New systematic review – temporal trends of perfluoroalkyl acids in humans and in the environment
NEWS | 2017-11-27
In 2000, the industrial sector began to phase out some Poly- and perfluorinated alkylated substances (PFASs). EviEM has conducted a systematic review of how these and following actions have affected concentrations of perfluoroalkyl acids (PFAAs) in the environment and in humans. The report has now been published.
In 2014, following a suggestion by the Swedish Chemicals Agency, EviEM initiated a review of how concentrations of PFAAs have changed with time in humans and in the environment. The main objective was to investigate whether any changes could be related to voluntary and regulatory restrictions in manufacture and use of long-chain PFASs. The review team has been chaired by Cynthia de Wit, Professor at the Department of Environmental Science and Analytical Chemistry (ACES), Stockholm University, and the review project has been managed by Magnus Land, EviEM.
Diverse body of evidence and heterogenous results
The systematic review included human samples as well as biological and abiotic environmental samples. The included PFAAs were perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs). The review also included perfluorooctane sulfonamide (FOSA). Most of the studies were conducted in North America and Europe followed by the Arctic. A small number of additional studies have been conducted in East Asia.
In regions where regulations and phase-outs have been implemented, human concentrations of Perfluorooctane sulfonic acid (PFOS), Perfluorodecane sulfonic acid (PFDS), and Perfluorooctanoic acid (PFOA) are generally declining, while previously increasing concentrations of Perfluorohexane sulfonic acid (PFHxS) have begun to level off. Rapid declines for some PFOS-precursors have also been consistently observed in human studies. In contrast, limited data indicate that concentrations of PFOS and PFOA in humans are increasing in China where the production of these substances have increased. Human concentrations of longer-chained PFCAs (9-14 carbon atoms) are generally increasing, or show insignificant trends based on datasets with low power to detect a trend.
For environmental samples there are no clear patterns of declining trends. Most substances show mixed results, but a majority of the trends are based on datasets with low power to detect a trend and appear to be insignificant. The evidence base for environmental samples is thus relatively weak. However, in environmental biological samples, increasing trends predominate for concentrations of PFCAs with 9-14 carbon atoms.
Links to our final report on the systematic review, including additional files, as well as a summary and a fact sheet can be found in the right margin.