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Cl eo(oBuaCTec(zntcs Inc Page 3 <br /> Groundwater Monitoring Report <br /> Project No 770 2 <br /> September 18,2000 <br /> i <br />� 1.3 Laboratory Analyses <br /> ' The groundwater samples collected on August 28, 2000 were delivered to Sherwood Lab <br /> (Department of Health Services Certification No 1400), of Hilmar, California, for analysis <br /> Sherwood analyzed the three monitoring well groundwater samples for <br /> • 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 /> I • TEPH- Diesel, Kerosene, Dielectric and Motor Oil by EPA method 3510/8015(M) <br /> Additional samples were sent to Entech Analytical Labs, Inc , from Sherwood Labs for the <br /> analysis of <br /> • Lead by EPA method 200 7 <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 /> 2.0 FINDINGS AND DISCUSSION <br /> The results of theroundwa <br /> g ter sample analysis show the following <br /> • The laboratory results indicate that diesel range petroleum hydrocarbons have impacted <br /> the groundwater in the vicinity of wells MW-4, MW-5, MW-6 and MW-105 <br /> • Minor BTEX constituents are also present at levels ranging <0 3 — 3 ug/1 in wells MW-4, <br /> MW-5, MW-6 and MW-105 <br /> • Gasoline, kerosene, and motor oil range petroleum hydrocarbons were not present in any <br /> of the groundwater samples at concentrations above the laboratory reporting limits <br /> • Lead was detected in wells MW-3 and MW-6 at 21 and 17 ug/1, respectively There does <br /> not appear to be correlation between lead and diesel contamination as MW-3 did not <br /> contain diesel but MW-6 did <br /> ' The lateral extent of the diesel groundwater plume is currently defined to the southeast by <br /> MW-2, and to the northeast by MW-3 The vertical extent of the plume may be defined by <br /> ' MW-105, but further analysis is needed to determine if the contaminants detected are a <br /> drilling artifact Well MW-6, which is located directly down gradient of well MW-5, <br /> indicated lateral attenuation occurs as evidenced by the lower diesel concentrations in well <br /> MW-6 _ <br /> GTI makes the following recommendations <br /> 4 • Continue quarterly groundwater monitoring to complete four consecutive events for <br /> determining direction and contaminant trends <br />