By CHRIS YAGELO
Capital News Service
LANSING — Environmental groups are blasting a proposed easing of state rules on acceptable amounts of a possible cancer-causing contaminant.
The change in the Department of Environmental Quality rules would allow 150 parts per trillion of dioxin in residential areas, up from the current accepted level of 90 ppt.
Officials at the Michigan Environmental Council said that the rules change could open the state to contamination from other materials that lack state oversight.
MEC policy director James Clift charged that the revision would allow polluters free reign over all decisions involving sites of toxic contamination.
Clift also said the change sets a dangerous precedent, which could possibly lead to the public being exposed to unsafe levels of hazardous chemicals.
Ken Silfven, press secretary for DEQ, argues that the change in numbers is part of a routine process.
“What we’re doing is updating exposure factors for about 300 compounds, of which dioxins are one,” Silfven said. “This is a process we do from time to time.”
Some of the criteria the state had for measuring exposure factors were based on events that aren’t likely to occur, Silfven said.
For example, the criteria did not take into account snow being on the ground during winter and also based the numbers on people wearing short sleeves and shorts for nine months out of the year, he said.
Dioxins are a family of chemical compounds formed by combustion processes, such as waste incineration or fossil fuel burning, by some chemical-making processes and by chlorine bleaching of paper. Only some of the dioxins are harmful to humans.
“Not all dioxins are toxic,” said John Giesy, a zoology professor at Michigan State University. “The different toxicities depend on where the chlorines are located on the compounds.”
Increased dioxin levels in the human body have been found to cause skin rashes, skin discoloration, liver damage, increased risk of certain cancers and possible reproductive or development effects on young children.
According to the U.S. Environmental Protection Agency, dioxins are found in most of the population in trace amounts.
The EPA estimates that about 95 percent of the dioxins found in the human body are from ingesting animal fats, although some people may have a higher amount from workplace exposure, industrial accidents or food contamination.
The foods in which dioxins are most commonly found are diary products, fish and meats.
“Dioxins, if they were in a mixture of oil and water, would eventually all end up in the oil,” Giesy said. “Dioxins accumulate more in fish than in plants because they would rather be in the fish than the water.”
Attorney General Jennifer Granholm opposes the rules change, saying current research does not support increasing the acceptable levels of dioxin.
“If anything, current scientific information suggests that the dioxin cleanup criterion should be tightened, not loosened,” Granholm said.
Recent analysis by a toxicologist in the Department of Community Health suggests that a cleanup criterion of 12 parts per trillion is needed to protect public health, she said.
Giesy argues that it is hard to determine exactly what number is correct.
“It is very hard to say if one number is right or wrong,” Giesy said. “The amount allowed in soil is different depending on the type of soil.”
Silfven said that most of the controversy would be abated when the EPA releases its final report on the toxicity of dioxins.
“We probably will base our numbers on EPA toxicity levels,” Silfven said. “For now, even the federal agency doesn’t have a final number. They just have a draft, and we’re not basing our numbers on a draft.”
© 2002, Capital News Service, Michigan State University School of Journalism
By CHRIS YAGELO