Addressing the Challenges to the Risk Assessment of Nanomaterials

Abstract

Risk assessment is a primarily evidence-based process employed by agencies, industry, and scientific communities to evaluate public health and environmental issues of concern. Moreover, it has become a dominant policy tool for informing regulatory and technological decisions and setting priorities for research and funding. Yet risk assessment also depends on the sociocultural and regulatory contexts of the issues. Different approaches have been adopted for assessing the potential risks posed by conventional chemicals and products for human health. In general, the traditional paradigm is a hazard-driven chemical-by-chemical approach, focusing on single toxic endpoints. Scientific committees currently anticipate a substantial change in this standardized process due to the demands for a reduction in animal testing. Questions have also been raised about the applicability of this general chemical-based form of risk assessment in the specific case of nanomaterials (NMs). Most scientists and stakeholders assume that the current standard methods are in principle applicable to NMs, but that specific aspects require further development. This paper presents possible technical improvements and additional supporting tools. Nanospecific risk assessment, however, also faces a number of substantial challenges and uncertainties. This leads to considerable scientific, political, and public scrutiny and an apparent decision-making gridlock. To improve its utility, the current understanding of risk assessment has to be moved toward an integrated form of assessment within increasingly participative and transparent processes.