Monolinuron

Herbicides

Active substance -> EU Pesticides database: Not approved

Pesticides -> Herbicides, Other

Pesticide (Monolinuron) -> USDA PDB

log Kow = 2.30

2.2

2.16

735 ppm in water at 20 °C; sol in alcohol, acetone, benzene, toluene

SOL IN DIOXANE, & XYLENE

Water solubility = 930 mg/l at 20 °C.

Readily soluble in chloroform, diethyl ether.

Solubility in water: none

80-83 °C

Brownish flakes; faint smell of amine; vapor pressure 1.1X10-5 mm Hg at 20 °C; MP: 75-78 °C /technical grade 92% AI/

80-83 °C

0.00015 [mmHg]

1.5X10-4 MM HG AT 22 °C

Vapor pressure, Pa at 22 °C: 0.02

Colorless solid; [ICSC]

COLOURLESS CRYSTALS.

Warning

H302: Harmful if swallowed [Warning Acute toxicity, oral]

P260, P264, P270, P273, P301+P317, P319, P330, P391, and P501 (click each P-code to see the statement)

Warning

H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]

P260, P264, P270, P273, P301+P317, P319, P330, P391, and P501 (click each P-code to see the statement)

Methemoglobinemia reported after poisoning by ingestion; [HSDB] May affect the blood causing anemia; [ICSC] Caused nausea or vomiting and weight loss in oral lethal-dose study of cats; Causes normocytic anemia in 90-day oral studies of rats and dogs; [RTECS]

Acute Tox. 4 (100%)

Acute toxicity - category 4

Acute Tox. 4 *

Fresh air, rest.

Rinse skin with plenty of water or shower.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Rest. Refer for medical attention .

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Monolinuron should be incinerated in a unit operating at 850 °C equipped with off gas scrubbing equipment. Recommendable methods: Incineration ... .

Do NOT wash away into sewer. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations. Do NOT let this chemical enter the environment. Personal protection: chemical protection suit including self-contained breathing apparatus.

TERRESTRIAL FATE: Based on a recommended classification scheme(1), measured Koc values ranging from 40(3) to 2025(11) indicates monolinuron should have medium mobility in soil(SRC). Volatilization of monolinuron should not be important from moist soil surfaces(SRC) given an estimated Henry's Law constant of 4.6X10-8 atm-cu m/mole(SRC), calculated from experimental values for vapor pressure(4) and water solubility(5). Volatilization is not expected from dry soil surfaces either(SRC) based on an experimental vapor pressure of 1.5X10-4 mm Hg(4). Half-lives for monolinuron in soil have been determined to be 60 days(2) and 33-66 days(6). According to biodegradation studies using mixed bacterial cultures(7-9), monolinuron is expected to biodegrade in soil(SRC). Photolysis of monolinuron should occur on soil surfaces(SRC) according to its degradation by light at wavelengths greater than 290 nm(10).

AQUATIC FATE: Based on a recommended classification scheme(1), measured Koc values ranging from 40(2) to 2025(13) indicate that monolinuron may adsorb to suspended solids and sediment(SRC) in water. Monolinuron will be essentially non-volatile from water surfaces based on an estimated Henry's Law constant of 4.6X10-8 atm-cu m/mole(SRC), calculated from experimental values for vapor pressure(3) and water solubility(4). Experimental BCF values ranging from <20 to 140(5-7), suggest that monolinuron will undergo moderate to high bioconcentration in aquatic organisms(SRC), according to a recommended classification scheme(8). The half-life of monolinuron in water has been determined to be 22 days(9). According to biodegradation studies using mixed bacterial cultures(10-12), monolinuron is expected to biodegrade in water(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), monolinuron, which has an experimental vapor pressure of 1.5X10-4 mm Hg at 25 °C(2), will exist as a vapor in the ambient atmosphere. Vapor-phase monolinuron is degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 27 hours(3,SRC). Particulate-phase monolinuron may be physically removed from the air by wet and dry deposition(SRC).

The Koc for monolinuron has been estimated and experimentally determined to be 200(1,4). The Koc for monolinuron has also been experimentally determined to be 69.2(2). An average Koc value has been reported to be 40 in soils with organic carbon contents ranging from 0.58-2.3%(3). The Koc for monolinuron has been determined to be 60.3(5). The Koc values determined for monolinuron ranged from 211 to 2025 with an average of 517 in eight Czechoslovakian soils with organic matter contents ranging from 0.1-4.6%(6). The average Koc value for monolinuron in 10 different soils was determined to be 271.5(7). Another average Koc value has been determined to be 60(8). According to a recommended classification scheme(9), these Koc values suggest that monolinuron should have slight to very high mobility in soil(SRC).

A 63 year old female drank 1 cup of Gramonol, containing monolinuron 14% and paraquat 10%. Nine hours post ingestion the patient was noted to have a cyanotic appearance. At 43 hours post ingestion she had a 36% methemoglobin level and a 7% sulfhemoglobin level. Hemolysis was also noted. The patient recovered after treatment with 50 mg of methylene blue. the patient's paraquat level was not in the serious risk category, and the patient's methemoglobinemia was attributed to monolinuron, which is metabolized to aniline.

Biodegradation of monolinuron in activated sludge resulted in a 0.9% loss of the initial concentration after 5 days(1). Monolinuron, dissolved in acetone/water and sprayed onto ground waste (compost), was demethylated in small amounts (0.4% of the extracted radioactivity) after 3 weeks to N-methoxy-N'-4-chlorophenyl-urea, whereas 86.2% of the extractable radioactivity was unaffected started material(2). A mixed bacterial culture (containing Gram-negative aerobic rods and Gram-positive aerobic non-spore-forming rods, and cocco-bacilli) from soil (sandy loam) was able to degrade monolinuron completely after 10 days(3).

IN SOIL IT DEGRADES TO 5.6% WITHIN 3 MO & TO LESS THAN 0.2% WITHIN 10 MO...

Duration of residual activity in soil is about 3-4 months (at 3 kg/ha).

Bioaccumulation tests using activated sludge, algae, and fish (golden ide) gave BCF values for monolinuron of 70 (5-day), 40 (1-day), and 20 (3-day), respectively(1). The BCF for monolinuron has been estimated to be 17 and 10 based on water solubility and Koc, respectively(2). Another BCF value monolinuron was calculated to be 22(3). The experimental BCF value of monolinuron in the algae Chloroella was 33 after exposure to 50 ug/l for 24 hours(4). The BCF value for monolinuron in fish (golden orfe) and algae (Chlorella Fusca) were experimentally determined to be <20 (3-day at 45 ug/l) and 60 and 140 (24 hours at 50 ug/l), respectively(5). According to a recommended classification scheme(6), the experimental BCF values suggest that monolinuron should undergo moderate to high bioconcentration in aquatic organisms(SRC).

The Henry's Law constant for monolinuron is estimated as 4.6X10-8 atm-cu m/mole(SRC) from its experimental values for vapor pressure, 1.5X10-4 mm Hg(1), and water solubility, 930 mg/l(2). This value indicates that monolinuron will be essentially nonvolatile from water surfaces(3,SRC). Monolinuron's vapor pressure(1) and Henry's Law constant(1,2,SRC) indicate that volatilization from moist and dry soil surfaces should not occur(SRC).

WHEN...FED TO ALBINO RATS, THE FOLLOWING METABOLITES WERE FOUND...FREE & BOUND AS GLUCURONIDES OR SULFATES: N-(2-HYDROXY-4-CHLOROPHENYL)-N'-METHYLUREA; N-(3-HYDROXY-4-CHLOROPHENYL)-UREA; TRACES OF N-(4-CHLOROPHENYL)-N'-METHOXYUREA, 2-AMINO-5-CHLOROPHENOL, 2-ACETAMINO-5-CHLOROPHENOL, N,N'-BIS-(4-CHLOROPHENYL)UREA, 2-ACETAMINO-6-CHLOROPHENOL, & N-(2-HYDROXY-4-CHLOROPHENYL)-N'-METHYL-N'-METHOXYUREA. N-(4-CHLOROPHENYL)UREA & TRACE OF 4-CHLOROANILINE WERE FOUND FREE ONLY. N-(2-HYDROXY-4-CHLOROPHENYL)-N'-METHYLUREA WAS FOUND IN BOUND STATE ONLY.

WHEN (14)C-LABELED MONOLINURON WAS FED TO HENS AT 0.25 & 25 MG/KG, 26% OF EXCRETED RADIOACTIVITY WAS PRESENT AS METABOLITE 4-CHLOROPHENYLUREA. 1-(2-HYDROXY-4-CHLOROPHENYL)UREA AND 1-(3-HYDROXY-4-CHLOROPHENYL)UREA ACCOUNTED FOR 21% OF EXCRETED RADIOACTIVITY.

In...plants, cleavage of the methyl & methoxy groups on the terminal nitrogen atom, simultaneous ring hydroxylation & formation of 3-(2-hydroxy-4-chlorophenyl)urea & the corresponding 3-hydroxy compound. Further degradation is presumably by way of formation of the aniline derivative & ring splitting.

Six hours after administration of monolinuron to pigs, collected urine was analyzed. The biotransformation products found included 3-(4-chlorophenyl)-1-hydroxymethyl-1-methoxyurea, desmethyl monolinuron, 4-chlorophenylurea, (4-chloro-2-hydroxyphenyl)urea, (4-chloro-3-hydroxyphenyl)urea, and glucuronides and/or sulfates of the latter two hydroxy compounds.

For more Metabolism/Metabolites (Complete) data for MONOLINURON (8 total), please visit the HSDB record page.

WHEN (14)C-LABELED MONOLINURON WAS FED TO HENS AT 0.25 & 25 MG/KG, 85-87% OF RADIOACTIVITY WAS EXCRETED IN URINE & FECES WITHIN 96 HR; MOST WAS IN URINE. THE ORGANS, INCLUDING BLOOD & BILE, CONTAINED APPROX 1% OF DOSE, & MUSCLE WAS ALMOST RESIDUE-FREE. EGG WHITES CONTAINED 0.31 & 0.53% AFTER 0.25 & 25 MG/KG; EGG YOLKS CONTAINED 1.82 & 3.72%. NO UNCHANGED MONOLINURON WAS FOUND IN FECES & URINE.

Absorbed by leaves & roots.

PENETRATES INTO WEEDS MAINLY THROUGH ROOTS BEING TRANSLOCATED IN PLANTS PREDOMINANTLY ACROPETAL.

Used as selective herbicide for vegetables, fruits, cereals, ornamentals, and other crops; [HSDB]

As of 1977, no longer produced in the USA; [HSDB]

Farming (Pesticides) [Category: Industry]

HERBICIDE FOR VARIOUS VEGETABLE & FRUIT CROPS; CEREAL CROPS & ORNAMENTALS

Selective herbicidal control of annual broad-leaf weeds and grasses in asparagus, berries, cereals, dwarf beans, grapes, leeks, maize, ornamental shrubs and trees, and potatoes.

(1977) NOT PRODUCED COMMERCIALLY IN US

(1979) NOT PRODUCED COMMERCIALLY IN US

REACTION OF 4-CHLOROPHENYL ISOCYANATE WITH (N-METHYL) HYDROXYLAMINE, FOLLOWED BY REACTION WITH DIMETHYL SULFATE

Reaction of N,O-dimethylhydroxylamine with p-chlorophenyl isocyanate (isocyanate addition).

ARESIN 50, A WETTABLE POWDER /WITH/ 50% ACTIVE INGREDIENT; EMULSIFIABLE CONCENTRATE, 2 LB AI/IMPERIAL GAL; EMULSIFIABLE CONCENTRATE, 2 LB ACTIVE MONOLINURON PLUS 4 LB 2,4-D (ISO-OCTYL ESTER)/IMPERIAL GAL; EMULSIFIABLE CONCENTRATE, 2 LB ACTIVE MONOLINURON PLUS 4 LB MCPA (MIXED BUTYL ESTER)/IMPERIAL GAL; EMULSIFIABLE CONCENTRATE, 1 LB ACTIVE MONOLINURON PLUS 2 LB DINOSEB (AS AMINE)/IMPERIAL GALLON. MONOLINURON 25% + LINURON 25% WP; MONOLINURON 12% + DINOSEB ACETATE 35% WP.

...COLLOIDAL SUSPENSION WITH PARAQUAT...

Urea, N'-(4-chlorophenyl)-N-methoxy-N-methyl-: INACTIVE

SELECTIVE HERBICIDE FOR CONTROL OF BROAD LEAF WEEDS & ANNUAL GRASSES. ... MOST IMPORTANT FIELDS OF APPLICATION: ASPARAGUS, BEANS, ORCHARDS, ORNAMENTALS, ORNAMENTAL SHRUBS, POTATOES, VINEYARDS, WHEAT.