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California Regional Water Quality Con- -A Board <br /> Central Valley Region <br /> o� <br /> Katherine Hart, Chair ��°°`��a.:._u <br /> Linda S. Adams 11020 Sun Center Drive#200, Rancho Cordova, California 95670-6114 Arnold <br /> Secretary for Phone(916)464-3291 •FAX (916)464-4645 Schwarzenegger <br /> Environmental http:l/www.waterboards.ca.gov/centralvalley ro ^ y DGovernor <br /> Protection I j��[E� rf, <br /> 2 August 2010 AUG 0 3 2M <br /> ENVIRUNMEN i HEAI-TH <br /> PERM T SERVICES <br /> Mr. Jack Badey <br /> EHS Manager, <br /> UniFirst Corporation <br /> 68 Jonspin Road <br /> Wilmington, MA 01887-1090 <br /> REVIEW OF CORRECTIVE ACTION PLAN, UN/FIRST, 819 HUNTER STREET, <br /> STOCKTON, SAN JOAQUIN COUNTY <br /> Unifirst, a wet-wash commercial laundry facility, operates at a site that formerly housed <br /> Parisian Industrial Laundry, which used the dry cleaning solvent tetrachloroethene (PCE). Dry <br /> cleaning solvents are found in groundwater beneath and downgradient of the Unifirst facility. <br /> Unifirst's site assessment has identified the lateral and vertical extent of the groundwater <br /> plume emanating from the former Parisian Laundry. <br /> Unifirst provided the following documents prepared by its consultant, AMEC Geomatrix, Inc. <br /> that describe the distribution of PCE and offer a proposed path to closure: <br /> • 19 April 2010 Groundwater Corrective Action Plan and <br /> • 10 May 2010 First Semiannual 2010 Groundwater Monitoring Results. <br /> California Regional Water Quality Control Board, Central Valley Region (Central Valley Water <br /> Board) staff have reviewed the documents and, as discussed below, concur that some <br /> pollutants found in groundwater are not a result of Parisian or Unifirst activities, but do not <br /> concur that monitored natural attenuation is an appropriate remediation strategy for PCE at <br /> this time. Unifirst must reduce the mass of PCE in groundwater and in unsaturated soil. <br /> Distribution of Solvents <br /> Central Valley Water Board staff concur that a plume of PCE and its breakdown products, <br /> trichloroethene (TCE), and dichloroethene (DCE) are present in groundwater, trending in the <br /> downgradient (northeastern) direction from the location of the former Parisian laundry facility. <br /> The center of mass appears to be near the eastern property boundary. At this location, PCE <br /> concentrations range from about 200 ug/L in shallow groundwater, which is about 30 feet <br /> below ground surface (bgs), to about 400 ug/L at about 50 feet bgs, decreasing to about 70 <br /> ug/L at about 100 feet bgs. TCE was found at 15 ug/L in a grab groundwater sample at 145 <br /> feet bgs. PCE or its degradation compounds have not been detected in groundwater 900 feet <br /> downgradient. <br /> In this neighborhood, there are additional sources of pollutants found in groundwater that may <br /> not be related to Parisian Industrial Laundry or Unifirst's activities. These are as follows: <br /> California Environmental Protection Agency <br /> CaRecycled Paper <br />