ARCHIVED REPORTS XR0000226 - Laserfiche WebLink

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T i FIELD ACTIVITIES ' Depth to Groundwater Measurements On March 23, 2004,representatives of Geocon measured the depth to groundwater in monitoring wells ' MW-9, MW-1l 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 -March 2004 During the First Quarter - 2004, the depth to groundwater in the twelve existing wells was recorded between 50 75 and 51 64 feet below TOC Based on the March 2004 groundwater elevation data, the groundwater beneath the Site appears to be directed toward the northeast at an average gradient of 0 004, which is consistent with historical groundwater flow A review of the last reported groundwater level measurements for the Site indicates that from November 2003 to March 2004 the groundwater ' levels in each of the wells increased an average of 2 16 feet 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 March 23, 2004, approximately three well volumes of water (4 5 to 78 gallons) was extracted from ' each well utilizing a 2-inch diameter submersible pump or a disposable bailer 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 eleven Department of Transportation-approved, 17-H, 55- gallon drums and temporarily stored onsite pending receipt of laboratory analysis The drums will be transported by ABCO Environmental Services to an appropriate disposal facility in April 2004 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, ter -amyl methyl ether (TAME), ethyl tert-butyl ether (ETBE), di-isopropyl ether (DIPE) and 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 The laboratory is currently preparing electronic data files for submittal to Geotracker Geocon will upload the data and provide Caltrans with a Geotracker confirmation number as soon as the process is complete Project No S8475-06-24J -2- April 22,2004