Impact of Returning the TNX Outfall Delta to a Wetter Condition on Radionuclide Mobility

A multi-faceted strategy has recently been proposed for mitigating contaminant migration at the TNX Outfall Delta. It involves (1) reducing runoff of drainage, seep, and atmospheric water, and (2) permitting the site to return to its wetter natural condition, thereby creating conditions where natural organic matter would build up and the sediment would become more chemically reduced. One manner in which the site (more specifically, the Inner Swamp) could be returned to a wetter condition is to build strategically located barriers, one between the contaminated site and the X8 Drainage Ditch and the second south of the contaminated site. The subject of this report is to evaluate the geochemical implications of this strategy on key risk drivers at the site, namely lead-212, radium-228, thorium-228, thorium-232, thorium-234, uranium-233, uranium-234, uranium-235, and uranium-238