Laserfiche WebLink
1 z" <br /> GEOMATRIX <br /> �-" Ms. Donna Heran <br /> San Joaquin County Public Health Services <br /> July 17, 2000 <br /> LW Page 2 <br /> approximately 1,000 feet north of the former UST area reportedly ranged from about 55 to <br /> 75 feet bgs. A gravel layer reportedly was observed between about 40 and 50 feet bgs during <br /> i.. the installation of the on-site monitoring wells. <br /> Based on the depth to water and the potential presence of a gravel layer beneath the UST area, <br /> L the proposed method for collecting shallow groundwater sample is the HydroPunch"'` (or <br /> equivalent method) as opposed to a direct push method. The boring for groundwater sampling <br /> will be advanced using the hollow-stem auger method. The sampling location will be about <br /> #• 10 feet to the northwest of the former UST location(Figure 2). If field observations indicate <br /> the presence of petroleum hydrocarbons in the soil samples collected from the unsaturated <br /> zone, the original boring will be backfilled, and a new boring will be advanced further away <br /> from the former UST location for groundwater sampling. The field and analytical methods are <br /> y described in the following sections. <br /> �•" HELD METHODS <br /> The groundwater sample will be collected in accordance with the attached Geomatrix <br /> environmental field protocols. Prior to sampling, a site health and safety plan will be prepared <br /> for the field activities. Drilling permit will be obtained from PHS/EHD, and Underground <br /> Service Alert will be notified for utility clearance. Soil cuttings,purge water, and equipment <br /> decontamination water generated from the field sampling activities will be temporarily stored <br /> in sealed and labeled 55-gallon drums to be placed on-site for later disposal by Dole. <br /> A boring will be advanced using the hollow-stem auger method to the top of shallow <br /> groundwater, anticipated to be 60 to 75 feet bgs. Soil samples will be collected at 5-foot depth <br /> intervals from the boring for lithologic logging, and field screening. The soil samples will be <br /> described using the Unified Soil Classification System visual-manual procedure (American <br /> Society for Testing and Materials Method D 2488). Soil samples will be examined for <br /> staining and/or odor that may indicate the presence of petroleum hydrocarbons. The <br /> headspace of the soil samples will be field screened for volatile organic compounds using a <br /> photoionization detector(PID). <br /> } <br /> LO After reaching the groundwater table, a HydroPunch, Simul-Probe, or equivalent sampler will <br /> be driven approximately 4 feet into the undisturbed water-bearing zone and opened to collect a <br /> groundwater sample. The groundwater sample will be collected using a disposable bailer and <br /> La the sample will be sealed, labeled, and placed immediately into an ice-cooled chest for <br /> subsequent delivery to a laboratory for chemical analysis under chain-of-custody procedures. <br /> If sufficient groundwater sample volume is collected, field parameters of pH, electrical <br /> �., conductivity, temperature, dissolved oxygen, and oxidation-reduction potential will be <br /> 11fr21deptdatalPROJEC n6508.0001document16508-01.doe <br /> �rr <br />