Long Range Transport of Atmospheric Microplastics Deposited Onto Glacier in Southeast Tibetan Plateau

Abstract

Microplastics (MPs) pollution has caused attentions globally due to their potential risk to the environment. In this work, MPs in snowpit samples collected from Demula (DML) glacier in the southeast Tibetan Plateau were investigated. The results showed that the average abundance of MPs in snow was 9.55±0.9 items L -1 , with dominated shapes by plastic fibers and films. The chemical composition of MPs from DML glacier and backward air mass trajectory modeling indicated that MPs in snow mostly originated from the long-range atmospheric transport, suggesting the glaciers can be a temporal sink of atmospheric MPs. The surface structure of the MPs was broken and adhered to a large amount of mineral dust and metal particles, revealing that the MPs in the snowpit had undergone severe weathering during transportation and after deposition. Based on the MPs data, multi-year average precipitation, and glacier mass balance of DML glacier, the deposition flux of MPs on DML glacier was estimated to be about 7640±720 to 9550±900 items m -2 yr -1 and the export from melting water was about 5.9±1.3 × 10 9 to 6.6±1.4 × 10 9 items yr -1 . These results can provide the current status of MPs pollution on the Tibetan Plateau glaciers and new data to the study of MPs in typical cryospehric regions.

Keywords: Microplastic pollution, Glacier, Long-range transport, Tibetan Plateau