Fish Acute Toxicity

Fish acute toxicity tests are used to assess potential risk to fish species and for other ecological regulatory needs associated with surface water contaminants. To meet EPA data requirements the test is typically conducted in three different fish species: a cold-water freshwater species, a warm-water freshwater species, and a marine/estuarine species. NICEATM is working with EPA and other partners to explore reducing animal use for fish acute toxicity testing.

Ecotoxicity testing determines hazard or risk presented to fish and other species by substances that may enter the environment. ICCVAM agency activities to reduce or replace animal use for ecotoxicity testing were discussed at the September 2021 meeting of the Scientific Advisory Committee on Alternative Toxicological Methods. The ICCVAM Ecotoxicology Workgroup has published a summary (Ceger et al. 2022) of selected U.S. federal agency needs for ecotoxicity testing, emerging technologies for evaluating ecotoxicity and environmental safety, and the potential applicability of those technologies for regulatory testing.

Curation and Analysis of Testing Data

As noted above, fish acute toxicity testing is conducted using three species per chemical. Thus, each chemical tested can potentially require up to 260 fish. NICEATM and EPA conducted a retrospective evaluation of existing data to explore the potential for relying on fewer fish species tests to support a protective ecological risk assessment (Ceger et al. 2023). The results support potentially using fewer than three fish species to conduct ecological risk assessments for the registration of conventional pesticides. Extracted data will be submitted to EPA’s Toxicological Reference Database.