EPA Proposes Changes to Methods for Analyzing Water Pollutants, including PFAS and PCBs

EPA is proposing to promulgate new methods and update the regulatory tables of approved methods for pollutant analysis under the Clean Water Act specified in 40 CFR Part 136. The proposed rule affects the methods used to analyze PFAS, PCBs, certain VOCs, and other pollutants. The Clean Water Act’s NPDES program requires permittees to use EPA-approved analytical methods to detect and measure pollutants at or below permit limits or water quality criteria. These methods must be used, for example, in applications for NPDES permits, sampling or reporting required by NPDES permits, and state Clean Water Act Section 401 certifications.

EPA describes six categories of changes included in the proposed rule, discussed in turn below:

1. Withdrawal of seven Aroclor parameters and associated methods for analyzing PCBs.

The proposed rule would withdraw the seven Aroclor parameters historically used to analyze PCBs. The Aroclor parameters and methods, first approved in the 1970s, are not capable of analyzing all 209 “congeners” (structurally related but distinct chemicals) comprising the class of chemicals referred to as PCBs. EPA proposes to replace Aroclor analysis with EPA Method 1628, which is capable of detecting the 209 PCB congeners directly. EPA notes the change will have no effect on existing permits and that it anticipates renewed permits will adopt the new Method 1628, resulting in a multi-year phase-out of Aroclor procedures.

2. Withdrawal of outdated methods.

The proposed rule would withdraw approval of certain colorimetric methods for 12 individual metals and one inorganic anion alternate test procedure, all of which EPA has determined are outdated and/or no longer supported by the sponsoring organization. Specifically, EPA proposes to withdraw 12 single-metal colorimetric methodology types that measure total metal concentration which were listed in 40 CFR 136.3, Table Ib. EPA has determined multiple inductively coupled plasma (ICP) and graphite furnace methods that are already approved and listed in Table Ib provide more accurate results. With respect to inorganic anions, the test “D6508 Rev. 2” is withdrawn as unsupported by the publishing organization. EPA Method 1664, Rev. A (for N-Hexane Extractable Material) also is withdrawn as outdated.

3. Simplification of sampling and preservation requirements for two volatile organic compounds (VOCs).

EPA proposes to change the sampling and preservation requirements for two VOCs, acrolein and acrylonitrile, to match those of other purgeable halocarbons. The proposed rule would change the preservation pH requirement from 4-5 to 2 and require hydrochloric acid to adjust the sample pH.

4. Minor corrections in the text and tables in 40 CFR Part 136.

The proposed rule would correct numerous typographical and organizational errors in 40 CFR Part 136, including the tables of methods. Practitioners should be aware the location and text regarding certain methods may be slightly different in the near future.

5. New EPA methods for new parameters, including PFAS and PCBs.

EPA proposes to add three new EPA methods and their associated parameters to 40 CFR 163.3. These include: (1) EPA Method 1621: Determination of Adsorbable Organic Fluorine in Aqueous Matrices by Combustion Ion Technology; (2) EPA Method 1628: PCB Congeners in Water, Soil, Sediment, Biosolids, and Tissue by Low-resolution GC/MS using Selected Ion Monitoring; and (3) EPA Method 1633A: Analysis of PFAS in Aqueous, Solid, Biosolids, and Tissue Samples by LC-MS/MS. The subject parameters (adsorbable organic fluorine, the 209 PCB congeners and Total PCBS, and the 40 target PFAS analytes in Method 1633A) are all added as new parameters in new Table Ij. Permitting authorities are not required to mandate monitoring for the subject parameters, but the proposed rule informs the permitting authority and discharger that available methods exist. Once the rule is final, the methods will be required for any permit regulating the subject parameters.

6. New methods published by a voluntary consensus standard body for new parameters, including PFAS.

EPA also proposes to add new methods published by voluntary consensus standard bodies for the 40 target PFAS of Method 1633A, peracetic acid, and hydrogen peroxide. The respective methods are (1) ASTM-D8421-24 Standard Test Method for Determination of PFAS in Aqueous Matrices by Co-solvation followed by LC/MS/MS; (2) Standard Method 4500-PAA Peracetic Acid (Residual); and (3) Standard Method 4500-H2O2 Hydrogen Peroxide (Residual).

Conclusion

Environmental managers, consultants, and engineers should be aware of the new methods and changes to existing methods contemplated in the proposed rule. Facilities can expect the subject parameters of the new methods to be regulated in future NPDES permits, and for the new methods to become standard for analyzing those parameters, which include PFAS and PCBs.

90 Fed. Reg. 6967; 40 C.F.R. Part 136