ARCHIVED REPORTS_XR0004384 - Laserfiche WebLink

Home Browse Search

• collect samples to confirm the vapor results The results of the investigation were presented in the Soil Assessment Report prepared by Upgradient in April 1998 Subsequently, one of the borings was converted to groundwater monitor welt VM-4 In August 1999, Upgradient installed two remediation. test wells within the mapped zone of soil contamination However, no hydrocarbons were detected in any of the soil samples collected from these wells One of the wells (VT-1) was screened with 4-inch PVC casing from 15 to 30 feet for future use in soil vapor extraction testing The other well (SW-1), was screened with 2-inch PVC casing from 29 5 to 31 5 feet for potential use as an air sparging well YO PROCEDURES The depth to groundwater was measured and water samples were collected on September 27, 2001 The wells were opened and allowed to equalize with atmospheric pressure before the depth to groundwater was measured Depth measurements were recorded on the Well Monitor Report (Appendix A) and are shown in Table 1 After water depths were measured, the wells were purged of standing water by the surge-and-purge method Between 6 and 8 gallons of water were removed from each well, and temperature and electrical conductivity were measured at 2-gallon intervals ,during purging (Appendix A) Purged water was stored in a DOT-approved dram in the southwest corner of the site After purging, samples were collected from each well Two 40-m1 vials were collected from each, labeled, and placed in a cooled ice chest The samples were later transported to Excelchem Environmental Laboratory for analysis The laboratory report is included in Appendix B 4.0 RESULTS 4.1 Depth to Groundwater and Hydraulic Gradient The depth to groundwater on September 27 averaged 314 feet (Table 1), which is about 5 inches shallower than it was at this time last year and 1 foot deeper than it was in June of this year Figure 3 illustrates the hydraulic gradient and general direction of groundwater flow There appears to be a shallow trough in the hydraulic gradient in the central portion of the site, which as somewhat unusual Normally, groundwater elevation contours are relatively linear in a northwest-southeast direction Due to this trough, the groundwater flow direction appears to be to the southeast 4 2 Analytical Results Total Petroleum Hydrocarbon and BTEX concentrations increased to some wells and decreased in others during the quarter(Table 2) Concentrations were much lower in VM-1 but much r 3 -