Actinide speciation in environmental remediation

Environmental actinide remediation is often performed in the absence of a clear understanding of the contaminant chemical forms. Remediation efforts are more concerned with the initial and final concentration of the contaminant actinides. Allowable final concentrations of actinides in remediation sites are mainly based on expected dose or prenegotiated levels. However, understanding the chemical forms of actinides in the environment is key to assessing their long-term behavior and developing enhanced analytical methods for their environmental detection. The dominant environmental chemical form will dictate the actinide transport behavior through solubility, colloid formation, or the interaction with natural ligands. This information can be used to evaluate the fate and potential transport of actinides. If the dominant environmental chemical species are understood, analytical methods for enhanced counting statistics and a reduction of counting error can be developed. A reduction in counting error will increase the fraction of verifiable waste below a given threshold, thereby increasing the rate of site clean up while reducing the cost. The impact of actinide speciation is presented in 2 sites contaminated with Am and Pu undergoing remediation. Actinide speciation has affected remediation strategies, regulatory response, and costs. (author)