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� F <br /> Page 1 of 2 <br /> Lori Duncan [EH] <br /> From : Nuel Henderson [EH] <br /> Sent: Wednesday, January 25, 2012 10: 39 AM <br /> To: Lori Duncan [EH] <br /> Subject: RE: 602 California Street, Stockton, CA - Stallworth Auto Sales - Baseline Sampling <br /> Looks ok to me, Lori. <br /> Nuel <br /> From : Lori Duncan [EH] <br /> Sent: Wednesday, January 25, 2012 9: 03 AM <br /> To: Nuel Henderson [EH] <br /> Subject: FW: 602 California Street, Stockton, CA - Stallworth Auto Sales - Baseline Sampling <br /> From : Daniel Villanueva [mailto: dvillanueva@advgeoenv.com] <br /> Sent: Tuesday, January 24, 2012 2 :58 PM <br /> To: Lori Duncan [EH] <br /> Cc: bmillman@advgeoenv.com; wlittle@advgeoenv.com; Robert E. Marty <br /> Subject: 602 California Street, Stockton, CA - Stallworth Auto Sales - Baseline Sampling <br /> Ms. Duncan, <br /> Advanced GeoEnvironmental (AGE) staff has reviewed the San Joaquin County Environmental Health <br /> Department (SJCEHD) directive letter dated 15 December 2011 for the site located at 602 California <br /> Street, Stockton, California . In the directive letter SJCEHD staff made several comments on the AGE- <br /> prepared Ground Water Remediation Feasibility Study Work Plan, dated 31 October 2011. Among the <br /> comments SJCEHD states that... "baseline alkalinity measurements must be taken to determine the <br /> amount of acid that would be necessary to reduce the pH level to the appropriate level to maintain <br /> solubility of the iron ." Additionally, SJCEHD states that... "baseline iron content in the groundwater <br /> should also be taken into consideration to determine the dosing requirement' . <br /> AGE agrees with SJCEHD that baseline alkalinity and dissolved iron content is an important consideration <br /> in design of the above pilot test and provides the following recommendations prior to re-submitting a <br /> revised Ground Water Feasibility Study Work Plan for the site: <br /> • Ground water samples should be collected from wells MW1A, MW-2, MW-6, MW-7, MW-8 <br /> and MW-10 and analyzed for dissolved iron and alkalinity; wells sampled should provide an <br /> adequate representation of the dissolved plume conditions in the "core" area of the plume <br /> where conditions are likely highly anaerobic and on the fringe of the "core" area of the plume <br /> where conditions are expected to more aerobic; <br /> • The recommended method for analyzing for dissolved iron and alkalinity from above selected <br /> monitoring wells is low-flow purging (defined as less than 1 L/minute and low-flow sampling as <br /> defined at less than 300 mL/minute) . The wells will be purged with a low-flow peristaltic pump <br /> with disposable tubing, or a low-flow down hole pump with the capability to reduce flow rates . <br /> 1 /25/2012 <br />