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Californi egional Water Quality trol Board <br /> Central Valley Region <br /> Katherine Hart, Chair <br /> Linda S.Adams 11020 Sun Center Drive#200, Rancho Cordova,California 95670-6114 Edmund G. Brown,Jr. <br /> Acting Secretary for Phone(916)464-3291 •FAX(916)464-4645 Governor <br /> Environmental <br /> Protection http://www.waterboards.ca.gov/centralvalley <br /> EIVED <br /> 1 June 2011 J� k 0 1 <br /> P011 <br /> Mr. Robert Garcia EWRONMENTAL <br /> TN <br /> Leprino Foods, Inc. PERMrr/sERVICE,3 <br /> 1830 West 38th Avenue <br /> Denver, CO 80217 <br /> SEMI ANNUAL REPORT AND WORK PLAN FOR SOIL AND SOIL VAPOR SAMPLING, <br /> LEPR/NO FOODS COMPANY, TRACY, SAN JOAQUIN COUNTY <br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff reviewed the following reports prepared by Tetra Tech GEO on your behalf for the <br /> facility at 2401 MacArthur Drive in Tracy (Site): <br /> 25 April 2011 Annual and Semiannual Groundwater Monitoring Report(Semi Annual <br /> Report) <br /> 19 May 2011 Work Plan for Direct Push Soil Sample and Soil Vapor Sample Collection <br /> (Work Plan) <br /> The Semi Annual Report shows that total petroleum hydrocarbon as diesel (TPHd) <br /> concentrations in seven of the eight wells sampled were below the water quality objective <br /> (WQO) of 100 micrograms per liter (Ng/L). Leprino proposes conducting soil and soil vapor <br /> sampling to evaluate the Site for potential closure. The Work Plan details the procedures for <br /> collecting soil samples near the 1993 soil sample locations GP-1 through GP-4. Leprino will <br /> evaluate the new soil data to assess whether remaining soil concentrations pose a threat to <br /> human health and the environment. In addition, Leprino proposes installing one soil vapor <br /> probe beneath the interior slab floor of the dry-powder storage building. Liquid phase <br /> hydrocarbons (i.e. "free product') have previously been observed on the groundwater surface <br /> at this location. <br /> Our comments are: <br /> 1 . Central Valley Water Board staff concur that the product recovery removal rate has <br /> diminished. During 2010 and 2011, the product recovery system removed less than <br /> one gallon of product despite having produced about 10 million gallons of water. Board <br /> staff concur that Leprino should stop operating the product recovery system and begin <br /> quarterly groundwater monitoring to evaluate the Site for any potential rebound of <br /> petroleum hydrocarbon concentrations, including free product. Leprino needs to <br /> maintain the system so that it can be restarted if necessary. <br /> 2. Leprino currently conducts semi annual groundwater monitoring and reporting in <br /> accordance with MRP R5-2007-0811. However, in order to evaluate the Site for <br /> rebound, you need to conduct four monitoring events before we consider the site for no <br /> California Environmental Protection Agency <br /> 0d Recycled Paper <br />