Yin, R;
Feng, X;
Hurley, JP;
Krabbenhoft, DP;
Lepak, RF;
Kang, S;
Yang, H;
(2016)
Historical Records of Mercury Stable Isotopes in Sediments of Tibetan Lakes.
Scientific Reports
, 6
, Article 23332. 10.1038/srep23332.
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Abstract
The Tibetan Plateau (TP), known as the “Third Pole”, is a critical zone for atmospheric mercury (Hg) deposition. Increasing anthropogenic activities in the globe leads to environmental changes, which may affect the loading, transport and deposition of Hg in the environment. However, the deposition history and geochemical cycling of Hg in the TP is still uncertain. Our records of Hg and Hg isotopes in sediment profiles of the two largest lakes in the TP, Lake Qinghai and Nam Co, show increased Hg influx since last century, with the maximum Hg influx enrichment ratios of 5.4 and 3.5 in Lake Qinghai and Nam Co, respectively. Shifts in negative δ 202Hg in Lake Qinghai (−4.55 to −3.15‰) and Nam Co (−5.04 to −2.16‰) indicate increased atmospheric Hg deposition through rainfall, vegetation and runoff of soils. Mass independent fractionation of both even-Hg (Δ 200Hg: +0.05 to +0.10‰) and odd-Hg (Δ 199Hg: +0.12 to +0.31‰) isotopes were observed. Positive Δ 200Hg suggest high proportion of precipitationderived Hg in the TP, whereas the positive Δ 199Hg results from Hg(II) photo-reduction. Both lakes show increasing Δ 199Hg since the 1900 s, and we conclude that with the decrease of ice duration, Hg(II) photoreduction may have been accelerated in these TP lakes.
| Type: | Article |
|---|---|
| Title: | Historical Records of Mercury Stable Isotopes in Sediments of Tibetan Lakes |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1038/srep23332 |
| Publisher version: | http://dx.doi.org/10.1038/srep23332 |
| Language: | English |
| Additional information: | Copyright © The Author(s). All rights reserved. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL SLASH UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS > Dept of Geography |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1478213 |
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