Science of the Total Environment – A case study using 2019 pre-monsoon snow and stream chemistry in the Khumbu Region, Nepal – – H. Clifford et al.

A case study using 2019 pre-monsoon snow and stream chemistry in the Khumbu Region, Nepal

Heather M. Clifford a,b,⁎, Mariusz Potocki a,b, Inka Koch c,d, Tenzing Sherpa c, Mike Handley a, Elena Korotkikh a, Douglas Introne a, Susan Kaspari e, Kimberley Miner a, Tom Matthews f, Baker Perry g, Heather Guy h, Ananta Gajurel i, Praveen Kumar Singh c,j, Sandra Elvin k, Aurora C. Elmore k, Alex Tait k, Paul A. Mayewski a

a Climate Change Institute, University of Maine, ME, USA
b School of Earth and Climate Sciences, University of Maine, ME, USA
c International Centre for Integrated Mountain Development, Lalitpur, Nepal
d Department of Geosciences, University of Tübingen, Tübingen, Germany
e Department of Geological Sciences, Central Washington University, WA, USA
f Department of Geography and Environment, Loughborough University, Loughborough, UK
g Department of Geography and Planning, Appalachian State University, NC, USA
h School of Earth and Environment, University of Leeds, UK
i Central Department of Geology, Tribhuvan University, Kathmandu, Nepal
j CoEDMM, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
k National Geographic Society, 1145 17th St. NW, Washington, DC, USA


This case study provides a framework for future monitoring and evidence for human source pollution in the Khumbu region, Nepal. We analyzed the chemical composition (major ions, major/trace elements, black carbon, and stable water isotopes) of pre-monsoon stream water (4300–5250 m) and snow (5200–6665 m) samples col-lected from Mt. Everest, Mt. Lobuche, and the Imja Valley during the 2019 pre-monsoon season, in addition to a shallow ice core recovered from the Khumbu Glacier (5300 m). In agreement with previous work, pre-monsoon aerosol deposition is dominated by dust originating from western sources and less frequently by transport from southerly air mass sources as demonstrated by evidence of one of the strongest recorded pre-monsoon events emanating from the Bay of Bengal, Cyclone Fani. Elevated concentrations of human-sourced metals (e.g., Pb, Bi, As) are found in surface snow and stream chemistry collected in the Khumbu region. As the most comprehensive case study of environmental chemistry in the Khumbu region, this research offers sufficient evidence for in-creased monitoring in this watershed and surrounding areas.


Science of the Total Environment 789 (2021) 148006