2024-23024. Final Recommended Aquatic Life Criteria and Benchmarks for Select PFAS

Table 1—Final Recommended Freshwater Aquatic Life Water Quality Criteria for PFOA and PFOS

Criteria component	Acute water column (CMC) 1	Chronic water column (CCC) 2	Invertebrate whole-body	Fish whole-body	Fish muscle
PFOA Magnitude	3.1 mg/L	0.10 mg/L	1.18 mg/kg ww 4	6.49 mg/kg ww 4	0.133 mg/kg ww.4
PFOS Magnitude	0.071 mg/L	0.00025 mg/L	0.028 mg/kg ww 4	0.201 mg/kg ww 4	0.087 mg/kg ww.4
Duration	1-hour average	4-day average	Instantaneous.3
Frequency	Not to be exceeded more than once in three years, on average	Not to be exceeded more than once in three years, on average	Not to be exceeded.5
1  Criterion Maximum Concentration.
2  Criterion Continuous Concentration.
3  Tissue data provide instantaneous point measurements that reflect integrative accumulation of PFOA or PFOS over time and space in aquatic life population(s) at a given site.
4  Wet-Weight.
5  PFOA and PFOS chronic freshwater tissue-based criteria should not be exceeded, based on measured tissue concentrations representing the central tendency of samples collected at a given site and time.

V. What are the EPA's saltwater acute benchmarks for protecting aquatic life from PFOA and PFOS?

Data limitations did not allow for derivation of PFOA or PFOS national recommended water quality criteria to protect saltwater organisms. Therefore, the EPA derived PFOA and PFOS aquatic life benchmark values under section 304(a)(2) of the CWA using the best available data on the effects of PFOA and PFOS to provide information that States and Tribes may consider in their water quality protection programs. These benchmark values are based solely on data and scientific judgments about the relationship between pollutant concentrations and potential environmental effects. Like national recommended water quality criteria, the EPA's acute PFOA and PFOS aquatic life benchmark values for saltwater are nonbinding and nonregulatory.

The EPA derived acute saltwater benchmarks using available toxicity data on PFOA and PFOS, supplemented with data estimated using the EPA's Web-ICE tool. With data gaps addressed using both laboratory and estimated toxicity test data, the acute saltwater benchmarks for PFOA and PFOS were calculated following methods outline in the EPA's Guidelines.¹ The EPA's acute saltwater benchmarks for PFOA and PFOS values are the maximum concentrations of these PFOA and PFOS (individually, not in mixture), with associated frequency and duration specifications, that are expected to support protection of aquatic life from acute effects in saltwater (see Table 2). ( print page 81079)

Table 2—Acute Saltwater Aquatic Life Benchmarks for PFOA and PFOS

Chemical	PFOA	PFOA
Magnitude	7.0 mg/L	0.55 mg/L.
Duration	One hour average.
Frequency	Not to be exceeded more than once in three years on average.

VI. What are the EPA's freshwater acute benchmarks for protecting aquatic life from eight additional PFAS?

Toxicity data to support benchmarks for these eight PFAS benchmarks were limited relative to the data requirements traditionally used to develop aquatic life criteria. Therefore, the EPA derived PFAS aquatic life benchmark values under section 304(a)(2) of the CWA using the best available data on the effects of these PFAS to provide information that States and Tribes may consider in their water quality protection programs. These benchmark values are based solely on data and scientific judgments about the relationship between pollutant concentrations and potential environmental effects. Like national recommended water quality criteria, the EPA's eight separate acute aquatic life benchmark values for eight different data-limited PFAS in freshwater are nonbinding and nonregulatory.

Compared to PFOA and PFOS, acute freshwater data were more limited for these eight PFAS that the EPA evaluated. The EPA developed the benchmarks by using the available laboratory-based data on the effects of those chemicals on freshwater organisms, supplemented with data estimated using the EPA's Web-ICE tool, following the same peer-reviewed approach applied in development of the acute saltwater benchmarks for PFOA and PFOS. With data gaps addressed using both laboratory and estimated toxicity test data, the acute benchmarks for these eight PFAS were calculated following methods outline in the EPA's Guidelines.¹

The EPA's acute freshwater benchmark values are the maximum concentrations of these PFAS (individually, not in mixture), with associated frequency and duration specifications, that are expected to support protection of aquatic life from acute effects in freshwaters (see Table 2 of this document). These acute benchmarks for these eight PFAS (Table 3) provide information for States and Tribes to consider as protective values in their water quality protection programs.

Table 3—Acute Freshwater Aquatic Life Benchmarks for Eight PFAS

Chemical	PFBA	PFHxA	PFNA	PFDA	PFBS	PFHxS	8:2 FTUCA	7:3 FTCA
Magnitude 1	5.3	4.8	0.65	0.50	5.0	0.21	0.037	0.012
Duration	One hour average.
Frequency	Not to be exceeded more than once in three years on average.
1  Values expressed as mg/L, or ppm.