SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 330541
CASRN 330-54-1
SynonymsDiuron
3-(3,4-Dichlorophenyl)-1,1-dimethylurea
DCMU
Analytical Methods EPA Method 553
EPA Method 632
EPA Method 8321
Molecular FormulaC9H10Cl2N2O

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use PRE-EMERGENCE HERBICIDE USED FOR GENERAL WEED CONTROL ON NON-CROP AREAS @ 10-30 KG ACTIVE INGREDIENT/HA; FOR SUBSEQUENT ANNUAL MAINTENANCE 5-10 KG/HA WILL PREVENT RE-INFESTATION BY SEEDLINGS. IT IS ALSO USED SELECTIVELY BEFORE EMERGENCE ON CROPS SUCH AS ASPARAGUS, CITRUS,COTTON, PINEAPPLE, SUGARCANE, TEMPERATE TREE, & BUSH FRUITS @ 0.6-4.8 KG/HA. DIURON IS NOW WIDELY EMPLOYED FOR INDUSTRIAL AREA WEED CONTROL, PARTICULARLY IN HIGHER RAINFALL CLIMATES. LOW WATER SOL & GREATER ABSORBANCY ON SOIL PARTICLES PERMITS LOW RATES TO HAVE WIDE APPLICATION. FOR GENERAL WEED CONTROL, DIURON IS SPRAYED OR SPREAD DRY (AS GRANULES) DENSE GROWTH SHOULD BE REMOVED BEFORE APPLICATION. INCR CONTACT ACTIVITY ON ESTABLISHED WEEDS OBTAINED WHEN APPLIED WITH A SUITABLE SURFACTANT ADDED TO SPRAY SUSPENSION. HERBICIDE FOR INDUST USES-EG, RAILROAD RIGHTS-OF-WAY HERBICIDE FOR AGRICULTURAL USES-EG, COTTON & CITRUS Pre-emergence herbicide, sugar cane flowering suppressant Effective against emerging and young broadleaf and grass weeds as well as mosses; suitable for both selective and total weed control. For use on alfalfa, asparagus, cotton, citrus, fruit orchards, sugarcane, wheat and vineyards.
Consumption Patterns INDUSTRIAL COMMERCIAL USES-EG, ON RAILROAD RIGHTS-OF-WAY, 57%; COTTON, 19%; CITRUS CROPS, 12%; DECIDUOUS FRUITS & NUTS, 3%; WHEAT, 3%; VEGETABLES, 2%; OTHER FIELD CROPS, EG, ALFALFA & SUGARCANE, 4% (1978 HERBICIDE USE)
Apparent Color WHITE, CRYSTALLINE SOLID
Odor ODORLESS
Boiling Point Decomposes at 180-190 deg C
Melting Point 158-159 DEG C
Molecular Weight 233.10
Sensitivity Data MAY IRRITATE EYES, NOSE, THROAT, & SKIN.
Environmental Impact Diuron is released to the environment during its use as a preemergence herbicide. Therefore it is primarily released on soil although releases into water occur from runoff and possibly in wastewater. It is a strongly adsorbed, highly persistent chemical and if released in soil will remain in the upper 5-10 cm of soil and have a half-life of about 330 days. If released into water diuron will adsorb to the sediment where it will slowly biodegrade after acclimation. The major product of the 6-7 degradation compounds that were isolated was 3,4-dichloroaniline and this metabolite may be further metabolized to an azobenzene derivative. In clear surface layers of water, sunlight irradiation will degrade diuron in a matter of days. Slow biodegradation may also occur. Bioconcentration in fish is not appreciable. Diuron will degrade in air probably within a half-life in the vapor phase of 5.8 days due to reaction with hydroxyl radical. Human exposure will primarily be in the workplace and fields where diuron is used.
Environmental Fate TERRESTRIAL FATE: Diuron is a highly persistent and fairly immobile herbicide. When applied to soil it has a mean half-life of approximately 330 days and will not leach below 5 to 10 cm from the surface . Metabolites of microbial degradation include the major metabolite, 3,4-dichloroaniline, and also 3-(3,4-dichlorophenyl)urea and 3-(3,4,dichlorophenyl)-1-methylurea. Some diuron is lost with evaporating water when the diuron is applied to the surface of the soil without being worked in deeply. The levels of diuron found in citrus groves in Florida in which it was used for 7-8 years ranged from 3.7 to 13.1% of the total diuron applied . The interval between the last application and the time of sampling was 1-12 months. AQUATIC FATE: If released into water, diuron will primarily be adsorbed to the sediment (where it may slowly dehalogenate after acclimation). Degradation occurs in acclimated organic-rich sediments at moderate temperatures (90%) degradation in 8 mo. Apparently biodegradation is surface catalyzed and would therefore be more apt to occur in waters where particulate matter was abundant. In surface waters diuron should photolyze within a few days. ATMOSPHERIC FATE: It is unlikely that appreciable quantities of diuron are released to the atmosphere although photolysis (half-life in hours) would be expected to degrade the herbicide fairly quickly. UNDER FIELD CONDITIONS @ LOWER SELECTIVE RATES, PHYTOTOXIC CONCN DISAPPEAR WITHIN 1 SEASON HIGHER SELECTIVE RATES MORE THAN 1 SEASON MAY BE REQUIRED. ACCUMULATION FROM ANNUAL APPLICATIONS @ SELECTIVE RATES TO SAME SOIL NOT A PROBLEM. STERILANT RATE ACTIVITY MAY BE NOTED MORE THAN 1 SEASON.
Drinking Water Impact DRINKING WATER: Not detected in British drinking water derived from lowland river water and ground water . GROUNDWATER: According to the EPA's Pesticides in Ground Water Data Base, Diuron has been found in water in 2 states as a result of field use . In one state the data was high quality and the contamination was a result of normal field use. Diuron was detected in 1 of 94 farm wells survyed in Ontario in 1984 . SURFACE WATER: Detected, not quantified in river water from lowland rivers in England and West Germany . Cape Fear River, NC (10 stations)-most samples did not contain diuron in detectable quantities although 4 samples approached 1.6 ppb, the limit set to protect aquatic life . The largest amount in the river was in the spring after application to fields as well as in summer when large amounts were in the soil . The total mass of diuron in the river was approximately constant in all reaches of the river . Between 1971 and 1985, 211 rural ponds in Ontario were analyzed for pesticides. Runoff and spray drift were responsible for diuron in two of these ponds at 4 and 25 ppb . EFFL: Runoff from field 21 days after application as an emulsion on foliage at 206 kg/ha - 74 ppb .

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