Quantitative cationic‐activity relationships for predicting toxicity of metals

Abstract

Developing and validating quantitative cationic-activity relationships or (Q)CARs to predict the toxicity metals is challenging because of issues associated with metal speciation, complexation and interactions within biological systems and the media used to study these interactions. However, a number of simplifying assumptions can be used to develop and validate (Q)CARs to predict the toxicity of metals: The ionic form is the most active form of a metal; the bioactivity of a dissolved metal is correlated with its free ion concentration or activity; most metals exist in biological systems as cations, and differences in metal toxicity result from differences in metal ion binding to biological molecules (ligand-binding). In summary, it appears that certain useful correlations can be made between several physical and chemical properties of ions (mostly cations) and toxicity of metals. This review provides a historical perspective of studies that have reported correlations between physical and chemical properties of cations and toxicity to mammalian and nonmammalian species using in vitro and in vivo assays. To prepare this review, approximately 100 contributions dating from 1839 to 2003 were evaluated and the relationships between about 20 physical and chemical properties of cations and their potential to produce toxic effects were examined.

Guidance on Selecting a Strategy for Assessing the Ecological risk of Organometallic and Organic Metal Salt Substances based on their Environmental Fate

“…However, few and very limited QSAR models have been published for OM and OMS. Developing and validating QSARs applicable to OM and OMS is challenging due to issues associated of speciation, complexation and interactions within biological systems, stability of the metal-ligand bond, kinetics of metal-ligand bond formation and degradation, and the medium used to study these interactions (Walker et al, 2003). …”

Similarities and Differences between the “Relativistic” Triad Gold, Platinum, and Mercury in Catalysis

“…The chemical nature of the compound plays a dramatic role since a particular element can be toxic or not depending on the compound considered. However, it is accepted that metals in cationic form, which coordinate the functional groups in biological systems or replace metals from the active sites, are dangerous species, [12] and it explains the different toxicity found for Pt, Au, and Hg. [13,14] Platinum metal is not toxic while the salts and complexes indeed are.…”

Quantitative Cationic Activity Relationships for Predicting Toxicity of Metal Ions from Physicochemical Properties and Natural Occurrence Levels

“…Walker et al [1] reviewed approximately 100 contributions dating from 1835 to 2003 to evaluate the relationships between about 20 physicochemical properties of cations and their potential to produce toxic effects. Some of these physicochemical properties represented size (e.g., atomic weight, atomic volume, density and ionic radii) while others represented electrochemical characteristics (e.g., oxidation potential, ionization potential, electropositivity, electronegativity, electron affinity and oxidation state).…”

“…Studies correlating physical and chemical properties of metal ions and toxicity published from 1835 to 2003 were recently reviewed [1]. All of the studies conducted from 1835 to 1950 described qualitative correlations, while some of the studies from 1950 to 1990 described quantitative correlations and all of the studies from 1990 to 2003 described quantitative correlations.…”