Modified-crop studies are called inconclusive
New York Times, USA, by Carol Kaesuk Yoon
Modified-crop studies are called inconclusive
Ever since genetically modified crops appeared, supporters and
detractors of the plants have made competing claims about whether
they are safe or harmful to the environment. Tomorrow, in what some
scientists say is the first comprehensive review of the published
scientific data, researchers will report that simple conclusions
cannot yet be drawn because the crucial studies have not yet been
done. Millions of acres of the crops have been planted in the United
States, their way paved by studies conducted by industry and
submitted to government regulators as evidence of safety but which
typically were not published in peer-reviewed journals.
For this review, the researchers examined only studies that other
scientists had determined were of high- enough quality to merit
publication. The researchers found that while genetically engineered
crops hold potential for both risk and benefit, scientists still know
little about the likelihood even of the environmental threats of
greatest concern. Also, almost no studies have been published
documenting ecological benefits.
The two authors of the study published in the journal Science are
fellows sponsored by the American Association for the Advancement of
Science, the world's largest nonprofit scientific federation. In
their study, in which they call for new research, the authors say
current data indicate that assessing ecological risks is likely to be
complex, with risks varying among crops, even among strains of a
single crop, between environments and over time. Some risks, they
say, may be so difficult and time-consuming to assess as to be
effectively unknowable.
"We're a ways away from really having answers," said Dr. LaReesa
Wolfenbarger, an ecologist who is doing her fellowship at the
Environmental Protection Agency and is co- author of the study with
Dr. Paul Phifer, a conservation biologist doing his fellowship at the
State Department. The authors emphasized that they had conducted the
study independently and did not speak for the government. "Some of
these questions are very elusive," Dr. Wolfenbarger said, "but that
doesn't mean that we stop studying them or make sweeping
generalizations that they don't exist." Scientists on both sides of
the debate called the review fair and accurate, though each side
interpreted the findings differently.
"It's a pretty reasonable summary and pretty well balanced," said Dr.
Robert Fraley, chief technical officer of the Monsanto Company. Dr.
Fraley played down the findings, however, saying that in several
years of commercial use, no ecological problems had yet been shown to
be caused by genetically engineered plants.
Dr. Jane Rissler, senior staff scientist at the Union of Concerned
Scientists, a group critical of the use of genetically modified
crops, called the paper "very fair and clear." Dr. Rissler said: "You
come out of this with a strong sense that we don't know very much
about the risks and the benefits. If we don't know, why are we doing
this?"
A spokeswoman for the Department of Agriculture, which oversees
regulation of genetically engineered plants, said scientists at the
department were reviewing the study.
The researchers examined 35 peer-reviewed studies. They looked at
risks including the production of "superweeds," the creation of new
viral diseases and unintended harm to nonpest species, like monarch
butterflies. They often found that while studies suggested a
potential for risk, other studies presented conflicting results
arguing against risk. In some cases, laboratory studies suggested
risk, but no studies in the field were conducted to test if harm
occurred.
And while some studies showed the potential for environmental
benefits from these crops, the researchers found they fell short of
documenting actual benefit. For example, a Department of Agriculture
study indicated a 1 percent decrease in the amount of pesticides used
on corn, cotton and soybeans in 1998, as an apparent result of the
adoption of genetically modified crops. Yet, Dr. Wolfenbarger said,
it remains unknown whether this decrease in pesticides translated
into any environmental benefit for wild species.