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compounds were reported. To evaluate this compound further, all wells will be tested for this compound next sampling event. A trace concentration of Fensulfothion was reported in well MW-5,which is a significant distance from the landfill (Figure 3). No other Organophosphate Pesticides were reported during this sampling event. Because of the distance from the landfill, the trace detection of one Organophosphate Pesticides at MW-5 is not likely related to the landfill; however, all wells will also be tested for this compound in the next sampling event. The metals reported are typically found in groundwater and there were no exceedences of concentration limits during this sampling event. Surface Water Surface water samples were not available this semester. Leachate Waste Discharge Requirements require monitoring leachate flow rate,pH, and Electrical Conductivity on a monthly basis (Table 3). Failure (and subsequent replacement) of the leachate meter display prevented the calculation of two months' flow rate. Vadose Zone Soil Gas Soil gasses were sampled on August 20, 2007. Samples were collected by first measuring the methane content using a CES-LANDTEC GEMTM 500 portable gas analyzer. The GEMTM 500 was operated until a steady-state gas composition indicated that the well was purged. After purging, gas samples were collected in 6-liter Summa canisters and sent to Atmospheric Analysis & Consulting, Inc. for analysis by EPA method TO-14A. Second Semester Results VOCs were detected in all soil gas samples (Table 4). The highest concentration of any VOC was found in SG-l. Freon 12 was most often reported with the highest concentration in a sample. The most VOCs (fourteen and seventeen)were reported in SG-11 and soil gas trench#1 respectively. Methane concentrations were 0 percent in all the wells except for 0.4 percent in SG-1 and 3.9 percent in SG-l1. Continuing detection of VOCs in soil gas since monitoring began in October 2003 with lack of impact by VOCs to groundwater at any well since February 2002 indicates that the presence of VOCs at these concentrations is a benign condition at this landfill. GROUNDWATER DIRECTION AND FLOW RATE Groundwater elevations were measured in monitoring wells MW-1,MW-2R, and MW-3 during the third and fourth quarters. The top of casing elevations for MW-4 and 5 will be surveyed in the first semester of 2008. Groundwater was determined to flow towards the southwest(Figures 3 and 4). The calculated average linear groundwater flow velocity in the third quarter was 70.87 feet per year based on a hydraulic gradient of Foothill Sanitary Landfill 9 Department of Public Works/Solid Waste 2`d Semester and Annual 2007 Groundwater Monitoring County of San Joaquin—January 31,2008