ARCHIVED REPORTS_XR0004413 - Laserfiche WebLink

Home Browse Search

In July 1996, three soil borings were drilled and two were converted to monitoring wells Contaminated soil was encountered in two of these, and one or more hydrocarbon contaminants were detected in water samples from all three, as well as in the previously drilled well (VM-1) The resulting data helped to partially define the limits of soil contamination, but the limits of groundwater contamination were not reached A soil vapor survey was conducted in March, 1998, in order to better define the extent of near- surface soil contamination This survey was followed by the dnllmg of two new soil borings to 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 3.0 PROCEDURES Monitor well VM-4 was completed on August 14, 1998, when V & W Drilling installed 55 feet of PVC casing in the open borehole Because the hole had been allowed to remain open since it was drilled in March, some up-hole sloughing of soil had occurred and it was necessary to drill out this material in order to reach the previous depth of 55 feet When this depth was reached, V & W installed 20 feet of slotted PVC casing and 35 feet of blank casing and then sanded the well annulus in accordance with County requirements The well completion details are shown on the accompanying boring log(Appendix A) Grouting was witnessed by Michael Infurna of EHD The well casing elevation was surveyed and all wells were monitored on August 18, 1998 Upon arrival at the site, the wells were opened and allowed to equalize with atmospheric pressure A Solinst water level meter was used to measure the depth to groundwater in the monitoring wells Depth measurements were recorded on the Well Monitor Report (Appendix B) and are shown in Table 1 The total depth of the wells was also measured and recorded After water depths were measured, a Grundfos submersibile pump was used to purge the wells of between three and five casing volumes, and the water was stored in DOT-approved drums in the southwest corner of the site. During purging, a Coring meter was used to measure pH, conductivity, and temperature, and these parameters were recorded on the Well Monitor Report After purging, samples were collected from each well. Three 40-m1 vials and one 1-liter amber bottle were collected from each, labeled, and placed in a cooled ice chest The samples were later transported to Excelchem for analysis The laboratory report is included in Appendix C 4.0 RESULTS 41 Depth to Groundwater The depth to groundwater has risen considerably since December 1997 (Table 1) Currently, the depth averages slightly less than 35 feet below grade The static water surface is now 11 to 13 feet above the screened interval in the first three wells, and approximately a foot over the screen 3