April 9, 2001 -- A chemical compound associated with Scotchgard®, the popular stain and spill repellant made by the 3M Company, may be more widespread in the environment than originally thought, according to a new research report. Although there have been no reports of adverse health effects from the compound, which can bioaccumulate in blood, the company began replacing the suspect chemical last year.
The study, funded by 3M, is reported in the April 1 issue of Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society. It is the first global survey and the first study to identify the compound, perfluorooctane sulfonate, or PFOS, in wildlife, says lead researcher John Giesy, Ph.D., of Michigan State University in East Lansing, Mich. The compound in Scotchgard® that repels oil and water can break down over time into PFOS, he said.
Giesy collected more than 2,000 animal tissue samples, from the Pacific Rim to Antarctica, and analyzed more than 400 for PFOS. He found widespread distribution of the chemical and levels in mammals, fish and birds that he described as "surprisingly high." The findings indicate the reach of PFOS into the food chain and the environment, although the amounts found in wildlife are still very small relative to those shown to cause damage in laboratory animals, he noted.
"What we've done is a global survey that shows you, for the first time, that this compound is out there," Giesy said. "We found a good testing method and discovered small amounts [of PFOS] in these remote areas. That surprised me."
Because PFOS accumulates in blood, there is concern about exposure to the chemical worldwide, although no human health problems have been seen in factory workers with occupational exposure to the compound more than 100 times that of the general population, according to Larry Zobel, 3M's medical director. That concern prompted the company to voluntarily begin phasing out the compound in May 2000 in favor of a more benign alternative.
The data from the study show higher PFOS concentrations among animals in urban-industrial areas, according to Giesy. Mammals had the highest doses, followed by birds and fish, he added. Further work is necessary to determine precisely how PFOS became so widespread that it can be found virtually anywhere, Giesy noted.
In previous laboratory testing, adverse health effects in animals were only seen at doses far higher than those found in the current study, according to Giesy. For example, he said, at doses more than 1,000 times greater than the worst study sample, rats' offspring died within days of birth.
PFOS will be phased out of use in all products by 2002, meaning that the compound will no longer be used in 3M products after existing supplies are sold, according to Zobel. Some reformulated Scotchgard® products, starting with carpet treatments, are already in the consumer market, and the rest will enter as supplies are exhausted. 3M is the only U.S. producer of PFOS.
John P. Giesy, Ph.D., is a professor in the department of zoology and at the National Food Safety and Toxicology Center at Michigan State University in East Lansing, Mich.
Materials provided by American Chemical Society. Note: Content may be edited for style and length.
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