ARCHIVED REPORTS XR0000728 - Laserfiche WebLink

Home Browse Search

ECOID 1 �r ATTACHMENT A A FIELD AND LABORATORY PROCEDURES Geoprobe® Drilling Subsurface soil samples will be collected using Geoprobe narrow diameter, direct push technology to approximately 15 to 20 feet below ground surface Borings will be logged by a SECOR International Incorporated geologist using the Unified Soil Classification System and standard geologic techniques Sod samples for logging will be collected at 5-foot depth intervals using a California-modified split-spoon sampler All soil samples for chemical analysis will be retained in acetate tubing, 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 All down-hole drilling and sampling equipment will be steam-cleaned following the completion of the soil boring Down-hole sampling equipment will be washed in a tri-sodium phosphate or alconox solution between samples Organic Vapor Procedures k Soil samples collected at 5-foot depth intervals 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 sod sample, placing this subsample in a sealed container (either a zip-lock bag or a mason far) 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 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 Groundwater Monitoring Well Installation and Development • Sod borings will be converted to groundwater monitoring wells by installing 2-inch diameter, flush- threaded, Schedule 40 PVC casing with 0 020-inch factory-slotted screen Approximately 15 feet of screen will be placed in the bottoms of the borings A grade of sand appropriate to the screen size will be placed in the annular space across the entire screened interval, and will extend approximately 2 feet above the top of the screen for the wells A bentonite seal will extend three feet above the sand pack The monitoring wells will be completed with neat cement from the bentonite seal to the ground surface The well casing will be topped with a locking cap The well head will be contained in • a watertight traffic-rated well box The boring logs will show well construction details t