SREL Reprint #2066

Predicting relative toxicity and interactions of divalent metal ions: Microtox® bioluminescence assay

Michael C. Newman and John T. McCloskey

Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802, USA

Abstract: Both relative toxicity and interactions between paired metal ions were predicted with least-squares linear regression and various ion characteristics. Microtox®  15 min EC50s (expressed as free ion) for Ca(II), Cd(II), Hg(II), Ni(II), Pb(II), and Zn(II) were most effectively modeled with the constant for the first hydrolysis (KH for Mn+ + H2O → MOHn−1 + H+ ) although other ion characteristics were also significant in regression models. The |log KH| is correlated with metal ion affinity to intermediate ligands such as many biochemical functional groups with O donor atoms. Further, ordination of metals according to ion characteristics, e.g., |log KH|, facilitated prediction of paired metal interactions. Pairing metals with strong tendencies to complex with intermediate or soft ligands such as those with O or S donor atoms resulted in strong interactions.

Keywords: Metal; Toxicity; Bioactivity; Microtox®; Bacteria 

SREL Reprint #2066

Newman, M.C. and J.T. McCloskey. 1996. Predicting relative toxicity and interactions of divalent metal ions: Microtox® bioluminescence assay. Environmental Toxicology and Chemistry 15:275-281.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).