FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

S E C O R Due Diligence Site Assessment Report March 31, 2005 Page 2 advanced using 8-inch hollow stem auger drilling equipment. Groundwater was not encountered during assessment activities. The locations of completed borings are illustrated on Figure 1. Physical descriptions of the soil types encountered at each sampling location were recorded on boring logs in accordance with the Unified Soils Classification System (USCS). The boring logs are included as Attachment A. Upon completion of each boring, the boreholes were backfilled from the bottom up with cement grout. The grout was placed in the borehole by a free-fall method approved by the county regulator. The boring was capped with concrete to match existing grade. Laboratory Analysis Soil samples collected during field activities were delivered under chain-of-custody to Severn Trent Laboratories (STL) of Pleasanton, California. This laboratory is certified by the State of California Department of Health Services Environmental Laboratory Accreditation Program to perform the analyses reported herein. Select soil samples collected from borings B-1 through B-6 were analyzed for total petroleum hydrocarbons calculated as diesel (TPHd) by EPA method 8015, total petroleum hydrocarbons calculated as gasoline (TPHg), benzene, toluene, ethylbenzene, xylenes (BTEX), and fuel oxygenates metyl tert-butyl ether (MtBE), tertiary butyl alcohol (TBA), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), ethylene dibromide (EDB), 1,2-di-chloroethane (1,2-DCA), tert-amyl methyl ether (TAME), and ethanol by EPA Method 8260B. Review of the soil sample laboratory data indicates the following: TPHg and BTEX were reported as not detected at or above the laboratory reporting limit in soil samples analyzed except for soil sample B-6@25'. TPHg and BTEX concentrations were reported in B-6@25' at 1,600 milligrams per kilograms (mg/kg), 3 mg/kg, 58 mg/kg, 22 mg/kg, and 120 mg/kg, respectively. • MtBE and TBA were reported in soil samples B-1@35', B-1@50', B-5@50', and B-6@50'. Maximum reported concentrations of MtBE and TBA were 6.3 mg/kg and 0.47 mg/kg, respectively. • TPHd concentrations were reported in soil samples B-1@35' and B-6@25' at 1,300 mg/kg and 19 mg/kg, respectively. • Organic vapors were measured in soil samples collected from borings B-1 through B-6 using a photoionization detector (PID). Organic vapor measurements ranged from 0.0 parts per million (ppm) to 80.0 ppm. Soil sample laboratory results are summarized in Table 1. Laboratory report and chain-of-custody documentation are in Attachment B. I\ConocoPhillips\Due Diligence\2787245\Report\2787245-Due Diligence Reoort.doc