September 18, 2024

Washington state updates Aquatic Life Toxics Criteria for the first time in 30 years, becomes first state to set criteria for 6PPD

The Washington State Department of Ecology recently published significant updates to the aquatic life toxics criteria for the first time since the early 1990s. The aquatic life toxics criteria limit the amount of toxic substances that may be introduced into waterbodies above natural background levels. The new criteria establish limits for 42 chemicals, including a first-in-the-nation numeric freshwater limit for 6PPD quinone, a chemical that is especially toxic for salmon and trout. Ecology also updated the criteria to include PFAS, making it one of the first states to implement EPA’s draft criteria for PFAS. And, Ecology updated criteria for numerous naturally occurring background metals, which may present challenges for NPDES permit holders in certain receiving waters. Ecology will use the updated criteria to establish water quality standards that generate the need for total maximum daily loads (TMDLs) and determine discharge limits in NPDES permits.

Updates to criteria for emerging contaminants

Ecology’s criteria rulemaking makes Washington one of the first states in the nation to implement EPA’s draft criteria for PFAS, and the first to implement criteria for 6PPD quinone.

PFAS are man-made chemicals, incorporated into countless industrial and consumer products since the 1940s. PFAS lead to numerous negative human health and ecological impacts. PFAS are considered “forever chemicals” because of how long it takes them to break down in the environment. Because of PFAS ubiquitous usage, most industrial facilities have likely used PFAS in some component of their process.

Ecology established for the first time in Washington acute and chronic freshwater levels and acute marine levels for two PFAS: PFOS and PFOA. Ecology based the criteria on EPA’s draft criteria, but the final rule departs from the process Ecology announced it would follow during the rulemaking process. In public presentations prior to finalizing the rule, Ecology stated it would not adopt recommendations for PFOS and PFOA until EPA finalized its draft criteria. EPA has not finalized its PFOS and PFOA criteria. Ecology nevertheless moved forward with the final rule, incorporating EPA’s draft criteria. In the response to comments, Ecology indicated that it believes the EPA draft criteria represents the best available science, and that it “will consider adopting updated criteria in the future.” Thus, the final criteria rules for PFOS and PFOA may still change, depending on EPA’s future regulatory actions.

In addition to moving ahead of EPA on PFOS and PFOA, Ecology’s final rule makes Washington the first state to implement criteria for 6PPD quinone, another emerging contaminant. The final rule includes only acute freshwater criteria for 6PPD quinone due to the limited data available for 6PPD quinone in the state. Ecology intends to update the criteria as more data becomes available.

While Ecology may update and add criteria for these emerging contaminants as more data become available, even the limited criteria for PFOS, PFOA, and 6-PPD in the final rule will impact both individual and general NPDES permit holders. Ecology bases individual permit limits on conservative estimate of the acute and chronic aquatic life criteria. And, the criteria are the most important factor in setting in general permits, including the Industrial Stormwater General Permit (ISGP). The draft 2025 ISGP, issued in July 2024, requires covered entities in only two industries (air transportation and waste management) to report PFOS, PFOA, and 6PPD. The permit does not include benchmarks, but the data collected from these two industries under the 2025 ISGP, along with the new aquatic life criteria, will likely help establish benchmarks in future iterations of the ISGP (and for more industries) and will likely help develop effluent limits in individual permits.

Permit holders should note Ecology’s clear willingness to regulate emerging contaminants, even as it continues to gather more state-specific data.

Updates to criteria for background metals

In addition to establishing criteria for notable emerging contaminants, Ecology also updated criteria for numerous naturally occurring background metals, such as silver, nickel, and zinc. And Ecology established criteria for aluminum for the first time. The final rule’s criteria are conservative, intended to be protective of the most sensitive ecosystems.

Because these metals are naturally occurring and vary by geography, entities may find it challenging to determine facility-specific natural background levels. For example, to calculate a receiving water’s natural background of aluminum, Ecology recommends that NPDES permittees collect pH, hardness, and Dissolved organic carbon data to obtain site specific aluminum criteria. Facilities that do not collect this data will be subject to the conservative default criteria. Every permit holder will need to consider the time and expense necessary to collect upstream and natural background data, or if the default criteria is acceptable. 

Final thoughts

Before Ecology implements the new criteria into TMDLs or permits, EPA must approve the final rule. Given that Ecology’s criteria are mostly based on EPA data and technical support and that Ecology implemented most of EPA’s comments on the draft rulemaking, EPA will likely approve most, if not all, the criteria, including for the emerging contaminants. The final aquatic life toxics criteria establish Washington as a vanguard regulator of emerging contaminants in water quality programs. We expect this regulatory trend to expand. Water quality criteria for emerging contaminants will likely become more stringent as Ecology continues to gather state-specific data.