Request for Question Clarification by
tlspiegel-ga
on
26 Mar 2005 07:40 PST
Here is the information on Aqua Master. If what I have posted as
clarifications for you answer your question, please post a Request for
Clarification asking me to post in the answer box.
GLYPHOSATE - M. Tu, C. Hurd, R. Robison & J.M. Randall
http://66.102.7.104/search?q=cache:nHh6TR3UX5QJ:tncweeds.ucdavis.edu/products/handbook/14.Glyphosate.doc+Monsanto+herbicide+AquaMaster+kills+frogs&hl=en
or: http://tncweeds.ucdavis.edu/products/handbook/14.Glyphosate.doc
(Monsanto) is now being manufactured by Dow AgroSciences and Monsanto
is now producing Aquamaster®
Synopsis
Glyphosate is a non-selective, systemic herbicide that can control
most annual and perennial plants. It controls weeds by inhibiting the
synthesis of aromatic amino acids necessary for protein formation in
susceptible plants. Glyphosate is strongly adsorbed to soil
particles, which prevents it from excessive leaching or from being
taken-up from the soil by non-target plants. It is degraded primarily
by microbial metabolism, but strong adsorption to soil can inhibit
microbial metabolism and slow degradation. Photo - and chemical
degradation are not significant in the dissipation of glyphosate from
soils. The half-life of glyphosate ranges from several weeks to
years, but averages two months. In water, glyphosate is rapidly
dissipated through adsorption to suspended and bottom sediments, and
has a half-life of 12 days to ten weeks. Glyphosate by itself is of
relatively low toxicity to birds, mammals, and fish, and at least one
formulation sold as Rodeo® is registered for aquatic use. Some
surfactants that are included in some formulations of glyphosate,
however, are highly toxic to aquatic organisms, and these formulations
are not registered for aquatic use. Monsanto?s patent for glyphosate
expired in 2000, and other companies are already selling glyphosate
formulations.
[...]
Water
Because glyphosate binds strongly to soils, it is unlikely to enter
waters through surface or sub-surface runoff except when the soil
itself is washed away by runoff, and even then, it remains bound to
soil particles and unavailable to plants (Rueppel et al. 1977, Malik
et al. 1989). Most glyphosate found in waters likely results from
runoff from vegetation surfaces, spray drift, and intentional or
unintentional direct overspray. In most cases, glyphosate will
dissipate rapidly from natural water bodies through adsorption to
organic substances and inorganic clays, degradation, and dilution
(Folmar et al. 1979; Feng et al. 1990; Zaranyika & Nyandoro 1993;
Paveglio et al. 1996). Residues adsorbed to suspended particles are
precipitated into bottom sediments where they can persist until
degraded microbially with a half-life that ranges from 12 days to 10
weeks (Goldsborough & Brown 1993; EXTOXNET 1996). At least one study
found that >50% of the glyphosate added directly to the waters of an
irrigation canal were still present 14.4 km downstream (Comes et al.
1976).
[...]
Environmental Toxicity
Aquatic Species
Glyphosate itself is of moderate toxicity to fish. The 96-hour LC50
of technical grade glyphosate for bluegill sunfish and rainbow trout
are 120 mg/L and 86 mg/L, respectively. Fish exposed to 5 mg/L of
glyphosate for two weeks were found to have lung damage and liver
damage was observed at glyphosate concentrations of 10 mg/L (Neskovic
et al. 1996). The technical grade of glyphosate is of moderate
toxicity to aquatic species, and the toxicity of different glyphosate
formulations can vary considerably. For example, Touchdown 4-LC® and
Bronco® have low LC50s for aquatic species (<13 mg/L), and are not
registered for aquatic use. On the other hand, Rodeo® has relatively
high LC50s (>900 mg/L) for aquatic species and is permitted for use in
aquatic systems. The surfactant in Roundup® formulations is toxic to
fish, however, Rodeo® has no surfactant, and is registered for aquatic
use.
The surfactant X-77 Spreader®, which is often used in conjunction with
Rodeo®, is approximately 100 times more toxic to aquatic invertebrates
than Rodeo® alone (Henry et al. 1994). The surfactant MONO818® is
included in Roundup® formulations because it aids the break-down of
surface tension on leaf surfaces, but it may also interfere with
cutaneous respiration in frogs and gill respiration in tadpoles (Tyler
1997 a,b). In addition, MONO818® is highly toxic to fish (Folmar et
al. 1979; Servizi et al. 1987). The LC50 of MONO818® is 2-3 mg/L for
sockeye, rainbow, and coho fry (Folmar et al. 1979; Servizi et al.
1987; Tyler 1997 a,b). The LC50 of Roundup® for bluegill sunfish and
rainbow trout is only slightly higher at 6-14 mg/L and 8-26 mg/L,
respectively. Similarly for Daphnia, the 96-hour LC50 of glyphosate
alone is 962 mg/L, but the LC50 of Roundup® drops to 25.5 mg/L
(Servizi et al. 1987). Roundup® is therefore not registered for use
in aquatic systems.
Despite these toxicity levels, Hildebrand et al. (1980) found that
Roundup® treatments at concentrations up to 220 kg/ha did not
significantly affect the survival of Daphnia magna or its food base of
diatoms under laboratory conditions. In addition, Simenstad et al.
(1996) found no significant differences between benthic communities of
algae and invertebrates on untreated mudflats and mudflats treated
with Rodeo® and X-77 Spreader®. It appears that under most
conditions, rapid dissipation from aquatic environments of even the
most toxic glyphosate formulations prevents build-up of herbicide
concentrations that would be lethal to most aquatic species.
=========
FINAL ENVIRONMENTAL IMPACT REPORT (FEIR)
http://www.valleywater.org/water/Technical_Information/Technical_Reports/_Reports/_SMP/feir/IIICommentsResponses.htm
Monsanto's Aquamaster® (an aquatic formulation formerly marketed as Rodeo®).
[...]
Aquamaster® and Rodeo® contain glyphosate and water without a
surfactant. The District generally adds the surfactants R-11® or
Target Pro-Spreader when using either Aquamaster® or Rodeo®.
[...]
For assessing the potential for toxic effects in fish, a reference
concentration of 1 mg/L will be used for glyphosate. This is about a
factor of 10 less than the lowest reported LC50 values (SERA 1996). At
this level, there is no reason to anticipate acute or long-term
effects in fish.
There is little evidence to suggest that aquatic animals will be
adversely affected by normal applications of glyphosate. Most species
of algae and macrophytes do not appear to be more sensitive than fish
or aquatic invertebrates to glyphosate.
[...]
AU-11
The impact on red-legged frog is minimized by avoiding known frog
activity areas and by using herbicides of low animal toxicity. The
District uses a gylphosate formulation registered for aquatic
application (AquaMaster by Monsanto, formerly known as Rodeo) and a
surfactant R-11. This combination is used extensively throughout
California for control of invasive giant reed (Arundo donax). The
California Department of Fish and Game, in conjunction with US EPA and
other parties conducted tests of glyphosate/R-11 application
effectiveness and toxicity in 1998. California Department of Fish and
Game, 1998, unpublished communication by Joel Trumbo, "Final Report
U.S. Environmental Protection Agency Grant Control of Giant Cane in
Riparian and Wetland Areas of Northern and Central California". That
study concluded "Rodeo® with R-11® applied aerially to control giant
cane poses no significant acute toxicity hazard to nontarget fish and
frog species. Herbicide and surfactant residues were 100 to 10,000
times less than would be necessary to produce acute mortality." The
District's selective hand application probably results in less actual
herbicide entering the water than from helicopter broadcast spray.
