Energy & Environmental Research Center
University of North Dakota
P.O. Box 9018
Grand Forks, ND 58202
Phone: (701) 777-5000
Fax: (701) 777-5181
News Release
OCTOBER 31, 1997 - FOR IMMEDIATE RELEASE
More Research Needed If Power Plant Mercury Emissions Are to be Controlled
GRAND FORKS, N.D. -- While regulators, environmentalists and industry debate whether there's enough evidence to warrant restrictions on mercury emissions from coal-burning power plants, researchers say that questions remain on how to accurately measure such emissions and control them in a cost-effective manner.
"A great deal more research must be done to develop the technologies needed to effectively measure and control mercury emissions," says John Pavlish, associate director of the Center for Air Toxic Metals (CATM) at the University of North Dakota Energy & Environmental Research Center (EERC). "Until we have a better scientific understanding of those issues and the technologies to deal with them, controlling mercury emissions from power plants will be difficult."
Pavlish was one of the more than 50 government regulators, industry representatives and researchers from the United States and Canada who met at the EERC recently for CATM's 4th Annual Meeting. Operating under a cooperative agreement between the U.S. Environmental Protection Agency (EPA) and the EERC, CATM is a partnership of government, industry and research organizations. Its focus is on understanding and measuring mercury as it is transformed during combustion, as well as developing technologies to control mercury and other air toxic emissions from power plants and incinerators.
Under directives of the 1990 Clean Air Act Amendments, EPA is studying 188 potentially hazardous air pollutants. Mercury is considered one of the most serious of these pollutants because of its ability to bioaccumulate in the aquatic food chain. It can harm the nervous systems of humans and wildlife that eat large quantities of fish. Unborn children are thought to be especially susceptible to increased levels of mercury.
In January 1998, EPA is scheduled to issue a report to Congress on mercury emissions from coal-fired power plants. It is one of two reports intended to help the EPA administrator determine whether the regulation of mercury emissions is necessary.
When coal is burned in a power plant, trace amounts of mercury in the coal are released. Researchers believe the mercury is emitted in two different forms or "species" elemental mercury and oxidized mercury. Oxidized mercury is soluble in water and can be captured by many pollution control systems currently in use. When it does reach the atmosphere, its lifespan in the environment is limited, and it usually is deposited not far from the source of emission.
However, elemental mercury doesn't dissolve in rainfall and can remain suspended in the atmosphere for up to two years. Consequently, it can be deposited almost anywhere in the world, making it a global environmental concern. Increased mercury levels in the atmosphere can lead to higher methylmercury concentrations in bodies of water. When methylmercury accumulates in fish populations, it can result in higher mercury concentration in humans and wildlife that eat the fish.
Martha Keating, an EPA lead environmental scientist who spoke at the CATM meeting, says that mercury speciation and methylation are critical factors in mercury fate and transport in the environment, but are not well understood. In addition, she notes that mercury emission control technologies vary widely in efficiency, availability and cost-effectiveness.
Steve Benson, director of the EERC's CATM program, says that although science has made a great deal of progress in understanding where mercury emissions originate and how mercury is deposited in the environment, a considerable amount of uncertainty remains in the area of mercury speciation.
"What's needed and one of several key areas in which the EERC is working is a better understanding of the effects of fuel quality and operating conditions on mercury emissions from power plants. Otherwise, it's difficult to know for certain whether technologies designed to limit those emissions are really doing the job," he says.
Keating says that even though mercury emissions in the U.S. have fallen from a 1993 estimated high of 220 tons per year to an estimated 150 tons per year in 1995, the number of health advisories on fish consumption have increased. Research shows that the mink, common loon and the Florida panther populations are showing signs of increased mercury in the environment, she notes. In addition, Keating says that 1 to five percent of the U.S. population faces an increased risk from elevated mercury levels.
Ralph Roberson, a technical consultant to the electric utility industry who spoke at the CATM meeting, quoted EPA's Science Advisory Board as saying that the "majority of the human population is not experiencing methylmercury exposures that are of concern from the standpoint of human health." He also noted results of a long-term study of the Seychelles Islands that detected no ill effects due to mercury, even though the islands' population consumes five to 10 times more fish than the general population in North America.
"In other words, the sky is not falling," Roberson says. "There is time for science and technology to adequately address our concerns about mercury in the environment."
Pavlish says the EERC and others are developing and testing technologies to control mercury emissions from coal-fired power plants. "Most of them are still in the experimental stages and haven't proven cost-effective when compared with technologies available to other industries," he explains. "But with additional research, we are confident that advancements will be made that offer low-cost mercury control options for the power industry."
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For More Information Contact:
Steve Benson, EERC associate director, at (701) 777-5177 or [email protected]
John Pavlish, CATM associate director, at (701) 777-5177 or [email protected]
Martha Keating, EPA environmental scientist, at (919) 541-5340
Ralph Roberson, technical consultant, RMB Consulting, at (919) 510-5102
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