The federal government is encouraging farmers to spread a chalky waste from coal fired power plants on their fields to loosen and fertilize soil, even as it considers regulating coal wastes for the first time. The material is produced by power plant ‘scrubbers’ that remove acid-rain-causing sulfur dioxide from plant emissions. A synthetic form of the mineral gypsum, it also contains mercury, arsenic, lead and other heavy metals.

The Environmental Protection Agency says those toxic metals occur in only tiny amounts that pose no threat to crops, surface water or people. But some environmentalists say too little is known about how the material affects crops, and ultimately human health, for the government to suggest that farmers use it.

"This is a leap into the unknown," said executive director of Public Employees for Environmental Responsibility. "This stuff has materials in it that we're trying to prevent entering the environment from coal-fired power plants, and then to turn around and smear it across agricultural lands raises some real questions."

With wastes piling up around the coal fired plants that produce half the nation's power, the EPA and U.S. Department of Agriculture began promoting what they call the waste’s "beneficial uses" during the Bush administration. An allegedly “beneficial use” of a byproduct of aluminum manufacturing is the sodium fluoride added to drinking water, toothpaste, dental rinses, etc. That chemical compound has serious harmful effects. Banned in Europe, it is widely used in the U. S.

Part of that push to use the waste material is to expand the use of synthetic gypsum a whitish, calcium-rich material known as flue gas desulfurization gypsum, or FGD gypsum. . .

Field studies have shown that mercury, the main heavy metal of concern because it can harm nervous system development, does not accumulate in crops or run off fields in surface water at "significant" levels, the EPA said. That government agency "believes that the use of FGD gypsum in agriculture is safe in appropriate soil and hydro geologic conditions". . .

Executive director of the Environmental Integrity Project, which advocates for more effective enforcement of environmental laws, said he is not overly worried about FGD gypsum's use on fields because research shows it contains only tiny amounts of heavy metals. But he said federal limits on the amounts of heavy metals in FGD gypsum sold to farmers would help allay concerns. . .

Since the EPA-USDA partnership began in 2001, farmers' use of the material has more than tripled, from about 78,000 tons spread on fields in 2002 to nearly 279,000 tons last year, according to the American Coal Ash Association, a utility industry group. (End Washington Post article)

Asso. Press, Washington Post (washingtonpost.com), December 23, 2009.