ARCHIVED REPORTS XR0001648 - Laserfiche WebLink

Home Browse Search

13 Site Specific Information Summaa o Depicted on enclosed figures are the site location and nearby surface waters(Figure 1), the site to scale and former tank locations(Figure 2), well and boring locations (Figure 3), the excavation area/former extent of impacted soil (Figure 4), and most recent {� groundwater gradient contours(Figure 5) o Water level data are presented in Table 4 During the investigative history of the site, tdepth to groundwater has ranged from 17 04 to 28 89 feet below grade o Tables 1, 2, 3, and 7 present the soil analytical results and Tables 5 and 6 present the groundwater analytical results o Soil remediation methodology is described in Section 3 4 Remedial Actions Natural biodegradation and aeration were used to remove petroleum hydrocarbons from the excavated soil on-site o Groundwater remediation methodology is described in Section 3 4 Remedial Actions Approximately 401,750 gallons of contaminated groundwater was removed and disposed of The remaining groundwater was remediated using passive natural biodegradation techniques M6.0 CONCLUSIONS AND RECOMMENDATIONS Excavation, natural biodegradation, and aeration successfully remediated the majority of contaminated I soil The groundwater that was impacted the most by the contanunated soil was removed, treated, and disposed of TPHg concentrations have decreased to nondetectable levels and BTEX and HVOCs concentrations have been below the MCLs since the contaminated soil was excavated in October 1995 IOver time the remaining petroleum hydrocarbons are expected to naturally biodegrade to nondetectable levels in soil and groundwater Case closure is recommended 7.0 WORKPLAN FOR WELL ABANDONMENT Smith Technology has prepared this workplan for the proposed abandonment of wells MW-1R through MW-6 at Holt Bros ' property located at 1541 West Charter Way, in Stockton, California (Figure 1) The locations of the monitoring wells are shown on Figure 3 A permit application and associated fee (check No ) is attached to this closure report Upon receipt of the well destruction permit, Smith Technology will schedule field activities The wells will be abandoned by a C57 licensed drilling company The well boxes and top two feet of casing will be removed Well MW-2 will be destroyed by overdrillmg the well casing to the bottom of the boring using 8-inch O D hollow stem augers After the former well boring is ' drilled out, the boring will be backfilled with neat cement from the bottom of the boring to the top w 1943311closure doc 7 SMTH