I have actually read this paper - it its entirety, and a number of
other studies. In fact, the EPA lab that I used to work at in Corvallis
did research on this topic for many years.
The truth is, that most experiments are designed to replicate what
would runoff or drift into a pond under normal conditions. Now,
subsequent research indicates that glyphosate - and 2,4-D - is actually
toxic to amphibians - and humans too, as a matter of fact. The issue,
as with all poisons, is one of dose. Direct mortality occurs at higher
dosages than are usually encountered when the glyphosate is present
alone. But the surfactant, which may or may not be directly toxic,
increases the absorption rate so that the animals recieve a much larger
dose much more quickly. Remember that amphibians have permeable skin
and thus compounds applied to it penetrate directly to the internal
organs.
This concept is well-known to most wildlife biologists, and when I
treated invasive giant knotweed along streambanks on several National
Wildlife Refuges, we used Rodeo (Garlon), as it is a more stable
compound, but we used it WITHOUT surfactants. That's right - 100%
straight syrup. Absorption was slower, so we injected where necessary.
Still killed the weeds, but without affecting the amphibian populations
in the area.
[NAFEX] Fwd: More Evidence that Monsanto's HerbicideRoundup is,
Lon J. Rombough, 07/02/2008