Description
Sodium acifluorfen was first registered in the United States in
1980 as the herbicide Blazer, by the Rohm and Haas
Company. In 1987, the BASF Corporation purchased the
registration and supporting data. In 2003, the US Environmental
Protection Agency (EPA) conducted an assessment to
determine if pesticide products containing the active ingredient
sodium acifluorfen were eligible for pesticide reregistration.
Results of the US EPA assessment were explained in
the Reregistration Eligibility Decision (RED) of sodium acifluorfen.
The RED document determined pesticides with the
active ingredient of sodium acifluorfen were eligible for reregistration
provided certain stipulations listed in the RED
document were met, which included additional label
requirements to limit the potential for drift. Under the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA) Section 3,
all new pesticides used in the United States must be registered
by the Administrator of the US EPA. There are 12 registrations
for sodium acifluorfen.
Chemical Properties
A diphenyl ether, is a combustible, off-white, light tan or brown solid.
Uses
Sodium acifluorfen is a member of a diphenyl ether group of
light-dependent peroxidizing herbicides. Sodium acifluorfen
is also a member of the nitrophenyl ether class of herbicides.
This class of herbicides can cause rapid disruption of cell
membranes in plants. Acifluorfen penetrates into
the cytoplasm and causes the formation of peroxides and
free electrons (requires light), ultimately destroying the
cell membrane. Destruction of the cell membrane prevents
translocation to other regions of the plant. In the
environment, sodium acifluorfen degrades to acifluorfen (or acifluorfen acid). Additionally, acifluorfen acid is
a degradation product of lactofen, another herbicide used on
agricultural crops and in forestry. Sodium acifluorfen can be
used alone or formulated with similar herbicides. Various
formulation types include liquid, ready-to-use, and soluble
concentrates. Agricultural crop applications are conducted by
aircraft and by broadcast and band treatment using ground
equipment. A trigger spray bottle for spot treatment is used by
both agricultural and residential applicators. Sodium acifluorfen
is primarily used on agricultural crops as a nonselective
herbicide for pre- and postemergent control of annual
broadleaf weeds and grasses. From 2001 to 2007, the annual
US agricultural consumption of sodium acifluorfen was estimated
at 300 000 pounds. An estimated 200 000 pounds of
the agricultural consumption was applied to soybean crops.
Sodium acifluorfen is also used on the agricultural crops
peanuts, rice, peas, and strawberries. Sodium acifluorfen is
registered for residential use; however, it is limited to spot
treatment with ready-to-use formulations. Residential
application of sodium acifluorfen is minor compared to
agricultural, since it is a nonselective herbicide that kills both
weeds and grasses.
General Description
White powder. Melting point 255- 257°F (124-125°C). Irritates skin and eyes. Used as a herbicide.
Air & Water Reactions
Water soluble.
Potential Exposure
A potential danger to those involved in the manufacture, formulation and application of this selective preemergence and postemergence herbicide used to control weeds and grass in soybean and peanut crops
Environmental Fate
Acifluorfen inhibits the enzyme protoporphyrinogen oxidase,
which catalyzes the dehydrogenation of protoporphyrinogen
IX to protoporphyrin IX. In the presence of light, accumulated
protoporphyrin can generate highly reactive oxygen species and
induce membrane lipid peroxidation. The peroxidation of the
lipid can result in a chain reaction and cause fragmentation and
destruction of the lipid. The consequence of lipid peroxidation
for a cell is loss of the membrane function. The primary target
organs for sodium acifluorfen are the liver and kidneys.
However, there are limited data that suggest cells can synthesize
cytochrome P450 for detoxification of sodium acifluorfen.
Further study is needed to confirm this.
Shipping
UN2588 Pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN3077 Environmentally hazardous substancessolid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required
Toxicity evaluation
Sodium acifluorfen is directly released into the environment as
a pre/postemergent herbicide. In the environment, sodium
acifluorfen dissociates to acifluorfen. Sodium acifluorfen has
an estimated Henry’s law constant of 6.03 × 10
-11 atmm3
mol
-1 derived from a vapor pressure of 1.33 ×105mm
Hg. Sodium acifluorfen has a water solubility of 62.07 g
100 ml1 (at 20°C) and an octanol/water partition coefficient
of 1.55. Additionally, sodium acifluorfen has a pKa of 3.86,
indicating it will exist in the anion form at pH values
from 5 to 9. Acifluorfen has an estimated vapor pressure of
1.5×10
-8mm Hg, Koc values from 44 to 684, and an estimated
pKa of 2.07.
The pKa of sodium acifluorfen indicates the compound
will exist in an anion form in the environment. Compared
to their neutral counterparts, anion forms do not strongly
adsorb to soils containing organic carbon and clay. Anions
do not volatilize, therefore it is highly unlikely that acifluorfen
will volatilize from dry or moist soil conditions.
Additionally, volatilization of sodium acifluorfen from water
surfaces is also highly unlikely. The estimated vapor pressure
of acifluorfen indicates that it will exist in both the vapor
and particulate phases in the ambient air. Based on the Koc
value range of 44–684, acifluorfen has a very high to low
mobility in soil. Adsorption and desorption are strongly
correlated to site-specific soil parameters such as pH and
mineral content.
Incompatibilities
Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Avoid contact with all sources of ignition.
Waste Disposal
In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers.
