Abstract
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 collected 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 increased monitoring in this watershed and surrounding areas.
Highlights
Glaciers and snow cover in high mountain regions play a significant role in regional hydrology and ecology (Immerzeel et al, 2020)
Ice core samples preserve the signature of past conditions, to estimate past atmospheric composition in the region, we sampled and analyzed the chemistry from the 3.5 m deep ice core drilled from the Khumbu Glacier (28.0039°N, 86.8583°E, 5300 m), directly below the Khumbu icefall (Fig. 1)
We compare the average concentrations of selected chemistry from the Khumbu Glacier ice core, snow, and stream samples from this study (Fig. 2), major crustal elements (Si, Fe, Al, Mg, Ca), major marine ions (Na+, Cl−), anions (SO42−, NO3−), and known anthropogenically-influenced elements (Pb, U, As, Bi, Cs) (Casey, 2012; Cong et al, 2010a; Dong et al, 2015; Gabrielli et al, 2020; Jiao et al, 2021; Kaspari et al, 2009b; Lee et al, 2008; Tripathee et al, 2014a)
Summary
Glaciers and snow cover in high mountain regions play a significant role in regional hydrology and ecology (Immerzeel et al, 2020). Long-term projections of amplified melt, in combination with other changing climatic factors like precipitation patterns, indicate increased pressure on water availability and food security for rural Himalayan communities (Wang et al, 2019). Meltwater from local glaciers such as the Khumbu Glacier is responsible for ~65% of the local domestic water supply during the dry, pre-monsoon season (Wood et al, 2020). The local population of 3500–6000 people in the Khumbu region depends on stream water for their drinking, irrigation, and ecological purposes (Wood et al, 2020). Around 57,000 trekkers, climbers, and local support teams make the trek to Everest Base Camp annually (Government of Nepal, 2020), with several thousand climbers seasonally residing at Everest Base Camp, depending upon the local streams derived from Khumbu Glacier melt for drinking/cooking
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
