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uwewxuxG.BRowe JR. <br /> --�.Nwo <br /> M,mxoR«�e RooeROuez <br /> Water Boards p1ECp <br /> Central Valley Regional Water Quality Control Board <br /> 29 September 2016 RECEIVED <br /> SEP 3 0 2016 <br /> Roger Huckins Jr. ENVIRONMENTAL HEALTH <br /> 3436 Admiral Drive PERMITISERVICES <br /> Stockton, CA 95209 <br /> FERNANDO'S PLACE, 1201 SOUTH CENTER STREET, STOCKTON, SAN JOAQUIN <br /> COUNTY, CASE# 390865 <br /> On behalf of the Central Valley Regional Water Quality Control Board (Central Valley Water <br /> Board), I am pleased to notify you that as of 1 June 2016, 1 am the assigned caseworker for the <br /> underground tank release case at Fernando's Place at 1201 South Center Street in Stockton <br /> (Site). <br /> I have reviewed the Ozone Pilot Test '& Semi-Annual Groundwater Monitoring Report— Third <br /> Quarter 2014 (Pilot Test Report) date d 20 March 2015, the Semi-Annual Groundwater Report— <br /> Fourth Quarter 2015 (4Q15 Report) dated 27 March 2016, and the Semi-Annual Groundwater <br /> Monitoring Report— Second Quarter 2016 (2Q16 Report) dated 29 August 2016, all submitted <br /> on your behalf by Advanced GeoEnvironmental Inc. (AGE). Additional lateral and vertical <br /> delineation of the extent of petroleum impacts in groundwater are needed at this Site, as well as <br /> an evaluation of alternative groundwater remedial technologies, and vapor intrusion risk <br /> assessment. Below are my comments on the current status of the assessment and cleanup of <br /> the petroleum released from the Site. <br /> 1. Seven (7) hydrologic units (HUs) have been investigated for impacts from petroleum <br /> impacts beneath the Site: 1) HU1 Upper is characterized as between 25-51 feet below <br /> the ground surface (bgs), 2) HU1 is characterized as between 60-70 feet bgs, 3) HU1 <br /> Lower is characterized as between 70 and 90 feet bgs, 4) HU2 is characterized as <br /> between 100-125 feet bgs, 5) HU3 is characterized as between 140-160 feet bgs, <br /> 6) HU4 is characterized as between 160-175 feet bgs, and 7) HU5 is characterized as <br /> between 193-198 feet bgs. Hydrocarbon pollution in groundwater has been reported as <br /> deep as 198 feet bgs, and groundwater flow direction in the different hydrologic units <br /> ranges from northwest to southeast. The extent of petroleum pollution in groundwater <br /> has not been adequately delineated laterally or vertically from the Site. <br /> Benzene concentrations as high as 850 ug/L were reported during second quarter 2016 <br /> in monitoring well MW-4E in HU5, approximately 16 feet east of former UST 1. <br /> Additionally, boring CPT-17 (2007), which is the furthest down-gradient sampling <br /> location (approximately 550 feet to the northeast), contained benzene concentrations of <br /> 560 ug/L in HU2, 57 ug/L in HU3, and 9.1 ug/L in HU4. Petroleum constituents should <br /> be delineated to the Water Quality Objectives (WQOs), to comply with the State Water <br /> Board's Low Threat Closure Policy (LTCP). The Water Quality Objective (WQO) for <br /> benzene is 1.0 ug/L. <br /> KARL E. LONGLEY SCD, P.E., CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER <br /> 11020 Bun Center Drive#200,Rancho Cordova,CA 95670 1 'Aa'Lv.waterboards.ca.0ov/contralvalley <br /> r,aECCIEP o.PEa <br />