Laserfiche WebLink
r <br /> w <br /> FIELD PROCEDURES' <br /> E <br /> Field Instruments <br /> Quorum Environmental Consultants, Inc. uses a photoionization detector (PID) in the field <br /> to screen samples for laboratory analysis and to make general evaluations of the extent of <br /> hydrocarbon-bearing soil at the site. These instruments measure the total concentration of <br /> ionizable compounds (including hydrocarbons) in vapor emitted from soil or water samples <br /> under ambient field conditions. Variations in soil type, soil temperature, moisture content, <br /> ambient air temperature, and vapor pressures of respective constituents affect the results. <br /> Laboratory analysis involves extraction of hydrocarbons from the sample under controlled <br /> laboratory conditions. As a result, readings obtained with a PID may not correspond to the <br /> results obtained by laboratory analyses. The geologist must evaluate the relative merit of <br /> the measurements made with a PID and the laboratory analyses in light of the field <br /> conditions existing at the site and the differences between field and laboratory methods. <br /> Soil Sampling Below The Former Tank Location <br /> Native soil is excavated from below the former position of. 'he tank in a backhoe (or similar <br /> machinery) bucket and evaluated using the PID. Soil samples are taken from the bucket <br /> by driving laboratory-cleaned brass sleeves into the soil.�� The samples are sealed in the <br /> sleeves using aluminum foil, plastic caps, and duct tape; labeled; and promptly placed in <br /> iced storage for delivery to a laboratory certified by the State of California. <br /> Sampling of Stockpiled Soil <br /> At the direction of the SJLHD one representative soil sample is collected for laboratory <br /> analysis from approximately each 25 cubic yards of stockpiled soil and from each individual <br /> stockpile composed of less than 25 cubic yards. Samples afire collected by removing the top <br /> 1 to 2 feet of soil and then driving cleaned brass sleeves into the soil. Samples are sealed <br /> in the sleeves using aluminum foil, plastic caps, and duct tae. The samples are labeled and <br /> promptly placed in iced storage for delivery to a laboatory certified by the State of <br /> California. <br /> i <br /> i <br /> i <br /> S <br /> i <br /> { <br /> 1 <br /> .I <br /> f <br /> f <br /> °I <br />