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in 1996. EXTOXNET no longer updates this information, but it may be useful
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E X T O X N E T
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EXTOXNET primary files maintained and archived at Oregon State
Revised June 1996
Trade and Other Names:
Trade names include Banfel, Banvel, Banvel CST, Banvel D, Banvel
XG, Dianat, Dicazin, Fallowmaster, Mediben, Metambane, Tracker,
The EPA has classified this General Use Pesticide (GUP) as
toxicity class III - slightly toxic. Products containing dicamba
bear the Signal Word WARNING. This is because of its irritating,
corrosive effect on skin and eyes.
Chemical Class: benzoic
Dicamba is a benzoic acid herbicide. It can be applied to the
leaves or to the soil. Dicamba controls annual and perennial
broadleaf weeds in grain crops and grasslands, and it is used to
control brush and bracken in pastures. It will kill broadleaf
weeds before and after they sprout. Legumes will be killed by
dicamba. In combination with a phenoxyalkanoic acid or other
herbicide, dicamba is used in pastures, range land, and non-crop
areas such as fence-rows and roadways to control weeds.
- Acute toxicity: Dicamba is slightly
toxic by ingestion and slightly toxic by inhalation or
dermal exposure . The oral LD50 for dicamba is 757 to
1707 mg/kg in rats, 1190 mg/kg in mice, 2000 mg/kg in
rabbits, and 566 to 3000 mg/kg in guinea pigs [1,6]. The
dermal LD50 in rabbits is greater than 2000 mg/kg (7).
The inhalation LC50 for dicamba in rats is greater than
200 mg/L . Symptoms of poisoning with dicamba include
loss of appetite (anorexia), vomiting, muscle weakness,
slowed heart rate, shortness of breath, central nervous
system effects (victim may become excited or depressed),
benzoic acid in the urine, incontinence, cyanosis (bluing
of the skin and gums), and exhaustion following repeated
muscle spasms [1,5]. In addition to these symptoms,
inhalation can cause irritation of the linings of the
nasal passages and the lungs, and loss of voice . Most
individuals who have survived severe poisoning from
dicamba have recovered within 2 to 3 days with no
permanent effects . Dicamba is very irritating and
corrosive, and can cause severe and permanent damage to
the eyes . The eyelids may swell and the cornea may be
cloudy for a week after dicamba is splashed in the eyes
. In some individuals, dicamba is a skin sensitizer
and may cause skin burns . There is no evidence that
dicamba is absorbed into the body through the skin .
- Chronic toxicity: Doses of 25 mg/kg/day
in the diet administered to rats for 2 years produced no
observable effects on survival, body weight, food
consumption, organ weight, blood chemistry, or tissue
structure [1,5,11]. Consumption of dicamba at high levels
over a long period of time has been shown to cause
changes in the liver and a decrease in body weight in
rats [1,5,11]. In mice, some enlargement of liver cells
has occurred .
- Reproductive effects: In a
three-generation study, dicamba did not affect the
reproductive capacity of rats . When rabbits were
given doses of 0.5, 1, 3, 10, or 20 mg/kg/day of
technical dicamba from days 6 through 18 of pregnancy,
toxic effects on the mothers, slightly reduced fetal body
weights, and increased loss of fetuses occurred at the 10
mg/kg dose [5,10]. These data suggest that dicamba is
unlikely to cause reproductive effects in humans at
expected exposure levels.
- Teratogenic effects: No teratogenic
effects have been shown in lab animals such as rabbits
and rats exposed to dicamba .
- Mutagenic effects: Dicamba has not been
shown to be a mutagen [5,10].
- Carcinogenic effects: Rats fed up to 25
mg dicamba/kg/day for 2 years showed no increased
incidence of tumors [5,10]. This evidence suggests that
dicamba is not carcinogenic.
- Organ toxicity: Chronic exposure can
lead to the development of the same symptoms as described
for acute exposure.
- Fate in humans and animals: Dicamba was
excreted rapidly by rats, mainly in the urine, when
administered orally or subcutaneously; 1 to 4% was
excreted in the feces . Mice, rats, rabbits, and dogs
excreted 85% of an oral dose as unmetabolized dicamba in
the urine within 48 hours of dosing. Eventually, between
90 and 99% of the dose was excreted unmetabolized in the
urine. This indicates that dicamba is rapidly absorbed
into the bloodstream from the gastrointestinal tract
. When dicamba was ingested daily in the feed, the
concentrations in different organs reached a steady state
within 2 weeks. When daily intake stopped, storage in the
organs declined rapidly . It is therefore concluded
that dicamba does not bioaccumulate in mammalian tissues.
- Effects on birds: Dicamba is practically
nontoxic to birds. The LD50 for technical dicamba in
mallard ducks is 2009 mg/kg. The 8-day dietary LC50 in
mallards and in bobwhite quail is greater than 10,000 ppm
- Effects on aquatic organisms: Dicamba is of low toxicity
to fish [5,7]. The LC50 (96-hour) for technical dicamba
is 135 mg/L in rainbow trout and bluegill sunfish,
greater than 100 mg/L in grass shrimp, and greater than
180 mg/L in fiddler crab and sheepshead minnow . The
LC50 (48-hour) for dicamba is 35 mg/L in rainbow trout,
40 mg/L in bluegill, 465 mg/L in carp, and 110 mg/L in
Daphnia magna, a small freshwater crustacean [5,7].
- Effects on other organisms: Dicamba
poses little threat to wildlife. Dicamba is not toxic to
- Breakdown in soil and groundwater:
Dicamba is moderately persistent in soil. The half-life
of dicamba in soil is typically 1 to 4 weeks . Under
conditions suitable for rapid metabolism, the half-life
is less than 2 weeks . Metabolism by soil
microorganisms is the major pathway of loss under most
soil conditions. The rate of biodegradation increases
with temperature and increasing soil moisture, and tends
to be faster when soil is slightly acidic. When soil
moisture increases above 50%, the rate of biodegradation
declines . Dicamba slowly breaks down in sunlight .
Volatilization from soil surfaces is probably not
significant, but some volatilization may occur from plant
surfaces . It is stable to water and other chemicals
in the soil . Dicamba does not bind to soil particles
and is highly soluble in water. It is therefore highly
mobile in the soil and may contaminate groundwater .
In humid areas, dicamba will be leached from the soil in
3-12 weeks .
- Breakdown in water: In water, microbial
degradation is the main route of dicamba disappearance.
Photolysis may also occur. Aquatic hydrolysis,
volatilization, adsorption to sediments, and
bioconcentration are not expected to be significant .
- Breakdown in vegetation: Dicamba is
rapidly taken up by the leaves and roots of plants, and
it is readily translocated to other plant parts. It some
plant species, dicamba accumulates in the tips of mature
leaves . Desirable broadleaf plants such as fruit
trees and tomatoes may be harmed during their growth and
development stages . Residues of dicamba on treated
plants can disappear through exudation from the roots
into the surrounding soil, metabolism within the plant,
or by loss from leaf surfaces .
- Appearance: Pure dicamba is an odorless,
white crystalline solid. The technical acid is a pale
buff crystalline solid .
- Chemical Name: 3,6-dichloro-O-anisic
- CAS Number: 1918-00-9
- Molecular Weight: 221.04
- Water Solubility: 6500 mg/L @ 25 C 
- Solubility in Other Solvents: acetone
s.; dichloromethane s.; dioxane v.s.; ethanol s.; toluene
s.; xylene s. 
- Melting Point: 114-116 C 
- Vapor Pressure: 4.5 mPa @ 25 C 
- Partition Coefficient: -0.5376 
- Adsorption Coefficient: 2 (salt) 
- ADI: Not Available
- MCL: Not Available
- RfD: 0.03 mg/kg/day 
- PEL: Not Available
- HA: 0.2 mg/L 
- TLV: Not Available
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- Phone: 905-639-7535
- Emergency: Not Available
References for the information in this PIP can be found in
Reference List Number 7
information in this profile does not in any way replace or
supersede the information on the pesticide product labeling or
other regulatory requirements. Please refer to the pesticide