Recent PFAS regulation by the US EPA has led to two compounds, PFHxS and PFOS, being in the news quite a lot. These compounds are six- and eight fluorinated carbon chain compounds that have historically been released to the environment and pose human health threats. Most notably, these compounds are often associated with aqueous film-forming foam (AFFF) use, aka firefighting foams used at airports and military bases.

The widespread use of this foam has led to elevated levels of these compounds in the environment, including on Cape Cod where much of the STEEP Superfund Center’s research has focused. In a recent study, led by Heidi Pickard, PhD, a former STEEP trainee under Elsie Sunderland at Harvard University, new revelations have been made about the uptake of PFAS from AFFF contamination in fish.

In the study, Harvard investigated the uptake of sulfonamide compounds by fish, a precursor to terminal compounds like PFOS or PFHxS. Despite their prevalence in environments impacted by AFFF, little is known about how these precursor sulfonamide compounds bioaccumulate in fish, or other life.

Fish collected from fresh and estuarine water on Cape Cod displayed greater accumulation of these sulfonamide precursors than many of the regulated terminal compounds. Specifically, bioaccumulation is measured through a calculation called bioaccumulation factor, or BAF. While it may sound complex, it’s actually quite a simple metric, that relates the concentration of PFAS in the fish to concentration of PFAS in the water. The more PFAS in the fish relative to the water, the more you can assume that PFAS compound accumulates in biota.

BAF values were 1-3 orders of magnitude higher for the sulfonamide compounds compared to their terminal endpoints in fish.  Furthermore, the study also observed that the concentrations of these precursors were comparable to concentrations of newly regulated compounds like PFOS.

This work illustrates the need for further research into the health effects of a wider range of PFAS, and the need for regulation efforts to continue. When considering the high levels at which these precursors are accumulating in fish, one can see there is still much to learn about the impact of PFAS on our world.

HM Pickard, F Haque, and EM Sunderland. Bioaccumulation of Perfluoroalkyl Sulfonamides (FASA). Environmental Science & Technology Letters 2024 11 (4), 350-356. DOI: 10.1021/acs.estlett.4c00143