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r Upgradient collected a fluid sample from one of these drums on March 3 . The fluid emitted an unusual hydrocarbon odor unlike gasoline, and Apache Plastics therefore authorized the analysis of this sample for chlorinated hydrocarbons (solvent) using EPA method 8010 . The sample was transported to Sequoia Analytical in a 1-liter amber bottle under chain-of-custody ( see Appendix B) . The compound 1, 2 dichloroethane was detected at a concentration of 200 Mg/l. The fluid was removed by vacuum truck on April 5 and transported under non-RCRA hazardous waste manifest by Petroleum Recycling Corporation (PRC) to its TSD facility in Patterson, California for disposal . A copy of the pick-up receipt is enclosed in Appendix D. Upgradient will forward a copy of the manifest to San Joaquin County Envionmental Health when received. 7 .0 CONCLUSIONS The operational and monitoring problems that were encountered during the f irst quarter of operation of the VES were corrected during the second quarter, and efficient operation was attained. Nearly 30, 000, 000 cu ft of vapors were withdrawn and combusted between October 1, 1994 and April 1, 1995, resulting in a net removal of more than 5, 000 lbs of hydrocarbons . VOC concentrations in the vapor stream varied from less than 1, 000 ppm to more than 20, 000 ppm during this period, but an overall decrease in concentrations appears to have occurred. This trend may have begun to reverse near the end of the monitoring period, when the air flow rate decreased as a result of the reduction in the size of the extraction unit. The destruction rate is anticipated to decrease during the next quarter of operation as a result of the reduced air flow. In its 1992 report, Remediation Systems estimated that 13, 000 lbs of hydrocabons are present in the vadose zone at the site. In a separate report, Kleinfelder Associates estimated that more than 28, 000 lbs are present. Using these estimates, between 20 and 40% of the total hydrocarbons have been destroyed. Extrapolating from the results to date, an additional five quarters of operation might be needed to recover the remaining hydrocarbons . However, now that the 460-inch engine has been replaced with a smaller unit, it is likely that more than five quarters of operation will be needed. Groundwater contamination is neither great nor widespread at the present time. Continued operation of the VES may cause a further reduction in contaminant levels . Therefore, Upgradient recommends continued monitoring of the wells . Second-quarter sampling should be scheduled for early June, 1995, before groundwater recedes below the screened interval of the monitoring wells .