Metal speciation, fate, bioavailability and impacts in the environment: from scientific understanding to policy

Uptake and use of the outcomes of scientific research is a worthwhile goal for regulators and policymakers, since it allows policies to be based on evidence while taking advantage of the most up to date possible scientific knowledge and expertise. Regulation of the environmental risks of metals, in waters and soils, is an area where process-based scientific research has been taken up and developed into practical tools for policymaking. This presentation will look at the issues of metal speciation and bioavailability and their implications for regulatory policy, and how the knowledge developed in response has ultimately been taken forward into practical tools for regulation. I will firstly show how the development of ecotoxicological and chemical knowledge and models (e.g. metal speciation modelling, the free ion activity model) over the past 40–50 years reached a stage where the development of practical tools, such as the Biotic Ligand Model, for assessing and predicting bioavailability became possible. I will demonstrate via examples how these tools have been developed and applied, and show how the knowledge they encapsulate has been used to develop further tools for practical application, such as the setting of Environmental Quality Standards. I will then show how research is continuing to develop tools, for example by broadening the scope of applicability of chemical speciation modelling to a wider range of metals, for assessing and predicting the toxic effects of mixtures of metals, and for predicting the long term fate of metals in the field. I will conclude with some observations on the likely future direction of research in the fields of metal speciation, fate and bioavailability, for example the increasing use of powerful computing abilities as a means of developing models for large scale and long term projections, and the ongoing need to develop tools to address issues such as mixture effects and the long term and large scale implications of metal release into the environment.