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,t . ATTACHMENT A FIELD AND LABORATORY PROCEDURES Soil and Groundwater Sampling Soil samples were collected by advancing 2-inch diameter brass sample liners into soil removed from an excavation by a backhoe bucket. Soil samples for chemical analysis were retained in the brass liners, labeled, and capped with Teflon sheets, plastic end caps, and Teflon tape. Groundwater samples were collected from the test pit excavations using a clean teflon bailer and placed into appropriate EPA-approved containers. The test pits were not purged prior to sampling. The soil and groundwater samples were then sealed in plastic bags, placed on ice, and transported to the laboratory accompanied by the appropriate chain-of-custody documentation. • Organic Vapor Procedure Selected soil samples were analyzed in the field for ionizable organic compounds using a photo-ionization detector with a 10.2 eV lamp. The test procedure involves measuring approximately 30 grams from an undisturbed soil sample, placing this subsample in a clean glass jar, and sealing the jar with aluminum foil secured under a ring-type threaded lid. The jar is warmed for approximately 20 minutes, the foil pierced, and the head-space within the jar tested for total organic vapor measured in parts 'per million as benzene (ppm; volume/volume). The instrument was previously calibrated using a 100-ppm isobutylene standard (in air) and a sensitivity factor of 0.55, which relates the photo- ionization sensitivity of benzene (10.0 ppm) to the ionization potential of isobutylene (5.5 ppm). Results of these tests were used to assist in selection of samples for laboratory analysis. Groundwater Sampling Groundwater sampling was performed using techniques approved by the Regional Water Quality Control Board. Groundwater samples were collected using a Teflon bailer and placed into appropriate EPA-approved containers. The samples were labeled, logged 3 100011 WREPORT A- 1 November 30, 1994