CHURCHVILLE, Va.-Five years ago, a group of Minnesota school kids hunting frogs in a wetland discovered that nearly half of the frogs had deformities of the hind legs. Their findings spread over the Internet, feeding into other reports of deformed frogs, declining frog populations and speculation that pesticides were causing deep-seated damage to global ecology.
Eventually, misshapen frogs were found in over 40 states. The Minnesota kids were told by environmental groups that they had gathered the final proof that man-made pesticides should be banned.
The Sierra Club's magazine trumpeted, "How Pesticides are Creating Deformities in Frogs." A headline in Iowa's Des Moines Register newspaper read, "Deformed Frogs Stun Scientists." A Reuter story warned, "U.S. Frog Deformities Could Be Linked to Pesticide."
Now Science magazine has published two papers that demonstrate a natural cause for the deformed frogs: natural parasites. It seems that tiny flatworms burrow into tadpoles and cause frog abnormalities ranging from no hind legs to six extra legs.
One research project examined five species of frogs in 12 U.S. locations and concluded that the deformities are characteristic of parasitic attacks, not chemicals.
A second group of researchers exposed tadpoles to the flatworms in controlled laboratory experiments and found the frogs got the same kinds of deformities as were found in the wild. A control group of tadpoles, protected from the parasites, developed normally.
Undaunted, Judy Helgen of the Minnesota Pollution Control Agency insists, "for us, chemicals are (still) the leading hypothesis."
Of course, the state's environmental protection agency is not totally disinterested in the question. If pesticides are the cause of deformed frogs, then the agency will get more budget to deal with the problem. It will write important new regulations to control what farmers do. Its press conferences will draw lots of reporters.
If deformed frogs are simply another harsh fact of nature, then it will get no extra money and might even have to answer embarrassing questions about why it was conducting large-scale scaremongering based on a school nature trip.
Other researchers across the country still loudly announce that "we don't have all the answers yet" and claim that their lines of inquiry should continue to be funded.
But if the problem turns out to be parasites, not pesticides, they realize their funding will dry up. Almost nobody cares about deformed frogs in the wilds of Minnesota unless they can be used for a political statement.
The Natural Resources Defense Council, World Wildlife Fund, Consumers Union (the publisher of Consumer Reports) and other eco-groups have resigned from President Clinton's food safety advisory panel because they can't produce enough proof of risk for even this green-oriented administration to ban big groupings of man-made pesticides.
The same newspapers that ran the scare headlines on deformed frogs probably also ran Consumer Reports magazine's self-deluded "toxic index" story on the supposed dangers of pesticide residues on fruit. After all, pesticides have been one of the most reliable and longest-running scare stories in the history of journalism. No doubt these papers will simply await the next toxic terror opportunity.
Once again, eco-suspicion has run far ahead of science and embarrassed itself. A few years ago, "pesticides and pollution" were accused of killing dolphins; the killer turned out to be a virus.
Now the National Cancer Institute says that nonsmoking cancer rates in the United States began to decline 30 years ago, even though pesticide use has continued unabated. Medical researchers say our diets and our genes are the major nonsmoking cancer sources. As a country, we eat too many fatty foods and too few fruits and vegetables.
Someday, when advances in biotechnology allow us to rely less heavily on pesticides, historians will look back and snicker at the hysteria over those chemicals that helped cut cancer risks and saved room on the planet for wildlife.
Meanwhile, the frog scare is gone, but stay braced for the next scare headlines on pesticides.
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