SITE INFORMATION AND CORRESPONDENCE

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i 4 Kleinfelder and the San Joaquin County Local Health District (SJCLHD). SJCLHD was included in the site visits and sampling events to the degree that they were available or chose to be at the site. The following SJCLHD staff were at the site during the excavation or sampling activities: + Diane Hinson • Kasey Foley • Harlan Knoll • Lititia Resch As soon as analytical results were received and reviewed, they were presented in reports to the City of Stockton with the recommendation that they be submitted to the SJCLHD for review. It is Kleinfelder's understanding that the City of Stockton did submit the reports to SJCLHD, and that the reports were reviewed by SJCLHD prior to construction of the new garage which is now at the site. Kleinfelder collected soil samples at each of the four underground storage tank and sump sites. Analytical results indicated that constituents were below laboratory reporting limits, or in the case of one sample, below a level of concern (0.34 mg/kg xylenes). Based on visual observations at the site and the analytical results, Kleinfelder did not recommend additional assessment or remediation at the site. In their recent letter, PHS/EHD indicated that there was some missing information or areas of concern in the data provided in the reports. The following section of this letter addresses the PHS/EHD comments: 1. Comment: Tank#1 and #2 On October 6, 1988, two 1,000 gallon USTs were removed, and soil samples were collected without PHS/EHD inspection. There is no record of the depth at which these soil samples were collected. No contanunation was detected in the two samples collected (#18691 and #18692); however, the detection limits used were elevated. Current detection limits for soil are 0.005 parts per million (ppm) for benzene, toluene, ethylbenzene, xylene and 1.0 ppm for total petroleum hydrocarbons (TPH).- The detection limits which were used for analysis were 0.05 ppm B, 0.I ppm T and X, 0.2 ppm E, and 10 ppm TPH. PHS/EHD staff observed the uncovered tanks on October 4, 1988 and noted odors and stained soil around the top of the tanks. These former tanks were located approximately 20 feet east of Sutter Street and 250 feet south of Market Street. Response: Diane Hinson was at the site after the tanks were discovered at the site. Sampling schedules were coordinated with SJCLHD. The depths of the soil samples were not included in the report, however, the report does state that the samples were collected beneath the tanks. Kleinfelder followed SJCLHD guidelines and collected the samples from the native soil 1.5 to 2 feet beneath the bottoms of the tanks or backfill material. GL3-44(1994) Page 2 of 5 June 1, 1994 Copyright 1994 Kleinfelder, Inc_ hLEItiFU-DER ?240 `orihho€nt Parktvav, 5,int i E:n,,t, C:.', 95407 .70'i 571-1881