Scientists are narrowing in on pesticides as the cause of deformities
At first it seemed like a bad dream or an oddball freak of nature. In August 1995, a
class of Minnesota middle-school students on a field trip to a farm wetland found a frog
with a missing leg. Then another and another. By the end of their trip, the students had
caught 22 frogs, half of which had missing or deformed legs.
The students reported their observations to the Minnesota Pollution Control Agency.
Within weeks of their widely publicized discovery, more reports of deformed frogs poured
in from other areas. Now the Great Lakes region, New England, the Pacific Northwest, and
the St. Lawrence River valley in Quebec are North American hot spots for deformed frogs.
Whodunit? A final verdict has yet to be reached, but the leading suspects are
pond-dwelling parasites called trematodes and chemical contamination from pesticides and
Scientists have linked parasites to frog deformities in the Pacific Northwest and the
Northeast but exonerated them elsewhere. In the case of the Minnesota frog deformities, a
research group led by National Institute of Environmental Health Sciences biochemist James
Burkhart points to a still unidentified chemical or combination of chemicals as the most
likely culprits. The group's report, published in last December's Environmental Health
Perspectives, adds to the work of other scientists who suspect pesticides or other
chemicals that disrupt endocrine systems.
Meanwhile, Canadian research has identified agricultural pesticides as a main cause of
frog deformations in a farm-rich area outside Montreal. Seven years ago, veterinarian
Martin Ouellet began tracking the overall abundance and health of frogs in the St.
Lawrence River valley, particularly in ponds on farms that use pesticides. "I was
expecting to find a lot of tumors and cancers," Ouellet says, since fish in polluted
waters often develop such symptoms. Instead, he found a variety of deformities, including
missing and malformed legs.
Since then, Ouellet has examined 30,000 frogs in 100 ponds. In ponds exposed to
pesticides through spraying drift, runoff, or careless disposal of pesticide containers,
15 to 20 percent of the frogs were deformed. In unexposed control ponds, misshapen frogs
amounted to 2 percent or less-a level that conforms to what scientists believe is a
natural rate of deformity. "It's very clear that there are many things that can cause
deformities," Ouellet concludes. "In my area, there is a clear association with
Together with a team of scientists from McGill University and the Canadian Wildlife
Service, Ouellet examined the genetic condition of St. Lawrence River valley frogs.
Abnormal DNA profiles, the researchers found, were significantly more common in frogs from
pesticide-laden ponds, whether or not the frogs had obvious deformities. The ponds Ouellet
studied were tainted with carbofuran, used on corn crops, and azinophos-methyl, used on
potato fields. He notes that specifying exactly which ingredient in the "cocktail of
pesticides" is hurting the frogs will require more research.
Another Canadian study found that pesticides may cause wild frogs problems beyond DNA
changes and deformities. Exposure to the pesticide endosulfan at very low levels (similar
to those at which it might drift over a pond from aerial spraying) can cause lethargy and
twitching in tadpoles, making them easier for predators to catch.
Scientists are notoriously cautious about drawing broad conclusions from their data.
Still, one biologist studying the Minnesota deformities confided that his research has
changed his shopping habits: he now buys only pesticide-free produce.Kathryn
Battle of the Bigs:
Oil companies and Detroit pass the buck
Proponents of new clean-air standards have found an unlikely ally: Detroit. Auto
manufacturers are supporting a requirement that gasoline contain less
pollution-causing sulfur. Carmakers are backing the measure because sulfur
damages catalytic converters, which are critical to efforts to reduce tailpipe
pollution. To no
one's surprise, the oil companies are fighting the proposal. They say that
retooling refineries will be costly, causing the price of gasoline-at its lowest
level in decades-to increase up to six cents a gallon.
But Detroit has hardly turned green. It is nowhere near as
excited about another clean-air proposal, one that would prohibit sport utility
vehicles, minivans, and pickup trucks (collectively known as "light trucks") from
polluting more than cars.
Clean-air activists are urging the Environmental Protection Agency to be firm
Big Three and Big Oil. "If we want our kids to breathe clean air," says Ann
Mesnikoff, director of the Sierra Club's Clean Car campaign, "we need both
cleaner cars and cleaner gas."
According to the EPA, 107 million Americans breathe dirty air, and autos create a
large-and easily targeted-part of the problem. The agency's proposed clean-air
regulations would address the light-truck loophole, sulfur levels in gasoline,
and particulate pollution created by diesel engines. The most comprehensive
attempt to tackle air pollution since passage of the Clean Air Act amendments in
1990, the rules should be finalized by the end of the year.
The Sierra Club and state pollution-control officials want a nationwide sulfur
standard modeled after the one already in effect in California: 30 parts per
million, compared to
the current national average of 300 parts per million. According to the State and
Territorial Air Pollution
Administration, an association of government air-pollution-control officials,
reducing sulfur levels nationwide would be the equivalent of taking 54 million
cars off the road. The oil industry wants to exempt western states from the new
rules, because they have low populations and fewer Clean Air Act violations than
the rest of the country.
"Their message," says Mesnikoff, "is 'let western states stay dirty.' " She
points out a serious problem with inconsistent regulations: if drivers from
clean-gas states buy fuel in dirty states, they could damage their
emission-control systems and pollute the air when they return home.
Closing the light-truck loophole will contribute to clean air just as
dramatically. These vehicles, which don't have to meet the same fuel-efficiency
standards as cars, are also allowed to spew more pollutants per mile. Both
loopholes are holdovers from the early 1970s, when "light trucks" were treated
less stringently than passenger cars because they were a small part of the
market, used primarily as farm and work vehicles. Today, these light trucks are
more often substitutes for cars, and they now outsell passenger cars in the
California has already done away with the discrepancy in emission standards
between cars and light trucks, effective in 2004. And since Ford already produces
several sport-utility behemoths whose tailpipe emissions are no worse than their
cars', the handwriting is on the wall for other manufacturers. Predictably, the
industry is whining about the cost of the proposed regulation. But their bottom
lines will hardly be affected, because every large sport utility vehicle sold can
generate $10,000 or more in profit. The California Air Resources Board says that
light trucks can meet the new standards for under $250. Because so many people
drive these vehicles, benefits to the environment will add up quickly.
But the problem won't truly be solved until enough drivers ignore
Detroit's ad blitz, take a deep breath, and exercise restraint in the showroom.
While the 5,600-pound Lincoln Navigator is one of a few sport utes that meet the
EPA's low-emission standard, it still gets only 12 miles per gallon as it lumbers
along to the supermarket or soccer practice. Over its lifetime, it will spew more
than 70 tons of carbon dioxide, the primary global-warming pollutant. If that
doesn't make you choke, Ford is readying its next loophole vehicle: the
19-foot-long Excursion. This "sport" ute is so heavy that fully-loaded versions
may be able to ignore the so-called light-truck emissions standards entirely.
Finding themselves staring into the tailpipe of this global-warmer while stuck at
a stoplight, some drivers may decide it ignores standards of decency, too. Reed
Rocky Mountain Hothouse Flowers
At the same time Rocky Mountain National Park is trying to ban commercial
helicopter flights into backcountry areas, it is approving chopper transport for
tenderfoot government workers.
For the past three years, government soil scientists working in the park's Mummy
Range and Paradise Park wilderness areas have hiked in, but now they're tired and
want to fly, according to Public Employees for Environmental Responsibility. In a
memo approving the request, park officials noted that the "agency culture and
individual backgrounds" of the scientists "do not lend themselves towards days of
hiking and camping without the normal accoutrements." The head scientist
explained that he wanted a shower at the end of the day. A dip in a mountain lake
won't do?Paul Rauber
MYTHBUSTER: Not Clean Enough
In December, the Better Business Bureau called on the Washington, D.C.-based
Nuclear Energy Institute to stop running advertisements claiming that nuclear
power is "environmentally clean." By neglecting to mention the nuclear waste and
air pollution caused by producing nuclear fuel, the bureau said, the nuclear
industry's ads went too far in trumpeting the safety and cleanliness of nuclear
What motivated the longtime champion of complaining consumers everywhere to take
on the nuclear industry? Utility deregulation. In the past, the nuclear industry
might have gotten away with image ads touting whatever environmental virtues they
could conjure up. But now that they're players in the consumer marketplace, the
bureau reasons, it's time to tell the truth.
"We felt it is very important that, as this market opens up, claims about the
environment be very clear and very specific," said Andrea Levine, director of the
national advertising division at the Council of Better Business Bureaus in New
York. "You can sort of think of it as a warning shot to the industry."
Environmental groups applauded the bureau's move, and the institute promised to
consider the nonbinding decision in future advertisements.