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i r , aSan Joaquin County Environmental Health Department DIRECTOR i. ). • ' �, ' .O Donna Heran, REHS 600 East Main Street y Stockton , California 95202 -3029 PROGRAM COORDINATORS 9pP Margaret Lagorlo, REHS Robert McClellon, REHS �'q' • - -��F Website: www.sjgov. org/ehd Jeff Carruesco, REHS, RDI yC i FO R 4 Phone : (209) 468-3420 Kasey Foley, REHS Fax: (209) 464-0138 08 October 2009 Remo Canepa Canepa's Car Wash 1536 N . Hunter Stockton, CA 95204 Subject: Canepas Car Wash 6230 Pacific Avenue Stockton CA Site Code: 1225 The San Joaquin County Environmental Health Department ( EHD ) has reviewed Quarterly Status Report — Second Quarter 2009 (QR) dated 14 September 2009, and Soil-Vapor Survey Work Plan (WP), dated 09 July 2009 , both prepared by Advanced GeoEnvironmental , Inc. (AGE). In the QR, AGE concurred with the groundwater monitoring schedule directed by the EHD by letter dated 21 July 2009 , except for the inclusion of the soil vapor extraction (SVE) wells SV- 1 through SV-9 on a semi-annual frequency and monitoring well MW-8 on a biennial frequency. AGE pointed out that MW-8 had been destroyed and that wells SV-1 through SV-9 are tightly spaced remediation wells , not monitoring wells , and that they essentially duplicate the information obtainable from monitoring well MW-1 . AGE gave the 40-foot screen intervals of the SV wells as ending at total depth of 49 feet below surface grade (bsg ) and MW-1 being screened from 25 to 45 feet bsg . AGE recommended sampling only SV- 1 , as the more distal and isolated vapor extraction well , and not sampling the other soil vapor extraction wells. The EHD obviously erred in directing sampling of the destroyed MW-8; that directive is rescinded. The EHD also erred by not providing a clear technical justification for sampling the SVE wells. That directive was intended to assist you to document a post-1993 release by enabling you to acquire sufficient data to demonstrate such a release had occurred . By letter dated 17 April 2009 , the EHD had commented on your report titled Evaluation of Analytical Data (EAD) dated 31 December 2008 , in which your consultant, AGE, recommended that the EHD issue an unauthorized release (UAR) for a new release from your underground storage tank (UST) system, based on an interpretation by a third party of the occurrence of heptanes and butanes in several groundwater samples . In the 17 April letter, the EHD commented on AGE's conclusions and recommendations in the EAD by noting an alternative explanation for the data presented and recommended several lines of evidence that may be helpful for determining the more likely alternative — a new release or cross contamination . Data recommended by the EHD to be collected included : the concentrations of the compounds (heptanes and butanes) in the various wells and their areal distribution , the concentrations normally encountered in known fresh releases , the decay, diffusion and dispersion rates of the compounds in the subsurface , etc. Intuitively, the Comment and WP Approval Letter 1009