Defining exposure science

Exposure science: a view of the past and milestones for the future

BACKGROUND

The study of human exposure to environmental toxicants has evolved as a scientific field over the past 30 years.

OBJECTIVES

This review provides a historical perspective on the growth of exposure science as a field, with some emphasis on the results from initial observational studies in obtaining information needed for generating hypotheses on significant human contact with environmental agents, testing the performance of models, and reducing exposures to protect public health.

DISCUSSION

Advances in activity pattern and behavioral research that established a suite of variables needed to accurately define contact and factors that influence contact are also discussed. The identification and characterization of these factors have played a pivotal role in the growth of the field and in developing exposure reduction strategies. Answers to two key questions on the relevance and fundamental value of exposure science to the fields of environmental health and risk management are presented as a path forward: a) What does one do with such exposure information? b) What roles does exposure science play in situations beyond observational analyses and interpretation?

CONCLUSIONS

The discussion identifies the need for more focused use of observational studies of exposure for epidemiologic analyses. Further, the introduction and use of new tools and approaches for hypothesis testing that can improve the use of exposure science in prevention research for risk management is needed to affect the source-to-effect continuum. A major restructuring of the field is not required to achieve innovation. However, additional resources for training and education are required to ensure that the potential for exposure science to play a central role in reducing and preventing excess risk within environmental/occupational health is achieved.

Moving toward exposure and risk evaluation of nanomaterials: challenges and future directions

Nanotechnology, the commercial development of engineered nanomaterials, promises breakthrough innovations by enhancing the performance of existing consumer products and enabling development of new devices, architectures, and applications. Although these materials and applications are being developed at an explosive pace, a fundamental understanding of any potential human health and environmental risks resulting from exposure throughout the lifecycle of these materials has not advanced as rapidly. Past experience has demonstrated that successful introduction of a new technology occurs more readily if it is precipitated by a robust appreciation for any inherent risks associated with the technology. Such understanding allows the timely development of occupational and consumer exposure standards that might be needed to protect human health and the environment. Although risk is recognized as the product of hazard and exposure, too often exposure patterns are poorly characterized, and risk is based primarily or exclusively on the hazard characterization. The extent of exposure to nanomaterials in currently available commercial products is relatively unknown. Given the number of commercial products that claim to contain engineered nanomaterials, it is possible that human and environmental exposure to these materials is widespread. This paper is intended to highlight the importance of exposure assessment for determining the potential risks of nanomaterials. In essence, this is a call to action to the community of exposure scientists, toxicologists, and risk assessors to develop, consider, and incorporate requisite exposure information in the risk assessment of nanomaterials. Without an integrated approach, it will be difficult to meaningfully assess the risks of nanomaterials, realize their potential benefits, and foster their sustainable development.