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<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
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