| In the highly charged debate over biotech crops, supporters
and critics can agree on one thing: New strains are sold and planted
before much is known about their ecological effects - and too little is
being done to find out about them.
Genetically engineered corn, soybeans and cotton already are staples on
millions of acres of farmland in North America. Yet studies of potential
risks often are conducted after a new strain of gene-spliced seeds has
taken root on farms - too late for the environment or the approval
process.
As a result, some researchers say, the world's fields are becoming a
laboratory for the largest unplanned ecological experiment in agricultural
history.
"We look at genetically modified crops, and we know what the
potential hazards may be," says Alan McHughen, a plant geneticist at
the University of Saskatchewan in Saskatoon. "But we want to know
what the hazards really are before they go out" into the marketplace.
"The question of hazards is real, and it's not going to go
away," he adds.
Two recent studies highlight potential ecological risks of genetically
engineered crops.
In the current issue of the journal Science, a pair of British
scientists suggest that starling populations could drop by as much as 90
percent if farmers adopt a new strain of sugar beets tailored to tolerate
herbicides. Using a computer model, the scientists found that the
starlings' plight depended on how widely farmers adopted the sugar beets
and how much herbicide they applied to their fields - depriving the birds
of the weed seeds they eat.
Ironically, the threat to the birds didn't come from the plants
themselves, but from farming practices that could result from the plants'
introduction.
Also, late last month, researchers from Iowa State University in Ames
published the results of experiments studying genetically modified corn
and butterflies. It suggests that monarch butterflies are threatened by
pollen from corn that's engineered to produce a toxin fatal to a pest
called the European corn borer.
The work, which appeared in the journal Oecologia, is the latest in a
series of yes-it-does, no-it-doesn't results from various scientists
trying to determine whether the pollen seriously threatens the
butterflies.
On a scientific level, "there is nothing terrible about any of
these studies," even when results appear contradictory, says Jane
Rissler, a senior scientist at the Union of Concerned Scientists. "No
one study is really definitive; you need an accumulation of evidence over
time."
But researchers say they face a number of hurdles in trying to build
that body of knowledge.
First, the regulations governing tests can be counterproductive.
Scientists must isolate test fields of key crops such as corn and canola
because they produce copious amounts of pollen, which can be blown beyond
the field and inadvertently mix with other plant species. Yet offsite
effects are among the risks scientists want to quantify.
Moreover, test plots are vulnerable to attacks from activists who
oppose any use of genetically engineered crops.
On Aug. 25, a group called the Los Nios del Maiz claimed responsibility
for an attack that destroyed 1,500 to 2,000 corn plants and damaged a
range of other plants in four greenhouses at the University of California
at San Diego's biology field station. Only a small fraction of the plants
the group destroyed were the result of genetic engineering, according to
Maarten Chrispeels, director of the university's Center for Molecular
Agriculture.
In other cases, it can be difficult to repeat experiments. "The
amount of transgenic material (genetic information that can be
transferred) is limited," says John Obrycki, one of the Iowa State
University scientists involved in the most recent corn-pollen study.
Initially, it's possible to work with the seeds' developers to find out
whether a plant is likely to pass a trait or toxin to another species. But
here in the United States, regulators require only a one-year trial before
a seed strain is approved for sale. Once the seeds go on sale, Obrycki
says, companies often are less willing to give them to researchers wanting
to conduct further tests for potential risks. He argues that the approval
process should require two years of testing instead of one.
Finally, funding remains tight for risk studies. In the U.S., for
example, the Department of Agriculture spends about $1.7 million a year
for risk assessment.
"That's a tiny amount of money compared with what the biotech
industry spends to develop and market new products," says Rebecca
Goldburg, a senior scientist at Environmental Defense.
The result, critics say, is an approval process that lacks sufficient
data to assess the risk of genetically engineered crops.
That theme also emerges from a generally biotech-friendly report from
the National Academy of Sciences. In the April study, the academy noted
that, as the proportion of genetically engineered crops and the rate of
their introduction increases, more research is needed to assess risks to
human health and the environment.
Yet others say more money for risk studies is not the answer. They
argue that scientists should mine data already accumulating on biotech
crops. Such information can be incorporated into models that can help
researchers predict possible environmental outcomes from planting
genetically engineered crops.
Yet even data-mining proponents look longingly at a comprehensive
research project under way in Britain to address risks from biotech crops.
The government is spending 8 million ($11.7 million) over three years to
look at the effects of modified corn, canola, and sugar beets.
Says Frank Forcella, a plant geneticist with the University of
Minnesota at Morris: "That level of funding for field experiments is
fantastic even by Yankee standards." |