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Ul � Working To Restore Nature Groundwater elevation data suggests an irregular groundwater surface exists beneath the site The groundwater flow net beneath the site historically has varied considerably The irregularities in the measured depths-to-water may be due to the heterogeneous nature of the soils and/or the varying well depths A groundwater gradient map for the March 23, 1994 monitoring event is presented on Figure 2 Groundwater samples were collected from wells MW2, MW3, MW4, MW5, and MW6, after purging at least three casing volumes of water or purging dry A thickness of 0 02 feet of floating hydrocarbon product was measured in well MW1, therefore, no sample was collected from this well Monitoring wells were purged and sampled according to RESNA's Quality Assurance/Quality Control Plan (on file with PHS/EHD) Well purge logs are included as Attachment 1 LABORATORY ANALYSIS The groundwater samples were transported under chain of custody protocol to Sequoia Analytical Laboratory, Redwood City, California (FLAP #1894) for analysis of benzene, toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA method 8020, total petroleum hydrocarbons as gasoline (TPHg) and as diesel (TPHd) utilizing EPA method 8015 modified, and halogenated . volatile organics (VOCs) utilizing EPA method 8010. Laboratory analyses of the sample collected from well MW2 detected the presence of a non- diesel mix (C 13-C 18) in the TPHd range at 590 ppb No other petroleum hydrocarbon analytes were detected in the sample collected from well MW2 The sample collected from well MW3 contained contaminants in the diesel range at 64 ppb noted on the laboratory report as "discrete peaks" Laboratory analyses of the sample collected from well MW5 detected the presence of benzene (1 0 ppb), total xylenes (0 91 ppb), and TPHg (230 ppb, non-gas mix) Samples collected from wells MW4 and MW6 did not detect any petroleum hydrocarbon constituents above method detection limits Analytical results of petroleum hydrocarbon constituents are summarized in Table 2 Laboratory data sheets and chain-of-custody documentation are included in Attachment 2 A single VOC analyte was detected in the sample collected from well MW2 MW2 contained 21 ppb 1,2-dichloroethane No VOCs were detected at or above method detection limits in samples collected from wells MW3, MW4, MW5, or MW6. Analytical results of VOCs are summarized in Table 3 Laboratory data sheets and chain-of-custody documentation are presented in Attachment 2 1500771QUARTLYIIQR-1994 FNL 2