H. Bolton, D. Girvin
May 23, 1996
Citations
0
Influential Citations
16
Citations
Journal
Environmental Science & Technology
Abstract
Nitrilotriacetic acid (NTA) is a synthetic chelating agent that was used to decontaminate nuclear reactors and was disposed at Department of Energy waste sites. NTA may influence the mobility and fate of radionuclides in soils and sediments if it is not biodegraded. Because it was unclear how adsorption of NTA would influence its degradation, experiments were conducted in a model system containing gibbsite and Chelatobacter heintzii with 60CoNTA at pH 7 and NTA at pH 6 and 8. The rates of NTA desorption from gibbsite were pH dependent (desorption half-lives at pH 6, 7, and 8 were 80, 16, and 1 h, respectively, while that of Co at pH 7 was 2.5 h for equal molar CoNTA). Degradation rates of NTA in solution by C. heintzii decreased as pH decreased and depended on the dominant form of NTA in solution (e.g., biodegradation rates for HNTA2- > AlOHNTA- > CoNTA-). The degradation of NTA was significantly slower when NTA was adsorbed to gibbsite. This difference was observed at pH 6 and 8 with NTA and at pH 7 with...