ARCHIVED REPORTS_XR0005249 - Laserfiche WebLink

Home Browse Search

Former Bt.acon Station No 12474 January 17, 2005 Stockton, California _ Quarterly Groundwater Monitoring Report Health Services-certified analytical laboratory (FLAP No 2236) located in Davis, California The samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg), the volatile aromatic compounds benzene, toluene, ethylbenzene and total xylenes (BTEX), and the fuel oxygenate methyl-t-butyl ether (MTBE) by Environmental Protection Agency (EPA)-Method 8260B -Wells-MW-13 through_MW_-17 were_also_analyzed for 1,2- dichloroethane (DCA) by Environmental Protection Agency (EPA) Method 8260B Groundwater Monitoring Results i Depth-to-groundwater measurements were subtracted from the surveyed TQC elevations to calculate groundwater elevations Groundwater elevation data, as summarized in Table 1, were_used=to-construct=the=groundwater=elevation=contour=map-shown_on=Figure=2 The groundwater flow direction in the dispenser island area varied from eastward to southeastward under an approximate gradient of 0 001 Groundwater analytical results are summarized in Table 1 Benzene concentration data were used to construct an isoconcentration map as shown on Figure 3 Analytical reports are contained in Attachment C Historical groundwater level and analytical data collected prior to 1998 are summarized in Tables 1 and 2 in Attachment D GeoTracker Electronic Data Deh-werables The analytical electronic data deliverable (EDD) is uploaded by Kiff The groundwater well measurement file EDD (GEO_WELL) for this quarterly monitoring event was uploaded by Horizon The GEO_WELL upload confirmation sheet for this quarter is contained in Attachment F Recommendations In February 2004, Horizon drilled and installed additional groundwater monitoring wells j (MW-13 though MW-17) for the purpose of evaluating the extent of impacted groundwater conditions The draft report of the investigation is in preparation Installation of a vapor extraction system (VES) and an air sparging system was completed in August 2004 The San Joaquin Valley Air Pollution Control District issued a modified Authority to Construct permit in October Final equipment connections were made in December 2004 Start up of the VEW is expected in January_2005 474gmr 0404 clot Project No 1474 47 2 HORIZON ENVIRONMENTAL INC.