Aquatic Life Criteria and Methods for Toxics

Related Information

The U.S. Environmental Protection Agency bases aquatic life criteria on how much of a chemical can be present in surface water before it is likely to harm plant and animal life. The agency designs aquatic life criteria to protect both freshwater and saltwater organisms from short-term and long-term exposure.

On this page:

Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and their Uses

The EPA's 1985 Guidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses (the Guidelines) describe a process that uses information from many areas of aquatic toxicology to derive national criteria for the protection of aquatic ecosystems.

EPA Activities Related to Revising the Aquatic Life Guidelines

The existing Guidelines for Deriving Water Quality Criteria for the Protection of Aquatic Life and Their Uses have not been updated since 1985. Although they were based on science of that time, the years since have witnessed substantial scientific advancement in aquatic toxicology, aquatic biology, fate, transport, and effects modeling, and ecological risk assessment. Such advancements, coupled with increasing complexity of water quality impairment issues, requires criteria derivation approaches beyond the existing Guidelines methods.

The EPA has begun the process of revising the existing Guidelines used to derive National Ambient Water Quality Criteria for the protection of aquatic life. The EPA will consider new and alternative methods for deriving aquatic life criteria to inform revision of the agency existing guidance using the newest most appropriate science available.

Proceedings from EPA's Frequency and Duration Experts Workshop

The EPA’s Office Water (OW) convened a Frequency and Duration Experts Workshop on September 11–12, 2019 in Arlington, Virginia. Invited technical experts representing academic, state, federal and international institutions met and discussed the science of frequency and duration of exposure-related to Aquatic Life Ambient Water Quality Criteria for toxic chemicals. The purpose of the workshop was not to reach consensus on specific topics, but instead to gather and discuss the currently-available science about frequency and duration of such criteria for the protection of aquatic communities. Presentations and discussions during this workshop are summarized in the meeting proceedings and will be considered by the EPA when evaluating the state of the science for development of Aquatic Life Ambient Water Quality Criteria.

Cooperative Research and Development Agreement for Aquatic Life Bioavailability Modeling for Metals

The EPA has signed a Cooperative Research and Development Agreement (CRADA) with eight metals associations in order to leverage the knowledge and resources of scientists inside and outside of the agency to better protect aquatic life. Current science demonstrates that water chemistry parameters (e.g., pH, dissolved organic carbon, and hardness) can affect the toxicity of metals by affecting the bioavailability of metals in the water to aquatic species. Through the CRADA, the EPA will work collaboratively with the metals associations to develop a common modeling approach that can predict the bioavailability and toxicity of metals. Using the resulting peer-reviewed modeling approach, the EPA plans to develop updated Aquatic Life Ambient Water Quality Criteria for metals to better support states, territories and Tribes with criteria that reflect the most current science and are easier to implement than current approaches. Bioavailability models and criteria developed for each metal through the CRADA will be open for external peer review and public comment.

Common Effects Approach for Aquatic Life Protective Values for Pesticides

The EPA has undertaken an effort to harmonize aquatic effects assessment methods for pesticides to provide a common basis for evaluating the effects of these chemicals on aquatic life under the Clean Water Act (CWA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) using the latest scientific knowledge. Current evaluations have focused on promoting consistency in aquatic effects within the agency and maximizing efficient use of resources by leveraging existing work by the Office of Chemical Safety and Pollution Prevention and the Office of Water to derive aquatic life protective values for pesticides under the CWA. These protective values could be considered for potential use by state and Tribes in establishing water quality standards for their waters. 

Contaminants of Emerging Concern Including Pharmaceuticals and Personal Care Products

It is important for the EPA to be able to evaluate the potential impact of contaminants of emerging concern (CECs), including pharmaceuticals and personal care products (PPCPs), on aquatic life and have an approach for determining protective levels for aquatic organisms. CECs and PPCPs are increasingly being detected at low levels in surface water, and there is concern that these compounds may have an impact on aquatic life.

Metals Aquatic Life Criteria and Chemistry Map (MetALiCC-MAP)

The Metals Aquatic Life Criteria and Chemistry Map, or MetALiCC-MAP (v 1.0) is a tool to support states, Tribes and stakeholders in determining protective aquatic life ambient water quality criteria for metals. Several metals aquatic life criteria require water chemistry data as inputs (e.g., pH, water hardness, ions and dissolved organic carbon) to calculate criteria.

This interactive web-available Geographic Information Systems (GIS)-based mapping tool provides water chemistry information and calculates aquatic life criteria for aluminum and copper. Information is provided for the entire conterminous United States. Tribes, states, and other water quality stakeholders can use this tool to develop aquatic life criteria that reflect their spatial scale of interest – from a very small area like a specific site or particular stream segment to a very large area that spans a state or multiple states. This tool may be especially useful when water chemistry data needed to calculate criteria are limited or not available.

To develop this tool the EPA compiled, analyzed and applied publicly-available national water chemistry data presented in the US Geological Survey (USGS) National Water Information System (NWIS) database.

Acute 6PPD-q and 6PPD Aquatic Life Screening Values for Freshwater

The EPA's Office of Water (OW) developed acute aquatic life screening values for two widely distributed rubber-tire associated compounds, 6PPD-Quinone (6PPD-q) and 6PPD. The screening values are based on the latest scientific knowledge about the short-term (acute) toxicity of 6PPD-q and 6PPD to aquatic organisms, including sensitive species like coho salmon, in freshwaters of the U.S. While data limitations do not allow the EPA to derive recommended 6PPD-q and 6PPD water quality criteria for fresh or estuarine and marine waters that follow the EPA’s Guidelines methods at this time, the agency has derived screening values using the best available toxicity data.

SOP and DERs for Systematic Review of Ecological Toxicity Data in Aquatic Life and Aquatic-Dependent Wildlife

The EPA’s Office of Water (OW) is sharing its existing Standard Operating Procedures (SOP) and Data Evaluation Records (DERs) for systematic review of ecological toxicity data in aquatic life and aquatic-dependent wildlife. The SOP and DERs provide information on OW’s systematic review of ecological effect studies in the development of Ambient Water Quality Criteria and other values for the protection of aquatic life and aquatic-dependent wildlife. The SOP is generally consistent with procedures developed by the EPA’s Office of Chemical Safety and Pollution Prevention to support a common approach to data evaluation for chemicals.

Water Quality Criteria

Contact Us about Water Quality Criteria
Contact Us about Water Quality Criteria to ask a question, provide feedback, or report a problem.
Last updated on December 20, 2024