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Groundwater Analytical Results <br /> TPHg was detected in samples collected from wells MW-13, MW-14, VM-1 and VM-2 at <br /> concentrations of 58, 810, 280 and 11,000 µg/1, respectively TPHd was detected in the groundwater <br />' samples collected from wells VM-1 and VM-2 at concentrations of 270 and 1,800 pg/], respectively <br /> Benzene was detected in groundwater samples collected from wells MW-14, VM-1 and VM-2 at <br /> concentrations of 190, 31 and 4,800 gg/1, respectively Toluene was detected in wells MW-14 and <br />' VM-2 at concentrations of 1 1 and 64 gg/l, respectively Ethylbenzene and total xylenes were also <br /> detected to wells MW-14, VM-1 and VM-2 at concentrations ranging from 5 2 (VM-1 - total <br /> xylenes) to 600 (VM-2 - ethylbenzene) pg/l FOCs were not detected above their respective <br />' laboratory method detection limits in each of the groundwater samples TPHg, TPI-Id and benzene <br /> concentrations for the Fourth Quarter - 2002 monitoring event are depicted on Figure 3, Petroleum <br /> Hydrocarbons in Groundwater-December 2002 <br />' CONCLUSIONS AND RECOMMENDATIONS <br />' The highest concentrations of dissolved phase petroleum hydrocarbons appear to be limited to the <br /> immediate vicinity of the former UST excavation area (monitoring wells MW-14, VM-1 and VM-2) <br /> Geocon recommends that the Central Valley Regional Water Quality Control Board (CVRWQCB) <br /> consider the Site for possible low risk closure and regulatory "no further action" status Pending <br /> evaluation by the CVRWQCB, the next quarterly monitoring event is scheduled for March 2003 <br /> If there are any questions concerning the contents of this report, or if Geocon may be of further <br />' service, please contact the undersigned at your convenience <br /> Sincerely, <br /> GEOCON CONSULTANTS,INC <br /> 0 <br /> � <br /> u d, , CEG � �' 46fn� M Rebecca L Silva, REA <br /> rode anager No OC13�1�°`� � Project Scientist <br /> RLS JEJ sb <br /> \`Q <br />' (5) Addressee <br />' Attachments Figure 1, Vicinity Map <br /> Figure 2, Groundwater Elevation Map -December 2002 <br /> Figure 3, Petroleum Hydrocarbons in Groundwater -December 2002 <br /> Table 1, Summary of Groundwater Elevation and Analytical Data <br /> Appendix A, Summary of Historical Groundwater Analytical Data <br />' Appendix B, Monitoring Well Sampling Data Sheets <br /> Appendix C, Laboratory Reports and Chain of Custody Records L-4$a�— <br /> 1 <br /> Project No 59475-06-24C -3- January 23 2003 <br />