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ENVIRONMENTAL HEALTH DEPARTMENT SAN JOAQUIN COUNTY _:• �� .G Unit Supervisors Donna K.Heran,R.E.H.S. Carl Bor man,R.E.H.S. y: � Director 304 East Weber Avenue, Third Floor g x Mike Huggins,R.E.H.S.,R.D.I. Al Olsen,R.E.H.S. Stockton, California 95202-2708 Douglas W.Wilson, R.E.H.S. -•..�P Program:Manager Telephone: (209) 468-3420 Margaret Lagorio, R.E.H,S, �!F oR� Laurie A.Cotulla,R.E.H.S. Program Manner Fax: (209) 464-0138 Robert McClellon,R.E.H.S, S g Mark Barcellos,R.E.H.S. LYNN WALL JUN 16 2003 PORT OF STOCKTON PO BOX 2089 STOCKTON CA 95201-0246 Re: Port of Stockton Site Code:1282124 Site 3, Port Roads 14 & G RO#: 000673 Stockton, CA. San Joaquin County Environmental Health Department (EHD) has reviewed two reports, Results of Additional Assessment and Remediation Evaluation of Petroleum Hydrocarbons in Groundwater dated April 2003 and First Quarter 2003 Groundwater Monitoring Report(QMR) dated June 2003 as submitted by your consultant, Geomatrix Consultants, and has the following comments. The first report detailed the installation one deep soil boring, "B3-14" and three new shallow monitoring wells (MW3-4, MW3-5, and MW3-6) during January and February 2003. One grab groundwater sample was collected from B3-14. No soil samples were collected from this boring. The groundwater sample collected at 40 feet below ground surface (' bgs) was analyzed for TPHg, BTEX, MtBE, 1,2-DCA, TAME, and EtBE and laboratory results indicated only DIPE was detected at 0.88 ggll. The monitoring wells were installed 100 to 150 feet outward triangularly from the former underground storage tank (UST) pit and were constructed of 2" PVC screened casing from —9' bgs to 24' bgs. Groundwater or soil samples were not collected from these soil borings that were converted to the new monitoring wells. The second report, the QMR, covered a groundwater sampling event held on February 20, 2003. AI`six monitoring wells were sampled during this event and this was the first sampling event for the three new monitoring wells. The existing three monitoring wells, MW3-1, MW3-2, and MW3-3, exhibited historical patterns for groundwater petroleum detections, with MW3-2 and MW3-3 TPHg concentrations at 6,700 µgll and 4,000 µg11 respectively. Benzene for these same two wells was consistent with historical levels of 160 µg11 and 14 µg11 respectively. Of the three new monitoring wells, only MW3-6 reported any detectable concentrations of petroleum. TPHg was detected in MW3-6 at 6,800 µg11 and Benzene was detected at 1,700 gg/l. MtBE was non-detect at 0.5 µg/l. Recommendations included in the monitoring well installation report recommended that the "site conditions conform to a low-risk groundwater case ......and recommend that monitored natural attenuation be the remedial action for the site". With only one sampling event from the new wells conducted, EHD considers remedial action alternative selection premature at this time. Additional groundwater sampling events are needed before such conclusions can be supported.