ARCHIVED REPORTS XR0000287 - Laserfiche WebLink

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In February 2000, the mass of petroleum hydrocarbons in soil was estimated at approximately 485 Pounds for TPHg and 8 pounds for benzene The mass of petroleum hydrocarbons in groundwater beneath the Site was estimated to be approximately 2 grams of TPHg and 0 7 grams of benzene The t groundwater plume beneath the Site may extend beneath B Street Review of the historical soil analytical data indicates petroleum hydrocarbon impacts at intervals between 35 and 66 feet below the ground surface (bgs) with the exception of the tank removal soil samples collected between 12 and 14 feet bgs Approximate locations of the groundwater monitoring wells are depicted on Figure 2 ' FIELD ACTIVI'T'IES ' Depth to Groundwater Measurements On May 10, 2002, representatives of Geocon measured the depth to groundwater in monitoring wells ' MW-1 through MW-12, VW-1 and VW-2 using a battery operated water level meter The measurements were obtained from a surveyed reference point at the top of the well casing (TOC) The approximate well locations and site features are depicted on Figure 2, Groundwater Elevation Map-May 2002 During the First Quarter - 2002, the depth to groundwater in wells MW-1 through MW-12, VW-1 ' and VW-2 was recorded between 47 83 and 49 28 feet below TOC Based on the May 2002 groundwater elevation data, the groundwater beneath the Site appears to be directed toward the southeast at an approximate gradient of 0 0019 which is consistent with historical groundwater flow t A summary of the TOC elevations, depth to groundwater measurements and Mean Sea Level groundwater elevations is presented on Table 1 Well Purging and Sampllns7 MApproximately three well volumes of water (35 to 66 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 14 Department of Transportation-approved, 17-H, 55- gallon drums and temporarily stored onsite pending receipt of laboratory analysis The drums are scheduled to be transported by ARCO Environmental Services to an appropriate disposal facility in June 2002 ANALYTICAL METHODS AND RESULTS LaboratorV 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, 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 Project No 58475-06-24 -2- June 24,2002