Robust Exposure Assessment in Refining Risk Assessment

Although assessments of consumer exposure are routinely undertaken, these seldom occur at a level beyond the use of simple substances in common consumer products. It is therefore appropriate to ask whether we really understand the true nature of consumer exposures (substance formulations, market penetration, regionality, habits and practices, exposure determinants) or even understand enough of consumer behaviour to make accurate predictions of consumer exposure (primary determinants of exposure for a given setting; aggregate and mixed exposures; external vs internal; population vs individual behaviours).
This presentation briefly reviewed some of the considerations behind how consumer exposure assessments are undertaken and then examined whether resources are currently deployed in an optimal manner. Key questions include: what might be the most appropriate strategies for assessing consumer exposures and what should be the considerations that inform our approaches for gap filling? How can the uncertainties associated with consumer risk assessments best be characterised and reduced and what might be some priorities for future work in the field – and suitably accounted for in risk management decision-making. Areas that need to be addressed include the perception of reality arising from the misapplication of modelled data which could result in risk management decisions that do not reflect real life exposures (e.g. cyclohexane in modelling adhesives). A key challenge is the quality and reliability of existing human and consumer exposure data. When considering strategies for improved exposure assessment, Dr Money concluded that these must be about optimising the application of existing knowledge; applying the most suitable available models and the most suitable data sources; applying techniques for improving the robustness of estimates and tiered and targeted strategies for data acquisition and application. In closing, he put forward approaches to shift the paradigm (see slide below). A key challenge is unlocking ‘non confidential’ information from market surveys such as habits and practices data: this is non-product-specific information (and therefore unlikely to be viewed as confidential) and would be extremely relevant to exposure assessment.

In the audience discussion that followed, it was suggested that Read Across for exposure could be useful in certain situations, but that criteria would be needed to ensure confidence in such read across approaches. Definitions for exposure-based read across would be required. In addition, the need for concentration data and presence probability data was discussed. Obtaining such data has been tried, with some, but limited success (cosmetics, food, and most successfully – fragrances). Workshop participants recommended that learnings from these initiatives should be incorporated into other chemicals sectors. Trade associations such as the ACC and Cefic would be the logical owners for such an activity.