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0•1.1-011-1A <br />Water Boards <br />EDMUND G. BROWN JR. <br />GOVERNOR <br />/*lb MATTHEW RODRIQUEZ <br />SECRETARY FOR <br />ENVIRONMENTAL PROTECTION <br />Central Valley Regional Water Quality Control Board <br />12 March 2018 <br />Navdeep Mehta <br />SM Horizon Corporation <br />4360 Jessica Circle <br />Fremont, CA 94555 <br />-RECEIVED <br />MAR 15 2018 <br />ENVIRONMENTAL HEALTH <br />DEPARFNIENT <br />QUICK-N-SAVE #2, 2057 EL DORADO STREET, STOCKTON, SAN JOAQUIN COUNTY, <br />CASE# 391086 <br />Central Valley Regional Water Quality Control Board staff reviewed the Additional Site <br />Investigation Report and Low Threat Closure Policy Evaluation (Assessment Report) dated <br />8 February 2018, submitted on your behalf by Stratus Environmental Inc. (Stratus) for the <br />Quick-N-Save #2 unauthorized petroleum release at 2057 El Dorado Street in Stockton (Site). In <br />the Assessment Report, Stratus details the advancement of 2 shallow soil borings in the vicinity <br />of the former waste oil tank (WOT), one on-site and two off-site downgradient deep cone <br />penetration test (CPT) borings, and provides an evaluation of Site conditions as compared to <br />criteria established in the Low Threat Underground Storage Tank Case Closure Policy (LTPC). <br />Stratus recommends additional efforts to delineate petroleum hydrocarbons in groundwater <br />impact and additional remedial measures at the Site. Stratus also states that an inactive <br />underground storage tank remains in place on the Super Sport Tires property at 2070 El Dorado <br />Street, across the street from the Site (east; downgradient), and recommends an environmental <br />investigation at this property. <br />Central Valley Water Board staff has the following comments on the current status of <br />assessment and cleanup of the petroleum release at the Site: <br />1. In the Assessment Report Stratus states that LTCP Groundwater-Specific criteria are not <br />met because current benzene and methyl tert butyl ether (MTBE) concentrations exceed <br />3,000 ug/L and 1,000 ug/L, respectively. Central Valley Water Board staff concur that <br />Site conditions do not meet Groundwater-Specific criteria. July 2017 (most recent) <br />groundwater quality data is presented in Table 1 below. <br />Table 1 — July 2017 Groundwater Quality Data <br />Monitoring <br />Well Screened <br />Interval Range <br />(ft bgs) <br />Depth to <br />Water <br />(ft bgs) <br />Max <br />TPHg <br />(ug/L) <br />Max <br />Benzene <br />(ug/L) <br />Max <br />Toluene <br />(ug/L) <br />Max <br />Ethyl- <br />benzene <br />(ug/L) <br />Max <br />Xylenes <br />(ug/L) <br />3,460 <br />Max <br />MTBE <br />(ug/L) <br />23,000 <br />Max <br />TBA <br />(ug/L) <br />39,000 15-50 16-18 100,000 5,300 6,700 1,400 <br />TPHg=total petroleum hydrocarbons as gasoline; MTBE=methyl tert butyl ether; TBA=tert butyl alcohol; ft bgs=feet below ground <br />surface; ug/L=micrograms per liter <br />KARL E. LONGLEY ScD, P.E. CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER <br />11020 Sun Center Drive #200, Rancho Cordova, CA 95670 I www.waterboards.ca.gov/centralvalley <br />0 RECYCLED PAPER