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Cracking Down on Mercury

Monday, December 9th, 2013

by Kristen Minogue

Ally Bullock, a technician in SERC's mercury lab, draws pore water samples from Berry's Creek. (SERC)

Ally Bullock, a technician in SERC’s mercury lab, draws pore water samples from a mid-Atlantic Superfund site. (SERC)

There are places in the U.S. so polluted, eating fish or crabs from their waters isn’t just unhealthy—it can be illegal. The Environmental Protection Agency calls sites like that “Superfund sites,” a label for abandoned or neglected sites that became dumping grounds for hazardous waste. Some of the highest levels of mercury contamination in the U.S. exist in Superfund sites. Cynthia Gilmour knows this first-hand. As a microbial ecologist at the Smithsonian Environmental Research Center, she has worked in several.  But short of digging up the polluted sediments and dumping them elsewhere (an expensive and ecologically risky proposition), not many methods exist to get rid of the problem.

“If we use the traditional technologies of removing that and putting it in a landfill, we don’t have a wetland anymore,” says Upal Ghosh, an environmental engineer from the University of Maryland, Baltimore County, who works with Gilmour.

This fall, Gilmour and Ghosh explored a new technique: using charcoal to trap it in the soil.

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Methylmercury Microbes More Widespread Than Realized

Thursday, September 12th, 2013
New places scientists discovered can contain the microbes--Archaea and Bacteria--that create the dangerous neurotoxin methylmercury. (SERC & ORNL)

New places scientists discovered can contain the microbes–Archaea and Bacteria–that create the dangerous neurotoxin methylmercury. (SERC & ORNL)

Microbes that live in rice paddies, northern peat lands and beyond are among the several types of bacteria researchers at the Smithsonian Environmental Research Center and Oak Ridge National Laboratory have just learned can generate highly toxic methylmercury.

This finding, published Wednesday in Environmental Science & Technology, explains why methylated mercury, a neurotoxin, is produced in areas with no previously identified mercury-methylating bacteria. Methylmercury—the most dangerous form of mercury—damages the brain and immune system and is especially harmful for developing embryos. Certain bacteria transform inorganic mercury from pollution into toxic methylmercury.

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Better know a trace element: Mercury

Monday, January 11th, 2010

An interview with Cindy Gilmour, mercury researcher.

Cindy Gilmour doing mercury research in a marsh

Senior scientist Cindy Gilmour studies how anaerobic bacteria – found in places like the marsh soils above – transform mercury into methylmercury. Methylmercury poses a bigger problem than inorganic mercury because it bioaccumulates.

This January the Maryland Healthy Air Act goes into effect. It aims to significantly reduce emissions of air pollutants from the state’s coal-fired power plants. Mercury, like sulfur dioxides and nitrogen oxides, is one of the pollutants that can be released into the atmosphere during the combustion of coal and other fuels. The new law requires mercury emissions to be reduced by 80% now, and 90% by 2013, relative to a 2002 baseline. Maryland is just the latest to join a growing roster of states that have adopted tougher emissions regulations.

Cindy Gilmour will pay close attention to the impact of these new regulations on mercury levels in the Chesapeake Bay and its watersheds. Gilmour is a senior scientist at the Smithsonian Environmental Research Center (SERC), in Edgewater, Maryland. She took a few minutes to answer some questions about the science of mercury, why it’s of concern and what she does to monitor it in ecosystems.
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