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ENVIRONMENTAL HEALTH DEPARTMENT <br /> oQa"'N SAN JOAQUIN COUNTY <br /> �.. _�..•oG Unit Supervisors <br /> Lleran,R.E.H.S. Carl Borgman,R.E.H.S. <br /> Donna K. <br /> Director 304 East Weber Avenue, Third Floor Mike Huggins,R.E.H.S.,R.D.1. <br /> Al Olsen,R.E.H.S. Stockton, California 95202-2708 Douglas W.Wilson,R.E.H.S. <br /> proal-am Manager Telephone: (209) 468-3420 Margaret Lagorio,R.E.H.S. <br /> �Ci fi 6-0,4 Laurie A.Cotulla,R.E.H.S. Robert McClellan,R.E.H.S. <br /> program Manager Fax: (209) 464-0138 Mark Barcellos,R.E.H.S. <br /> APR 1 6 2003 <br /> WILLIAM BERGVALL <br /> 2977 YGNACIO VALLEY RD <br /> WALK= CREEK CA 94598 <br /> RE: FORMER AMERICAN FOREST PRODUCT <br /> 2801 WEST LANE <br /> STOCKTON CA <br /> San Joaquin County Environmental Health Department (EHD) has reviewed Closure Request <br /> Addendum Report, 1, 2-DCA Investigation (the report) dated July 22, 2002 prepared by URS <br /> Group, Inc. (URS). Five direct-push strataprobes were advanced at the site and six grab <br /> groundwater samples were collected in May 2002. Analytical results of the grab <br /> groundwater sample from soil boring HP-1 were 170 micrograms per liter (µg/1) 1,2- <br /> dicholorethane (1,2-DCA) at 50 feet below surface grade (bsg), 130 �tg/l 1,2-DCA at 65 feet <br /> below surface grade (bsg), 4.0 �tg/l 1,2--DCA from HP-2 at 52 feet bsg, 2.3 µg/l <br /> tetrachloroethene (PCE) from HP-6 at 50 feet bsg, 4.9 µg/l PCE from HP-7 at 50 feet bsg, <br /> and 4.4 pg/l PCE from HP-8 at 52 feet bsg. The report included a recommendation for site <br /> closure. <br /> During a telephone conversation on March 27, 2003, Central Valley Region Water Quality <br /> Control Board (CVRWQCB) and EHD concurred that the closure request should be denied <br /> at this time. The vertical and horizontal extent of the 1,2-DCA in groundwater has not been <br /> fully delineated. California Department of Health Services (DHS) has established a <br /> Maximum Contaminant Level (MCL) for 1,2-DCA in drinking water at 0.5 µg/l. The <br /> concentration of 1,2-DCA in the current grab water samples as well as in the previous <br /> quarterly monitoring well samples exceeded the MCL. Additional investigation is needed to <br /> delineate the lateral and vertical extent of 1,2-DCA. <br /> Historical groundwater low in the area has been 80 feet bsg according to San Joaquin <br /> County Flood Control and Water Conservation District publication Lines of Equal Depth to <br /> Groundwater for 1993. DMW-2 was screened from 60 feet to 80 feet bsg. Analytical results <br /> of DMW-2 samples were 9.7 Vg/11,2-DCA in August 2000, 5.5 µg/l in November 2000, <br /> and 1.4 �tg/l in December 2001. Minimum sampling depth to address the vertical <br /> delineation of the 1,2-DCA contamination at this site has been 80 feet bsg. EHD had <br /> previously approved fork Plan for 1,2-DCA Investigation dated Apri12, 2002 prepared by URS <br /> on the condition that CPT hydro-punch technology be used to collect grab groundwater <br /> r " <br />