Advanced Approaches for Species Surrogacy in Chemical Risk Assessment

Meeting Format

The meeting will be open to all who want to participate in knowledge exchange and to potentially collaborate on advancing the topic. The overall goal of the topical meeting is to engage in knowledge exchange with the goal of gathering information that an expert group (steering committee and select speakers) can distill into publication summarizing the state of the science and identifying further needs into articles to be submitted for publication in SETAC journals and disseminated though presentations at SETAC meeting and in SETAC Webinars and Technical Issue Papers.

Scope of the Meeting

Chemical risk assessment routinely relies on a limited number of sentinel species to inform protection of a much broader range of taxa. These surrogate species enable extrapolation of hazard and risk to related taxa or species of interest in the context of chemical risk assessment. While this practice is well established, it often relies on pragmatic safety factors or overly conservative approaches that lack grounding in mechanistic, exposure and/or ecological information.

Recent advances in toxicokinetics, toxicodynamics, comparative biology, species traits, computational modelling, and data integration provide new opportunities to strengthen the scientific basis for species surrogacy. In parallel, the increasing availability of curated toxicity databases and bioinformatics tools enables more transparent and defensible cross‑species extrapolation. These scientific advances, often referenced as New Approach Methods (NAMs), are ready for review and synthesis to improve the approaches used for species surrogacy in chemical risk assessment and ultimately increase confidence in regulatory decision‑making while minimizing the use of vertebrate animals in testing.

SETAC is convening this meeting as a continuation of its long tradition of bringing together environmental professionals, to advance the state of knowledge on various topics and resolve technical issues to identify solutions for pressing environmental challenges. The meeting is planned in a manner consistent with SETAC’s principles of multidisciplinary, multi-stakeholder engagement and science-based objectivity, is ideal for this topic.

Sessions

1. Exploring Toxicokinetics Across Species
   
   Chairs: Jon Arnot, Arnot Research and Consulting and Michelle Embry, Health and Environmental Sciences Institute
   
   Toxicokinetics describes rates of absorption, distribution, metabolism, and excretion of a substance. It links external exposure to an internal concentration within an organism (e.g. blood plasma concentration, tissue concentrations, predicted concentrations at the molecular site of activity, etc.).  The similarities and differences in toxicokinetics between species, even closely related species, can be a determining factor for species similarities and differences in their sensitivity to chemicals. This session  welcomes talks about how considerations of toxicokinetics can be used in species extrapolation.
2. Reviewing Toxicodynamics Across Species
   
   Chairs: John Colbourn, University of Birmingham and Jessica Head, McGill University
   
   Toxicodynamics is the study of the mechanisms of action that occurs when a chemicals interacts with a biological target – molecule, cell..etc. when suing sepceis extrapolation, It is important to consider whether the biological response  known to occur in one species (i.e., surrogate species) is conserved in other species (e.g., species of concern in risk assessment). Conservation of biological response and more directly of a chemical-biomolecular interactions can be evaluated computationally across species. This session will explore how considerations of toxicodynamics can be used in species extrapolation. This session will explore how considerations of toxicokinetics can be used in species extrapolation. Talks about tools such as Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS), that focuses on protein sequence and structural conservation across the diversity of species to predict chemical susceptibility, and and Genes to Pathways Species Conservation Analysis (G2P-SCAN), which considers gene, protein, and pathway conservation across a subset of species, and other computational approaches are welcome.
3. Considering Species Traits in Species Surrogacy
   
   Chairs: Paul J. Van den Brink, Wageningen University and Mark Johnson, US Army Public Health Center (Retired)
   
   The term trait refers to specific attributes of organisms that are both inherent and characteristic to those organisms such as life history, morphology, physiology, and ecology. It is well established that the traits of organisms dictate their fitness and therefore potential sensitivity to chemical stressors. Talks that describe the state-of-the-science in collecting knowledge of functional traits across species, focusing on current and developing approaches, as well as how they can be applied to understand impacts to fitness of individuals and populations across species/taxa are welcome.
4. Leveraging Existing Data in Species Surrogacy
   
   Chairs: Luigi Margiotta-Casaluci, College London and Rebecca Dalton, Environment and Climate Change Canada
   
   Existing toxicity data should be leveraged whenever possible to improve predictions of toxicity to untested (target) species. Various tools exist that predict toxicity to an untested species using the known toxicity of the chemical to a surrogate species including interspecies correlation models, quantitative structure activity relationships (QSARs) and species sensitivity distributions (SSDs). Talks in this session should aim to review and summarize the latest techniques in this area to set the stage for a identifying a multifaceted, harmonized approach for assembling and integrating lines of evidence for improving cross-species extrapolations to improve risk assessment.