||Monitored Natural Attenuation of Inorganic Contaminants in Ground Water. Volume 3: Assessment for Radionuclides Including Tritium, Radon, Strontium, Technetium, Uranium, Iodine, Radium, Thorium, Cesium, and Plutonium-Americium.
The current document represents the third volume of a set of three volumes that address the technical basis and requirements for assessing the potential applicability of MNA as part of a ground-water remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. Volume 3, titled Assessment for Radionuclides Including Tritium, Radon, Strontium, Technetium, Uranium, Iodine, Radium, Thorium, Cesium, and Plutonium-Americium, consists of individual chapters that describe (1) the natural processes that may result in the attenuation of the listed contaminants and (2) data requirements to be met during site characterization. Emphasis is placed on characterization of immobilization and/or radioactive decay processes that may control contaminant attenuation, as well as technical approaches to assess performance characteristics of the MNA remedy. A tiered analysis approach is presented to assist in organizing site characterization tasks in a manner designed to reduce uncertainty in remedy selection while distributing costs to address four primary issues: (1) Demonstration of dissolved plume stability via radioactive decay and/or active contaminant removal from ground water; (2) Determination of the rate and mechanism of attenuation by immobilization; (3) Determination of the long-term capacity for attenuation and stability of immobilized contaminants; and (4) Design of performance monitoring program, including defining triggers for assessing MNA failure, and establishing a contingency plan.