WORK PLANS - Laserfiche WebLink

Home Browse Search

• r„r �.✓ 16 July 2002 AGE-NC Project No. 95-0135 Page 4 of 7 3.3. CPT DRILLING AND SAMPLE COLLECTION AGE proposes to advance four paired CPT soil borings at the site as part of site assessment activities. Proposed CPT soil boring locations are illustrated in Figure 2. The CPT borings will be advanced to characterize lithology, model potential contaminant migration pathways and to assess the vertical extent of MTBE-impacted groundwater.Based onthe distribution ofMTBE encountered to date during the ongoing investigation, AGE proposes to advance the CPT soil borings in the following locations: • Immediately west of the UST location; • At the western edge of the site near well MW-1; • In the sidewalk across El Dorado Street, west of the site; and • On the sidewalk across Lafayette Street, down-gradient of the former UST area. The first boring at each location will be a cone penetrometer (CPT) bore; the CPT will acquire a continuous lithologic record to define the hydrologic units. A second boring subsequently will be advanced immediately adjacent to the first bore to acquire soil and grab ground water samples in targeted zones based on interpreted lithologic data and assessment needs. The borings will be advanced to approximately 100 feet bsg, or until grab ground water samples no longer demonstrate hydrocarbon impact; total depths of borings may vary according to hydrogeologic conditions encountered during drilling activities. Ground water and selected soil samples will be analyzed by a California Department of Health Services (DHS)-certified laboratory for: • Total petroleum hydrocarbons as gasoline (TPH-g) and methanol, in accordance with EPA Method 8015 Modified; • Benzene, toluene, ethylbenzene and xylene (BTEX) and MTBE in accordance with EPA Method 8260; and • Oxygenated fuel additive compounds di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), MTBE, tertiary-amyl methyl ether (TAME) and tertiary butanol (TBA), ethanol, ethylene dibromide (EDB) and 1,2-dichloroethane (1,2-DCA) in accordance with 8260 Modified, respectively. Laboratory reports for soil and ground water analysis, testing methods, laboratory quality assurance/quality control (QA/QC) reports, and sample chain of custody documentation will be presented in a report of findings and recommendations. Advanced GeoEnviromnental,Inc.