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Page 1 of 2 <br /> Frank Girard! [EH] <br /> From: Tony_Mindling@URSCorp.com <br /> Sent: Thursday, August 14, 2008 9:49 AM <br /> To: Frank Girardi [EH] <br /> Cc: wabergvall@yahoo.com <br /> Subject: American Forest Products, Stockton <br /> Frank -- <br /> Since I didn't have the well installation report in front of me when we spoke this morning, I <br /> thought I would pass on a brief summary of the recent r lume delineation results. <br /> I <br /> i <br /> Two new wells were installed to assess vertical plumed lineation. DMW-10 was placed about 300 <br /> feet downgradient of the former source area and screen d from 40 to 50 feet bgs to assess shallow <br /> groundwater. 1,2-DCA was below detection in DMW-10. DMW-14 was located at the source area <br /> adjacent to two shallower wells. It is screened 90-100 f et bgs. 1,2-DCA was also below detection <br /> in that well. Thus it appears that the plume is confined to the intermediate depth where the <br /> contaminant is observed in wells screened generally from 60-70 feet bgs. <br /> i <br /> Three new wells were placed to assess lateral extent of the plume downgradient of the former <br /> source area. All were screened generally from 60-70 feer. bgs. DMW-11, about 300 feet directly <br /> downgradient, showed a 1,2-DCA concentration of 0.8 u /L - basically right at the detection limit. <br /> The result for DMW-13, placed to the left side of the plu e, was below detection. The result for <br /> 1,2-DCA in DMW-12, placed to the right side of the plume, was 1.9 ug/L, which is slightly above <br /> the detection limit. <br /> We concluded that the plume had been defined vertically, and also laterally as extending about 300 <br /> feet downgradient and 200 feet laterally. We also noted n the conclusions that concentrations in all <br /> of the wells are declining, particularly in DMW-9, where it is possible with linear regression to <br /> estimate that 1,2-DCA concentrations would decrease to below the detection limit in less that ten <br /> years. <br /> We look forward to receiving your comments on the report, and hopefully a recommendation for <br /> closure, in the next few weeks. <br /> H <br /> Regards, <br /> Tony Mindling <br /> Senior Hydrogeologist <br /> URS Corporation Americas <br /> 2870 Gateway Oaks Drive Suite 300 <br /> Sacramento, California 95833 <br /> (916) 679-2293 <br /> email: t©ny m.i.ndhng@urscor.p corn <br /> tel: 916.679.2293 <br /> fax:530.885.7947 <br /> cell: 916.812.8037 <br /> 8/25/2008 <br />