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------ VATCi ASSOCIATES I N C . volumes of water. Purged water was contained in labeled 55-gallon drums (DOT H), and stored On site. Groundwater samples were collected after physical parameters (pH, temperature, and conductivity) were monitored and had stabilized. Dedicated disposable bailers with bottom- emptying devices were used to collect samples from the wells. Field purge logs are presented in Attachment 1. Laboratory analytical results in wells MW3 and MW4 were inconsistent with historical results, and subsequently wells MW3, MW4, and MW7 were resampled on July 9, 2002 employing the same procedures. LABORATORY ANALYSES Collected groundwater samples were analyzed by Argon Laboratories, a State-certified laboratory, for total petroleum hydrocarbons as diesel (TPHd) utilizing EPA method 8015. A split sample collected from well MW3 on July 9, 2002, was submitted to Excelchem, a State- certified laboratory, to confirm the results. Analytical results are summarized in Table 3. Laboratory data sheets and chain-of-custody documentation are included in Attachment 2. r; Laboratory results indicate that TPHd was detected in groundwater samples collected from well MW4 on July 9, 2002 at a concentration of 6,700 parts per billion (ppb). Analysis of samples collected from wells MW1, MW2, MW3, MW5, MW6 and MW7 on May 31, 2002, and wells MW3 and MW7 on July 9, 2002, did not indicate the presence of TPHd above method detection limits. RECOMMENDATIONS ATC recommends an additional quarterly monitoring event to better evaluate the site/ongoing levels of TPHd'and monitoring of the skimmer. If free product is encountered in the skimmer, it will be removed from the skimmer and stored on site. The next groundwater monitoring episode is scheduled to be performed in September 2002 and will include sample collection from monitoring wells MW 1 through MW7. w:162574.021quart1y12gmr2002.doc 2