Complexation of plutonium(IV) by EDTA

Ethylenediaminetetraacetic acid (EDTA) is a potentially significant agent for enhancing the mobility of plutonium and other actinides in the environment, however the existing literature data may not be valid at environmentally relevant pH values (pH 5--8). The authors are studying the EDTA complexation of plutonium(IV) to: confirm/refute existing literature data; determine if EDTA can compete with carbonate ions (such that plutonium(IV) carbonate complexation constants could be derived); and determine the potential for actinide migration at mixed-waste contaminated sites. Preliminary experiments have produced spectra of the EDTA-plutonium(IV) complex at pH 8.4 which, when carbonate is added, show significant spectral changes suggesting that a mixed EDTA-plutonium(IV)-carbonate complex is present which has not previously been reported. A brief review of the literature is presented followed by discussion of the results of experiments in progress