2018 Recommended Aquatic Life Water Quality Criteria for Aluminum/U.S. EPA Draft Technical Support Document: National Association of Clean Water Agencies Comments

The National Association of Clean Water Agencies (“NACWA”) submitted September 13th comments on the United States Environmental Protection Agency (“EPA”) document titled:

Draft Technical Support Document: Implementing the 2018 Recommended Aquatic Life Water Quality Criteria for Aluminum (“Draft Document”)

See EPA-823-D-19-001.

EPA’s stated purpose in issuing the Draft Document is to assist states and authorize tribes in implementing the agency’s Recommended Final Aquatic Life Ambient Water Quality Criteria for Aluminum.

Water Quality Criteria (“WQC”) are ambient water quality conditions that are deemed protective of the uses established for a waterbody. States are required by the Clean Water Act to adopt WQC protective of the designated uses. The WQC must specify the maximum concentration of pollutants that may be present in the water without impairing its suitability for certain uses. They generally assume three forms.

1. Numerical terms reflecting maximum concentration of a particular pollutant in the receiving water
2. Bioassay or biomonitoring results which reflect mortality rates of certain waterborne organisms relative to the concentrations of particular pollutants
3. Terms narrative in nature

The Draft Document contains four sections which address:

1. What flexibility does a state or authorized tribe have when adopting the EPA’s recommended aluminum criteria into its water quality standards, and what are the advantages and potential challenges of each approach?
2. How often and over what time period should a state or authorized tribe collect input parameter data? What if DOC data are insufficient?
3. What methods can be used to reconcile model outputs and derive criteria values that will result in protection of aquatic life at a site?
4. How can a state or authorized tribe implement the aluminum criteria in its Clean Water Act programs?

The September 13th NACWA comments state general support for the Draft Document for what the organization describes as the “flexibility granted to state regulatory authorities when implementing the criteria.” It specifically supports EPA’s:

. . . departure from the static 1988 aluminum criteria and the acknowledgment that aluminum bioavailability depends on the site-specific water chemistry characteristics of pH, total hardness, and dissolved organic carbon (DOC) concentrations.

The rationale for this statement is NACWA’s belief that recommending states “use a range of these water quality input parameters in order to calculate the potential bioavailability of aluminum and potential toxicity to aquatic life is a positive reflection of an evidence-based scientific approach.”

NACWA does cite specific comments from its member Clean Water Services, which it states has addressed aluminum-related water quality issues and has certain concerns. Those concerns are placed in the following categories:

• Methodology Reflects the Worst-Case Scenario
• Implementation Includes a Flawed, Overly Stringent Sampling Approach
• EPA Should Consider Alternative Extraction Methods

A copy of the NACWA comments can be downloaded here.