Review and evaluation of exposure models in the framework of the 4FUN project
Résumé
The assessment of risks to human health from chemicals is of major concern for policy and industry and ultimately benefits all citizens. In this process, exposure assessment is generally considered to be the weakest point, because currently available tools show major flaws such as lack of integrated approach for assessment of combined stressors (i.e. a number of potential pollutants), widespread use of 'worst-case' scenarios leading to over-conservative results and lack of uncertainty/sensitivity tools that allow identifying the important exposure drivers. To overcome these drawbacks, the FP6 project 2-FUN produced prototype software containing a library of models for exposure assessment, coupling environmental multimedia and pharmacokinetic models. The objective of the 4FUN project is to demonstrate, innovate and exploit this prototype software, to standardise it, to transfer it to stakeholders and guarantee its long term technical and economic viability. In order to optimize the prototype, the 2-Fun tool and other exposure tools were evaluated. First, a list of existing exposure tools, mainly multimedia models similar to 2-FUN, was composed based on literature review. The models were selected to cover a comprehensive range of exposure situations, in terms of the sources of exposure, the exposure pathways, and the receptor populations. Next, all exposure models were reviewed using a set of transparent and structured criteria, which were organised according to four lines of evidence: reliability, relevance, uncertainty and practical use. Each line of evidence is subdivided into categories, which are further subdivided into specific sub-categories. Finally, subcategories are composed of assessment criteria, which are evaluated through the use of questions. This approach makes it possible to put the 2-FUN tool in perspective and to identify the list of actions necessary for updating the design of the 2-FUN tool.