ARCHIVED REPORTS XR0006864 - Laserfiche WebLink

Home Browse Search

3.3 Well Development and Ground-water Sampling ' After installation, the new monitoring wells (MW-12 and MW-13) were checked for the presence of floating product and the depth to water was measured (see Table 1). The wells were developed using a surge block and hand-pumping techniques by EMCON Associates field personnel on August 24, 1992. Development water was stored on site in labeled 55-gallon drums pending receipt of analytical data to determine the proper ' disposal method. Since no floating product was detected in the wells, the wells were allowed to stabilize after development and were then purged and ' sampled as described in Appendix D. In addition, EMCON Associates purged and sampled the existing on-site wells. Samples were collected from wells MW-10 and MW-11. Wells MW-3, ' MW-4, and MW-5 were dry, and well MW-9 was obstructed; therefore, samples could not be collected. 1 3.4 Sample Analysis ' Two soil samples from each exploratory soil boring were submitted to a state-certified analytical laboratory for chemical analysis. Soil samples from borings MW-12 and MW-13 collected approximately 10 feet belowthe depth of the bottom of the excavation, and the samples collected just above first-encountered ground water were submitted for chemical analysis. The soil sample collected from the bottom of boring B92-1 and the sample collected at a depth of 10 feet from this boring were selected for chemical analysis. The 10-foot sample was chosen because it had a slight product odor. The soil samples were analyzed for TPHG, BTEX, and total petroleum ' hydrocarbons as diesel (TPHD). The ground-water samples collected from the new monitoring wells and the previously installed monitoring wells were analyzed for TPHG, BTEX, and TPHD. ' 3.5 Analytical Results Soil and ground-water sample analytical results are presented in Tables 2 and 3, respectively. Certified analytical reports are presented in Appendix E. The soil samples collected from borings MW-12 and 692-1 did not contain detectable concentrations of TPHG, TPHD, or BTEX. The soil sample collected from boring MW-13 at a depth of 41 feet contained TPHG and TPHD at concentrations of 6,200 and 750 milligrams per kilogram (mg/kg), respectively. This sample also contalned toluene, ethylbenzene, and xylenes at concentrations of 200, 75, and 440 mg/kg, respectively. The sample did not contain a detectable concentration of benzene. The sample ' pjO\Of9010f900020.1 ag 3 - 3 Rev. 0 December 15, 1992 1