SITE INFORMATION AND CORRESPONDENCE

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V San Joaquin County DIRECTOR NDonna Heran, REHS Environmental Health Department �,.•_,-„�„e-.,p ASSISTANT DIRECTOR 600 East Main Street Laurie Cotulla,REHS �+ :{ Stockton, California 95202-3029 PROGRAM COORDINATORS .'• Carl Borgman,REHS Mike Huggins, REHS, RDI V. Website: www.sjgov.org/ehd Margaret Lagorio, REHS Lr F Phone: (209) 468-3420 Robert McClellon, REHS Fax: (209) 464-0138 ,teff Carruesco, REHS, RDI Kasey Foley,REHS January 7, 2009 Joe Toste Jr. Toste Farms Inc. 2480 Toste Road Tracy, CA 95376 Subject: Tracy Marine Sales 2353 Toste Road Tracy, CA The San Joaquin County Environmental Health Department (EHD) has reviewed our file and the "Quarterly Report — Third Quarter 2008" dated November 24, 2008, prepared by Advanced GeoEnvironmental, Inc. (AGE) for the above subject site and provides the following comments. There are ten ozone injection wells connected to the ozone generator that comprise the ozone system operating at this site. Two of the ozone wells (0-3 and 0-4) have deep screened intervals (41.5 to 44 feet below surface) and the other eight ozone wells have screen intervals of 17.5 to 20 feet below surface. Operation of the ozone system began in June 2004. The "Quarterly Report — Second Quarter 2004° prepared by AGE states that the operation protocol of the manufacturer was followed that consisted of two-hour ozone injection at each sparge point and that after a cycle through the ozone wells was completed, the ozone injection was stopped for two hours and then the injection cycle restarted. The groundwater contamination at this site has been documented to be in the shallow groundwater monitoring wells with screen intervals of 5 to 20 feet below grade. Currently, the only groundwater contamination evidenced by samples from the monitoring wells is found in the area of MW7. The concentrations of contamination in the samples from this well have significantly reduced. Current reports prepared for this site do not detail how the ozone system is operated. According to reports, the ozone system did not operate for 30 days in April 2008 and 21 days in September 2008 and was to be repaired. The EHD directs that the current operation of the ozone system be assessed and that injection is limited to the shallow injection points near MW7. This should be completed within 20 days of the date of this letter. When contaminant concentrations have declined and it can be estimated that water quality goals will be obtained in a reasonable amount of time, operation of the ozone system should cease and post remedial monitoring should begin.