Quantifying Ice?Sheet Derived Lead (Pb) Fluxes to the Ocean; A Case Study at Nioghalvfjerdsbræ

Concentrations of the toxic element lead (Pb) are elevated in seawater due to historical emissions. While anthropogenic atmospheric emissions dominant source dissolved Pb (dPb) Atlantic Ocean, evidence is emerging a natural associated with subglacial discharge into ocean but this has yet be constrained around Greenland. Here, we show from cavity underneath Nioghalvfjerdsbræ floating ice tongue, previously unrecognized dPb NE Greenland Shelf. Contrasting cavity-inflowing and cavity-outflowing waters, constrain net-dPb flux as 2.2 ± 1.4 Mg·yr?1, which ?90% originates dissolution glacial bedrock sediments. We propose that retreat ongoing many glaciers on Greenland, shifts sediment dynamics, enhanced meltwater discharges shelf waters may result pronounced changes, possibly increases, fluxes coastal waters.