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File No. 20-3978-OI.P02 KLEINFELDER November 12, 1996 Each sample is individually labeled. The label includes Kleinfelder's name,job number, the date and time the sample was collected, the employee number of the individual who performed the sampling, and a unique five-digit sample identification number. B-2.4 Hydropunch Groundwater Sampling Hydropunch is a method to collect representative groundwater samples from boreholes without the need to install monitoring wells. This method is usually used as an exploration tool for screening groundwater quality and reducing the number of wells needed at a site. A boring is drilled to the desired sampling depth, usually to the top of the groundwater surface, using hollow stem augers. The Hydropunch system, consisting of a steel drive point attached to a stainless steel barrel with an internal PVC slotted screen, is driven 2 to 3 feet past the bottom of the boring into the uppermost water bearing zone. The barrel is connected to the surface using clean, 2-inch diameter hollow steel rods. The barrel is then pulled back 1 to 2 feet exposing the internal PVC screen to the soil. Groundwater then enters the barrel through the screen under hydrostatic pressure and is brought to the surface with a clean, Teflon or stainless steel bailer. The samples are immediately labeled and placed in an iced sample container. Equipment used for Hydropunch sampling is decontaminated prior to use at each sampling location by steam cleaning, or by scrubbing in a trisodium phosphate or non- phosphate detergent wash followed by a distilled water rinse. B-2.5 Collection of BAT Probe Groundwater Samples One-time groundwater samples are collected using a BAT Probe, which is an in situ groundwater sampling device. The borings are first advanced to a point immediately above the desired sampling depth where groundwater is encountered. A stainless steel drive tip equipped with a stainless steel filter is lowered into the boring at the end of a 2.5-inch diameter galvanized steel pipe and pushed using the drill rig approximately 6 to 12 inches into the soil/aquifer formation at the bottom of the boring. A sterilized, glass, vacuum sealed sampling ampoule (tube), similar to a standard volatile organics (VOA) vial, is then lowered through the pipe down to the tip with a cable. Between the tip and the sample tube is a double-sided hypodermic needle (syringe), which simultaneously punctures the seals on the stainless steel drive tip and the septum of the glass sample ampoule. The vacuum in the sample ampoule draws groundwater through the tip into the glass ampoule. The glass ampoule is then pulled out of the pipe, disengaging the syringe. The septum in the glass ampoule and drive tip reseals after the syringe is removed. To reduce the potential for introducing contaminants into the samples, the drive tip, galvanized pipe, and other equipment used for sample collection are steam cleaned and/or washed with trisodium phosphate or non-phosphate detergent solution and double rinsed with distilled water prior to use. The sample probe and filters are cleaned in TSP solution and rinsed with methyl alcohol followed by a distilled water rinse prior to use. New, factory-sterilized syringe needles, O-rings, septum's and sample tubes are used for each sample. 20-3978-0/.P02/MP960132/WR960015 Page B-2 01996, Kleinfelder, Inc.