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Former Beacon Station No 12419 October 29,2002 5tQckton.California T Groundwater Groundwater Monitoring Report 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 Groundwater Monitoring Results Depth-to-groundwater measurements were subtracted from the surveyed TOC elevations to calculate groundwater elevations Groundwater elevation data were used to construct a groundwater contour map as shown on Figure 2 The groundwater flow direction ranged from west to northwest under gradients ranging from approximately 0 004 to 0 007 Groundwater analytical results are summarized in Table 1 Benzene concentration data from this sampling event were used to construct a benzene 1 so concentration map as shown on Figure 3 Copies of the laboratory data sheets and chain-of-custody documents are included as Attachment C Recommendations Horizon recommends continued quarterly monitoring be performed to evaluate trends in the . groundwater gradient and concentrations of dissolved hydrocarbons over time The Problem Assessment Report / Corrective Action Plan (PAR/CAP) for the site submitted in March 2002 has been approved by the San Joaquin Country Environmental Health Department Horizon is in the process of designing soil vapor extraction and air sparge remediation systems as proposed in the CAP GeoTracker Electronic Data Deliverables The analytical electronic data deliverable (EDD) is uploaded by Kiff The groundwater well measurement file EDD (GEO_WELL) for this quarterly monitoring event has been uploaded by Horizon The GEO_WELL file upload confirmation sheets for this and the previous four quarters are contained in Attachment E 419gmr02Q3 doc Project No 1419 45 2 HORIZON ENVIRONMENTAL INC.