FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

' *4./ Project No. 58100-06-30 September 15, 1995 Page 3 NAW DRILLING AND SAMPLING �- Eight soil borings (SBI through S138) were advanced to depths ranging from 7.8 to 14.0 meters (25.5 to 46 feet) bgs in order to evaluate potential soil and groundwater impacts in the vicinity of the former refueling operations. Soil boring locations are depicted on the Site Plan, Figure 2. Borings SBI through SB4 were located within or in the immediate vicinity of the UST excavation. Borings SB 1 and S132 were advanced through the former UST excavation to aid in evaluating the maximum potential petroleum hydrocarbon concentrations and depth of vertical migration in native soil beneath the former USTs. Boring SB2 was advanced to a maximum depth of 14.0 meters (46.r--- feet) bgs in an attempt to encounter groundwater for monitoring well construction in order to evaluate groundwater quality. Groundwater was not encountered to a maximum depth of 46 feet--.-- bgs. Borings S135, S136, and S138 were located within and in the immediate vicinity of the former dispenser island. SB5 was advanced within the former dispenser island excavation to a maximum depth of 9.5 meters (31 feet) to aid in determining the maximum potential petroleum hydrocarbon concentrations and depth of vertical migration in native soil beneath the former diesel dispenser. `" S137 was located in the area of the former product piping elbow and was advanced to a depth of 8.1 meters (26.5 feet) bgs. v Soil samples were collected at approximate 1.5 meter (five foot)vertical intervals utilizing a 50.8- mm (two-inch)diameter split spoon sampler equipped with 152.4-mm-long by 50.8-mm (six-inch- long by two-inch) diameter stainless steel sample tubes to facilitate sample handling and storage. 'j The borings were logged under the supervision of a California Certified Engineering Geologist utilizing the Unified Soil Classification System. The sample tubes were capped, labeled and chilled pending transport to an analytical laboratory. Soil samples were field screened with a +.• flame-ionization detector (FID) to assess possible qualitative indicators of volatile organic compounds. The soil sample locations and FID readings are recorded on the attached boring logs presented in Appendix B. Drill cuttings generated from the drilling operations were stored onsite �. in DOT 17H 55-gallon drums pending the receipt of analytical data and subsequent disposal following regulatory protocol. Quality assurance/quality control procedures provided during the field exploration activities included cleansing/rinsing of the sampling equipment and steam cleaning the augers prior to and between borings. Cleansing/rinsing of the sampling equipment was performed prior to the collection of each soil sample by washing the equipment with a trisodium phosphate solution followed by subsequent tap water and deionized water rinses.