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FIRST QUARTER,2003 GROUNDWATER MONITORING REPORT JAAIAR OIL DISTRIBUTION JUNE 2003 SCOPE OF WORK Groundwater monitoring and sampling activities were conducted at the site on March 13, 2003. The following is a brief summary of the scope of work authorized by 7A LAR. • Measure depths to groundwater in monitoring wells MW-1 through MW-5. • Purge a minimum of three equivalent well volumes of groundwater from each of the wells and monitor for pH, temperature and conductivity. • Collect groundwater samples from the monitoring wells. Analyze water samples from the five monitoring wells for total petroleum hydrocarbons as gasoline (TPH G), total petroleum hydrocarbons as diesel (TPH D); benzene, toluene, ethylbenzene, and total xylenes (BTEX); and the fuel oxygenates MTBE, TBA, DIPE, ETBE and TAME. Prepare this QMR for submittal to the County and Regional Board. QUARTERLY GROUNDWATER MONITORING . Groundwater Elevations Prior to gauging depths to groundwater, the groundwater monitoring wells were checked for the presence of free floating hydrocarbons using an interface probe. No free product was present in any of the wells. Depths to groundwater measurements were then taken from each well from surveyed marks on the casing using an electric water level sensor or interface probe. Monitoring Wet!Purging The wells were purged using a new disposable bailer until a minimum of three equivalent well volumes of water were removed from each well. Groundwater purged from the wells was placed into DOT approved 55-gallon drums and stored on-site, prior to disposal by GHH. During the groundwater purging operations, physical parameters such as pH, temperature and conductivity were monitored and recorded on field data sheets, which are included in Appendix A. Groundwater purging was discontinued when the physical parameters indicated above appeared to stabilize in the purged groundwater. To reduce the potential for cross contamination between wells, all purging and sampling equipment were washed in a trisodium phosphate solution and rinsed in potable water prior to each usage. Groundwater Sampling Prior to sampling, the wells were allowed to recharge to a minimum of 80% of their initial static water levels. Groundwater samples were collected from each well using a new disposable bailer. 3