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Answering the Call for Improved Chemical Alternatives Assessments (CAA) Joel A. Tickner,*,† David C. Dorman,‡ and Marilee Shelton-Davenport§ †
University of Massachusetts Lowell, Massachusetts 01854, United States North Carolina State University, Raleigh, North Carolina 27607, United States § National Research Council, Washington, D.C. 20001, United States safety assessment, where the goal is to identify a safe level of exposure or characterize the risk associated with a given level of exposure. A number of CAA frameworks exist and while there are significant similarities between them, there are also important differences, including how uncertainties, exposures, and impacts across different life cycle stages are addressed. Gaps and differences in methods will need to be addressed; yet, it is critical that CAA processes be flexible so they can be adapted to varied decision contexts and avoid “paralysis by analysis”. Some may argue that the flexibility in alternatives assessment may not ensure consistency in CAA results across firms or agencies. However, while consistency is a laudable goal, it is rarely achievable, even for existing tools such as risk assessment. Flexibility in the alternatives assessment process provides an opportunity for adaptable evaluation−while ensuring that at least comprehensive thinking and assessment of potential trade-offs occurs. (2) CAAs would benef it from research and development ef forts that support the incorporation of novel data streams (e.g., high throughput in vitro assays and in silico approaches). Existing CAA frameworks predominantly rely on traditional toxicology data streams to assess the human health and environmental hazards of chemical use. While useful, this s knowledge about chemical impacts on health and approach does not take advantage of the many developments in ecosystems continues to increase, so will pressures to toxicity testing that have occurred over the past decade. Given avoid certain chemicals and chemical processes. Identifying and the paucity of data, which can slow down CAAs, it is important adopting alternatives to chemicals of concern is not that future CAA frameworks incorporate the use of in vitro and straightforward. As such, there are a growing number of efforts other high-throughput assays, toxicity pathway-centric assays, by scientists, policymakers and others to improve chemical into the assessment process to address gaps in traditional alternatives assessment (CAA) approaches, processes for knowledge. Similarly, it is important that emerging developidentifying, comparing and selecting safer alternatives to ments in toxicity testing be able to support the evaluation, chemicals of concern.1 Two main drivers in these assessments comparison (including hazard categorization) and design of are to identify safer chemical alternatives and avoid situations safer chemicals and materials, not simply to obtain more refined where a substituted chemical is found to be unsuitable (i.e., risk estimates. As science has advanced in this area, there are “regrettable substitutions”).2 immediate opportunities to fill data gaps or screen for potential It is important that entities demanding, selecting, or adopting unexpected consequences using novel approaches. For example, alternatives to chemicals of concern have adequate processes assay results obtained in the nematode, Caenorhabditis elegans, and a knowledge base to ensure thoughtful consideration of the could simultaneously help predict toxicity to people and the soil choices. The foundational elements needed to make more compartment in ecotoxicity assessments. Zebrafish (Danio informed chemical substitution choices were recently considrerio) data could, with additional focused research, provide a ered by a U.S. National Research Council (NRC) Committee useful substitute for the longer fish ecotoxicity reproduction charged with developing a Framework to Guide the Selection studies traditionally conducted with other fish species. Future of Chemical Alternatives.3 research efforts are needed to develop principles or tools that A number of key steps may improve CAA as a science-policy support the benchmarking, integration, and hazard categodiscipline, similar to how the NRC “red book” on risk 4 rization of high throughput data on chemical effects, especially assessment elevated that field: (1) Alternatives assessment should be increasingly embraced and conducted in chemical selection. The goal of alternatives assessment is to inform Received: November 6, 2014 substitution actions. It is different from a risk assessment or Published: January 27, 2015 ‡
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© 2015 American Chemical Society
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DOI: 10.1021/es505446x Environ. Sci. Technol. 2015, 49, 1995−1996
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Environmental Science & Technology
(2) Tickner, J. et al. Alternatives Assessment in Regulatory Policy: History and Future Directions. In Issues in Environmental Science and Technology, 36, Chemical Alternatives Assessments; Hester, R. E., Harrison, R.M., Eds.; Royal Society of Chemistry: London, 2013; pp 253−292. (3) A Framework to Guide Selection of Chemical Alternatives; National Research Council: Washington DC, 2014; http://www.nap.edu/ catalog.php?record_id=18872. (4) Risk Assessment in the Federal Government: Managing the Process; National Research Council, Washington DC, 1983; http://www.nap. edu/openbook.php?record_id=366&page=R1. (5) Tickner, J. A.; Schifano, J. N.; Blake, A.; Rudisill, C.; Mulvihill, M. J. Advancing safer alternatives through functional substitution . Environ. Sci. Technol. 2015, 49 (2), 742−749.
in the context of different regulatory (and marketplace) requirements inherent in CAAs. Tools that transparently capture how different data streams are considered and integrated into the assessment process to predict hazards, as well as tools to help visualize new types of data, will be critical to facilitating communication of the complex information on chemical alternatives. (3) Knowledge on physicochemical properties can serve a critical role in alternatives assessment processes. A growing body of literature shows that a number of physicochemical properties, including how chemicals interact with different media, and the molecular attributes that define its reactivity, can provide important information related to a chemical’s ecological and human health hazards and exposure potential. Despite these scientific advancements, these types of data are infrequently used in the CAA process. (4) CAA processes should be integrally linked to green chemistry research and development. In many cases, superior alternatives will not be available for a particular chemical function. In these cases, research and innovation are necessary to design new chemical alternatives or identify other ways to meet the function of the chemical (what might be termed functional substitution)5 and the needs of industry and the consumer. In some cases, this provides an opportunity to develop a new chemical that meets functional needs or to develop an innovative concept that solves the problem in a different way. In cases where no known chemical substitutions are identified, the design of new chemical alternatives may be part of the solution. Early design efforts should consider how to reduce risks to humans and the environment, in addition to the usual emphasis on product performance. There has been significant growth in the field of CAA in the past several years and this growth is expected to continue. The NRC calls for the development of new tools and methods, ones that comprehensively but flexibly encourage the use of the best available science while facilitating informed, expedient decisions. This will require new, accessible data sources and tools and support for small and medium sized firms and agencies that do not have significant scientific resources. Following this NRC framework would facilitate responsiveness to increasing market pressures to avoid chemicals of concern. This could lead to a more robust alternatives assessment research agenda to guide theory and practice in this ever growing effort.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS The authors would like to acknowledge the U.S. Environmental Protection Agency's Office of Research and Development for sponsoring the National Research Council study, A Framework to Guide Selection of Chemical Alternatives, referred to in this article.
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REFERENCES
(1) Current Landscape of Alternatives Assessment Practice: A MetaReview; OECD: Paris, 2013; http://www.oecd.org/officialdocuments/ publicdisplaydocumentpdf/?cote=ENV/JM/ MONO(2013)24&docLanguage=En. 1996
DOI: 10.1021/es505446x Environ. Sci. Technol. 2015, 49, 1995−1996
