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11 Working To Restore Nature Groundwater samples were collected from wells MW2, MW3, MW4, and from groundwater in the excavation pit using dedicated disposable bailers The samples were placed immediately on ice and transported to Argon Mobile Labs (DHS Cert #1873) and analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX), TPHg and total petroleum hydrocarbons as diesel (TPHd) using EPA methods 8015/8020 No petroleum hydrocarbon constituents were detected in any sample Groundwater analytical results are summarized on Table 2 Laboratory data with chain of custody documentation are included as Attachment 2. SOIL PILE SAMPLING The stockpiled soil was resampled on September 26, 1994 A RESNA technician collected 30 discrete soil samples, one for every 50 cubic yards of soil, in accordance with San Joaquin County Public Health Services, Environmental Health Division (PHS/EHD) correspondence dated March 24, 1994. The samples were collected a minimum of two feet below the surface of the soil pile into prewashed brass tubes, capped with Teflon tape and plastic end caps and transported on ice, under chain of custody, to Argon Mobile Labs Samples were analyzed for TPHd, TPHg, and BTEX No petroleum hydrocarbons were detected in any samples Soil sample locations are shown on Plate 3 Analytical results are summarized in Table 3 . Laboratory reports and chain of custody documentation are included in Attachment 3 DESTRUCTION OF MONITORING WELL MW1 As discussed in RESNA correspondence dated August 31, 1994, monitoring well MW1 was destroyed as a result of unstable side walls to the excavation pit Although a portion of the broken well casing can be seen lying across the floor of the pit, the intact well remnant is not visible above the pit floor The well remnant has been covered with dirt and mud from the excavation side walls and is no longer accessible. RESNA has maintained that this well remnant poses no threat as a potential conduit for vertical transport of contaminants All portions of the well from ground surface to approximately 15 to 18 feet below grade have been destroyed by caving into the excavation Groundwater currently exists at approximately 15 feet below grade The entire well remnant exists within the saturated zone and there will be no conduit from the surface after backfilling has occurred Furthermore, two rounds of groundwater samples collected from the excavation pit contained no detectable hydrocarbons, indicating that replacement of this well is not warranted CONCLUSIONS AND RECOMMENDATIONS Based upon analytical results of groundwater samples collected from the groundwater monitoring wells and two rounds of samples collected from the open excavation, it appears 1500591SR102794 doc 2