SETAC Globe - Environmental Quality Through Science
13 April 2017
Volume 18 Issue 4

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Upcoming SETAC Focused Topic Meeting: Advances in Risk Assessment of Chemical Mixtures

Eric Van Genderen, International Zinc Association, Durham, NC and Mary Ann Ottinger, University of Houston, Houston, TX, Meeting Co-chairs

Understanding the joint toxicity of complex chemical exposures is essential in protecting the environment and public health. This understanding is formulated from independent (additive), facilitated (potentiated or synergistic) or antagonistic relationships from exposure to multiple substances that involve toxicokinetic and toxicodynamic interactions. Chemical management initiatives across the globe have prompted the need for science supporting oversight of chemical mixtures in the environment. Over the years, SETAC has held several events, including a SETAC Pellston Workshop®, a SETAC Special Science Symposium and a European Food Safety Authority Colloquium with the aim of reviewing the current state of the science and approaches for establishing mixture risk assessment and chemical management. The upcoming SETAC Focused Topic Meeting on Risk Assessment of Chemical Mixtures will be held from 6–8 September 2017, in Denver, Colorado, USA, and will evaluate the interplay between scientific knowledge on the environmental hazard, exposure and risk of chemical mixtures and its consideration in chemical regulation and management. Please submit an abstract by 29 June.

Attendees are encouraged to present:

  • An overview of current knowledge to build on previous workshops and symposia to establish background information on the subject of mixtures risk assessment
  • Information and an overview of recent advances in our scientific understanding of mixture toxicology
  • An understanding of the relative importance of kinetic and dynamic relationships
  • Perspectives on what tools are currently available to assist in more accurate risk predictions for mixtures
  • Current regulatory initiatives on mixtures risk assessment and the challenges of integrating the science of mixture chemistry and toxicology into regulatory frameworks from multiple jurisdictions (Australia, Canada, Europe and the USA)

Meeting objectives include the following:

  • Summarize and critically reflect on the state of the science as elaborated in recent workshops, research reports and scientific publications
  • Identify and analyze national and international regulatory frameworks that specifically consider environmental and human health impacts from exposure to the various types of chemical mixtures
  • Provide an overview of the various tools available, including in vitro tools, in silico methods, alternative lines of evidence, and tiered approaches in endpoint characterization and hazard index development (e.g., species sensitivity, target organ or organ system, mode of action, mechanism or mixture interaction type)
  • Scope the evolving science in understanding the consequences of indirect ecological effects from exposures to mixtures
  • Work towards defining useful data requirements for public officials and agencies on combined exposures in different contexts (jurisdictional constraints in terms of precautionary, protective and predictive approaches)
  • Provide insights to the current science of chemical composition, concentration and complexity of ambient environmental mixtures as an input function for designing appropriate toxicological assessments
  • Identify the different types of relevant mixtures in the environment and what methods and approaches are suitable under different scenarios (e.g., combinations of environmental media and chemical classes, integrating read-across methods)
  • Characterize the relative importance of additive versus synergistic, potentiated and antagonistic responses from exposures to environmental mixtures in both toxicokinetic and toxicodynamic frameworks
  • Account for the composite effect from exposure to background substances (e.g., metals, major ions, pH, DOC, dissolved oxygen, carbon dioxide)
  • Consider advances and scope further directions in microbiome research, exposome characterization, use of biomonitoring data (e.g., National Health and Nutrition Examination Survey) and mimetic responses (endocrine disruption)

All who are working in this area are encouraged to participate by submitting abstracts on presentations relevant to mixture exposure and effects characterization to this session.

Authors’ contact information: and

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