US EPA's Latest Assessments: Stringent Inorganic Arsenic Limits PFDA PFAS Peer Review Report

The US Environmental Protection Agency (EPA) has opened a 60-day public comment period on the draft Toxicological Review of Inorganic Arsenic under the Integrated Risk Information System (IRIS). This draft, prepared by the Center for Public Health and Environmental Assessment (CPHEA) within EPA's Office of Research and Development, evaluates the toxicological effects of inorganic arsenic. The public comment period, which opened on October 16, 2023, will remain open until December 15, 2023.

BACKGROUND:

Inorganic arsenic is used in various industrial applications, including the hardening of copper and lead alloys, glass manufacture, and as a catalyst in the production of ethylene oxide. Given its widespread use, understanding its potential health risks is of paramount importance. The draft IRIS assessment, if finalized, could lead to stricter federal regulations on the use of inorganic arsenic in these industries.

KEY ASPECTS:

The latest evaluation introduces an overall reference dose of 0.031 µg/kg per day, which is well-supported by evidence that links inorganic arsenic to circulatory system disorders. The potential adoption of this reference dose has significant implications for the regulation of inorganic arsenic in various products and processes. While the EPA's Integrated Risk Information System program previously classified arsenic as carcinogenic, this classification remains unaltered in the latest draft.

However, the draft assessment looks more closely at the risks beyond cancer, including new data on noncancerous effects. These include effects on the cardiovascular system, neurodevelopment, pregnancy, and diabetes. The draft assessment conveys a high level of confidence in the role of inorganic arsenic compounds in the development of cardiovascular disease and diabetes, and a moderate level of confidence in their association with pregnancy, birth, and neurodevelopmental effects.

This comprehensive evaluation of the health effects of inorganic arsenic underscores the critical importance of regulating the use of this compound in various industries. To participate in the public comment process and have your say on these proposed regulations, visit the IRIS website or the public docket, with Docket ID No. EPA–HQ–ORD–2012–0830. The EPA welcomes input from stakeholders, scientists, and the public to help shape the future regulation of inorganic arsenic.

PFDA Review

The EPA also published a report detailing an external peer review of its preliminary IRIS assessment of perfluorodecanoic acid (PFDA), a long-chain PFAS. The reviewers generally agreed with the EPA's initial findings on the effects of PFDA on the immune system and development, but also provided additional perspectives. In the preliminary draft, a provisional overall reference dose of 4*10-10 mg/kg/day was established, based on considerations of immunotoxicity and developmental toxicity. However, the report underscores that the information currently available is insufficient for a comprehensive evaluation of the risks associated with PFDA.