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�. M-01- _ <br /> G <br /> GROUND-WATER MONITORING AND SAMPLING PROCEDURES <br /> - Prior to sampling, the depth to water was measured in all monitoring wells using an electronic <br /> immersion probe. All measurements were read to the nearest 0.01 foot. If free product was present, <br /> the depth to free product and the depth to water werz measured using an interface probe and an <br /> observation simple was collected with a clear teflon bailer for confirmation. No analytical samples were <br /> collected from monitoring wells containing more than 0.25 inch of free product. <br /> — The monitoring wells were sampled on December 18, 1990. Prior to purging, each well was checked <br /> with a Oear teflon bailer in order to observe the possible presence of floating hydrocarbons. Purging <br /> was accomplished using a stainless steel or teflon bailer. The bailer was thoroughly cleaned prior to <br /> each sampling using a trisodium phosphate(TSP)solution followed by a 1017o methyl alcohol solution, <br /> -A and then rinsed twice with potable vrrter. The wells were purged prior to sarr.?ling until pH, <br /> conductivity,and temperature values stabilized. Generally,this resulted in the removal of approximately <br /> 3 to 5 well volumes of ground water from each well during the purging process. The water obtained <br /> from purging was placed in Iabeled 55-gallon drums and stored on-site. The bailer rope was replaced <br /> after,each sampling. Samples recovered from each wea were decanted into two appropriately prepared <br /> and labeled 40=m1 volatile organic anaiysis(VOA)bottles. A travel blank(numbered as MW-A)was <br /> also submitted for quality assurance. One travel blank per site will be analyzed. Duplicate samples will <br /> only be 2nalyzed by the laboratory when directed by Du Pont Environmental Remediation Services. <br /> The sample bottles were immediately placed in an ice chest and maintained at 4"C until delivery to a <br /> State of California licensed laboratory. Routine chain-of-custody procedures were employed. <br /> a — <br /> woo... ..... <br /> A - 1 <br /> f <br />