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r <br /> San Joaquin Cou ity DIRECTOR <br /> ur <br /> Donna Heran REHS <br /> O <br /> o?° '" � Environmental Health <br /> �. All <br /> G M ennartment <br /> ASSISTANT DIRECTOR <br /> f ' �2� 600 East Main Stre t Laurie Cotulla,REHS <br /> s F; Stockton, California 952 2-3029 PROGRAM COORDINATORS <br /> • . Carl Borgman,REHS <br /> - �• <br /> p : ri�P Website: www.sjgov.org ehd Mike Huggins, REHS, RDI <br /> Q LF o R Margaret Lagorio, REHS <br /> Phone: (209) 468-342D Robert McClellon, REHS <br /> Fax: (209) 464-0138 Jeff Carruesco, REHS,RDI <br /> Kasey Foley,REHS <br /> October 23, 2008 <br /> IIC William Bergvall MCD Lazares Stockton LLC <br /> Former American Forest Products 343 East Main Street. STE 318 <br /> 2977 Ygnacio Valley Road, #241 Stockton, CA 95202 <br /> Walnut Creek, CA 94598 <br /> Subject: Former American Forest Products <br /> 2801 N. West Lane <br /> Stockton, CA <br /> The San Joaquin County Environmental Health De artment (EHD) has reviewed Second <br /> Quarter 2008 GroundWater Monitoring Report (QMR) dated July 30, 2008 and Well <br /> Installation Report, Monitoring Wells DMW-10, DMW-11, DMW-12, DMW-13, and <br /> DMW-14 (WIR), dated July 31, 2008, submitted on your behalf by URS Corporation <br /> Americas (URS) and comments as follows: <br /> During April 2008, groundwater monitoring w IIs DMW-10, DMW-11, DMW-12, <br /> DMW-13, and DMW-14 were installed to provide lateral and vertical delineation of 1,2- <br /> dichloroethane (1,2-DCA) contamination in groundwater downgradient and cross- <br /> gradient of the source area in the shallow ground water zone between 32 and 52 feet <br /> below surface grade (bsg), in the intermediate gr undwater zone between 52 and 72 <br /> feet bsg, and in the deeper water zone in the source area at depths greater than 80 feet <br /> bsg. <br /> In the WIR, URS concludes that closure requirements have been met, including <br /> completion of the vertical and lateral delineation f the extent of the 1,2-DCA ground <br /> water contamination, and demonstrating declining groundwater concentrations of 1,2- <br /> DCA in all wells with a projected date of the year 2016 to drop below laboratory <br /> analytical detection limits due to natural attenuation. URS concludes in the WIR and <br /> QMR that the lateral extent of the 1,2-DCA co tamination plume is defined cross- <br /> gradient toward the east by DMW-13, screened f om 60 to 70 feet bsg, and DMW-2, <br /> screened from 63 to 78 feet bsg, with 1,2-DCA concentrations of less than 0.50 <br /> micrograms per liter (pg/1) in both monitoring wel s; and is "effectively demonstrated" <br /> downgradient to the north by DMW-11, screened from 58 to 68 feet bsg, and cross- <br /> gradient toward the west by DMW-12, also sere ned from 58 to 68 feet bsg, with <br /> concentrations of 0.80 micrograms per liter (flgll) end 1.9 pg/l, respectively. URS notes <br /> in the WIR and QMR that the vertical extent of t e 1,2-DCA contamination plume is <br /> defined at the source area by DMW-14, scree ed from 90 to 100 feet bsg, with <br /> concentrations below detection limits during the 2nd quarter 2008 monitoring event. <br /> Ttie-1=HiD agrees that the plume of dissolved-1,2=D _A-has-been delineated'vertically and <br /> laterally in the cross-gradient and upgradient direct ons and the initial data in the down- <br /> gradient direction appears to be favorable. The trend of declining 1,2-DCA <br /> K WORD-Site Specific Letters and DocslWest Lane 28011081023dire tive <br />