Recent research has demonstrated that total metal or metalloid concentrations in waters are not the most appropriate variables for the risk assessment of aquatic systems. There is increasing awareness by different regulatory bodies in the USA and Europe that the bioavailable fractions of metals/metalloids could be better descriptors of their risks. One approach are Biotic Ligand Models (BLM) which employ site specific assessments of metals risks by considering environmental factors influencing dissolved metals interaction in the aquatic environment (e.g., dissolved organic carbon, water hardness, pH). BLM were developed for different species and both, acute and chronic exposure.

In this context we here provide information on metal and metalloid bioavailability and the application of BLM and bioavailability-based software tools for freshwater risk assessment. This website is an initiative of the task group of the IUPAC sponsored project “Consideration of bioavailability of metals/metal compounds in the aquatic environment” (#2011-060-1-600; IUPAC project page)

A first outcome of the project is a review on the current state of the application of bioavailability-based approaches in risk assessment approaches:
Consideration of the bioavailability of metal/metalloid species in freshwaters: experiences regarding the implementation of biotic ligand model-based approaches in risk assessment frameworks
Rüdel H, Díaz Muñiz C, Garelick H, Kandile NG, Miller BW, Pantoja Munoz L, Peijnenburg WJ, Purchase D, Shevah Y, van Sprang P, Vijver M, Vink JP
Environ Sci Pollut Res Int (2015) 22, 7405-7421
link to journal