SITE INFORMATION AND CORRESPONDENCE

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Mr.James Barton ' August 7,2002 Page 5 . groundwater were measured, and the groundwater was visually observed for color, turbidity, and the ' presence of floating chemical product. Physical parameters were recorded on water sample field data sheets included in Appendix A. Upon removal of the appropriate purge volume, stabilization of the measured parameters, and allowing water level recovery to 80% of the static level; samples were collected from each well using a dedicated disposable PVC bailer. Groundwater samples were decanted into prelabeled laboratory-supplied ' glassware, placed in an ice-filled cooler, and transported under chain-of-custody documentation to STL San Francisco of Pleasanton, California, a state-certified analytical laboratory. Second Quarter 2002 groundwater samples were analyzed for TPHg and TPHd by EPA Method 8015 Modified. Laboratory analytical reports and chain-of-custody records are included in Appendix B. Results of quarterly groundwater monitoring activities for the Second Quarter 2002 are summarized with historical results in Table 1. ' Groundwater Elevations ' A groundwater elevation contour map based on the June 26,2002 groundwater elevation data is presented as Figure 3. During the June 26, 2002 monitoring event, groundwater elevations ranged from—12.03 to 2.53 feet relative to mean sea level (msl). The maximum groundwater elevation change between the ' Fourth Quarter 2001 event and the June 26, 2002 monitoring event was an increase of 1.35 feet in well MW-3. Historical groundwater sounding data is summarized in Table 2. N Interpretation of the groundwater elevation contour map during the Second Quarter 2002 indicates groundwater flow is directed away from Potato Slough towards the southeast under an average hydraulic gradient of approximately 0.08 feet per foot (ft/ft). This groundwater flow pattern is consistent with ' historical monitoring data as shown in Table 3. Free Product Monitoring and Removal From Well MW-3 ' Marina personnel continued to monitor and change the hydrophobic hydrocarbon absorbent sock in well MW-3 on an approximate biweekly basis to provide continuous absorption and removal of free product. The absorbent material removes free phase petroleum hydrocarbons while dissolved phase contaminants ' attenuate naturally. Visual observations of the groundwater color prior to installing the absorbent socks have been noted as being yellow and murky; however, after installation of the absorbent socks Marina personnel have observed the groundwater to be generally clear. No free product was observed floating on ' the groundwater surface during the Second Quarter 2002. Second Quarter 2002 Analytical Results ' Groundwater analytical results for the Second Quarter 2002 are summarized on Table 1 and displayed graphically on Figure 4. TPHd was detected in wells MW-3 and MW-4 at respective concentrations of ' 2,600 and 720 micrograms per liter (ug/1). TPHg was reported at a concentration of 130 ug/l in the sample from well MW-3, and was not detected above the reporting limit of 50 ug/L in well MW-4. ' Comparison to Historical Analytical Results The concentrations of TPHd reported in wells MW-3 and MW-4 represent an increase since the last monitoring event conducted in December 2001, but are well below historical maximum concentrations ' 1ATower Park\QMR\2002 QMR\Q2-2002\2nd QTR 2002.dcc SECOR Intemational Inc.