Life always seems to get more complicated. The more we think we understand, the more we realize simple cause and effect rarely tell the story. This is true in environmental assessment, as understanding grows methods continue to evolve over time; models incorporate greater levels of complexity. This is certainly the case with health risk assessment, which initially focused on assessing the impacts of one chemical substance on human health. While still necessary, many assessments now incorporate the broader context of environmental receptors, and increasingly, risks are assessed from mixtures, rather than just the individual components. Models and measurement methods are more sophisticated, and assays are increasingly based on biological mechanisms.
Lately there has been increased emphasis on life cycle considerations in risk analysis. This is a natural progression of increasing complexity in understanding the impacts of substances. In part, we now know that only considering the raw material is too simple and doesn’t represent the reality of exposures that occur during the life cycle of a product. At the raw material stage, yes, occupational exposure can be assessed from the neat material. But as consumers, we see a different version of product, often mixed into a matrix, where there may be limited potential for exposure, or at a minimum it will be different than in a factory. Further, many substances end up in products that are components, think of a circuit on a board, in an electronic device. While as consumers we may be protected from these substances, at the end of life, when the products are recycled or disposed of, the raw material, or a related material transformed by the environment, is released to air, water, or land, creating many pathways for potential exposure.
Risk analysis has begun to address these life cycle considerations in assessment methodologies. The National Nanotechnology Initiative is held a public meeting this week, in part to gain input on how to approach the life cycle in risk analysis. While logical and simple, incorporating life cycle considerations will have implications for regulators and other governmental scientists. The frameworks are emerging, and there aren’t yet standards, although the International Standards Organization ISO has issued guidance. The U.S. Forest Products Laboratory, a part of the U.S. Forest Service, used Nano LCRA to assess priorities for nanocellulose environmental health and safety research. U.S. Environmental Protection Agency has conducted several case studies of nanomaterial applications using Comprehensive Environmental Assessment. Stay tuned, as the cutting edge for risk analysis steps up to the complexity of the twenty-first century.