Laserfiche WebLink
snA <br /> Working to Restore Nature <br /> I� <br /> with a direction of flow toward the northeast and a hydraulic gradient of 0 001 According <br /> to N&B, gasoline hydrocarbons have been detected in soil near the tank cavity and <br /> groundwater beneath the site. <br /> SUPPLEMENTAL II VESTIGATION <br /> The investigation was conducted in accordance with our Work Plan 123020 01W dated <br /> September 15, 1993 and Site Safety Plan 123020 dated September 15, 1993 Our field <br /> procedures are described in an attachment to this report <br /> r Field Work <br /> On October 20 and 21, 1993, a RESNA field geologist observed Western Strata Exploration <br /> (Westex) of West Sacramento, California drill two offstte and four onsite soil borings (HP-1 <br /> through HP-6) to groundwater (16 5 to 17 feet below grade) RESNA collected groundwater <br /> samples from these borings using a Hydropunch sampling device Westex also drilled three <br /> additional soil borings onstte (B-1, B-2, and B-3) to 15 feet below grade These borings <br /> were converted to vapor extraction wells (VW-1, VW-2, and VW-3) Groundwater was not <br /> encountered in these borings <br />�. The geologist collected soil samples from the borings at approximately 5-foot intervals for <br /> possible laboratory analyses and to characterize the geology beneath the site Samples were <br /> logged using visual and manual methods and classified according to the Unified Soil <br /> Classification System (Plate 3) Sediments consisted of silt, clay, and sand and are shown <br /> on the Logs of Borings (Plates 4 through 12) <br /> Ii <br /> On October 21, 1993, our geologist collected soil samples (one composite of four samples) <br /> from the stockpiled soil for analyses to evaluate disposal options <br /> Laboratory Methods and Results <br /> 0 Select soil samples from the borings and the composite soil sample were analyzed for total <br /> petroleum hydrocarbons as gasoline (TPHg) and benzene, toluene, ethylbenzene, and total <br /> xylene isomers(BTEX) using Environmental Protection Agency(EPA) Methods 8015/8020 <br /> Groundwater samples were analyzed for TPHg and BTEX using modified EPA Method <br /> 8015/8020 Samples were analyzed at Sparger Technology in Sacramento, California <br /> (Department of Health Services Hazardous Waste Testing Laboratory Certification 1614) <br /> Copies of the Chain of Custody Records and laboratory analysts reports are attached <br /> Results of analyses of soil samples collected from borings B-1, B-2, and B-3 indicated TPHg <br /> was detected at concentrations ranging from 2 4 parts per million (ppm) to 700 ppm and <br /> 1215bnn/I Mo 01 2 <br />