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in 1996. EXTOXNET no longer updates this information, but it may be useful
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EXTOXNET primary files maintained and archived at Oregon State
Revised June 1996
Trade and Other Names:
Trade names for products containing diuron include Crisuron,
Diater, Di-on, Direx, Karmex, and Unidron. It is often used in
combination with other pesticides such as bromacil and
Diuron is a General Use Pesticide (GUP). The U.S. EPA classifies
it as toxicity class III - slightly toxic. However, products
containing diuron bear the Signal Word WARNING because it can
irritate the eyes and throat.
Diuron is a substituted urea herbicide used to control a wide
variety of annual and perennial broadleaf and grassy weeds, as
well as mosses. It is used on non-crop areas and many
agricultural crops such as fruit, cotton, sugar cane, alfalfa,
and wheat. Diuron works by inhibiting photosynthesis. It may be
found in formulations as wettable powders and suspension
Formulation: It may be
found in formulations as wettable powders and suspension
- Acute toxicity: Diuron is slightly toxic
to mammals. The oral LD50 in rats is 3400 mg/kg. The
dermal LD50 is greater than 2000 mg/kg [4,8]. Some signs
of central nervous system depression have been noted at
high levels of diuron exposure. For humans, the only
reported case of acute, oral exposure to the herbicide
produced no significant symptoms or toxicity [4,8,10].
- Chronic toxicity: Male rats given
extremely high doses of diuron over a 2-week period
showed changes in their spleen and bone marrow. Other
chronic effects attributed to moderate to high doses of
the pesticide over time included changes in blood
chemistry, increased mortality, growth retardation,
abnormal blood pigment, and anemia. When fed small
amounts of diuron in food for 2 years, animal species
showed no adverse effects [4,8].
- Reproductive effects: Daily low doses of
diuron fed to female rats through three successive
generations caused significantly decreased body weight of
offspring in the second and third litters. The fertility
rate remained unaffected . It is unlikely that diuron
will cause reproductive effects in humans at expected
levels of exposure.
- Teratogenic effects: Diuron is
teratogenic at high doses. Administered to pregnant rats
on days 6 through 15 of gestation, it produced no birth
defects in the offspring at doses of up to 125 mg/kg/day.
However, doses of 250 mg/kg/day caused wavy ribs, extra
ribs, and delayed bone formation. There were also weight
decreases in offspring at 500 mg/kg/day. There was no
increase in the severity of the rib deformation at this
higher dose [4,8]. Pregnant mice given very high doses of
diuron (nearly 2000 mg/kg/day) exhibited reproductive and
embryotoxic effects. Developmental effects were found in
their offspring [4,8].
- Mutagenic effects: Diuron does not
appear to be mutagenic. The majority of tests have shown
that diuron does not produce mutations in animal cells or
in bacterial cells [4,8].
- Carcinogenic effects: Limited evidence
indicates that low level exposures to diuron does not
cause cancer .
- Organ toxicity: Low doses of diuron over
extended periods of time can cause enlargement to the
liver and the spleen .
- Fate in humans and animals: Diuron is
excreted in the feces and urine of test animals.
Breakdown of the compound is similar in animals, plants,
and soil. Cows fed very low doses of diuron in their
diets had small amounts of residues in whole milk. Cattle
fed small amounts accumulated low levels of diuron in fat
and muscle, liver, and kidney [4,8].
- Effects on birds: Diuron is slightly
toxic to birds. In bobwhite quail, the dietary LC50 is
1730 ppm. In Japanese quail and ring-necked pheasant, it
is greater than 5000 ppm. The LC50 is approximately 5000
ppm in mallard ducks [4,8].
- Effects on aquatic organisms: The LC50
(48 hour) values for diuron range from 4.3 mg/L to 42
mg/L in fish, and range from 1 mg/L to 2.5 mg/L for
aquatic invertebrates. The LC50 (96-hour) is 3.5 mg/L for
rainbow trout [4,8]. Thus, diuron is moderately toxic to
fish and highly toxic to aquatic invertebrates.
- Effects on other organisms: Diuron is
non-toxic to bees .
- Breakdown in soil and groundwater:
Diuron is moderately to highly persistent in soils.
Residue half -ives are from 1 month to 1 year . Some
pineapple fields contained residues 3 years after the
last application. Mobility in the soil is related to
organic matter and to the type of the residue. The
metabolites are less mobile than the parent compound
. In California, diuron has been found in groundwater
in the 2 to 3 ppb range. It has also been found in
Ontario groundwater where it has been linked with land
- Breakdown in water: Diuron is relatively
stable in neutral water. Microbes are the primary agents
in the degradation of diuron in aquatic environments
- Breakdown in vegetation: Diuron is
readily absorbed through the root system of plants and
less readily through the leaves and stems .
- Appearance: Diuron is a colorles
crystaline compound in its pure form .
- Chemical Name:
N-(3,4-dichlorophenyl)-N,N-dimethyl urea 
- CAS Number: 330-54-1
- Molecular Weight: 233.10
- Water Solubility: 42 mg/L @ 25 C 
- Solubility in Other Solvents: s.s. in
acetone, benzene, butyl stearate 
- Melting Point: 158-159 C 
- Vapor Pressure: 0.41 mPa @ 50 C 
- Partition Coefficient: Not Available
- Adsorption Coefficient: 480 
- ADI: Not Available
- MCL: Not Available
- RfD: 0.002 mg/kg/day 
- PEL: Not Available
- HA: 0.01 mg/L (lifetime) 
- TLV: 10 mg/m3 (8-hour) 
DuPont Agricultural Products
Walker's Mill, Barley Mill Plaza
P.O. Box 80038
Wilmington, DE 19880-0038
- Phone: 800-441-7515
- Emergency: 800-441-3637
References for the information in this PIP can be found in
Reference List Number 9
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