Apr 11

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4/11/2023 12:00 PM  RssIcon


Weck Labs' expertise in testing for PFAS spans more than 17 years and we provide continuous development to meet new regulatory drivers. Weck Laboratories currently offers several methods for determination of PFAS including EPA methods 537.1, 533, Draft 1633 and methods compliant to the Department of Defense (DoD) QSM 5.4 Tables B-15 and B-24. Weck can currently test for 44 PFAS compounds.

Learn more about Weck Labs PFAS Testing Here

EPA 537.1 and EPA 533 Method Comparison

EPA 533 is a newer method that encompasses more targets than 537.1, with 25 targets for 533 compared to only 18 targets for 537.1. While there is some overlap between the 537.1 and 533 target lists, the 533 targets focus on the shorter-chain PFAS which are more likely to be found in the environment. The extraction technique for 533 relies on anion exchange, which is much more selective for PFAS than the reversed-phase extraction for 537.1, reducing some potential matrix effects in field samples. 537.1 uses conventional internal standard quantitation, but 533 uses isotopic dilution quantitation for the highest possible level of data quality. Isotopic dilution effectively allows the laboratory to perform a matrix spike on every single sample, and automatically account for challenging matrices on a per-sample basis. Overall, 533 is a more robust and complete method for PFAS analysis in drinking water than 537.1. The data quality is higher with 533, and it can tolerate a greater variety of matrices. 533 is suitable for various sample types, such as source water, water re-use, and finished drinking water. Both methods require that Field Reagent Blanks (FRBs) be sampled and analyzed if field samples have hits above the MRL. Some regulatory programs may require that all FRBs be analyzed so be sure to verify the requirements and budget for the additional cost. Weck Labs is approved by the US EPA for UCMR 5 for both EPA 533 and 537.1

UCMR 5 Approval Letter

EPA Draft Method 1633 and DoD QSM Compliance Method

In 2021, the U.S. Environmental Protection Agency (EPA), in collaboration with the U.S. Department of Defense (DoD), published Draft EPA 1633 method to test per- and polyfluoroalkyl substances (PFAS) in different environmental matrices. The 3rd draft version of the method was issued in December of 2022. EPA Draft Method 1633 is an isotope dilution LC-MS/MS method which incorporates testing of up to 40 PFAS compounds. While broadly conforming to the DoD Quality Systems Manual Table B-15 quality standards for PFAS analysis, EPA 1633 standardizes the procedures and extends them to more complex matrices such as wastewater, biosolids, leachate and tissue. QSM v5.3 Table B-15 lists the specific requirements for analyzing PFAS in matrices other than drinking water. QSM v5.4 was published in late 2021, adding Table B-24 to refine Draft Method 1633 for DOD projects in wastewater, surface water, groundwater, soil, biosolids, sediment, landfill leachate, and tissue. Weck Laboratories is accredited by the Departments of Defense and Energy for both QSM 5.4 Table B-15 Compliance method and EPA 1633 (QSM 5.4Table B-24).

DoD ELAP Accreditation

Weck Laboratories will add specific state certifications for EPA 1633 as accreditations become available.

PFAS Target List by Method

News from the US EPA

Proposed National Primary Drinking Water Regulation

In March 2023, EPA took a key step to protect public health by proposing to establish legally enforceable levels for six PFAS known to occur in drinking water, fulfilling a foundational commitment in the Agency’s PFAS Strategic Roadmap. EPA is also proposing health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these six PFAS.

Compound Proposed MCLG Proposed MCL (enforceable levels)
PFOA Zero 4.0 parts per trillion (ppt or ng/L)
PFOS Zero 4.0 ppt
PFNA 1.0 (unitless) Hazard Index 1.0 (unitless) Hazard Index
PFHxS 1.0 (unitless) Hazard Index 1.0 (unitless) Hazard Index
PFBS 1.0 (unitless) Hazard Index 1.0 (unitless) Hazard Index
HFPO-DA (commonly referred to as GenX Chemicals) 1.0 (unitless) Hazard Index 1.0 (unitless) Hazard Index

The propsed rule would require public water systems to:

Monitor for these PFAS
Notify the public of the levels of these PFAS Reduce the levels of these PFAS in drinking water if they exceed the proposed standards.

Read more: Per- and Polyfluoroalkyl Substances (PFAS) | US EPA

PFAS in Clean Water Act Permitting

In December 2022, EPA issued a companion memo providing guidance to states on how to use the Clean Water Act's National Pollutant Discharge Elimination System (NPDES) permitting program to reduce harmful PFAS pollution. This memo expands upon an earlier memo issued to EPA Regions in April 2022 and is a critical step in EPA's efforts to restrict PFAS at their source.


News from California State Water Board

EPA Method 533 required for drinking water compliance monitoring in California

Under PFAS General Order DW-2022-0001_DDW, effective January 1, 2023, public water systems in California must begin quarterly monitoring of samples for PFAS using EPA Method 533.

Copy of General Order

Current notification levels can be found at: Per- and Polyfluoroalkyl Substances (PFAS) | California State Water Resources Control Board

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