Data and Diversity in the Development of Acute Water Quality Criteria in the United States

Abstract

The US Environmental Protection Agency (USEPA) is responsible for the development of water quality criteria, regulatory standards that protect aquatic organisms from harmful chemical exposure. Although these criteria are intended to be broadly protective of aquatic life, the data used to derive criteria do not necessarily reflect the actual diversity of natural communities nor are they available for most chemicals. In addition, although the USEPA's current procedures emphasize using toxicity data with a certain minimum amount of biological diversity, the quantitative impact of such diversity on criteria is unclear.In the present study we assessed the changes to acute toxicity data over time, determined the prevalence of significant taxonomic differences in sensitivity, and investigated the effect of biological diversity on criteria. We found major gaps in existing toxicity data that we hypothesize have contributed to the absence of acute criteria for the majority of chemical pollutants. Taxonomic patterns of sensitivity in these data are abundant, although the resolution of the patterns is relatively poor. In addition, we found that the amount of biological diversity in a toxicity data set and the data set's taxonomic composition does not quantitatively affect criteria in most cases. Because the USEPA has published acute criteria for fewer than 20% of priority pollutants and the persistence of major gaps in toxicity data over the last 37 years, we recommend that the USEPA consider revisions to their water quality criteria guidelines that will expedite the criteria development process and advance the responsible management of pollutants in the aquatic environment.

Phylogeny predicts tolerance in aquatic animals for only a minority of chemicals

“…We also investigated whether life stage, exposure type, chemical origin, or mode of action (MOA) affected signal and evaluated the influences of experimental temperature and pH on chemical sensitivity using phylogenetic methods. The application of CSE methods to environmental risk assessment and regulation has been a recent focus in aquatic toxicology (Raimondo, Jackson, and Barron 2010; Coleman and Edmands 2022; Schlekat et al 2010; Lewis and Thursby 2018), so here our analysis specifically dealt with data similar to those used in water quality criteria development.…”

“…In recognition of this danger, regulatory bodies like the United States Environmental Protection Agency (EPA) manage pollution in part by setting numeric criteria that are intended to protect life by limiting the accumulation of hazardous concentrations of chemicals in the environment. The development of such criteria depends on empirical data that describe the concentrations of chemicals that inflict adverse effects on organisms, however, most chemicals do not have robust toxicity datasets (Coleman and Edmands 2022; Wheeler et al 2002; Dowse et al 2013).…”

Advancing Fifth Percentile Hazard Concentration Estimation Using Toxicity-Normalized Species Sensitivity Distributions

“…Conventionally, SSDs have been derived from experimentally determined toxicity data for a single chemical, and the derived HC5 values are chemical-specific. Computational advances have allowed for filling toxicity data gaps in species number and diversity using predictive modeling and leveraging data for groups of toxicologically similar chemicals (e.g., Coleman and Edmands 9 and Willming et al 10 ). Recently, Giddings et al 8 developed the toxicity-normalized SSD (SSDn) approach, a grouped chemical method that creates a single combined SSDn by normalizing toxicity data using a species tested in all members of the chemical group (a normalization species or nSpecies).…”