Book Description

This Annual Report presents the data and evaluates the progress of the three-component remedy implemented for remediation of groundwater contamination at Test Area North, Operable Unit 1-07B, at the Idaho National Laboratory Site. Overall, each component is achieving progress toward the goal of total plume remediation. In situ bioremediation operations in the hot spot continue to operate as planned. Progress toward the remedy objectives is being made, as evidenced by continued reduction in the amount of accessible residual source and decreases in downgradient contaminant flux, with the exception of TAN-28. The injection strategy is maintaining effective anaerobic reductive dechlorination conditions, as evidenced by complete degradation of trichloroethene and ethene production in the biologically active wells. In the medial zone, the New Pump and Treat Facility operated in standby mode. Trichloroethene concentrations in the medial zone wells are significantly lower than the historically defined concentration range of 1,000 to 20,000 [mu]g/L. The trichloroethene concentrations in TAN-33, TAN-36, and TAN-44 continue to be below 200 [mu]g/L. Monitoring in the distal zone wells outside and downgradient of the plume boundary demonstrate that some plume expansion has occurred, but less than the amount allowed in the Record of Decision Amendment. Additional data need to be collected for wells in the monitored natural attenuation part of the plume to confirm that the monitored natural attenuation part of the remedy is proceeding as predicted in the modeling.