Short-Term Environmental Impacts of Illite Clays When Used as an In Situ Method for Remediating (137)Cs-Contaminated Wetlands.

Hinton, T. G. ; Koo, B. ; Watson, S. I. ; Fletcher, D. E. ; Coughlin, D. P.

Technical Information Center Oak Ridge Tennessee

关键词: Illite;    Environmental impacts;    Wetlands;    Clays;    Cesium;   

RP-ID  :  DE2004824528

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Over 1,200 hectares (3,000 acres) of wetlands such as L-Lake; Par Pond; Ponds A, 2, 4, 5, and B; canals; and several creeks (e.g. Steel Creek, Lower Three Runs, and Pen Branch) on the Savannah River Site (SRS) are contaminated with 560 Ci of 137Cs. These environmentally sensitive wetlands pose a significant remediation challenge to the Department of Energy (DOE). A new technology is needed to avoid environmentally destructive remediation. Current muck and truck technologies destroy the sensitive ecosystems, and may increase dose to workers. Because of relatively low amount of clay and weak 137Cs retention capabilities of kaolinite dominant sediments on the SRS, 137Cs has a greater bioavailability here than at any other DOE site. We have previously shown that naturally occurring illite minerals, with a high complexing capability for 137Cs, can sequester 137Cs and reduce its bioavailability when applied to 137Cs contaminated wetlands. Previous research showed that an in situ remediation method using illite minerals reduced 137Cs concentrations in the water 25- to 30-fold, in aquatic plants 3- to 5-fold, and in fish 2- to 3-fold. During this funding period (Fy03) we re-sampled study sites in Pond A and R-Canal that had been treated in 2001 with illite clays. The data revealed that 137Cs concentrations in water are still lower than untreated control sites, some 112 weeks later. This encouraging result indicates that the in situ remediation technique has a longer-term effectiveness than was previously reported. This positive finding occurred despite the study site experiencing a severe drought, as well as flooded conditions during the two-year period. Studies on the in situ application of illite minerals to 137Cs-contaminated wetlands continue to produce positive results. Additional measurements are needed, however, to determine the long-term effectiveness of the technique, and the environmental impacts on parameters not measured in this study. When coupled to earlier work, the results reported herein support the use of illite applications to 137Cs-contaminated wetlands on the SRS as an attractive alternative to more environmentally destructive remediation methods.