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Leveraging New Approach Methodologies to Complement Aquatic Life Criteria Derivation
Citation:
Schaupp, C., C. LaLone, B. Blackwell, G. Ankley, AND Dan Villeneuve. Leveraging New Approach Methodologies to Complement Aquatic Life Criteria Derivation. SETAC North America 42nd Annual meeting, Portland, OR, November 14 - 18, 2021. https://doi.org/10.23645/epacomptox.19074032
Impact/Purpose:
Presentation to the SETAC North America 42nd Annual meeting Nov 2021. Data from new approach methodologies (NAMs) such as in vitro high throughput screening and in silico approaches are increasingly available to support chemical safety assessments. The current research explores the application of NAMs to complement and support derivation of aquatic life criteria, specifically looking at the ability of such methods to provide estimates of exposure concentrations of concern for toxicological effect as well as mechanistic insights that can inform problem formulation and determination of critical species coverage for criteria derivation. To illustrate the potential applications a case study in which NAMs-based points of departure for four compounds were compared to published water quality criteria from the US, Canada, or Australia and NAMs-based mode of action inference was compared with literature derived in vitro effects. These results are intended to aid the Office of Water in understanding how NAMs may complement derivation of aquatic life criteria and or other provisional values that can guide states and stakeholders regarding contaminant concentrations of concern.
Description:
The USEPA’s 1985 guidelines for the derivation of aquatic life criteria (ALC) are robust, but data intensive. This is one factor contributing to the fact that fewer than 100 ALC have been established, and values remain outstanding for many thousands of chemicals. Thus, alternative analyses/processes that can provide provisional values to guide states, tribes, and other stakeholders while data accumulate and more rigorous criteria are derived, would be beneficial. The overarching purpose of this study was to assess the feasibility of using data from new approach methodologies (NAMs) like ToxCast to derive first-pass, provisional values to guide chemical prioritization and resource management as a complement to traditional ALC derivation. To address this goal, the study objectives were to 1) estimate chemical potency using data from NAMs for four compounds with available ALC, 2) evaluate the utility of using NAMs data to elucidate potential mechanisms of toxicity to guide problem formulation, and 3) evaluate the species relevance/applicability of toxicity pathways for compounds with clearly defined mechanisms of action as a means to evaluate whether minimum data requirements could potentially be waived when deriving a more formal ALC. Briefly, points of departure were derived from ToxCast data based on the 5th percentile of the distribution of activity concentration above cutoff (ACC) values falling below the cytotoxic burst. Mechanistic inferences were made based on active target hits in ToxCast and, where applicable, assessed for taxonomic conservation using SeqAPASS. Without adjusting for uncertainty, ToxCast-based PODs for nonylphenol (14.5 µg/L), pentachlorophenol (193 µg/L), PFOA (347 µg/L), and PFOS (19.5 µg/L) aligned closely (within a factor of 10) with corresponding national water quality guidelines/criteria from the US (nonylphenol, pentachlorophenol), Canada (PFOS), or Australia (PFOA). Moreover, pathways of toxicity gleaned from the NAMs data were reflective of in vivo-based findings from the literature. These results, while preliminary, and based on a limited number of substances, support the potential application of NAMs data to complement traditional ALC derivation approaches and prioritization. The contents of this abstract neither constitute, nor necessarily reflect, US EPA policy.
URLs/Downloads:
DOI: Leveraging New Approach Methodologies to Complement Aquatic Life Criteria Derivation
SCHAUPP SETAC 2021 PRESENTATION_10-25-2021.PDF (PDF, NA pp, 2456.478 KB, about PDF)