ARCHIVED REPORTS_XR0011996 - Laserfiche WebLink

Home Browse Search

iDuring the second quarter 2004, GRO, benzene, and MTBE were not reported in wells MW-2 and MW-7. GRO and benzene were also not reported in wells MW-1, MW-3, MW-9, and MW-10. Benzene was not reported in well MW-5. DIPE (1.1 µgll-)was reported in well MW-9. 1,2-DCA was reported in wells MW-7 (2.1 pg/L), MW-8 (34 gg/L), MW-9 (5.3 lig/L), and MW-10 (1.1 µg&). TBA, ETBE, TAME, EDB, or ethanol were not reported in any of the wells. During the second quarter 2004, the average DO levels in observation wells (MW-3 through MW-10) varied in the range of 0.9 mg/L to 10.1 mg/L, while the average DO levels in background monitoring wells (MW-1 and MW-2)were in the range of 1.1 mg/L to 1.7 mg/L. During the second quarter 2004, higher DO levels in the range of 4.8 to 12.3 were observed in wells MW-7 and MW-9 (located approximately 10 feet from the injection point). Changes in COD and TOC concentrations appear to correspond to GRO concentrations indicating biochemical activity in the subsurface (see Figures 11 and 12). A consistent correlation of heterotrophic plate counts corresponding to changes in petroleum hydrocarbon concentrations or DO levels was not observed during the second quarter 2004. Based on the field and laboratory data collected to date, the ozone injection system appears to be supplying ozone and oxygen to the subsurface as designed. LIMITATIONS This report was prepared in general accordance with accepted standards of care that existed at the time this work was performed. No other warranty, expressed or implied is made. Conclusions and recommendations are based on field observations and data obtained from this work and previous investigations. It should be recognized that definition and evaluation of geologic conditions is a difficult and inexact art. Judgments leading to conclusions and recommendations are generally made with an incomplete knowledge of the subsurface conditions present. More extensive studies may be performed to reduce uncertainties. This report is solely for the use and information of our client unless otherwise noted. ATTACHMENTS: • Table 1 Groundwater Elevation and Analytical Summary • Table 2 Groundwater Analytical Results for Oxygenates and Additional Compounds • Table 3 Monitoring Plan Summary • Table 4 Physical Parameter Summary • Table 5 Analytical Parameter Summary • Figure 1 Site Location Map • Figure 2 Site Plan • Figure 3 Groundwater Elevation Contour Map (Second Quarter 2004) • Figure 4 Groundwater Analytical Summary (Second Quarter 2004) • Figure 5 DO Variation With Time (MW-1, MW-2, MW-5, MW-7, and MW-9) • Figure 6 GRO, Benzene, MTBE Variation with Time at MW-4 • Figure 7 GRO, Benzene, MTBE Variation with Time at MW-5 • Figure 8 GRO, Benzene, MTBE Variation with Time at MW-6 • Figure 9 GRO, Benzene, MTBE Variation with Time at MW-7 • Figure 10 GRO, Benzene, MTBE Variation with Time at MW-8 • Figure 11 COD, TOC, GRO Variation with Time at well MW-4 • Figure 12 COD, TOC, GRO Variation with Time at well MW-6 • Appendix A Field Data Sheets • Appendix B Sampling and Analysis Procedures • Appendix C Certified Analytical Reports with Chain-of-Custody Documentation and EDF Verification PABp-Arco for URS154691Quarterly120041Arco_5469_2QO4,doe 5TKA7"U3