David Streets and colleagues explain that humans put mercury into the atmosphere by burning fossil fuels and through mining and industrial processes. Mercury is present in coal and the ores used to extract gold and silver.
Much information exists about recent releases of mercury, but there is little information on releases in the past. To find out how much impact people have had over the centuries, the scientists reconstructed human additions of mercury to the atmosphere using historical data and computer models.
Their research shows that mercury emissions peaked during the North American gold and silver rushes in the late 1800s, but after a decline in the middle of the 20th century, are quickly rising again thanks mostly to a surge in coal use. They report that Asia has overtaken Europe and America as the largest contributor of mercury.
Recent data suggest that mercury concentrations in the atmosphere are declining, and this is not consistent with their conclusion of increasing emissions. Changing atmospheric conditions may be partly responsible, but more work is also needed to understand the fate of large amounts of mercury in discarded products like batteries and thermometers. The researchers predict mercury released from mining and fuel may take as many as 2,000 years to exit the environment and be reincorporated into rocks and minerals in the Earth.
The authors acknowledge funding from the Department of Energy, the National Science Foundation and from the Harvard University NIEHS Center for Environmental Health."All-Time Releases of Mercury to the Atmosphere from Human Activities"
Michael Woods | EurekAlert!
"Make two out of one" - Division of Artificial Cells
19.02.2020 | Max-Planck-Institut für Kolloid- und Grenzflächenforschung
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19.02.2020 | Max-Planck-Institut für Marine Mikrobiologie
The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.
Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...
Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.
Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...
Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices
The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...
Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.
Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.
After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.
"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.
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