[APWG] Fw: frogs & roundup
jferriga
jferriga at vt.edu
Fri Apr 8 17:49:48 CDT 2005
I feel obliged to add my two cents since my thesis work was an amphibian
toxicology project and one of the chemicals we investigated was the commercial
formulation of Roundup.
In our study found the LC50 of Roundup to be 20 mg/L to Rana pipiens. We also
investigated repeated exposures of 10mg/L and lower to other amphibian spp.
tadpoles (wood frog and grey treefrog) and eggs (wood frog and American toad)
but did not find significant effects on survival.
Reylea's new study reports Roundup at a concentration of 3.8 mg/L resulted in
complete mortality of leopard frog and grey tree frog tadpoles in a day. I
haven't read the journal article yet but was forwarded this summary article
http://sciencenow.sciencemag.org/cgi/content/full/2005/405/2 I don't know why
the diff between our study and Reylea's but it could be spp diffs and lab
conditions - we tested species individually in tanks with sediment and water -
Reylea's tanks were designed to more closely simulate a pond ecosystem with
plankton, a mix of tadpole spp and other organisms - according to Science Now.
Other studies have reported the toxicity of glyphosate and POEA to amphibians
- I'll list the refs at the end
Roundup® herbicide contains isopropylamine (ipa) salt of glyphosate formulated
with approximately 15% POEA. As others have mentioned, previous studies have
shown amphibians and other aquatic organisms to be particularly sensitive to
glyphosate formulations containing POEA - that is why Rodeo or similar without
POEA is recommended for water use.
Perkins et al. [25] used the Frog Embryo Teratogenesis Assay-Xenopus (FETAX)
to determine effects of Roundup® and ipa salt of glyphosate without a POEA
surfactant. LC5 and LC50 values of 5102 and 7299 mg/L were respectively
determined for glyphosate alone. The Roundup® herbicide LC5 and LC50 values
were 19.18 and 28.2 mg/L respectively (results reported as acid equivalent
values in Perkins study and were converted to mg/L here for comparison ). In
a genotoxicity study, Clements et al. used the alkaline single-cell gel DNA
electrophoresis assay to examine DNA damage in Rana catesbeiana tadpoles
exposed to various concentrations of Roundup®. Tadpoles exposed to 6.75-27.0
mg/L of herbicide showed significant increases iin DNA and cell damage
compared to control tadpoles.
Other organisms
Gardner and Grue looked at survival of duckweed, Daphnia and rainbow trout on
nontarget wetland spp in Washington after exposure to Garlon 3A (5L/ha) and
Rodeo (1L/ha) in purple loosestrife treatment areas. Survival of organisms
were monitored at least 24 h following application of each herbicide. Neither
chemical was associated with significant decreases in survival of duckweed,
Daphnia or rainbow trout (although they did think Rodeo sign affected duckweed
growth 48 h after treatment).
Other studies on Ecorelevant Levels
Newton et al. evaluated glyphosate herbicide residues in forest brush field
ecosystems in the Oregon Coast Range that were aerially treated with 3.3 kg/ha
glyphosate. The half-life of glyphosate ranged from 10 to 27 days in foliage
and litter and 29 to 40 days in soil. The treated stream peaked at 0.27 mg/L
and decreased rapidly. Stream sediment picked up glyphosate residues more
slowly than water but reached higher levels. In general, concentrations were
higher and persisted longer in sediment than in water. Sorry Steve, no info on
breakdown of POEA in this study. Pond concentrations, of course are likely
higher than streams. The Science Now article says Reylea reports that 3.8
mg/L is about the highest concentration of Roundup to be found in nature.
Amphibians are a sensitive group but are not standardly used for determining
eco-toxicity of pesticides and toxicity
of a pesticide is usually determined by testing the toxicity of the active
ingredient, not chemical formulations which include surfactants.
I recognize herbicides as effective tools in invasive plant management and we
use Roundup in our program. We do take care to use glyphosate without POEA
formulations of herbicides when working close to water bodies (usually within
10 m) or in wet areas. Well I don't think toxicity should be overblown, I do
think Reylea's study and others like it are good reminders that ecotoxicity is
a complex issue, (as is ecosystem management), and we should continue to
investigate toxicities to non-target organisms, esp sensitive organisms like
amphib spp. and be judicious in our pesticide use (sorry I don't have a
formula for judicious) but I think common sense and good pesticide safety
practices are definitely in order.
Hope this helps and doesn't just muddy the water even more.
Jan Ferrigan
Invasive Plant Program Coordinator
Arlington County, VA
Some refs on glyphosate and formulations - I can't find the Lancet journal
article in my files but if I remember correctly that study estimated the
amount of Roundup used by some Japanese people to commit suicide and it was
somewhere around a cup - showing POEA is probably not a great drink
Folmar, LC, Sanders, HO, Julin AM. 1979. Toxicity of herbicide glyphosate and
several of its formulations to fish and aquatic invertebrates. Archives of
Environmental Contamination and Toxicology 8:269-278.
Sawada, Y, Nagai Y, Yamamoto I. 1994. Probable toxicity of surface-active
agent in commercial herbicide containing glyphosate. Lancet 1:299.
Martinez, TT, Brown, K. 1991. Oral and pulmonary toxicology of the surfactant
used in Roundup herbicide. Proceedings of Western Pharmacology Society
34:43-46.
Bidwell, JR, Mann, RM. 1999. The toxicity of glyphosate and several glyphosate
formulations to four species of southwestern Australian frogs. Arch Environ
Contam Toxicol 36:193-199.
Perkins PJ, Boermans, HJ, Stephenson, GR. 2000. Toxicity of glyphosate and
triclopyr using the frog embryo teratogenesis assay-Xenopus. Environmental
Toxicology and Chemistry 19:940-945.
Clements CS, Ralph S, Petras M. 1997. Genotoxicity of select herbicides in
Rana catesbeina tadpoles using the alkaline single-cell gel DNA
electrophoresis (comet) assay. Environmental and Molecular Mutagenesis
29:277-288.
Gardner and Grue 1996. Effects of Rodeo and Garlon 3A on nontarget wetland
species in Central Washington. Envir Tox and Chem Vol 15 No 4 pp 441-451
>===== Original Message From Jil_Swearingen at nps.gov =====
>Hi,
>
>Please see article below about the impacts of the surfactant
>"polyethoxylated tallowamine" on amphibians. The surfactant is an
>ingredient in Roundup. Glyophosate was not responsible for the frog kills.
>
>Thank you,
>
>Jil
>
>----- Forwarded by Jil Swearingen/NCR/NPS on 04/05/2005 01:35 PM -----
>
> Bruce Badzik
> To:
> 04/04/2005 03:11 cc:
> PM PDT Subject: Fw: frogs & roundup
>
>
>
>
>In case you have not seen this yet. It is important to note that at the
>bottom of the article, it notes that it is not glyphosate that causes the
>problem, but the surfactant. This is something that is not new news,
>contrary to the last line of the article. That is why there is Aqua Master
>(formerly Rodeo), it is Roundup without the surfactant. The use of Roundup
>in a manner such as done in this study would be a violation of the law.
>
>-----------------------------------------------------------------------------
----------------------------------------------------------------------------
>
> Roundup® highly lethal to amphibians, finds University of Pittsburgh
> researcher
>
> PITTSBURGH--The herbicide Roundup® is widely used to eradicate weeds. But
> a study published today by a University of Pittsburgh researcher finds
> that the chemical may be eradicating much more than that.
>
> Pitt assistant professor of biology Rick Relyea found that Roundup®, the
> second most commonly applied herbicide in the United States, is "extremely
> lethal" to amphibians. This field experiment is one of the most extensive
> studies on the effects of pesticides on nontarget organisms in a natural
> setting, and the results may provide a key link to global amphibian
> declines.
>
> In a paper titled "The Impact of Insecticides and Herbicides on the
> Biodiversity and Productivity of Aquatic Communities," published in the
> journal Ecological Applications, Relyea examined how a pond's entire
> community--25 species, including crustaceans, insects, snails, and
> tadpoles--responded to the addition of the manufacturers' recommended
> doses of two insecticides--Sevin® (carbaryl) and malathion--and two
> herbicides--Roundup® (glyphosate) and 2,4-D.
>
> Relyea found that Roundup® caused a 70 percent decline in amphibian
> biodiversity and an 86 percent decline in the total mass of tadpoles.
> Leopard frog tadpoles and gray tree frog tadpoles were completely
> eliminated and wood frog tadpoles
> and toad tadpoles were nearly eliminated. One species of frog, spring
> peepers, was unaffected.
>
> "The most shocking insight coming out of this was that Roundup®, something
> designed to kill plants, was extremely lethal to amphibians," said Relyea,
> who conducted the research at Pitt's Pymatuning Laboratory of Ecology. "We
> added
> Roundup®, and the next day we looked in the tanks and there were dead
> tadpoles all over the bottom."
>
> Relyea initially conducted the experiment to see whether the Roundup®
> would have an indirect effect on the frogs by killing their food source,
> the algae. However, he found that Roundup®, although an herbicide,
> actually increased the amount of algae in the pond because it killed most
> of the frogs.
>
> "It's like killing all the cows in a field and seeing that the field has
> more grass in it--not because you made the grass grow better, but
> because you killed everything that eats grass," he said.
>
> Previous research had found that the lethal ingredient in Roundup® was not
> the herbicide itself, glyphosate, but rather the surfactant, or detergent,
> that allows the herbicide to penetrate the waxy surfaces of plants. In
> Roundup®, that surfactant is a chemical called polyethoxylated
> tallowamine. Other herbicides have less dangerous surfactants: For
> example, Relyea's study found that 2,4-D had no effect on tadpoles.
>
> "We've repeated the experiment, so we're confident that this is, in fact,
> a repeatable result that we see," said Relyea. "It's fair to say that
> nobody would have guessed Roundup® was going to be so lethal to
> amphibians."
>
> Abstract:
>
http://www.esajournals.org/esaonline/?request=get-abstract&issn=1051-0761&volume=15&issue=2&page=618
> http://www.eurekalert.org/pub_releases/2005-04/uopm-rhl040105.php
>
>
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