ARCHIVED REPORTS XR0001225 - Laserfiche WebLink

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APPENDIX O FIELD AND LABORATORY PROCEDURES Monitoring Well Installation Three sod borings will be converted to groundwater monitoring wells by installing 2-inch diameter flush-threaded, Schedule 40 PVC casing with 0 010-inch factory-slotted screens The length of screen size will be determined based on conditions observed in the field and in consultation with a California registered geologist Graded sand, appropriate to the screen size, will be placed in the annular space across the entire screened interval, and will extend not more than 2 feet above the top of the screened interval A hydrated bentonite seal will extend from the sand pack to the well box The well casing will be topped with a locking cap The wellhead will be contained in a watertight well box, traffic rated and flush mounted The boring logs will show well construction details Monitoring Well Development The wells will be developed after completion The development procedure for each well will consist of pumping or bailing water from the well until the water is visibly clear, the well goes dry, or until a maximum of ten casing volumes have been removed Upon completion of well construction, the wells will be surveyed by a surveyor licensed in the state of California The well casing elevations will be surveyed in accordance with applicable AB 2886 requirements j I Organic Vapor Monitoring Procedures j Soil samples collected at 5-foot depth intervals during drilling and will be analyzed in the field for volatile organic compounds using a photo-ionization detector (PID) equipped with a 10 2 UV lamp or aflame ionization detector (FID) The test procedure will involve measuring approximately 30 grams of soil from an undisturbed soil sample, placing this sub-sample in an unused sealed container (either a zip-IockTm bag or a mason far) The container will be allowed to warm for approximately 20 minutes in the sun, then the head-space within will be tested for total organic vapor concentrations, measured in parts per million as benzene (ppm, volume/volume) The instrument will be calibrated prior to drilling using a lab certified 100-ppm isobutylene standard (in air) and a sensitivity factor of 55, that 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 Sod samples for logging purposes will be collected at 5-foot intervals from approximately ten feet bgs to the total depth of the boring Vapor headspace monitoring will be conducted on sod samples collected in 5-foot intervals from ten feet bgs to total depth of the boring Selected sod samples collected in the vicinity of the former waste oil tank will be submitted to a California state certified laboratory, and analyzed as outlined in section 10 1 of the preceding report Following development, groundwater samples will be collected from each well Selected groundwater samples will be submitted to a California State Certified Laboratory, and analyzed for the presence of TPHg, TPHd, BTEX, MtBE by Environmental Protection Agency (EPA) method 8015 and 8260E •