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Deformed frogs spur tap-water warning

Tainted water probably is to blame for the deformities of frogs that were born with extra or misshapen limbs, missing or shrunken eyes and small sex organs. As a precaution, some households are being told not to drink tap water.

Reports of deformed frogs have come from throughout Minnesota, two dozen other states and Canada over the past two years, and researchers say water is almost certainly the cause."We're as close to 100 percent as you can get," said George Lucier, director of the environmental toxicology program at the National Institute of Environmental Health Sciences in North Carolina, which is working with the Minnesota Pollution Control Agency.

Researchers took water from three northern Minnesota wetlands where deformed frogs had been seen, mixed that water with tap water in varying ratios, and used the mixtures to grow frogs' eggs. Plain tap water was also tested, as was 100 percent wetlands water.

When the researchers used mixtures with more than 50 percent wetlands water, most of the African clawed frog embryos showed a wide range of abnormalities. The frog is a different species from those found in the wild in Minnesota, but lends itself to lab research. Even some samples of plain tap water produced deformed embryos.

The next step will be a chemical analysis of the water to learn what particular contaminant is lurking. Researchers also will try to determine whether the contaminant has an effect on humans.

The state is distributing bottled water at four northern Minnesota households where tap water samples produced deformed frog embryos. Peder Larson, commissioner of the state Pollution Control Agency, would not specify the locations, but said nearby residents also had been notified.

"We have no indication at all right now that this is a human health concern," Larson said Tuesday. "It was a precaution that we thought was reasonable."

The agencies have been working on the study since April with several partners. The contaminated water came from wetland sites where high numbers of deformed frogs have been found.

The findings are preliminary and haven't been reviewed or replicated.

The preliminary findings don't rule out other potential causes, such as ultraviolet radiation, parasites, viruses, disease or a combination of factors.