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sl _ <br /> Quick and Save # 1 Page 2 of 2 <br /> 1901 S . El Dorado Street January 16, 2009 <br /> s <br /> r <br /> additional CPT borings to assess the vertical and lateral extents of impacted <br /> groundwater. <br /> The EHD does not concur with the recommendation for additional CPT borings at this <br /> time; the EHD is concerned that the similarity of TPH-g and benzene, toluene , ethyl <br /> benzene, and xylenes (BTEX) concentrations, over a fairly narrow range, in the deep <br /> groundwater samples and in some of the deep soil samples and soil samples outside the <br /> "core" area may represent cross contamination from more intensely impacted shallow <br /> ground water. <br /> The EHD believes it would be more beneficial to install additional groundwater <br /> monitoring wells to define the later extent of impacted ground water in the water table <br /> zone and confirm the CPT data for groundwater in the sand units approximately 75 to 80 <br /> feet bsg and 95 to 105 feet bsg in what appears to be the contaminant source area near <br /> MW-2 and CPT-2. Submit a workplan to the EHD by March 20, 2009 to install additional <br /> monitoring wells to assess the lateral and vertical extent of impacted groundwater in soil <br /> units likely to serve as migration pathways for the dissolved contaminants. <br /> If you have any questions , please contact Frank Girardi , Senior Registered <br /> Environmental Health Specialist, at (209) 953-7868. <br /> 4 �� --- <br /> Frank Girardi, REHS Nuel C. enderson, Jr. , PG <br /> Senior Registered Environmental Health Specialist Engineering Geologist <br /> c: James Barton , RWQCB , 11020 Sun Center Dr. #200, Rancho Cordova , CA 95670 <br /> c: Maria Carranza , Staff Scientist, AGE, 837 Shaw Road , Stockton , CA 95215 <br />