Linuron

Description

Linuron is found as white crystals that have no smell. It is very slightly soluble in water. Linuron can enter the body either by ingestion of contaminated food or water or by dermal contact. Linuron can cause nausea, vomiting, and diarrhea. Eye contact can cause irritation. There is little evidence available as to the effects of exposure to linuron on human health. However, exposure to linuron at normal background levels is unlikely to have any adverse effect on human health.

Chemical properties

White crystalline solid or powder. Odorless. Commercial product may be available a water soluble or emulsifiable concentrate.

The Uses of Linuron

Linuron is used to control annual and perennial broadleaf and grassy weeds on crop and noncrop sites. It is used as a pre- and post-emergent herbicide. It works by inhibiting photosynthesis in target weed plants. It is used in soybean, cotton, potato, corn, bean, pea, winter wheat, asparagus, carrot, and fruit crops. It is also used on crops stored in warehouses and storerooms. Linuron is classified by the US Environmental Protection Agency (EPA) as a Restricted Use Pesticide (RUP).

The Uses of Linuron

Selective pre- and post-emergence herbicide. A restricted use pesticide.

The Uses of Linuron

Selective preemergence and postemergence herbicide used on a wide variety of food crops to control many annual broad-leaved and grass weeds.

Definition

ChEBI: A member of the class of ureas that is N-methyl urea substituted by a methoxy group at position 1 and a 3,4-dichlorophenyl group at position 3.

General Description

Colorless crystals. Non corrosive. Used as an herbicide.

Air & Water Reactions

Hydrolyzed slowly by acids and bases.

Reactivity Profile

A urea derivative.

Health Hazard

Lowtomoderatelytoxicbyingestion—LD50varying with experimental animals; 4-hourexposure to its vapors at 48 mg/m³ was lethalto rats; toxic properties similar to those ofMonuron.
LD50 oral (rat): 1146 mg/kg
LD50 oral (mouse): 2400 mg/kg
LD50 inhalation (rat): 48 mg/m³ /4 h.

Agricultural Uses

Herbicide: Inhibits photosynthesis. Linuron is a selective, pre-emergence herbicide used to control grasses and broadleaf weeds in carrots, beans, peas, asparagus, maize, potatoes, soybeans, sorghum, wheat, bananas, coffee, cotton and ornamentals. It is also used for control of annual weeds in storehouses, roadsides, fence rows and other noncrop lands. Linuron is frequently used in formulations with other herbicides, insecticides and fungicides.

Trade name

AFALON®; ALIBI®; ALISTELL®; BROADCIDE 20EC®; BRONOX®; CERTOLLIN ONIONS®; CLOVACORN EXTRA®; CROP WEEDSTOP®; DU PONT 326®[C]; FF6135' HERBICIDE 326®; GARNITAN®; H 326®; GEMINI®[C]; HERBICIDE 326®; HOE 2810®; JANUS®; LANDSIDE®; LINNET®; LINEX®; LINOROX®; LINUREX®; LOREX®; LOROX®[C]; MARKSMAN 1®; NEMINFEST®; ONSLAUGHT®; PRE-EMPT®; PREMALIN®; PROFALON®; ROTILIN®; SARCLEX®; SCARCLEX®; SINURON®; STAY KLEEN®; TEMPO®; TRIFARMON FL®; TRIFLURON®; TRILIN®; URANUS® (trifluralin + linuron); WARRIOR®

Safety Profile

Poison by inhalation. Moderately toxic by ingestion. Mutation data reported. A selective herbicide used in farming. Vlihen heated to decomposition it emits very toxic fumes of Cl and NOx. See also 3-@-CHLOROPHENYL)-1,1 DIMETHYLUREA.

Potential Exposure

Inhibits photosynthesis. Linuron is a selective, pre-emergence urea herbicide used to control grasses and broadleaf weeds in carrots, beans, peas, asparagus, maize, potatoes, soybeans, sorghum, wheat, bananas, coffee, cotton, and ornamentals. It is also used for control of annual weeds in storehouses, roadsides, fence rows and other noncrop lands. Linuron is frequently used in formulations with other herbicides, insecticides, and fungicides

Environmental Fate

Soil. Linuron degraded in soil forming the common metabolite 3,4-dichloroaniline (Duke et al., 1991). In an aerobic, biologically active, organic-rich, pond sediment, linuron was converted to the intermediate 3-(3-chlorophenyl)-1-methoxymethylurea. This compound further degraded to unidentified compounds (Stepp et al., 1985).
Linuron was degraded by Bacillus sphaericus in soil forming N,O-dimethylhydroxylamine and carbon dioxide (Engelhardt et al., 1972). Only 1 ppm 3,4-dichloroaniline was identified in soils after incubation of soils containing 500 ppm linuron (Belasco and Pe
The half-lives for linuron in soil incubated in the laboratory under aerobic conditions ranged from 56 to 88 days with an average of 75 days (Moyer et al., 1972; Hance, 1974; Usorol and Hance, 1974). In field soils, the average half-life for linuron was 8
Plant. Undergoes demethylation and demethoxylation in plants (Hartley and Kidd, 1987). Metabolites identified in carrots 117 days after treatment were 3,4-dichlorophenylurea, 3-(3,4-dichlorophenyl)-1-methylurea and 3,4-dichloroaniline. About 87% of the linuron remained unreacted (Loekke, 1974).
Photolytic. When an aqueous solution of linuron was exposed to summer sunlight for 2 months, 3-(3-chloro-4-hydroxyphenyl)-1-methoxy-1-methylurea, 3,4-dichlorophenylurea and 3-(3,4-dichlorophenyl)-1-methylurea formed at yields of 13, 10 and 2%, re

Metabolic pathway

The main photoproducts initially formed in the phototransformation of linuron and chlorbromuron in aqueous solution result from photolysis, i.e. hydroxylation with release of the halide ion, and from elimination of a methoxy group. The orientation of the reaction depends on the wavelength: short wavelengths (254 nm) favor demethoxylation and photolysis in the meta position,whereas, with black light longer than 330 nm, photolysis in the para position is the main reaction observed. In soils, 4-bromo-3-chloroaniline is identified as a soil degradation product of chlorbromuron.

Shipping

UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.

Toxicity evaluation

As a reproductive and developmental toxicant, linuron works via androgen receptor antagonist activity; that is, it competes with testosterone for binding to the androgen receptor. In mouse tissues, linuron competitively blocked transcription through androgen receptor induced by dihydrotestosterone in a concentration-dependent manner.

Incompatibilities

Amides are 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, and epoxides. Similar organic amides react with azo and diazo compounds, releasing toxic gases. Contact with reducing agents can release flammable gases. Amides are very weak bases but they can react as acids, forming salts. Mixing amides with dehydrating agents such as such as phosphorus pentoxide or thionyl chloride generates the corresponding nitrile

Waste Disposal

Incinerate in a unit operating at 850C equipped with off-gas scrubbing equipment. Containers must be disposed of properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office