Kinetic control of metal biouptake in natural waters

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This research program (to be called 'new approach') intends to develop a more realistic approach to metal toxicity to freshwater aquatic organisms and to humans, which will be applicable to all metals in natural waters. The new approach will be based on rates of dissociation reactions of metal complexes. The new approach will calculate the coupled flux of diffusional transport of metal M and metal complex ML to the surface of the organisms instead of the current practice of calculating the chemical speciation at chemical equilibrium using the Windermere Humic Aqueous Model (WHAM), which is based on chemical equilibrium. Because natural waters are dynamic systems which are never at chemical equilibrium, the current chemical-equilibrium-based approach gives wrong estimates of free metal ion concentrations (which are widely correlated with ecotoxicity) in natural waters. The kinetics-based approach will provide the actual metal speciation instead of the current practice of chemical equilibrium speciation. The better health of aquatic biota as a result of this 'new approach'will promote the acceptance of the approach by regulatory agencies.