Reduction of the bioavailable PFAS fraction in sediments using 3D printable polymer-zeolite clay composites.

As per- and polyfluoroalkyl substances (PFAS) pose a global environmental threat, effective and practical methods for reducing PFAS risk are crucial. To test the effectiveness of a novel treatment for immobilizing PFAS in sediment, 3D-printed (3DP) structures containing zeolite known to adsorb PFAS were inserted into a field-collected sediment (∑PFAS 140 ng/g dw) and a spiked sediment (∑PFAS 38,000 ng/g dw) for 14 days concurrently with estuarine amphipods (Leptocheirus plumulosus) to test efficiency in reducing PFAS concentrations in sediment, sediment porewater, overlying water, and bioaccumulation in tissue. Free zeolite powder and 3DP-clay structures were also tested to investigate effects of zeolite and the 3DP structures separately. Both zeolite treatments proved effective in reducing PFAS, with ∑PFAS reductions for the 3DP zeolite treatments up to 80-95% in sediment and water, and >99% in the porewater and overlying water of the free zeolite powder treatments. By reducing PFAS from the sediment and water, the 3DP zeolite also decreased PFAS bioaccumulation into the amphipods, with a 34% and 85% reduction of ∑PFAS in amphipod tissue from the field and spiked treatments, respectively. While both the 3DP and free zeolite powder treatments reduced PFAS from the sediment and water, exposure to free zeolite powder in sediment resulted in complete amphipod mortality whereas the 3DP zeolite did not significantly impact survival. As 3DP zeolite structures were successful in reducing multiple PFAS analytes from sediment, they represent a promising option for both laboratory toxicity and bioavailability reduction studies and further research and development on scalability and effectiveness in a field setting to reduce PFAS mobility and risk.