Fate of perfluoroalkyl substances in the Third Pole proglacial lake basins

Abstract

AbstractHow will climate change influence the accumulation of pollutants in remote mountainous lakes? To answer this question, we collected sediment cores from two glacial lakes (one is small and close to glacier, and the other is large and far from glacier) in the Third Pole and quantified deposition fluxes of perfluoroalkyl substances (PFAS). The trends of PFAS fluxes broadly correspond with their historical emissions and phase-out. Besides of emission, glacial meltwater strongly impacts the accumulation of PFAS in small lake, while precipitation exhibits great impact on that of big lake. We then optimized a multi-media fugacity model to explore how PFAS transport along proglacial rivers before entering the big lake and found that river sediments intercept ~ 12% of PFAS from glacial meltwater. Impact of proglacial river-sediment on pollutant accumulation have been greatly underestimated, although role of climate was concerned before.