Laserfiche WebLink
Report on Soil and Ground-Water Evaluation September 11", 1989 <br /> Proposed ARCO Station, Woodbridge, California AGS 39044-1 - - <br /> Laboratory to collect and analyze. soil vapor at.16 sampling locations. Equipment used to <br /> sample soil vapor included a hardened steel drive-tip, a downhole sampling assembly with <br /> vacuum vials,-steel probe rods with an outside diameter of 1.75 inches, and a driving unit. <br /> The probe rod and drive-tip were hydraulically pushed to a predetermined depth at-which <br /> point the drive-tip was opened. The sampling assembly was then.-lowered through the <br /> hollow center of the probe rod to collect a vapor sample. This method helps eliminate <br /> contamination by atmospheric gas, giving a reliable. and reproducible reading of the <br /> concentration of hydrocarbon vapor in the soi:l.at-the sample depth. Because each sample <br /> vial is the same size (i.e., constant volume of gas)-and is evacuated to the_same degree, the <br /> number of variables associated with vapor sampling are.reduced. Reduction in variation <br /> of the vapor sampling procedure provides consistency in_sampling at different depths and <br /> locations. - <br /> After the samples were collected the probe holes were backfilled with neat cement as <br /> prescribed by the SJLHD. Locations-of probe holes were measured relative to other. <br /> facilities at the site using a Wild NA-24 automatic level and stadia rod. <br /> Selection of Sample Locations and Depths <br /> Because no structures impeded the-survey, the.sample locations were spaced nearly evenly <br /> across the site . Soil-vapor samples were collected at 16 locations at a depth of 12- feet. <br /> 8 <br /> APP/led Geosystems <br />