ARCHIVED REPORTS_2003 FEASABILITY STUDY REPORT AND SITE ASSESSMENT WORK PLAN

Home Browse Search

S ECO R - ATTACHMENT G FIELD AND LABORATORY PROCEDURES Soil Borings and Sampling The soil borings will be drilled using a 4-inch hand auger to depths of approximately 10 feet bgs. The sampler will be driven a maximum of 18 inches using a slide sampler. Soil samples collected for chemical analysis will be retained in brass liners, capped with Teflon squares and plastic end caps, and sealed in clean zip-lock bags. The samples will be placed on ice for transport to the laboratory accompanied by chain-of-custody record. Down-hole augering and sampling equipment will be steam-cleaned prior to and following completion of each sample interval. Temporary Well Installation and Sampling The borings will be converted to temporary groundwater monitoring wells by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0.020-inch factory-slotted screen. Approxi- mately 10 foot of screen will be placed in the bottom of each boring and threaded to a solid well k casing section will extend above the ground surface approximately one foot. Groundwater samples will be collected using dedicated polyethylene tubing and a peristaltic pump, placed into appropriate EPA-approved containers, labeled, placed on ice, and transported to a California State Certified laboratory accompanied by chain-of-custody documentation. Water Quality measurements including conductivity, turbidity, temperature and PH will be collected during well sampling activities. Organic Vapor Monitoring Procedures Soil samples collected at 5-foot depth intervals during hand augering and will be analyzed in the field for ionizable organic compounds using a photo-ionization detector (PID) with a 10.2 UV 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 to 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. 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. Laboratory Procedures for Soil and Ground water Samples Selected soil and water samples collected will be analyzed for the presence of TPHg and TPHd by EPA Method 8015, BTEX and fuel oxygenates MtBE, EtBE, TBA, TAME, DIPE, EDB, and 1,2-DCA by EPA 8260 and total lead by EPA Method 7421. Soil Cuttings and Rinsate Water Soil cuttings generated during drilling operations will be temporarily stored on site and covered with plastic sheeting pending characterization and disposal. Soil cuttings will be removed by Chevron's disposal contractor to an appropriate disposal facility. Water generated during steam cleaning will be temporarily stored in DOT-approved 55-gallon drums pending transport by Chevron's disposal contractor to an appropriate disposal or treatment facility. Soil cuttings and rinsate water drums will be temporarily stored on site for approximately 4 to 8 weeks.