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ATTACHMENT A FIELD AND LABORATORY PROCEDURES Geoprobe and Hand Auger Soil Boring Subsurface soil samples will be collected using Geoprobe narrow diameter, direct push technology to approximately 10 feet below ground surface. A SECOR International Incorporated geologist using the Unified Soil Classification System and standard geologic techniques will log the borings. Samples will be collected by hand auger in areas inaccessible to the Geoprobe°. Soil samples from the hand auger boring will be collected using a slide hammer and clean brass sampling sleeves. Soil samples from the Geoprobe borings will be collected using a California-modified split-spoon sampler. Soil samples for chemical analysis will be retained in clean brass sampling sleeves, capped with Teflon squares and plastic end caps, and sealed in clean zip-lock bags. Groundwater samples will be collected using a hydropunch sampler and clean dedicated acetate tubing attached to a peristaltic pump. The samples will be placed on ice for transport to the laboratory accompanied by chain-of- custody documentation. Down-hole sampling equipment will be washed in a tri-sodium phosphate or alconox solution between samples. Organic Vapor Procedures Soil samples collected during drilling will be analyzed in the field for ionizable organic compounds using a photo-ionization detector(PID) with a 10.2 eV lamp or a flame ionization detector(FID). The test procedure will involve measuring approximately 30 grams from an undisturbed soil sample,placing this subsample in a sealed container(either a zip-lock bag or a mason jar). The container will be warmed for approximately 20 minutes (in the sun), then the head-space within will be tested for total organic vapor, measured in parts per million as benzene (ppm; volume/volume). The instrument will be calibrated prior lo drilling using a 100-ppm isobutylene standard(in air) and a sensitivity factor of 55, which relates the photo- ionization potential of benzene to that of isobutylene at 100 ppm. The results of the field testing will be noted on the boring logs. PID and FID readings are useful for indicating relative levels of contamination, but cannot be used to evaluate hydrocarbon levels with the confidence of laboratory analyses.