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$©F; CLEARWAri ER G R O U P, I I'N C. - purging activities to insure that the sample is representative of the aquifer.: Purging will continue until at least three well casing volumes have been removed, 'the physical parameters stabilize, or until the -well .completely._ . dewaters. Stability is defined`as a'change of less than 0.2 pH units, less than : : 10% in micro mhos, and less than 1.0 degree Centigrade. . Wells which dewater or demonstrate.a slow,recharge, may be sampled after fewer than three well volumes have been removed.' Well purging: orm infation will be recorded on a purge data sheet:. All meters will .be calibrated daily. Purge water will.be stored 'on.site in D:O.T:-approved 55 gallon :drums, sealed .and labeled. ..The water .will be removed,to an appropriate disposal 'facility by a.- licensed .:licensed hauler. Ground water samples will be collected immediately. after purging or when the well has recharged to at least 70% of its static water level. Samples will be . . ; collected using polyethylene bailers, either disposable-or dedicated to the well. Samples .for analytes most sensitive to volatilization .will be collected -first. Water samples will be placed} in theappropriate container. for that analysis, labeled, documented on a chain of custody forst and..placed on ice in a cooler for transport to a state-approved analytical laboratory. To prevent contamination of the samples, CGI personnel will adhere to the following procedures in the field:. i� • A new, clean pair of latex gloves will be used for each well to be sampled. _ Groundwater samples will Abe collected in the expected order of increasing degree of contamination. When collecting samples for volatile organic analysis, CGI personnel. will minimize the amount of Fair passing through the sample. This helps - _ prevent the air from stripping the volatiles from the water. . Sample bottles should be filled by slowly running the sample down the side of the bottle until there is a convex meniscus over the mouth of the bottle. The lid is then carefully screwed onto the bottle such that no air bubbles are . present within the bottle. -�`If a bubble. is present, the cap is removed..and additional water is added' to the sample container. After resealing the sample container,'if bubbles still are present inside, the sample container is discarded and the procedure is repeated. 5 CLEARWATER GROUP,INC. 4 April 28, 1995 4 `