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a l Cjeola ica[Tecaits 2M. ' 9 Page 4 Groundwater Monitoring Report r Project No. 750.2 4 -7 i December 27,2000 I The purge water was placed in a 55 gallon DOT approved container, properly labeled and stored on site until its proper disposition can be arranged. ' Groundwater monitoring field logs are included in Appendix C. 1.3 Laboratory Analyses The groundwater samples collected on December 1, 2000 were delivered to Sherwood Lab (Department of Health Services Certification No. 1400), of Hilmar, California, for analysis. j _ I The groundwater samples were analyzed for: i • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX). { • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 503018015(M). } i Additional samples were sent to Entech Analytical Labs, Inc. from Sherwood Labs for the j analysis of. • Fuel oxygenated compounds (MTBE, DIPE, ETBE, TAME & TBA) by EPA method 8260. . The detection limits for the above analyses are listed in Table 2 of Appendix A and the lab data is presented in Appendix B. ' 2.0 FINDINGS AND DISCUSSION I; ii The results of the groundwater sample analyses show the following: i • Well MW-1 is impacted with gasoline range petroleum hydrocarbons and this is consistent with past events. I ' • The discretely screened deep well MW-101 contained BTEX, TPH-G and MTBE concentrations above the laboratory reporting limits. Additional monitoring is necessary ' to determine contaminant trends. • Cross gradient well MW-5 contained 177 ug/1 TPH-G. ! ; • Vertical gradient gradient was calculated and determined to be downward and an order of magnitude greater than the water table well horizontal gradient. • Quarterly groundwater monitoring will continue at the site. The next event will occur by March 2001. + A Vapor Zone Remediation - Corrective Action Plan dated October 31, 2000 has been j ! submitted to San Joaquin County PHS/EHD for approval. I , i I I