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 Rick Relyea at the University of Pittsburgh has recently had published several journal articles
that link the use of Roundup® to global amphibian decline (Arch. Environ. Contam. Toxicol. 48,
351-357, Eco. Appl. 15(4), 1118-1124). While the thought that one stressor is at fault for this
phenomenon may be comforting to some, the conclusions of his
ecological assessment are based on both incorrect assumptions and model
selection. The author was able to generate some toxicity values slightly
less than those known for Roundup® by testing the frogs for 16 days
rather than the standard four days, with solution renewal every four days.
The slightly lower-than-previous values should not have been unexpected
since the exposure period was four times longer than normal. The use of
renewal every four days also simulated retreatment at 4, 8, and 12 days after the initial treatment.
Toxicologists have grappled with the ramifications of static versus static-renewal versus flow-through for some time. He also generated a value that would have placed the material in a
“highly toxic” category, but this was with a predator in the same cage - a design that is not
acceptable for pesticide toxicity testing, in addition to the length of the test. The author then
uses the toxicity values for a deterministic ecological risk assessment of Roundup® applied to a
one-foot pond with no overhead vegetation (using dispersion modeling). Not surprisingly, the
author’s toxicity values were close to modeled concentration values - apparently supporting his
underlying hypothesis. The flaw in the ecological assessment is that Roundup® is not used for
aquatic sites and there would be no need for glyphosate at all if there wasn’t overhead
vegetation. The author concedes that the component that is most lethal to amphibians in
Roundup® is the surfactant, not the glyphosate. The EPA knew this based on the
aforementioned values and so did the registrant. That is why when glyphosate is registered for
use in aquatic sites (as Rodeo®), it is not formulated with a surfactant. The user must add a
surfactant to it (and usually the surfactant is much less toxic than the one in Roundup®). This is
a prime example of poor assessment design leading to apocalyptic predictions (at least for
amphibians).
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 The
EPA recently issued an experimental use permit (EUP) to Syngenta Seeds to test a
B.t. line of corn in a number of states. The proposed issuance was put to
public comment on November 5, 2003. Fourteen comments were received, all of
which objected to the issuance. Commenters expressed concerns regarding human
health, non-target organisms, genetic stability of the plant-incorporated
protectant, invasive species, endangered species, B.t. protein in soil,
insect resistance and management, impact of this EUP on the use of foliar B.t.,
impacts on organic crops and farmers, identity preservation, and several other
topics. The EPA responded that “for organic products under NOP, the fact that
some portion of the crop was pollinated by B.t. corn from a crop planted
outside the boundaries of an appropriately segregated organic crop would not
adversely impact the farmer’s ability to sell the crop as organic.” The Agency
went on to state that it “has concluded that there is a reasonable certainty
that no harm will result from dietary exposure to this protein as expressed in
genetically modified corn.” The EUP was issued on August 10, 2005, and it was
effective from May 6, 2004 until August, 15, 2005, leaving the company only five
days to do the work.
Note: Keep in mind this is only using 2.9 g of toxin to protect 300 acres of
corn - an amazingly small amount.
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