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San Joaquin Cou tY
<br /> DIRECTOR
<br /> q
<br /> Qu iN Donna Heran, REHS
<br /> .� Environmental Health Department
<br /> ).• " .O ASSISTANT DIRECTOR
<br /> 600 East Main Stre t i Laurie.Cotulla,REHS
<br /> Stockton Caiiforni
<br /> a'952 2-3029
<br /> -�
<br /> PROGRAM•COORDINATORS
<br /> Carl Borgman,-REHS
<br /> .P Mike Huggins,REHS, RDI
<br /> cQ �.•N� Website: www.sjgov.org ehd � � '
<br /> 'Margaret Lagorio, REHS
<br /> Phone: (209}46$-342 Robert McClellon, REHS
<br /> Fax: (209) 464-0138 Jeff Carruesco,REHS,RDI
<br /> Kasey Foley, REHS
<br /> October 23, 20108
<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-1q DMW-11, DMW-92, DMW-93, 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, ©MW-1,2,,
<br /> DMW-13, and DMW-14 were installed to provided ateral and vertical delineationof 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,attenuati. p.-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 from 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 wets; 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 screened from 58 to 68 feet bsg, with
<br /> concentrations of 0.80 micrograms per liter (pgll) and 1.9 pg/l, respectively. URS notes
<br /> in the WIR and QMR that the vertical extent of the 1,2-DCA contamination plume is
<br /> defined at the source area by DMW-14, screened from 90 to 100 feet bsg, with
<br /> concentrations below detection limits during the 2nd quarter 2008 monitoring event.
<br /> The--EHD--agreeslhat-the-plume of dissolved 1-,2-D0A has been delineated-vertically and
<br /> laterally in the cross-gradient and upgradient directions and the initial data in the down-
<br /> gradient direction appears to be favorable. he trend of declining 1,2-DCA
<br /> HMORD-Site Specific Letters and DocslWest Lane 28011081023dire tive
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