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N- l <br /> Geo4icafTechnics_7=. <br /> Groundwater Monitoring Report Page 3 <br /> Project No.750.2 <br /> August 24,2000 <br /> A chain of custody document, listing all samples collected, accompanied the samples <br /> field to laboratory, thereby providing a means to track their movement and insure heir <br /> r integrity. <br /> The purge water was placed in a 55 gallon DOT approved container, properly labeled and <br /> stored on site until its proper disposition can be arranged. ' <br /> Groundwater monitoring field logs are included in Appendix C. <br /> 1.3 Laboratory Analyses <br /> The groundwater samples collected on July 14, 2000 were delivered to Sherwood Lab <br /> (Department of Health Services Certification No. 1400), of Hilmar, California, for analysis. <br /> The three-groundwater samples were analyzed for: <br /> • Benzene, Toluene,Ethyl Benzene, and Xylene (BTEX) <br /> Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M). <br /> • Fuel oxygenated compounds (MTBE, DIPE, ETBE, TAME & TBA) by EPA method <br /> 8260. <br /> Y` • The detection limits for the above analyses are listed in Table 2 of Appendix A and the <br /> ,f.. lab data is presented in Appendix B. <br /> 2.0 FINDINGS AND DISCUSSION <br /> The results of the groundwater sample analyses show the following: <br /> L • Currently only one monitoring well (MW-1) shows impact from gasoline range <br /> g <br /> petroleum hydrocarbons and its additives. <br /> a The concentrations in MW-1 are lower then those found in the groundwater hydropunch <br /> sample collected from HP-1 by approximately an order of magnitude. <br /> • MTBE concentrations in MW-1 decreased from 220 ug/I for the initial April 2000 event <br /> to 23 ugll during the July 2000 event. <br /> • Groundwater contamination appears to be defined to the north, east and south by non- <br /> detects in HP-6, MW-3 and MW-2/HP-3 respectively. <br /> Quarterly groundwater monitoring will continue at the site. The next event will occur by <br /> October 2000. <br /> • A Vapor Extraction Pilot Test was completed and a Vapor Extraction Pilot Test Report <br /> dated August 8, 2000 has been submitted to Sart Joaquin County PHS/EHD. <br /> GTI completed a June 29, 2000 work plan for three additional monitoring wells, which <br /> was approved by PHS/EHD on July 7, 2000. A cost pre-approval application has been <br /> submitted to the USTCFP for review. <br /> E <br />