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I lilt I I 1 i� JI Methods and Procedures _ The ground water was sampled in six monitoring wells by a Western Geo-Engineers (WEGE) geologist, working directly, under the supervision of California Registered Geologist #3037: Using a resistance probe, WEGE personnel measured the depth: to ground ! water prior to sampling each well. A product thickness was then measured using a cleaned, clear bailers. A fresh bailer was used for each well . These special bailers are designed and built by WEGE to recover the exact product thickness. If no .product was ; present in the well, a water sample was' collected. 9 Each well was purged before collecting water samples. MW1 , MW2, j MW3, MW5, MW6 and MW7 were sampled after purging the wells of j enough water that temperature, pH and conductivitystailized. This data is presented in Appendix B. . The purged water was contained in a labeled, secured 55 gallon drum on site. From the I well information a ground water contour surface was plotted and a flow direction inferred. This is presented in Figure 4. The wells were allowed to recover after purging. A water sample was then collected -with a fresh bailer'. Each sample was divided 1 among four 40-m1 vials. The vials are supplied by the laboratory or a chemical supply company and are pre-cleaned to exact EPA } protocols . The sample vials were labeled as to station, well, time and sampler, and documented on the chain-of-custody sheet. They were then placed into an ice chest and cooled to 4-C with ice. The samples were delivered to a California State Certified Laboratory and signed over to the lab using standard chain-of- custody procedures . } CHEMICAL ANALYSIS RESULTS i The samples were analyzed at Chemtech Analytical Laboratories (DHS#359 ) for Total Fuel Hydrocarbons (gasoline) , with BTEX distinction, utilizing EPA Methods 5030 and 602, respectively. As noted under Purpose and Scope above, water samples were collected from MW1 , MW2 , MW3 , MW5, MW6 and MW7 . Of these laboratory- analyzed samples , all samples were Below Reportable Limits (BRL) J with the exception of MW3 which contained 15 ppb Benzene. r The analytical results and the pertinent gathering data are listed in Table 1 , and the laboratory report is included in Appendix C. ` ' HYDROCARBON CONTAMINATION i The wells sampled during this monitor round indicate non r detect for petroleum hydrocarbons with the exception of MW3 . The aquifer test data (Appendix A) along with the lithologic cross section and hydraulic gradient across the site infer that velocities of the ground water ares such that natural bio- degradation is taking place. F 3