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a. Vol Clayton ENVIRMMENEAL CONS JLTA NIS We use the ambient temperature headspace method to screen individual samples for the presence of ve.Aous hydrocarbon vapors. We gather a soil or water sample and place it in a sample jar or zips^ck plastic bag so that there is a vacant headspace in the container. If a sample jar is used, the mouth is covered with foil and the lid is screwed on. The sample is then allowed to reach ambient temperature (usually in 10-15 minutes) causing any hydrocarbon vapors to volatilize into the headspace. Monitoring of the headspace in the jar or plastic bag is done with an OVM by piercing the foil or bag with the OVM probe. This method allows for a rough indication of the presence and concentration of hydrocarbon vapors in a particular sample. s SOIL SAMP ZG .w• Soil samples are taken every 5 feet, at areas of obvious contamination, or as otherwise specified, with a California modified split-spoon sampler that is lined with three six-inch brass tubes. The sampler and rod are inserted into the borehole to the current depth and a hammer of known weight and height above the sampler are allowed to free-fall onto the rod, advancing the assembly 18 inches into undisturbed soil. Clayton uses the number of blows necessary to drive the sampler into the ground to help evaluate the consistency of materials encountered. The sampler is then pulled from the borehole and disassembled, and the three brass tubes are separated for inspection and labeling. i Clayton uses new brass liners or iLners cleaned with a trisodiuin phosphate (TSP) solution, double rinsed with clean tap water, and air dried prior to each sampling. The sampler is also cleaned with TSP and rinsed with tap water between sampling events. Soil samples selected for laboratory analysis are left in the brass liners, sealed with aluminum IVA foil and plastic caps, taped for air tightness, labeled, and immediately placed into a pre-cooled ice chest chilled to less than 4°C. Labels contain the following in€ormation: site name, date 1 and time sampled, borehole number and depth, and the sampler's initials. The samples are l transported +firider chain-of-custody to a state-certified laboratory. The Iaboratory analyzes soil samples within the prescribed holding time,storing them at temperatures below 4°C at all times: Pending results of laberatory analysis, excess drilling and sampling cuttings are placed into Department of Transriortation (DOT)-approved drums, labeled with the name of the site, address and Well number, and left at the site. Uncontaminated soil may be disposed of by the client. Soil found to contain levels of contaminants above local or state action levels will . , require that the client dispose of it in accordance with hazardous waste regulations. At the client's request,we will assist with the disposal of contaminated soil. WELL CQNSTRt1 Q --- - oreholes are converted-to-mon2to:ing wells by placing 2-inch or4-inchdiameter-.well-casing- -- with flush threaded joints and slotted screen into the borehole. Construction materials �. include polyvinyl chloride (PVC), stainless steel, or low carbon steel. The most suitable . material for a particular installation will depend on the parameters to be moc stored. All �-� 2