Multidecadal declines in particulate mercury and sediment export from Russian rivers in the pan-Arctic basin

Scott Zolkos; Alexander V Zhulidov; Tatiana Yu Gurtovaya; Vyacheslav V Gordeev; Sergey Berdnikov; Nadezhda Pavlova; Evgenia A Kalko; Yana A Kuklina; Danil A Zhulidov; Lyudmila S Kosmenko; Alexander I Shiklomanov; Anya Suslova; Benjamin M Geyman; Colin P Thackray; Elsie M Sunderland; Suzanne E Tank; James W McClelland; Robert G M Spencer; David P Krabbenhoft; Richard Robarts; Robert M Holmes

doi:10.1073/pnas.2119857119

Multidecadal declines in particulate mercury and sediment export from Russian rivers in the pan-Arctic basin

Proc Natl Acad Sci U S A. 2022 Apr 5;119(14):e2119857119. doi: 10.1073/pnas.2119857119. Epub 2022 Mar 28.

Authors

Scott Zolkos^{1

2}, Alexander V Zhulidov³, Tatiana Yu Gurtovaya³, Vyacheslav V Gordeev⁴, Sergey Berdnikov⁵, Nadezhda Pavlova⁶, Evgenia A Kalko³, Yana A Kuklina³, Danil A Zhulidov³, Lyudmila S Kosmenko⁷, Alexander I Shiklomanov⁸, Anya Suslova², Benjamin M Geyman¹, Colin P Thackray¹, Elsie M Sunderland^{1

9}, Suzanne E Tank¹⁰, James W McClelland¹¹, Robert G M Spencer¹², David P Krabbenhoft¹³, Richard Robarts¹⁴, Robert M Holmes²

Affiliations

¹ John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138.
² Woodwell Climate Research Center, Falmouth, MA 02540.
³ South Russia Centre for Preparation and Implementation of International Projects, Rostov-on-Don 344090, Russia.
⁴ Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow 117997, Russia.
⁵ Southern Scientific Center of the Russian Academy of Sciences, Rostov-on-Don 344000, Russia.
⁶ Melnikov Permafrost Institute, Siberian Branch of Russian Academy of Sciences, Sakha Republic 677010, Russia.
⁷ Hydrochemical Institute of the Federal Service for Hydrometeorology and Environmental Monitoring, Ministry of Natural Resources and Environment of the Russian Federation, Rostov-on-Don 344090, Russia.
⁸ Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824.
⁹ Department of Environmental Health, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA 02115.
¹⁰ Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
¹¹ Marine Science Institute, University of Texas at Austin, Port Aransas, TX 78373.
¹² Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306.
¹³ Upper Midwest Water Science Center, Mercury Research Laboratory, United States Geological Survey, Middleton, WI 53562.
¹⁴ World Water and Climate Foundation, Courtenay, BC V9N 0E2, Canada.

Abstract

SignificanceRussian rivers are the predominant source of riverine mercury to the Arctic Ocean, where methylmercury biomagnifies to high levels in food webs. Pollution controls are thought to have decreased late-20th-century mercury loading to Arctic watersheds, but there are no published long-term observations on mercury in Russian rivers. Here, we present a unique hydrochemistry dataset to determine trends in Russian river particulate mercury concentrations and fluxes in recent decades. Using hydrologic and mercury deposition modeling together with multivariate time series analysis, we determine that 70 to 90% declines in particulate mercury fluxes were driven by pollution reductions and sedimentation in reservoirs. Results suggest that Russian rivers likely dominated over all other sources of mercury to the Arctic Ocean until recently.

Keywords: Arctic; long-term; mercury; riverine export; sediment.