ARCHIVED REPORTS_XR0002455 - Laserfiche WebLink

Home Browse Search

CLEARNIFAVER ' G R O U P Environmental Services I Groundwater sampling results for gasoline range hydrocarbons are summarized as follows Depth to groundwater range 9 65 (MW-2) to 11 78 (MW-8) feet below top-of-casing (TOC) Flow direction and gradient Southeast at approximately 0 006 feet/foot Benzene concentration range From not detectable (MW-2, MW-3, MW- 4) to 120 micrograms per liter (µg/L) in I MW-5B Toluene concentration range From <0 50 gglL (MW-2, -3, -4, -7, &MW- 8) to 40 (MW-5B) Ethylbenzene concentration range From <0 50 gg/L (MW-2, -3, -4, -7, &MW- 8) to 40 LEI (MW-5B) Xylenes concentration range From <0 50 gg/L (MW-2, -3, -4, -7 & MW- 8) to 81 (MW-5B) TPH-g concentration range From <50 gg/L(MW-2 and MW-4) to 3,100 (MW-5B) MTBE concentration range Not detected in concentrations exceeding indicated laboratory method reporting limits (<0 50 to <5 0 ) The groundwater flow direction and gradient as determined by the March 16, 2004 sampling event is substantially similar to previous monitoring events Groundwater elevation and ' analytical data are included in Table 1 A groundwater elevation map based on the March 16, 2004 groundwater elevation data was prepared and is presented as Figure 3 Dissolved-phase ' hydrocarbon distribution maps, based on the March 16, 2004 groundwater analytical results, providing iso-concentration contours of TPHg and benzene in groundwater are presented as IFigure 4 and Figure 5 respectively Analytical reports for this groundwater monitoring event are included as Appendix B 2.3 Monitored Natural Attenuation Analyses IAs suggested in Clearwater's Corrective Action Plan and subsequently approved by the SJC/SJC/EHD, MNA testing was continued at the site for the fourth quarter 2003 The testing ZB178C RAP 6 May 18,2004