Deposition of PFAS 'forever chemicals' on Mt. Everest

Mt. Everest, one of the most coveted climbing mountains on earth, also contains the highest altitude chemical contamination on land. We analyzed meltwater and snow samples from the Khumbu Glacier for "forever chemicals" per- and polyfluoroalkyl substances (PFAS) for the first time. Our research team utilized solid-phase extraction (SPE) and liquid chromatography/tandem mass spectrometry in an LC/MS/MS to identify pollutants sampled from Everest Base Camp, Camp 1, Camp 2, and Everest Balcony. From the 14 PFAS compounds tested using the EPA Method 537.1, we found PFOS, PFOA, and PFHxA in Mt. Everest snow and meltwater. The highest concentrations found were 34.5 ng/L and 18.7 ng/L at Base Camp and Camp 2, respectively; however, PFAS species were also found within one order of magnitude in all sampling sites with detection, suggesting a ubiquitous presence on the mountain. The relatively high levels of PFAS in the near environment indicate loss from the gear used by trekkers, as the concentrations are higher than background levels from atmospheric deposition. While providing only a one-season fingerprint for pollutants on Mt. Everest these are the highest PFAS samples ever retrieved, with concentrations indicating the need for further sampling to determine human health risk.