Operators of the Davis County garbage-burning plant say that the ash their incinerator produces is within federal standards for its toxic metal content.
Jim Young, manager of the Davis County Solid Waste Management and Energy Recovery District, said that the ash, the byproduct of burning trash, contains less than the federal limit for heavy metals including lead, cadmium, mercury and arsenic.Some of the ash produced by the 150 mass burn plants in operation in the United States have come under scrutiny because it contains high levels of toxic elements. Some of the hazardous ash has been sold as fertilizer or used as road base. Metals from the ash also have a potential of leaching into groundwater if improperly buried.
District officials provided the Deseret News with a June 1987 leachable ash test performed by a private Salt Lake laboratory that showed that there was .160 mg per liter of lead and .035 mg per liter of cadmium in the ash. The EPA test limit for lead is 5.0 mg per liter and 1.0 mg per liter for cadmium.
Cadmium is a potentially cancer-causing metal and lead can harm the central nervous system, blood-forming tissues, kidneys, lever and gastro-intestinal system.
State Health Department chemists said that a related test found the ash contained less than "threshold" levels of heavy metals.
Young said he believes that if a similar test were conducted now, it would yield similar results. State hazardous and solid waste officials have asked the district to provide regular ash tests to them, but they have no regulatory authority to require the tests.
"We really don't have any authority to require that so it didn't go anywhere," said Mary Pat Bock, geologist with the Bureau of Solid and Hazardous Waste.
The district has been taking samples of the ash monthly but has not been regularly testing them, Young said.
A pamphlet used to promote the burn plant depicts ash being used as fertilizer. Young said that the district hasn't ruled out selling its ash for fertilizer or road base if a market develops for it.
Currently the district is burying the ash at a nearby landfill. Burning trash at the Davis plant reduces its volume by about 90 percent, Young said.
While the district had previously buried ash mixed with other trash in its landfill, a potentially hazardous practice, it is now burying the ash separately in a clay-lined landfill. It will begin burying the ash in state-of-the-art synthetic-lined landfill next April, Young said.
Environmentalists maintain that even that may not be enough. They have suggested that plants' airborne fly ash and bottom ash be buried separately. The fly ash, which they contend has higher levels of toxic compounds, should be buried in toxic waste dumps, they say.