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ATC Associates Inc. <br /> 1117 Lone Palm Avenue,Suite 201 <br /> Modesto,California 95351 <br /> 209-579-2221 <br /> fax:209-579-2225 <br /> ASSOCIATES INC. <br /> risk and based on proximity to the site, the water supply wells observed in the vicinity of the site <br /> were judged not likely to be impaired by the petroleum hydrocarbon impacted groundwater plume. <br /> Due to the adoption of Resolution No. 2009-0042 by the State Water Resources Control Board <br /> (SWRCB), groundwater monitoring and sampling activities were reduced to a modified <br /> semiannual/biennial schedule. In a letter dated June 22, 2009, fhe SJCEHD requested to collect <br /> groundwater samples from wells MW-1, MW-4, MW-5, and MW-8 semi-annually and from all wells <br /> at the site biennially. Based on the request,the wells will be sampled using the schedule below. <br /> Odd Digit Years Even Digit Years <br /> First Quarter Third Quarter First Quarter ��Third Quarter 7-,2 <br /> MW-1,MW-4, MW-1, MW-4, MW-1, MW-4, All wells <br /> MW-5, and MW-8 MW-5, and MW-8 MW-5, and MW-8 <br /> Additionally, the SJCEHD granted ATC's request to discontinue analyzing groundwater samples <br /> collected from the site for di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), 1,2- <br /> dichloroethane(1,2-DCA), and 1,2-dibromoethane (EDB). <br /> �l JartvArtj :ZZI Z410 <br /> GN/Confirmation groundwater samples were collected from the site to evaluate the lateral and vertical <br /> Wr extent of impacted groundwater beneath the site. A soil boring (SB-6) was advanced to first <br /> encountered groundwater to evaluate the lateral extent of impacted groundwater northwest of the <br /> source area. Two discrete grab groundwater samples (HP-1 and HP-2) were collected using a <br /> hydropunch sampling tool in the vicinity of CPT-2. HP-1 was advanced to an approximate depth of <br /> 45 feet bgs and 14P-2 was advanced to an approximate depth of 70 feet bgs.—MT E was the only <br /> analyte of interest detected in the groundwater sample collected from SB-6. None o the analytes of <br /> interest were detected in the groundwater samples collected from HP-1 and HP-2. <br /> SCOPE OF WORK <br /> Planning and Permits <br /> ATC will obtain the necessary SJCEHD permits for the advancement of five soil borings. ATC will <br /> schedule field personnel and equipment, notify Underground Services Alert to locate underground <br /> utilities as required,and perform other necessary field preparation and job start-up activities. <br /> Installation of Soil Gas Sampling Points <br /> This task includes mobilization to the site, advancing five soil borings, characterizing soil cuttings, <br /> and completing the borings as temporary soil gas sampling points. The proposed locations of the soil <br /> gas sampling points are based on the known distribution of petroleum hydrocarbons and/or fuel <br /> oxygenates in groundwater with respect to nearby structures. Estimated soil gas sampling point <br /> locations are shown on Figure 3. , <br /> To evaluate the potential for vapor intrusion hazards from subsurface soil and/or groundwater, five <br /> soil borings will be advanced to depths approximately six feet bgs each. The borings will be <br /> advanced using truck mounted Strataprobe drilling rig employing narrow diameter, direct push <br /> S:\Environmental\25847\38\Workplans\2010 May SGS.doc 3 <br />