collected by WA was below the detection limits of I ppm for TFHC. and _ `.0 ppm fox- B „ 5 on these resu3sed tsFran- .Forka.;_of . the. . LDE'W.-authorized.: $athe � .. ..�. _ I deve_loprnent water to theground surface: - LI Prior to the 8 September saillpling, B&C discharged the drummed. : WA � .. development water. They then directed their sampling purge water to the ` emptied ' drums. At the conclusion of their sampling, Lthey collected samples from the ,drums which were composited at B&C- and analyzed by EPA Method 602 for , x BTX CC/PID analysis of the B&C purge water indicated 1,203 ppb benzene, L50. Ppb ethylbenzene, -.160 ppb toluene and 1.60or total xylene isomers This .water will be disiosed of. appropriat:ely. Analytic results for water samples are presented in Table 2 and copies of laboratory report forms are included in -Attachment: B. GROUND WATER GRADIENT Top-of-casing (TOC) elevations were surveyed on. 1.1 August 1987. The datum elevatiois :for, the survey . was USGS benchmark -#191, located at the southeast .corner. of the intersection of Lodi Avenue and Stockton ".Street =-TOC- elevations and water level data,are presented in Table. 3-. Two Grater table elevation maps were prepared for' this investigation. Figure 3 shows water level data collected on 25 Au ust a I' g and Figure 4 shows data. collected on 11 September -1987. Both figures indicate a'' north to northeastward ground water -flow, although Figure 3. indic4tzs a more pronounced eastward component. The gradients shown in Figures 3 and 4 are opposite to the southwestward direction of groundwater flow suggested by local topography and the regional hydraulic gradient.