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CalifornilVegional Water Quality Coa-ol Board <br /> Central Valley Region <br /> Katherine Hart, Chair <br /> 11020 Sun Center Drive,#200,Rancho Cordova,California 95670-6114 <br /> Matthew Rodriquez (916)464-3291 •FAX(916)464-4645 Edmund G.Brown Jr. <br /> Secretaryfor hUp://www.waterboards.ca.gov/centralvalley Governor <br /> Environmental Protection <br /> RECEIVED <br /> 31 August 2011 SEP 01 2011 <br /> Mr. Robert Garcia ENVIRONMENTAL HEALTH <br /> Leprino Foods, Inc. PERMIT/SERVICES <br /> 1830 West 38th Avenue <br /> Denver, CO 80217 <br /> JUNE 2011 GROUNDWATER MONITORING REPORT AND REQUEST FOR NO FURTHER <br /> ACTION, LEPRINO FOODS COMPANY, TRACY, SAN JOAQUIN COUNTY <br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff reviewed the June 2011 Groundwater Monitoring Report and Request for Site <br /> Closure/No Further Action Determination (Report) prepared by Tetra Tech GEO on behalf of <br /> Leprino Foods Company (Leprino) for the facility at 2401 MacArthur Drive in Tracy (Site). On <br /> 20 May 2011, Leprino discontinued operation of the product recovery system at the Site. In <br /> June, Leprino collected soil and soil vapor samples to evaluate the Site for potential closure. <br /> The Report includes a summary of the recent groundwater, soil, and soil vapor sample results. <br /> On 25 June 2011, Leprino collected groundwater samples from Site monitoring wells and total <br /> petroleum hydrocarbons as diesel (TPHd) concentrations in seven of the eight wells were <br /> below the water quality objective (WQO) of 100 micrograms per liter (Ng/L). Monitoring well <br /> MW-6 contained TPHd at a concentration of 240 pg/L. Free product was observed in recovery <br /> well RW-7 at a thickness of 0.03 foot. <br /> In June 2011, Leprino drilled four soil borings near the 1993 and 1994 soil boring locations <br /> and collected soil samples. The maximum TPHd concentration in 1993/1994 was <br /> 2,600 milligrams per kilogram (mg/kg). The maximum TPHd concentration in 2011 was <br /> 3.2 mg/kg. Later in June, Leprino collected two soil vapor samples from beneath the dry <br /> powder storage warehouse at five and 10 feet below ground surface (bgs). The five-foot bgs <br /> sample contained the maximum concentrations of TPHd and naphthalene at <br /> 2,900,000 micrograms per cubic meter (Ng/m3) and 170 Ng/m3, respectively. These <br /> concentrations exceed the California Regional Water Quality Control Board, Bay Area Region <br /> Environmental Screening Levels for commercial/industrial land use. Leprino also collected <br /> indoor air samples from within the dry powder storage warehouse and detected naphthalene <br /> and TPHd at concentrations of 0.0051 Ng/m3 and 18 Ng/m3, respectively. TPHd <br /> concentrations in indoor air are slightly higher than the ESL of 14 Ng/m . As a preventative <br /> measure Leprino "...has initiated ventilation of soils beneath the building." <br /> Our comments are: <br /> 1. Central Valley Water Board staff concur with Leprino's proposal to collect three <br /> additional quarters of groundwater monitoring data to evaluate the Site for potential <br /> California Environmental Protection Agency <br /> ed Recycled Paper <br />