Open AccessRadiotoxicity of neptunium(V) and neptunium(V)-nitrilotriacetic acid (NTA) complexes towards Chelatobacter heintzii
Author(s) -
James E. Banaszak,
Donald T. Reed,
Bruce E. Rittmann
Publication year - 1997
Language(s) - English
Resource type - Reports
DOI - 10.2172/495744
Subject(s) - neptunium , nitrilotriacetic acid , chemistry , nuclear chemistry , californium , precipitation , metal , americium , radiochemistry , inorganic chemistry , plutonium , chelation , physics , organic chemistry , quantum mechanics , meteorology , neutron
The objective of this work was to investigate the toxicity mechanisms of neptunium and the neptunium-NTA complex towards Chelatobacter heintzii. The results show that metal toxicity of aquo NpO{sub 2}{sup +} may significantly limit growth of Cl heintzii at free metal ion concentrations greater than {approx} 10{sup {minus}5} M. However, neptunium concentrations {ge} 10{sup {minus}4} M do not cause measurable radiotoxicity effects in C. heintzii when present in the form of a neptunium-NTA complex or colloidal/precipitated neptunium-phosphate. The neptunium-NTA complex, which is stable under aerobic conditions, is destabilized by microbial degradation of NTA. When phosphate was present, degradation of NTA led to the precipitation of a neptunium-phosphate phase