Impacts of mineral dust on soils and vegetation at Lù’àn Mân (Kluane Lake), Yukon Territory).

Dust is a major aerosol in the atmosphere. Atmospheric dust originates from human activities or natural processes and the deposition of dust affects several ecological and biogeochemical processes. Lù’àn Mân (61°13’03’’ N, 138°37’34’’ W) is located between the Ruby Ranges on the east and the Kluane Ranges in the St. Elias mountains on the west, and on the traditional lands of Kluane, Champagne-Ashihik, and White River First Nations. Kaskawulsh Glacier, located 25 km from the A’ą̈y Chù (formerly the Slims River) delta, began to retreat in the nineteenth century and this retreat accelerated in the late twentieth and early twenty-first centuries. In 2016, Slims Lake had partially drained, leading the water to be re-routed from A’ ą̈y Chù into Kaskawulsh River. Therefore, the level of Lù’àn Mân fell, and the drying of the riverbed became an important source of aeolian sediments and important dust storms were observed. We studied dust and trace elements deposition in the area in lichens and soils. The objective of this study was to determine the impacts of dust deposition on trace elements concentrations in vegetation and soils along a deposition gradient. To do this, we sampled lichens (Peltigera canina) and soils at sixty sites in the zone affected by the dust storms. We analyzed six trace elements (Ni, Cu, Zn, As, Cd, Pb) by ICP-MS. The results showed that the sites close to the delta had higher trace element concentrations than the sites 10 and 20 km away.