New ”fingerprinting” method tracks mercury emissions from coal

October 9th, 2008 - 2:41 pm ICT by ANI  

Washington, Oct 9 (ANI): University of Michigan researchers have developed a new tool that uses natural “fingerprints” in coal to track down sources of mercury emissions polluting the environment.
Mercury is a naturally occurring element, but some 2000 tons of it enter the environment each year from human-generated sources such as incinerators, chlorine-producing plants and coal-burning power plants.
Mercury is deposited onto land or into water, where microorganisms convert some of it to methylmercury, a highly toxic form that builds up in fish and the animals that eat them.
In wildlife, exposure to methylmercury can interfere with reproduction, growth, development and behavior and may even cause death.
Effects on humans include damage to the central nervous system, heart and immune system. The developing brains of young and unborn children are especially vulnerable.
“There has been a lot of controversy about how much mercury is coming from different types of industrial activities, compared to natural sources, but it has been difficult to figure out the relative contributions,” said co-author Joel Blum, the John D. MacArthur Professor of Geological Sciences and a professor of ecology and evolutionary biology.
For the past eight years, Blum and co-workers have been trying to develop a way of reading mercury fingerprints in coal and other sources of mercury.
The hope was that they could then find those same fingerprints in soil and water bodies, much as a detective matches a suspect’’s fingerprints to those found at a crime scene, and use them to figure out exactly what the sources of mercury pollution are in certain areas.
“For some time, we weren”t sure that it was going to be technically possible, but now we”ve cracked that nut and have shown significant differences not only between mercury from coal and, say, metallic forms of mercury that are used in industry, but also between different coal deposits,” Blum said.
The fingerprinting technique relies on a natural phenomenon called isotopic fractionation, in which different isotopes of mercury react to form new compounds at slightly different rates.
Combining mass-dependent and mass-independent isotope signals, the researchers created a powerful fingerprinting tool.
“Scientists have models and other ways of estimating how much mercury will be deposited locally, but we may, for the first time, be able to directly differentiate between mercury coming from local plants and mercury that has been transported longer distances,” said Blum.
In a project already underway, Blum’’s research group hopes to pinpoint which of the many mercury sources in the San Francisco Bay area are contributing most to the contamination of fish and wildlife. (ANI)

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