ARCHIVED REPORTS_XR0011298 - Laserfiche WebLink

Home Browse Search

I Geological TuhAks Inc. Page 4 Additional Site Characterization and 3"t Quarter Groundwater Monitoring Project No.989.2 October 31,2002 0.020 inch screened interval and was topped by a two foot bentonite pellet transition seal installed on top of the filter pack. A surface seal was achieved by pumping a neat cement grout (augmented with <4% bentonite). The wells were surged using a clean surge block to achieve maximum filter pack density prior to installing the bentonite transition seal. The well was secured with a locking watertight cap encased in a flush mounted traffic rated well box. The boring logs (Appendix B) contain the details of construction. Soil cuttings and drilling decontamination water were placed in DOT-17 55-gallon drums and stored on site until their disposal can be arranged. ' 2.2 Soil Investigation ' 2.2.1 Soil Sampling Procedure On July 30, 2002, V&W Drilling and Geological Technics personal mobilized to the site. A GTI geologist collected soil samples and maintained a log from the soil borings. The samples were gathered in 6.0-inch brass liners using a 2A-inch modified California split spoon sampler. The middle 6.0-inch brass liner was selected for laboratory analyses. The ends were covered with Teflon sheets and sealed with plastic caps. The brass liners and plastic caps were washed with an Alconox solution and double rinsed prior to use. The sampling technician wore disposable gloves while collecting all samples. Soil samples from MW-7, MW-9, and MW-101 were submitted for laboratory analysis and a screening process was used to gather information through field observations. Soil samples were not collected from MW-8 due to the drilling method discussed in section 2.1. The field screening included: ' • Sediment type, especially grain size and clay content • Moisture content ' 0 Visible evidence of contamination (i.e., color change due to reduction of iron or discoloration from hydrocarbons and other pollutants) • Odor (OVM was not functioning and field observations were noted relating to odor in soil samples) Details on the geology encountered during the well installation, as well as the field observations, are included in Section 3.2, Geology and Field Observations. See Appendix B, Boring Logs for more information. ' 2.2.2 Soil Laboratory Analyses The following summarizes the soil sample testing used for this phase of work. The soil samples collected on July 30, 2002, were delivered to Sherwood Labs (California ELAP No. 1400), of Hilmar, California, for the following analyses: • Benzene, toluene, ethylbcnzene and xylene (BTEX) by EPA method 8020 ' • Gasoline range petroleum hydrocarbons (TPH-Gasoline)by EPA method 8015(m) • Volatile Organic Compounds by EPA method 8260 ❑ MTBE, DIPE, ETBE, TAME, TBA, 1,2 DCA and EDB