Laserfiche WebLink
' Creatag coal rechnics Inc Page 6 <br /> 4`h Quarter 2003 Groundwater Morutonng Report <br /> Project No 507 2 <br /> Apnl 12,2004 <br /> ' 3.0 CONCLUSIONS AND RECOMMENDATIONS <br /> ' Conclusions <br /> I Elevated concentrations of BTEX, TPH-G and MTBE are present in a laterally limited <br /> groundwater plume that is centered on MW-9 <br /> ' 2 The MTBE and previously monitored 1,2-DCA plumes are insignificant in comparison <br /> to the BTEX and TPH-G plumes <br /> 3 The lateral extent of the contamination plume is defined to the east, northeast and <br /> ' southeast by wells MW-3, MW-2 and MW-i respectively <br /> 4 The TPH-G plume is defined to the northwest and southwest by wells MW-10 and MW- <br /> 7 respectively <br /> ' 5 The BTEX/TPH-G groundwater contamination plume is defined by MW-109 in the <br /> vertical plane, which is screened 40 feet below MW-9 This suggests that the vertical <br /> gradient is not moving the contaminants to any degree <br /> 6 The groundwater gradient flows to the northeast or east with relatively flat slopes, which <br /> appears not to significantly influence contaminant migration <br /> ' 7 The site exhibits a predominantly downward component of vertical groundwater flow, <br /> which is approximately the same slope as the horizontal gradient These components of <br /> groundwater flow appear not to cause preferential contaminant migration <br /> 8 The groundwater contaminant concentrations are on the rise, which correlates with a <br /> decrease of groundwater levels The center of the plume has not migrated beyond the <br /> source area giving evidence that the plume is not migrating laterally or vertically by <br /> ' advective flow <br /> 9 The data shows that the plume is stable and is not being degraded by natural <br /> biodegradation causes <br /> ' Recommendations <br /> • Maintain the modified quarterly monitoring schedule <br /> • A work plan for "In Situ Remediation Feasibility Study" dated September 20, 2002 and <br /> an addendum to the plan were submitted to San Joaquin County Environmental Health <br /> Department (SJC EHD) SJC EHD approved the study in their March 20, 2003 letter <br /> and requested a detailed work plan for evaluation GTI submitted our June 10, 2003 <br /> "In-Situ Remediation Pilot Test" work plan for an in-situ hydrogen peroxide injection <br /> pilot project and SJC EHD issued approval of the work plan in their September 10, <br /> 2003 letter The installation of three, 3/4" diameter monitoring wells was completed on <br /> February 5, 2004 and the injections began in mid March 2004 <br /> 1 <br />