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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 Afalon, Garnitan, Linex, Linorox, Linurex,
Lorox, Premalin, Sarclex, and Sinuron. Linuron is often used in
formulations with herbicides, insecticides, and fungicides.
Linuron is a slightly toxic compound in EPA toxicity class III.
It is a General Use Pesticide (GUP). Labels for products
containing linuron must bear the Signal Word CAUTION.
Linuron is a substituted urea pre- and post-emergence herbicide
used to control annual and perennial broadleaf and grassy weeds
on both crop and non-crop sites. It works by inhibiting
photosynthesis in target weed plants. It is labeled for field and
storehouse use in such crops as soybean, cotton, potato, corn,
celery, parsnips, sorghum, asparagus, and carrots.
- Acute toxicity: Linuron is of slight
toxicity by ingestion, with reported oral LD50 values of
1200 to 1500 mg/kg in rats, and 2250 mg/kg in rabbits
[4,8]. The reported dermal LD50 in rabbits is greater
than 5000 mg/kg [4,8]. It has been reported to be a skin
sensitizer in guinea pigs, and an eye irritant in
rabbits, but not a skin irritant in rabbits [4,8]. The
4-hour inhalation LC50 is 6.15 mg/L, which indicates
slight toxicity by this route .
- Chronic toxicity: Skin sensitization was
seen in guinea pigs repeatedly exposed . Alterations
in red blood cells were seen in rats given 2.75 mg/kg/day
over 2 years . Anemia was seen in dogs at doses above
6.25 mg/kg/day .
- Reproductive effects: In a
three-generation study, no reproductive effects were
observed at doses of 12.5 mg/kg/day . These data
suggest that reproductive effects are unlikely in humans
at expected exposure levels.
- Teratogenic effects: Pregnant rabbits
fed high doses of linuron during the sensitive period of
pregnancy had normal offspring at doses of up to 25
mg/kg/day, even though maternal weight gain was reduced
[4,14]. In rats, doses of 6.25 mg/kg/day did not produce
teratogenic effects. These data suggest that linuron is
not likely to cause birth defects.
- Mutagenic effects: Linuron caused
mutations in one microbial assay . But in several
other mutagencity and genotoxicity assays, including the
Ames assay, E. coli culture assay, Chinese hamster ovary
cell culture assay, and whole animal studies, linuron
showed no mutagenic or genotoxic activity [4,8,21]. Thus,
it appears that linuron is either nonmutagenic or
- Carcinogenic effects: Several animal
studies of mice, rats, and dogs have shown that it
produces nonmalignant liver and testicular tumors. In
these studies, doses of 72.5 mg/kg/day in rats caused
testicular adenomas and 180 mg/kg/day in mice caused
hepatocellular adenoma [4,11,14,18]. These data are not
sufficient to determine linuron's carcinogenicity to
- Organ toxicity: Rats and dogs fed
linuron for 2 years had detectable residues of linuron in
their blood, fat, kidney, and spleen, but these did not
seem to be associated with adverse effects [4,18].
- Fate in humans and animals: In rats,
linuron breaks down completely after passing through the
liver [4,8]. It is thus unlikely to bioaccumulate in
- Effects on birds: Linuron is slightly
toxic to birds; the reported 5- to 8-day dietary LC50
valus are greater than 5000 ppm in Japanese quail, 3000
ppm in mallard ducks, and 3500 ppm in pheasants [4,8].
- Effects on aquatic organisms: Linuron is
slightly toxic to fish and aquatic invertebrate species.
The reported LC50 for linuron in trout and bluegill is 16
mg/L [8,11]. The median threshold levels, i.e. levels at
which adverse, sublethal effects were apparent in 50% of
the test animals, are greater than 40 mg/L in crawfish
and tadpoles exposed over a 48-hour period .
- Effects on other organisms: Linuron is
nontoxic to bees .
- Breakdown in soil and groundwater:
Linuron is moderately persistent in soils, with a field
half-life of 30 to 150 days in various soils and under
various conditions [19,34]. A representative field
half-life is estimated to be approximately 60 days .
Microbial degradation is the major process by which
linuron is lost from soils; photodegradation and
volatilization are not important contributors to its
breakdown . The metabolites of linuron
(3,4-dichloroaniline and carbon dioxide) are less toxic
than linuron . Linuron is moderately bound to soil,
and is soluble in water . Losses may occur through
transport of linuron in runoff water and on suspended
colloidal matter. Linuron has been found at very low
concentrations in well and groundwater samples in
Georgia, Missouri, Virginia, and Wisconsin .
- Breakdown in water: Linuron is slightly
to moderately soluble in water, and is not readily broken
down in water .
- Breakdown in vegetation: Linuron is more
readily absorbed by roots from soil application, than by
leaves from foliar application . The rate at which it
is absorbed, translocated, and subsequently broken down
(or metabolized) differs with various plant species .
- Appearance: Linuron is an odorless,
white crystalline solid .
- Chemical Name:
- CAS Number: 330-55-2
- Molecular Weight: 249.11
- Water Solubility: 81 mg/L @ 25 C,
slightly soluble 
- Solubility in Other Solvents: s.s in
aliphatic hydrocarbons, m.s. in ethanol, s. in acetone
- Melting Point: 93-94 C 
- Vapor Pressure: 2 mPa @ 24 C 
- Partition Coefficient: 3.0043 
- Adsorption Coefficient: 400 
- ADI: Not Available
- MCL: Not Available
- RfD: 0.002 mg/kg/day 
- PEL: Not Available
- HA: Not Available
- TLV: Not Available
DuPont Agricultural Products
Walker's Mill, Barley Mill Plaza
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