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1 f # <br /> Vogue Cleaners/Helen Higgins <br /> 2315 N.California St.,Stockton <br /> Page 2 of 2 <br /> This most down-gradient monitoring well in the rortheast direction, MW-9D, has only <br /> been sampled twice but these sampling events indicate that DCA is present in the <br /> ground water at concentrations above the maximum contaminant level (MCL). Although <br /> CPT-4 data has previously indicated DCA has not impacted deeper zones of concern in <br /> this area, the SJCEHD is concerned that the ground water grab sample from CPT-4 <br /> represented the ground water conditions at the tirne they were collected and analyzed <br /> and may not represent the ground water conditions now. Further investigation to define <br /> both the lateral and vertical extents of the DCA to the northeast may be needed if <br /> additional ground water data indicates that the pl ime is unstable or migrating, or this <br /> COC persists above the MCL, or does not show sic ns of naturally attenuating. <br /> Until the DCA plume is satisfactorily delineated to the northeast, the site will not qualify <br /> for MNA. <br /> Based on the current conditions of the site's ground water plume, the SJCEHD <br /> conditionally approves your request to reduce ground water sampling events to semi- <br /> annual for all but MW-9D, MW-8S, and MW-8D. Conditions of this approval include: <br /> • Sampling MW-3S, MW-3D, MW-5S and MW-5D quarterly for TPH-ss (gasoline <br /> is acceptable) and DCA. <br /> • MW-1, MW-1 S, MW-2S, MW-2D, MW-4S, MW-4D, MW-6S, and MW-6D are to <br /> be sampled for TPH-ss and DCA and ma have their sampling events reduced <br /> to once a year, during the period of highest ground water (March). <br /> If declining trends of contaminant concentrations are not shown for the wells associated <br /> with this site, additional investigation and active rerr ediation may be required. <br /> Please contact Michael Infurna at (209) 468-3454 r Nuel Henderson at (209) 468-3436 <br /> if you have any questions. <br /> Donna Heran, REHS, Director <br /> Environmental Health Department <br /> Michael J. Infurna Jr., ?e or REHS Nuel C. Henderson Jr., PG <br /> LOP/Site Mitigation Unit IV Engineering Geologist <br /> LOP/Site Mitigation Unit IV <br /> MI/ <br /> CC' CVRWQCB — James L. Barton <br /> SWRCB-CUF — Mark Owens <br /> Foothill Engineering — Michael Vlach, 8442 tory Ridge Way <br /> Antelope, CA. 95843 <br />