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Manta Brothers Service Station 15 November 6, 1992 i 3 3 Well Development , and Groundwater Sampling Following completion of the groundwater monitoring wells, the wells were developed by surging and balling to remove drilling residues and produce low turbidity ground ' water All development, purging, and sampling equipment was washed with TSP (tri- sodium phosphate) detergent, rinsed with clean tap water and deionized water, then allowed to air dry before each well was purged and sampled, to reduce the possibility of cross-contamination Prior to sampling, the ground water monitoring wells were 1 purged with a pre-cleaned bailer to remove stagnant water in the wells During purging, key parameters including temperature, conductivity, and pH were measured with a portable electronic meter and recorded The meter was calibrated prior to the sampling event The purging continued until the monitored parameters stabilized (usually after three to four casing volumes of groundwater have been removed) The groundwater monitoring wells were sampled after water in the wells had recharged to approximately 80% of the original ground water elevation If, during purging, the monitoring well was purged dry, then purging was stopped for five minutes to allow the well to recharge if the well did not recharge at a sufficient rate to continue purging the three to four casing volumes, the well was allowed to recharge and was then sampled Following purging, groundwater samples were collected with pre-cleaned TeflonTM bailers, and discharged with a non-aerating bottom emptying device into sterilized glass containers, capped with TetloniM septa, labeled, and chilled in an ice chest for transport Water samples were handled and transported according to the United ' States Environmental Protection Agency (USEPA) protocol to the DHS certified laboratory requested Sample identification and chain of custody procedures were ' utilized to ensure sample integrity and to document sample possession from the time of collection to its ultimate disposal The sample labels identify the lob number, sampler, date, time of collection, and sample number unique to the sample The proposed monitoring wells were surveyed relative to a permanent structure, and from a designated point on the north side of the top of the well casing, the groundwater levels were measured in each well to an accuracy of 001 feet ' EB-8101-3 9210-BO55 RPT ■