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Working To Restore Nature 1 Groundwater elevation data suggests an irregular groundwater surface exists beneath the site The groundwater flow net beneath the site historically has vaned 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 September 29, 1993 monitoring event is presented on Figure 2 Groundwater samples were collected from wells MW2, MW5, and MW6, after purging at least three casing volumes of water A thickness of 0 04 feet of floating hydrocarbon product was measured in well MW 1, 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 (cert #1210) 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 analysis of the sample collected from well MW2 indicated the presence of a non- diesel mix (C9-C19) in the TPHd range at 380 ppb No other petroleum hydrocarbon analytes were detected in the sample collected from well MW2 The sample collected from well MW5 indicated the presence of benzene (2 4 ppb), ethylbenzene (2 0 ppb), total xylenes (3 7 ppb), TPHg (440 ppb, gas and non-gas mix >C8) and TPHD (570 ppb, non-diesel mix C9-C13) The sample collected from well 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 VOCs were detected in samples collected from wells MW5 and MW6 VOCs detected in well MWS included 1,3 dichlorobenzene (14 ppb), 1,4-dichlorobenzene (12 ppb), 1,2- dichlorobenzene (22 ppb), cis-1,2-dichloroethene (2 2 ppb), trans-1,2-dichloroethene (5 4 ppb), and trichloroethene (5 0 ppb) VOCs detected in well MW6 included 1,2-dichlorobenzene (0 72 ppb), 1,1-dichloroethane (0 56 ppb) and cis-1,2-dichloroethene (0 52 ppb) No VOCs were detected at or above method detection limits in the sample collected from well MW2 Analytical results of halogenated volatile organics are summarized in Table 3 Laboratory data sheets and chain-of-custody documentation are presented in Attachment 2 Prqj Aisk\Qunrtly\QR-1043 FNL 2