New questions on genetically modified corn
11/14/2007
What do you get when you mix genetically modified corn and caddisflies? That's not the preamble to a joke.
Last
month, researchers funded by the National Science Foundation published
a study in the Proceedings of the National Academy of Sciences
providing the first documented evidence that toxins from genetically
modified corn may get into streams and harm insects that are an
essential food for fish.
The corn is known as BT corn, and it is
designed to manufacture a toxin that provides protection against
agricultural pests -- essentially, the plant that grows from BT corn
seed is a pesticide. The seed is manufactured by a number of large
biotechnology companies, and up until last summer, growing BT corn was
prohibited in Maine.
But a group of dairy farmers in the state
who wanted to grow the corn to feed their cows made the case that BT
corn can be grown more cheaply than conventional corn and thus offered
them competitive advantages -- advantages already enjoyed by farmers in
other states where the corn wasn't prohibited.
They pressed
their case with the state's Board of Pesticides Control, which was the
agency responsible for permitting the corn's planting because it is
considered a pesticide. Their case was met with resistance by the
state's growing number of organic dairy farmers, who asserted that
pollen drifting from the genetically modified corn would contaminate
organic corn used for feed, jeopardizing essential organic
certification for their operations.
The board made a Solomon's
judgment in July and declared it would permit BT corn to be planted in
the state -- but only under a set of strict rules to be devised by late
this year designed to protect organic farmers.
But while they were working on devising those rules this fall, the study about BT corn and caddisflies was released.
The
data in the study is worrisome enough that the board, which was due to
discuss the new rules later this week, should reverse course and
reconsider its permitting of BT corn use in Maine.
When the board
first considered the request for permission to plant BT corn, the major
issue of contention was the genetic contamination of organic corn by
genetically modified corn. That's because the EPA had previously
performed tests to determine the corn's effect on water resources --
and found no significant effects.
But those EPA tests were
problematic -- they didn't look at insects more closely related to the
ones the BT corn's pesticide targeted. So EPA's researchers potentially
missed an entire biological community that could be effected by the
corn. That's what the most recent study looked at. Where the EPA looked
at the crustacean species known as Daphnia, the more recent study
looked at caddisflies, one of the most important food sources for fish.
And what it found, according to the National Science Foundation,
was that the corn's "plant parts are washing into local streams." BT
corn pollen was also "being eaten by caddisflies." In laboratory tests,
"consumption of BT corn byproducts increased the mortality and reduced
the growth of caddisflies," and thus "the toxin in BT corn pollen and
detritus can affect species of insects other than the targeted pest."
Maine's
farmers are an important part of our state's economy, social fabric and
our landscape. Giving them more of a competitive edge is something we
should do -- if possible. But in this case, there's a competing value
that's potentially at risk if BT corn is planted and damages our water
resources. Maine's rivers and streams, the species that depend on them
and the fishing they provide are an equally important part of our
economy, social fabric and landscape. The introduction of a technology
that benefits one, but threatens another, must be carefully weighed.
At
the very least, the Board of Pesticides Control should revoke the BT
corn permits until they can be reconsidered in light of further study.
We
need to know the degree of toxicity posed by BT corn to caddisflies and
other aquatic insects. We need to know how long the toxins persist in
streams and how far the toxicity may travel once it gets into a stream.
The University of Maine's Mitchell Center for Environmental and
Watershed Research has strong staff expertise in stream ecology and
would be ideally suited to pursue this work.
In the meantime, BT corn should not be planted in Maine.
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