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cW y .1 <br /> t� <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 measurementG were read to the nearest 0.01 foot. If free product was present, <br /> the depth to free product and the depth to water were measured using an interface probe and an <br /> observation sample 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 October 9, 1990. Prior to purging,each well was checked with <br /> a clear teflon bailer in order to observe the possible presence of floating hydrocarbons. Purging was <br /> accomplished using a stainless steel or teflon bailer. The bailer was thoroughly cleaned prior to each <br /> sampling using a trisodium phosphate(ISP)solution followed by a 10%v methyl alcohol solution,and <br /> then rinsed twice with potable water. The wells were purged prior to sampling until pH,conductivity, <br /> i <br /> and temperature values stabilized. Generally,this resulted ii the removal of approximately 3 to 5 well <br /> volumes of ground water from each well during the purging process. The water obtained frocn purging <br /> was placed in labeled 55-gallon drums and stored on-site. The bailer rope was replaced after each <br /> sampling. Samples recovered from each well were decanted into two appropriately prepared and <br /> labeled 40-m1 volatile organic analysis(VOA)bottles. A travel blank(numbered as MW-A)was also <br /> submitted for quality assurat.ce. One travel blank per site will be analyzed. ?duplicate samples will only <br /> be analyzed by the laboratory when directed by Du Port Environmental Remediation Services. The <br /> sample bottles were immediately placed in an ice chest and maintained at 4`C until delivery to a State <br /> of California licensed laboratory. Routine chain-o€-custody procedures were employed. <br /> �w <br /> A - <br /> y <br /> xr l <br /> r _ <br /> 3� <br />