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Updating EnviroTox: developing transparent biology-driven approaches for defining acute and chronic experimental durations
Citation:
Connors, K., K. Fay, A. Samel, T. Norberg-King, AND M. Embry. Updating EnviroTox: developing transparent biology-driven approaches for defining acute and chronic experimental durations. SETAC North America, Fort Worth, TX, November 15 - 19, 2020. https://doi.org/10.23645/epacomptox.13179848
Impact/Purpose:
Predictive methods that address aquatic hazards of chemicals remain essential as thousands of compounds have yet to be tested. The Threshold for Toxicological Concern (TTC) is well-established for assessing human safety but has only recently been explored in the ecological context. TTC establishes an exposure level for chemicals, below which no appreciable risk is expected based on toxicity values for related chemicals. This approach has been extended to encompass ecological resources via ecoTTCs. These are summaries of the distribution of a large array of aquatic species level toxicity data on diverse chemical substances as ecosystem Predicted No Effect Concentrations (PNECs). EcoTTCs enable the prediction of untested chemicals based on similarly acting chemicals that share a structural attribute, mode of action, or functional use. An ecotoxicological database has been recently developed based on an assessment of published data and international chemical management programs, and the use of the ecoTTC concept may be useful for assessing chemicals at early tiers of the risk assessment process, providing hazard perspective on chemicals that toxicity data, guiding product development discussions, and assisting read across or category justifications.
Description:
The EnviroTox database was built to meet the needs of researchers and regulators to establish the ecological threshold of toxicological concern (ecoTTC), a pragmatic modeling approach that can be used to establish an exposure level for chemicals below which no appreciable risk to the environment would exist. The ecoTTCs are created from distributions of predicted no-observed-effect concentrations (PNECs) that can be derived using this uniquely curated chemical-effects database. Data contained within EnviroTox is curated to ensure each study meets the specifications for experimental duration, biological endpoint, and statistical approach required for an “acute” or “chronic” designation. Initial EnviroTox curation was completed entirely by hand using detailed decision diagrams. This required special considerations and expert review for all 1,500 unique species and 91,000+ entries in the database. A more streamlined approach is needed for standardizing and classifying new and relevant effects data so the EnviroTox database can be routinely updated. In this presentation we explore how to define “acute” and “chronic” experimental designations based on broad considerations of phylogeny, generation time, body size, regulatory guideline precedence, and other factors. Defining these experimental designations further supports the development and application of assessment factors. Challenges of data standardization and curation will also be highlighted. DISCLAIMER The views expressed in this presentation are solely those of the authors and do not represent the policies of the U.S. EPA. Mention of trade names or commercial products should not be interpreted as an endorsement by the EPA.
URLs/Downloads:
DOI: Updating EnviroTox: developing transparent biology-driven approaches for defining acute and chronic experimental durations