SITE INFORMATION AND CORRESPONDENCE

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�y Vogue Cleaners 1 Helen Higgrris 2315 N. California St., Stockton Page 2 of 2 previous data acquired from CPT1 at 77 to 82' bgs and 95 to 100' bgs, and CPT-2 at 70 to 75' bgs and 95 to 100' bgs. As these CPT points are in the generally down-gradient or cross-gradient directions (based on shallow water data), the SJCEHD will tentatively consider the vertical extent of dissolved 1,2-DCA to have been delineated, pending concurrence with this evaluation from the Central Valley Regional Water Quality Control Board (CVRWQCB). CPT-4 was placed approximately 80' northeast, obl que to down-gradient of MW-5S&D, to delineate the lateral and vertical extents of the elevated levels of 1,2-DCA present in these monitoring wells. Three ground water samples wee collected from CPT-4. 1,2-DCA was detected in the middle depth sample (67-72' bgs, ro ghly equivalent to the screen interval of MW-SD) at 4.9 ug/L. 1,2-DCA was not detected in the samples collected from 50-55' bgs or 102-107' bgs. The SJCEHD has evaluated the data and considers the 1,2-DCA detected in the CPT-4 middle depth sample to be an area where additional investigation is warranted. The SJCEHD believes the data indicates that the permeable unit approximately 70 to 80' bgs is the main contaminant migration pathway at dept-i. A monitoring well is needed in this general area and at this depth. The Plan proposes only monitoring wells (MW-7 & W-8) in the shallow (S) and deep (D) intervals toward the southeast areas offsite and does not include the additional site characterization in the CPT-4 area commented on above. Additionally, the proposed well screen intervals do not match the existing well screened intervals; as such, the Plan does not adequately address Phase 2 requirements noted in our May 10, 2006 correspondence. The Plan is inadequate and not approved as submitted. (H&S 25296.10[c][3]). Please submit a work plan addendum by December 15, 2006 that includes the installation of at least one monitoring well in the area near. CPT-4. Prior to constructing the deep zone monitoring well (MW-7D & MW-8D), the SJCEHD will require you to collect continuous core samples from 70' bgs to total depth for lithological evaluation. The SJCEHD will require five-foot screens of the deep monitoring wells to be constructed across the most permeable zone identified near the 70-80' bgs interval You may contact Michael Infurna at (209) 468-3454 Dr Nuel Henderson at (209) 468-3436 if you have any questions. Donna Heran, RENS, Director Environmental Health Department -Michael . Infurna Jr. Senio- r REHS Nuel C. Henderson Jr. PG LOP/Site Mitigation Unit IV , Engineering Geologist LOP/Site Mitigation Unit. IV MI/ r c: CVRWQCB —James L. Barton SWRCB-CUF — Mark Owens Foothill Engineering — Michael Vlach, 8442 Story Ridge Way, Antelop , CA 95843 I