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Wednesday, December 23, 2009

Flue Gas Desulfurization Gypsum Used On Farm Fields

The Environmental Protection Agency (EPA) and U.S. Department of Agriculture (DOA) are promoting "beneficial uses" of coal combustion waste (CCW). The Center supports such beneficial uses as long as they do not threaten human health or groundwater. Our recommended uses include concrete for highways, sewer pipes and other infrastructure uses that are not in direct proximity to humans. We oppose reuse of CCW for agricultural purposes, particularly those involving the food supply. We cautiously invoke the Precautionary Principle when it comes to CCW use.

Fly ash is one waste and another is the material produced by coal-fired power plant "scrubbers" that remove acid-rain-causing sulfur dioxide from plant emissions. This synthetic mineral gypsum also contains mercury, arsenic, lead and other heavy metals. Currently, EPA says those toxic metals occur in only tiny amounts that pose no threat to crops, surface water or people. The synthetic gypsum is a whitish, calcium-rich material known as flue gas desulfurization gypsum, or FGD gypsum. DOA promotess FGD gypsum's use in farming.

EPA is also drafting a regulatory rule for coal waste, in response to a spill from a coal ash pond near Knoxville, Tennessee one year ago. Ash and water flooded 300 acres, damaging homes and killing fish. The cleanup is expected to cost about $1 billion.The EPA propose regulations early next year, setting the first federal standards for storage and disposal of coal wastes. It is still unclear whether EPA include FGD gypsum in the draft rule.

According to EPA, 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. EPA believes that the use of FGD gypsum in agriculture is safe in appropriate soil and hydrogeologic conditions.

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 (ACAA), a utility industry group. They report that about half of the 17.7 million tons of FGD gypsum produced in the United States last year was used to make drywall. (Wash Post, 12/23/09)

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