SITE INFORMATION AND CORRESPONDENCE

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San Joaquin County DIRECTOR Environmental Health Department ©DISTnna NTHerDI REHS �o.•_ �.co ASSISTANT DIRECTOR 600 East Main Street Laurie Cotulla, REHS . { Stockton, California 95202-3029 PROGRAM COORDINATORS • _ _.._ __.........._. Carl Borgm REHS PW Miko Huggins, REHS. RDI 04�l.Fo�.4� Website: www.sjgov.org/ehd Margaret Lagario, REHS -- Phone: (209) 468-3420 Robert Mcclellon, REHS � Fax: (209) 464-0138 ,teff Carruesco, REHS. RDi Kasey Foley. REHS HELEN HIGGINS OCT 4 5 200 5815 MORGAN PLACE #16 STOCKTON CA 95219 RE: Vogue Cleaners SITE CODE: 231032 2315 N. California St. RO#: 607 Stockton, CA 95204 SWRCB-CUF#: 011775 The San Joaquin County Environmental Health Department (SJCEHD) has reviewed Third Quarter 2007 Monitoring (QMR) and has the following comments. In the conclusions section your consultant stated, "Comparing current values to the initial values, show a natural attenuation process is taking place" The SJCEHD has reviewed the ground water data for this site and has concluded that although some monitoring wells show a marked decrease in ground water contaminant concentration levels, some wells do not. In phone discussions with your consultant, Mr. Michael Vlach, the SJCEHD has learned that his intention is to not initiate an active remediation method at this site but to only sample and analyze ground water samples from the monitoring wells on a semi-annual basis. To allow an underground storage tank (UST) site to conduct only natural attenuation, known as Monitored Natural Attenuation (MNA) the SJCEHD advised Mr. Vlach that additional information is needed, such as data supporting conclusions that the ground water plume is delineated both laterally and vertically and that the natural forces acting on the contaminants have the ability to reduce the contaminant concentrations to acceptable levels within a reasonable time frame. Additionally, there must be a good understanding of the amount of residual contaminant mass remaining and how this mass affects the ground water quality beneath the site at the present time and in the future. There are two major constituents of concern (COC) at this site, total petroleum hydrocarbons as Stoddard solvent (TPH-ss) and 1,2—dicholoroethane (DCA). The TPH- ss plume is mostly in the upper water bearing zone at the eastern side of the site and is migrating slightly southwest, to just under California Street. Down gradient wells MW- 8S and MW-8D, southeast of the site do not contain detectable concentrations of TPH- Ss. The DCA plume is more extensive and is in both the shallow and the deeper aquifer zones onsite and offsite and, as the newly installed MW-9D has shown, has impacted the most down-gradient monitoring point toward the northeast, across California Street on private property.