Laserfiche WebLink
vir �Y� <br /> 011, : $Aecrpltsl5 M <br /> `� ���fienf RerS�ecirol T e <br /> Mr 1'l1011lasI so,%L-toh' <br /> Ulititillr217ic. ' <br /> 69S Wes tTI11refSIreet ` <br /> Hariford;Callforiala 93230 <br /> J Q'ii�i tei ly;Gi ounritit afet iVfnnitori ig l RerOdi tfion;S}sfcrit 2ejt"ort <br /> I but th Qlai,ter 20b7 <br /> - BE8C011 5tattton No.364 i .. <br /> i10 Easf Hanualer.;l:,anc Stoektan Galrforiia <br /> Conclusions and Recommendations $ ' <br /> Results of fourth quarter groundwater monitoring indicate continued decreasing hydrocarbon <br /> concentration trends in response to. the ongoing remedial actions. Hydrocarbon <br /> concentrations in groundwater in the immediate vicinity of the vapor extraction and air <br /> sparge wells have decre-ased'by one to two orders of magnitude since the initiation`of <br /> remediation systems operation. <br /> "Horizon completed installation of an additional monitoring well MW-14 in August 2006 <br /> according to the approved letter Work Plan dated April 21,2006. Three rounds of quarterly; <br /> ] sampling of monitoring well MW-14 since August 2006 indicate no groundwater <br /> hydrocarbon impacts. Horizon submitted Additional Monitoring Well Installalion'and <br /> 6 Updated Site Conceplual Model on December 7,2006. <br /> 1 ��D VT <br /> Horizon recommends that a groundwater concentration rebound test be conducted during first <br /> uarter 2008. The VES shall be shut in during January 2008 and remain non-operational <br /> unti l after the first quarter groundwater monitoring event tentatively planned for March 2008. <br /> Continued non-operation or re-start of the VES shall be evaluated on the basis of results of <br /> �i the first quarter 2008 groundwater monitoring. <br /> �y C/ Horizon further recommends destruction of deep monitoring wells MW-1 i through MW-13 <br /> eene a ween an ee eep an monitoring we MW-14(screened 1101-1195 to <br /> `1 <br /> cc cep . ese we s were ins a e to a ineate the vertical extent of petroleum <br /> hydrocarbon-impacted groundwater. Analytical results of groundwater samples from these <br /> wells-indicate that groundwater at the screened depths is not impacted by petroleum <br /> hydrocarbons and will not be impacted by the initial release that precipitated this remediation <br /> project. <br /> 641gmrQ407.doc 3 HORIZON ENVIRONMENTAL INC. <br /> project No.1641.410 , <br /> SAN JOAOUIN 00 _ <br /> TIWW <br /> �NAENTAL HEALTH <br /> 600 E. MAIN ST <br /> 066KTON CA 95W2 <br /> (M 4646 W <br /> so Rent <br /> i' t0"t Ofw <br /> tMM rl emes+t�of or locr alder' <br /> dM nd auftfire or <br /> I ; <br />