Laserfiche WebLink
1 ` <br /> I� f <br /> Soil and Groundwater Invests ation Report <br /> ARCO Facility No 6080 <br /> Lathrop,Cahfomia <br /> Page 2 <br /> transported offsite in September 1999 and was properly disposed of at a licensed facility <br /> (IT Corporation, January 27, 2000) <br /> Scope of Work <br /> The primary objectives of the fieldwork were to <br /> • Assess the vertical and lateral extent of petroleum impacted soil and groundwater, <br /> and <br /> • Evaluate the direction and gradient of groundwater flow beneath the site <br /> The scope of work implemented during the investigation consisted of <br /> • Advancing three (3) exploratory soil borings to depths of 26 to 28 feet below <br /> ground surface (bgs) and converting the borings to 4-inch diameter groundwater <br /> monitoring wells, <br /> • Collecting soil samples every five feet during drilling for lithologic description, <br /> field screening for petroleum hydrocarbons, and laboratory analysis, <br /> • Developing and sampling the groundwater monitoring wells, and <br /> • Surveying well casing elevations and establishing horizontal coordinates for each <br /> . monitoring well <br /> Soil Characterization <br /> Prior to implementation of field activities, well construction permits were obtained from <br /> PHS/EHD Underground Service Alert (USA) was notified 48 hours prior to work <br /> activities and a subsurface utility locator cleared the drilling sites PHSIEHD was <br /> subsequently notified of the work schedule <br /> A Delta geologist oversaw Western Strata Exploration Inc , a California licensed drilling <br /> company (C57 # 552198), complete work activities on June 12, 2000 Drilling was <br /> completed using 10-inch diameter hollow stern augers Soils were classified on-site <br /> using the Unified Soil Classification System (USCS) All work was performed under the <br /> direction of a California Registered Geologist Boring logs detailing soil stratigraphy are <br /> presented in Appendix A Drilling locations are presented in Figure 2 <br /> Soil samples from each interval were placed and sealed in plastic bags to allow the <br /> accumulation of volatile organic carbon (VOC) vapors within the airspace in the bags A <br /> portable flame-ionization detector (FID) was used to measure VOC concentrations from <br /> each sample in ppm FID results are shown on the boring logs in Appendix A FID <br /> results were also used to evaluate which soil samples should be sent to the laboratory for <br /> chemical analysis Soil samples were analyzed for TPHG, benzene, toluene, <br /> ethylbenzene, and total xylenes (BTEX compounds), dichloroethane (1,2 DCA), ethylene <br /> dibromide (EDB), and 5 oxygenate compounds (MTBE, Tertiary Butyl Alcohol (TBA), <br />