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GeofogzcafTecFinus Inc Page 4 <br /> Groundwater Monitonng Report <br /> Project No 770 2 <br /> F May 14,2002 <br /> F <br /> 1.3 Laboratory Analyses <br /> ' The groundwater samples collected on March 11, 2002, were delivered to Sherwood Lab <br /> (Department of Health Services Certification No 1400), of Hilmar, California, for analysts <br /> Sherwood analyzed the seven monitoring well groundwater samples for <br /> • Benzene, Toluene, Ethyl Benzene, and Xylene (BTEX)by EPA method 8020 <br /> • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) <br /> • TEPH- Diesel and Motor Oil by EPA method 3500/8100(M) <br /> ' The detection limits for the above analyses are listed in Table 2 of Appendix A while the lab <br /> analytical results are presented in Appendix B <br /> As required under AB2886, the laboratory data was submitted electronically to GeoTracker <br /> on April 30, 2002 - confirmation number 1444506943 <br /> ' 2.0 FINDINGS AND DISCUSSION <br /> The results of the groundwater sample analysis indicate the following <br /> • Diesel range petroleum hydrocarbons were detected in four of the site's seven <br /> monitoring wells <br /> ' • Well MW-5 contained 16800 4gll TPH-D and this is the highest level detected since the <br /> well's installation in August 2000 <br /> • Minor BTEX constituents are present at levels ranging from 0 5 — 3 7 ug/l in wells MW- <br /> 4 and MW-6 <br /> • Motor oil range petroleum hydrocarbons were not present in any of the groundwater <br /> ' samples at concentrations above the laboratory reporting limits <br /> • TPH-G was not present in any of the groundwater samples at concentrations above the <br /> laboratory reporting limits Four of the wells contained TPH-G for the September 2001 <br /> ' event only MW-1, MW-4, MW-6 and MW-105 <br /> • Deep well MW-105 did not contain contaminant concentrations above the laboratory <br /> ' reporting limits for the second consecutive event <br /> • The lateral extent of the diesel groundwater plume is currently undefined due to the <br /> continuing fluctuations in groundwater direction <br /> ' • The vertical extent of the plume is intermittently defined by MW-105 <br /> • Oxidation-Reduction Potential (ORP) measurements show that three of the site's seven <br /> monitoring wells are within the reaction depleted water caused by biodegradation of the <br /> ' contamination plume These wells exhibit negative ORP values and all of the well ORP <br /> data are included in Table 4 of Appendix A <br /> k <br />