Concepts Critical to the Next Generation of Human Health and Ecological Risk Assessment
Carla Beals, Environ
As ecological and human risk assessments head into the next generation, many practitioners believe that new methods should be developed and used to assess toxicity. This platform session discussed some new risk assessment concepts that differ from traditional approaches.
One approach, Integrative Approaches to Testing and Assessment (IATA), was discussed as a means to systematically use existing databases of information as well as emerging in silico and in vitro technologies to screen a chemical or group of chemicals. Examples using pesticides were discussed by K. Garber “Computational Toxicology: A More Efficient and Effective Testing and Assessment Paradigm for Chemical Risk Management” while L. Ritter “Integrating Emerging Technologies into Chemical Safety Assessment” noted that although IATA was a more reliable and predictive approach to assessing risk, it was unlikely to be used in the short-term and would need to be introduced incrementally while simultaneously informing the public about the effectiveness of the new system. G. Bruce “MABEL: Use of Preclinical Data to Set Acceptable Standards for Exposure” discussed using existing pharmacological and preclinical data to develop appropriate screening levels, or Minimum Anticipated Biological Effect Level (MABEL), for compounds such as PPCPs in drinking water. They noted that derived values from MABEL were protective and offered a promising approach for compounds with adequate data coverage. The use of transcriptomic data to determine exposure levels was discussed by R. Gentry, on behalf of R. Thomas, in “Using Transcriptomic Data in the Risk Assessment Paradigm.” Using a series of rat studies, Gentry compared transcriptional benchmark dose values with those derived from traditional approaches to show that the use of transcriptomic data would increase efficiency and decrease costs of chemical risk assessments.
As well as using existing databases of information to help determine exposure levels, shifts in the way we approach risk assessments were also discussed. K. Crofton discussed source to outcome pathways, such as Adverse Outcome Pathway (AOP), and summarized that well-developed and understood AOPs could provide insight about where research is needed thereby providing a framework for more efficient and predictive risk decision. Paul Price’s talk “Management of Risks from Cumulative Exposures to Chemicals: Moving Beyond TEQs and Hazard Indices” examined the World Health Organization’s new guidance to cumulative risk assessment using a tiered hazard assessment approach for the evaluation of mixtures. R. Stahl discussed how global climate change could affect risk assessments by altering fate of and transport of chemicals, increased use of toxic chemicals such as pesticides, and changes in human vulnerability. He described how risk assessments should account for global climate change factors as well as include a multi-stressor approach and a plan for adaptive management. Frank Gobas examined changing the current risk assessment approach to a unit-less activity-based approach which would allow more data to be used in a risk assessment; the data would be expressions of exposure and toxicity concentrations in similar units of activity.
All presentations provided encouraging evidence that with attainable improvements, risk assessments can be more predictive and reliable in their conclusions and for use in regulatory and management decisions.
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