ARCHIVED REPORTS XR0000232 - Laserfiche WebLink

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1FIIELD ACTIVITIES Depth to Groundwater Measurements ' On September 30, 2002, representatives of Geocon measured the depth to groundwater in monitoring wells MW-9, MW-11 through MW-14, MW-16, MW-19, MW-20, MW-24, MW-25, VM-1 and VM- 2 using a battery operated water level meter The measurements were obtained from surveyed reference points at the top of the well casing(TOC) The approximate well locations and site features are depicted on Figure 2, Groundwater Elevation Map- September 2002 ' During the Third Quarter - 2002, the depth to groundwater in the twelve existing wells was recorded between 5175 (MW-11) and 5262 (MW-13) feet below TOC Based on the September 2002 groundwater elevation data, the groundwater beneath the Site appears to be directed toward the ' northeast at an average gradient of 0 005 which is consistent with historical groundwater flow A summary of the TOC elevations, depth to groundwater measurements and Mean Sea Level groundwater elevations is presented on Table 1 ' Well Purging and Sampling On September 30, October 1 and 2, 2002, approximately three well volumes of water (4 to 76 gallons) were extracted from each well utilizing a 2-inch diameter submersible pump During the well purging activities, the groundwater was monitored for pH, electrical conductivity, temperature, and turbidity This information is included on the Monitoring Well Sampling Data Sheets presented ' in Appendix B Following the purging activities, groundwater samples were collected from the wells and decanted into four 40-milliliter volatile organic analysis vials and one one-liter amber glass bottle The samples were sealed, labeled, placed in an ice chest containing ice, and subsequently transported to the laboratory using standard chain-of-custody protocol ' The extracted groundwater was placed into 11 Department of Transportation-approved, 17-H, 55- gallon drums and temporarily stored onsite pending receipt of laboratory analysis The drums were transported by ABCO Environmental Services to Invirotech located in Lincoln, California on October 17, 2002 ' ANALYTICAL METHODS AND RESULTS Laboratory Analyses ' Groundwater samples were delivered to Creek Environmental Laboratories, Inc , a Caltrans-approved and California-certified analytical laboratory, for the analyses of TPHg and TPHd following EPA Test Method 8015, benzene, toluene, ethylbenzene and total xylenes (BTEX) following EPA Test Method 8020 and fuel oxygenate compounds (FOCs) including MTBE, tert-amyl methyl ether (TAME), ethyl tert-butyl ether (ETBE), di-isopropyl ether (DIPE) and tert-butanol (TBA) following EPA Test Method 8260 Groundwater analytical results are summarized on Table 1 Laboratory ' reports and chain-of-custody documentation are presented in Appendix C 1 Project No 58475-06-24B -2- November 5,2002