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R&B Trucking ... �+ Project No.01-37.1.1 March 27,1990 Page 5 The ground water was sampled in two rounds. The sampling procedure is described as follows: Upon arriving on site the gas driven pump is assembled and hooked up to an oil less compressor. The well is then unlocked and opened. The pump is then inserted into the well and is lowered to a depth of 6 to 8 inches from the bottom of the well. The compressor is then turned on and the pump activated. The pump is then adjusted for the pressure and exhaust cycles to maximize a consistent water flow from the well. At least five well volumes are pumped from the well into a 55 gallon Department of Transportation (DOT)approved container (a well volume is the amount of water contained within the well casing and filter pack with an assumed 25 percent porosity). After the five well volumes of water have been pumped from the monitoring wells and containerized, the well is then allowed to recharge for a short period (.5 to 1 hour). The well is then sampled using a polyethylene single check disposable bailer using a dedicated nylon rope. The sampling technician wearing disposable gloves then removes the bailer from its plastic bag and the rope is attached. A bailer blank is then collected by pouring deionized water into the bailer and emptying it into a sample vial. The bailer is then lowered into the well and carefully allowed to fill with water. The bailer is then raised from the well taking precaution not to agitate the contained water. An — emptying device is then coupled to the bailer and the water is then slowly transferred to the sample container(40 ml VOA vials and an amber 1 litre bottle). The vial is then capped, inverted, and tapped to check for any air bubbles that may be contained within the sample vial. After assuring that no air bubbles are contained in the sample, the vial is then labeled and inserted into a closed cell foam holder and placed in a cooler containing "blue ice" for transport to the laboratory. Sample vials from the same well are sealed in a zip lock plastic bag to prevent cross contamination. VOA samples may also be contaminated by diffusion of volatile organics through the septum during shipment and storage. To monitor possible contamination, a trip blank prepared from distilled deionized water is carried throughout the sampling,storage and shipping process. A chain of custody document is then filled out listing all samples collected. This document is used to track the samples and to insure their integrity. 4.0 MONITORING WELL CONSTRUCTION AND TESTING Geological Technics proposed and supervised the installation of three monitoring wells on this site. The wells were installed by Osterberg &Stewart, Inc. using a 6 inch inside diameter hollow stem continuous flight auger.