EPA Publishes IRIS Handbook and Final IRIS Assessment of Perfluorobutanoic Acid and Related Salts

Published On: December 27, 2022By Categories: Newsline

The U.S. Environmental Protection Agency announced the publication of two documents from its Integrated Risk Information System (IRIS) Program on December 22: The Office of Research and Development (ORD) Staff Handbook for Developing IRIS Assessments (IRIS Handbook) and IRIS Toxicological Review of Perfluorobutanoic Acid and Related Salts.

The IRIS Handbook provides procedures for staff developing IRIS assessments, including how to apply systematic review approaches. Systematic review uses prespecified scientific methods to identify, select, assess, and synthesize the findings of similar but separate studies.

In IRIS assessments, such studies are used to identify human health hazards associated with exposure to chemicals found in the environment and derive toxicity values for health effects resulting from exposure. The procedures set forth in the IRIS Handbook will apply to newly initiated IRIS assessments moving forward. The handbook will help the EPA continue its work to address PFAS (per- and polyfluoroalkyl substances).

The IRIS Program also released its final IRIS assessment of perfluorobutanoic acid (PFBA) and related salts. PFBA is a breakdown product of other PFAS that have been used in stain-resistant fabrics, paper food packaging, carpets, and consumer products; it has also been used for manufacturing photographic film.

The final IRIS assessment reviews the evidence on the potential noncancer and cancer human health effects resulting from exposure to PFBA. The final assessment found that sufficient oral exposure to PFBA likely causes thyroid, liver, and developmental effects.

The final assessment also includes a noncancer estimate of the amount of PFBA that one can ingest every day that is likely to be without harmful effects. These noncancer estimates can be used when conducting risk assessments to inform decision-making. Regarding PFBA’s potential cancer effects, the final assessment concludes that there is “inadequate information to assess carcinogenic potential.”

EPA researchers have been working on five IRIS PFAS assessments; the PFBA assessment is the first final IRIS PFAS assessment. The other four IRIS PFAS assessments in development are PFHxA (perfluorohexanoic acid), PFHxS (perfluorohexane sulfonate), PFNA (perfluorononanoic acid), and PFDA (perfluorodecanoic acid).

NGWA has long been an industry leader in providing PFAS research, education, and resources to the public and scientific communities. Learn more by visiting NGWA.org/PFAS, which is a complete resource center about the groundwater contaminants featuring a recently updated top-10 facts sheet, a position paper, and more.

Also found there is Groundwater and PFAS: State of Knowledge and Practice, which NGWA published in 2017 and is one of the first PFAS guidance documents to be released.

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