ARCHIVED REPORTS XR0000203 - Laserfiche WebLink

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1 20 INVESTIGATIVE METHODS 2'1 Soil Borings Six exploratory borings (VW-1, VM-1, VM-2, MW-11, MW-25 and MW-26) were advanced at the site between September 1995 and August 1996 Boring VW-1 was advanced on September 7, 1995, using a CME 75 truck-mounted hollow stem auger drill rig Boring VW-1 was advanced to a depth of approximately 101'/2 feet and was completed as a vapor extraction well Borings VM-1, VM-2, MW-11, MW-25 and MW-26 were advanced on August 6 and 7, 1996, using a BK-81 hollow stem auger drill rig Borings VM-1 and VM-2 were advanced to maximum depths of approximately 65 ' and 61 feet, respectively, and were completed as vapor extraction test monitoring wells Borings MW-11, MW-25 and MW-26 were advanced to maximum depths of 80, 76 and 75 feet bgs, ' respectively and were completed as groundwater monitoring wells The locations of all borings/wells are depicted on Figure 2 Drill cuttings were placed in Department of Transportation (DOT) 17-H 55-gallon drums which were labeled and stored on-stte pending disposal following regulatory ' protocol The borings were logged under the supervision of a California registered engineer utilizing the Unified Soil Classification System Copies of the boring/well logs and well permit from this ' investigation are presented in Appendix A 22 Soil Sampling Excluding boring MW-11, soil samples were collected from the five borings (VW-1,VM-1, VM-2, MW-25 and MW-26) at approximate 5-foot or 10-foot intervals utilizing a two-inch diameter split- spoon sampler equipped with six-inch long by two-inch diameter stainless steel sample tubes to facilitate sample handling and storage Soil samples were not collected from boring MW-11 because ' existing groundwater monitoring well MW-1 I was being replaced with a new well The soil samples were field screened with a photo-ionization detector to assess possible qualitative indicators of volatile organic compounds The sample tubes were capped, labeled, and chilled pending transport to ' an analytical laboratory The soil samples were delivered to Advanced Technology Laboratories (ATL), a California certified analytical laboratory, following standard chain-of-custody procedures Quality assurance/quality control procedures were provided during the field investigation These procedures included cleansing/rinsing the drilling augers prior to advancing each boring ' Cleansing/rinsing of the sampling equipment was also performed prior each sampling effort by washing the equipment with a trisodium phosphate solution followed by subsequent tap water and ' detonized water rinses Project No 58100-06-18A -5- December 9, 1996