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<br /> G R Q U3P., I n N C
<br /> Environmental Seruices'�il 10' 4
<br /> Ms. Lori Duncan April 12, 2000
<br /> San Joaquin County Public Health Services / Environmental Health Division
<br /> 304 East Weber Avenue
<br /> Stockton, CA 95202
<br /> Re: Ruiz Grocery, 4491 West Durham Ferry Road, Tracy, CA Site Code 1551
<br /> Dear Ms. Duncan,
<br /> —ThiS.=letter-foBOv.s'our. teleYri:,ne-disl.: io, yesterday-regarding-your review-of-.Clean.4ti dfel`s-Coil ii;;natlon.-Toil
<br /> Sampling, Groundwater Monitoring = First Quarter 2000, and Closure Request, dated March 27, 2000, for the
<br /> referenced project. During our discussion, you.indicated that your office generally concurred with the
<br /> recommendation for closure, but requested two additional quarters of verification monitoring to demonstrate
<br /> stabilization and/or .decrease in residual dissolved-phase contaminants. Upon completion of these two
<br /> quarterly monitoring events, a full year of monitoring will have taken place following remedial system shut-
<br /> down. We agreed that would be a good time to reevaluate data and process the closure request, assuming new
<br /> data were supportive of such,action.
<br /> As I mentioned earlier, this course of action will be easy to implement, as the Underground Storage Tank
<br /> Clean=up•FuAd had pre-approved quarterly monitoring costs through the end of 2000. During the next two
<br /> events; all seven monitoring wells will be gauged for depth to water to facilitate determination of flow
<br /> direction, but only wells MW-1 and MW-2 will be purged and sampled, in addition to sampling of the Domestic
<br /> Well" All other perimeter wells and deeper screened sparge wells were free of detectable contaminants levels
<br /> during the First Quarter 2000 monitoring event. Wells MW-1 and MW-2 are the only wells which have
<br /> .continued to contain detectable contaminants following the end of remediation, and thus, will serve as useful
<br /> points to demonstrate stabilizing or decreasing trends over time. Samples collected from MW, MW-2, and the
<br /> Domestic Well will be analyzed for concentrations of TPHg, and BTEX by EPA Methods 8015M and 8020, and
<br /> MTBE by EPA Method 8260B. Other Fuel Oxygenates (ETBE,TBA, DIPE, TAME) and Lead Scavengers (1,2-DCA,
<br /> -.'-EDB) will i oarbe arialyzed`for because Girl—If st Q arter 2000 groundwater sam0es were free Bf detectable levels
<br /> of'these compounds.
<br /> I truly appreciate your efforts in working together to bring this project toward closure. Clearwater staff will
<br /> contact you shortly to schedule the next sampling event for early May.
<br /> If you have any questions regarding this project, please,feel free to call me at (510),893-5160..
<br /> Sincerely'
<br /> Clearwater,-Group
<br /> rian Gwinn, R.G,
<br /> Chief Geologist
<br /> cc: Stella Ruiz, Ruiz Grocery,4491'West Durham Ferry Rd., Tracy, CA 95376
<br /> "Central Valley RWQCB, 3443 Routier Rd., Ste. A, Sacramento, CA 95827
<br /> 520.Third Street,Suite 104 ♦ Oakland',California 94607 + Telephone 510-893-5160 + Fax 510-893-5947
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