Laserfiche WebLink
GeologuolTech,tt Inc Page 3 <br /> Groundwater Monitoring Report <br /> Pioject No 507 2 <br /> • March 12,200 t <br /> ' All water purged from each monitoring well and not used as a sample wasp laced in a 55 <br /> gallon DOT approved container These drums were properly labeled and will be stored on <br /> site until their proper disposition can be arranged <br /> Groundwater monitoring field logs are included in Appendix C <br /> ' 1.3 Laboratory Analyses <br /> ses <br /> The groundwater samples collected on January 5, 2001, were delivered to Sherwood Lab <br /> (Department of Health Services Certification No 1400), of Hilmar, California, for analysis <br /> iSherwood analyzed the eiglit-groundwater samples <br /> 0 Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX) by EPA method 602 <br /> • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) <br /> Additional samples were sent to Entech Analytical from Sherwood Labs for the analysis of <br /> 0 MTBE, DIPE, ETBE, TAME and TBA by EPA method 8260 <br /> The results and detection limits for the above analyses are listed in Table 2 of Appendix A <br /> while the lab analytical results are presented in Appendix B <br /> 2.0 FINDINGS AND DISCUSSION <br />' The results of the groundwater sample analyses indicate the following <br /> O Wells MW-1, MW-2 and MW-3 continue to be free of detectable contamination <br /> • MW-4, MW-5 and MW-9 have significant BTEX and TPH-G contamination <br />' • MW-6 and MW-8 have slight BTEX and moderate TPH-G contamination <br /> • Wells MW-6 and MW-9 contained 9 7 and 880 ug/l MTBE, respectively Wells MW-4 <br /> and MW-5 did not contain MTBE above the Iaboratory detection limits, however it is <br /> noted that the limits are elevated due to the high levels of TPH-G present Gasoline <br /> oxygenates, DIPE, ETBE, TAME and TBA, are not present in any of the groundwater <br /> samples <br /> • The groundwater gradient is relatively flat and the direction of groundwater flow has <br /> varied during the course of the investigation The site is quite close to the San Joaquin <br /> River and tidal fluctuations might be responsible for the observed changes in <br /> groundwater direction <br /> 0 Oxidation-Reduction Potential (ORP) was measured (Table 3) and the results suggests <br /> that all of the wells are either in the core of the contamination plume or are immediately <br /> down giadient of the plume and are within the halo of reaction depleted water caused by <br /> biodegradation of the contaminants <br />