Hi Paul,
what the study showed is that sublethal doses of malathion can
negatively affect leopard frog tadpoles by affecting their food chain.
Sublethal to leopard frogs, but lethal to zooplankton. Its a matter of
insecticide/weedicide CONCENTRATIONS. Yes, it can be that in the field,
such concentrations are often lower than in the U Pitt tank study.
However there can be (and will be) instances where this concentration
may be reached or even exceeded, depending on topography/drainage,
rainfall and a host of other factors. Even with low concentrations,
there can be accumulations over time, which can then lead to a lag time
between application and observable effects. By then the momentum of
negative effects can be too high, and too late to reverse conditions, so
that the hundreds of leopard frogs that were flushed by a t-storm in MN
may not happen a few (?) decades from today...
The message I got from this study is that concentrations lower than lab
determined lethal doses can harm the organism in question, by also
harming the ecosystem - kind of an urging for ecotoxicology to put more
emphasis on ecosystems and not just organisms in isolation.
Hmm.. now what Monsanto says, well, lets say they would not wish to saw
the branch they're sitting on, would they..
Cheers,
amartya
Paul Cherubini wrote:
Dr. Rick Relyea wrote:
Pitt Research Shows That Low Concentrations of Common Insecticide
Can Decimate Tadpole Populations Through the Food Chain
Dr. Relyea, your study did not show that any routine, legally compliant
applications Malathion insecticide (such as the aerial applications typically
used for mosquito control) can decimate tadpole populations through the
food chain in a natural wetland system. It also did not demonstrate these
routine applications are capable of wiping out the zooplankton in
natural wetland systems, causing surface dwelling algae to grow rapidly
hence preventing sunlight from reaching the bottom-dwelling algae, which
tadpoles eat.
Instead, your studies were conducted in small, confined cattle tanks
http://www.chronicle.pitt.edu/?p=660 Monsanto has previously
pointed out that "It is not unusual for studies conducted in artificial
systems to demonstrate greater toxicity than studies conducted under
actual environmental conditions." A detailed rebuttal response from
Monsanto to your Roundup herbicide work can be found on Monsanto's
website:http://www.monsanto.co.uk/news/ukshowlib.phtml?uid=8800
Leopard and wood frogs naturally range across North America,
including Pennsylvania and the Northeastern United States. Once
plentiful, leopard frogs have declined in recent years.
Ironically, leopard frogs are still very abundant in regions of the USA
where Roundup herbicide and insecticide use has been very high
such as around the Roundup Ready soybean and corn monocultures
that cover ~70% of the land mass of southern Minnesota and Iowa:
http://i85.photobucket.com/albums/k75/4af/frogb.jpg
Example: Just two months ago during an evening thunderstorm I saw
hundreds of leopard frogs hopping across the farm roads in southern
Minnesota (Klossner, Minnesota) and hundreds of them ended up
being smashed by cars. I've experienced the same phenomenon along
the farm roads of Iowa many times. The chemical giants like Monsanto
and Dupont could make a documentary film for the public and
academic community substantiating this abundance if they wanted to.
Paul Cherubini
El Dorado, Calif.
