Laserfiche WebLink
San Joaquin County DIRECTOR <br /> Donna Heran,REHS <br /> 0 Environmental Health Department rpaASSISTANT DIRECTOR <br /> 600 East Main Street Laurie Cotulla,REHS <br /> Stockton, California 95202-3029 PROGRAM COORDINATORS <br /> Carl Borgman,REHS <br /> -s` Mike Huggins,REHS,RDI <br /> 0y.:= ;:P Website: www.Sjgov.org/ehd Margaret Lagodo,REHS <br /> �i FOR Phone: (209)468-3420 Robert McClellon,REHS <br /> Fax: (209)464-0138 Jeff Carruesco,REHS,RDI <br /> Kasey Foley,REHS <br /> February 7, 2008 <br /> Ms. Mabel Keir Ms. Nereida P. Lopez <br /> 1103 Grantland Court P. O. Box 6569 <br /> Modesto, California 95350 Stockton, California 95206 <br /> Subject: Lopez Properties <br /> 1601 Turnpike Road <br /> Stockton; California 95206 <br /> The San Joaquin County Environmental Health Department (EHD) has reviewed <br /> lithological and soil/groundwater analytical results from the installation of monitoring <br /> wells MW-9, MW-10, and MW-11, as well as analytical data for groundwater samples <br /> collected quarterly in 2007, submitted by Advanced GeoEnvironmental, Inc. (AGE) for the <br /> above-referenced site on your behalf. The EHD concurs with AGE's conclusion that the <br /> vertical extent of petroleum hydrocarbon contamination in soil appears to be defined in the <br /> source area. This is based on "non-detect" analytical results for contaminants of concern <br /> (COC) for soil samples collected in the former underground storage tank area at 100, 110, <br /> and 120 feet below surface grade (bsg) during the installation of monitoring well MW-9. <br /> The EHD also concurs with AGE's interpretation that the greatest concentrations of <br /> petroleum hydrocarbon contamination appear to be in a deeper zone beginning at <br /> approximately 50 feet bsg. This is inferred from observing that groundwater samples <br /> collected quarterly from monitoring wells screened between approximately 15 and 35 feet <br /> bsg have been reported as "non-detect" in five of the six monitoring wells surrounding <br /> MW-1 toward the north, west, southwest, and northeast. At the same time, groundwater <br /> samples collected from monitoring wells screened between approximately 50 and 65 feet <br /> bsg, and one deep monitoring well screened between 110 and 120 feet bsg, have been <br /> reported With significantly higher concentrations of COC. Therefore, the EHD concurs <br /> with AGE's conclusion that additional investigation is needed to define the vertical and <br /> lateral extent of petroleum hydrocarbon contamination in groundwater. Please submit a <br /> work plan to the EHD by May 1, 2008, that will address the COC in the deeper zones. <br /> By email on January 17, 2008, the AGE requested that groundwater collected from <br /> monitoring wells MW-2, MW-3,MW-4, MW-6, and MW-7 be sampled annually instead of <br />