Chlorbromuron

Terrestrial Fate: At application rates of 0.75 to 1 kg additive ingredient/ha, it can persist in soil for eight days or ... longer.

STABLE IN WATER OVER WIDE RANGE OF PH VALUES.

Duration of /herbicidal/ activity in soil greater than 56 days.

... FIELD & LAB SOIL DISSIPATION STUDIES SHOW CHEM HALF-LIFE FOR CHLORBROMURON OF APPROX 45 DAYS.

For more Environmental Fate (Complete) data for CHLORBROMURON (7 total), please visit the HSDB record page.

The bulb of rape celery grown in the presence of chlorbromuron did not contain measurable concns of this herbicide (detection limit=0.02 ug/g fresh weight)(1). Chlorbromuron was detected in 12 of 26 composite carrot samples collected from farm deliveries in Ontario, Canada between 1980 and 1985 (concns from 0.03-0.14 mg/kg)(2).

... FIELD STUDIES DEMONSTRATE RUNOFF UNDER NORMAL USE CONDITIONS IS INSIGNIFICANT. ... /IT/ IS LEACHED TO MODERATE EXTENT IN SOIL WHICH IS IMPORTANT FOR OBTAINING CONTROL OF DEEP GERMINATING WEEDS.

Soil adsorption coefficient: 460 (Experimental); 510 (Calculated). /From table/

An Rf value of 0.14 was measured for chlorbromuron on Hagerstown soil TLC plates(1). An average Koc of 380 was measured for 17 Australian soils(2). An average Koc of 217 was reported for chlorbromuron(3). Koc values from 561 to 3262 were measured in 5 Czechoslovakian soils with a mean value of 1557; adsorption was thought to be related to soil organic matter content(4). According to a recommended classification scheme(5), these measured Koc values suggest that chlorbromuron has slight to moderate mobility in soil(SRC). The vertical distribution of chlorbromuron in a sandy soil (pH=5.9, organic matter=1.13%) was measured following 10 cm of rain; concns were >2, 0, 0, 0 mg/kg at depths of 0-2.5, 2.5-5, 5-7.5, and 7.5-10 cm, respectively(2).

... SOIL DEGRADATION DATA DEMONSTRATE RAPID DEGRADATION OF CHLORBROMURON TO POLAR & NON-EXTRACTABLE CMPD. ... CHLORBROMURON HAS NO SIGNIFICANT EFFECT ON MICROBIAL POPULATIONS IN SOIL.

SOIL FUNGUS, RHIZOCTONIA SOLANI DEGRADED CHLORBROMURON TO DEMETHYLATED METABOLITE. OTHER METABOLITES WERE OBSERVED BUT NOT IDENTIFIED. WHEN R. SOLANI WAS INCUBATED WITH DEMETHYLATED METABOLITE, CMPD WITH RF= 3-(3-CHLORO-4-BROMOPHENYL)UREA WAS OBSERVED ...

Chlorbromuron was shown to undergo N-demethoxylation by Rhizoctonia solani in corn and cucumber systems. /From table/

... In the presence of the fungus Fusarium oxysporum, halogen ions were released into the culture medium from ... chlorbromuron.

For more Environmental Biodegradation (Complete) data for CHLORBROMURON (6 total), please visit the HSDB record page.

Bioconcentration factor predicted from water solubility = 68 (calculated); predicted from soil adsorption coefficient = 25 (calculated). /From table/

An estimated BCF value of 130 was calculated for chlorbromuron(SRC), using a measured log Kow of 3.09(1) and a recommended regression-derived equation(2). According to a classification scheme(3), this BCF value suggests that bioconcentration in aquatic organisms is high(SRC).

VOLATILIZATION IS NOT EXPECTED TO CONTRIBUTE TO DISSIPATION OF CMPD IN FIELD.

The Henry's Law constant for chlorbromuron is estimated as 4.4X10-9 atm-cu m/mole(SRC) from its experimental values for vapor pressure, 3.97X10-7 mm Hg(1), and water solubility, 35 mg/l(2). This value indicates that chlorbromuron will be essentially nonvolatile from water surfaces(3,SRC). Chlorbromuron's values for vapor pressure(1) and Henry's Law constant(1,2,SRC) indicate that volatilization from dry and moist soil surfaces should not occur(SRC).

... RABBIT--PRIMARY SKIN IRRITATION NONE.

IN 90-DAY FEEDING TRIALS THE 'NO EFFECT' LEVEL IN MALE RATS & DOGS WAS GREATER THAN 316 MG/KG DIET. IT IS SLIGHTLY TOXIC TO FISH.

SYMPTOMS OF POISONING: DEPRESSION, EMESIS, ATAXIA, DYSPNEA, DEPRESSED REFLEXES, HYPEREXCITABILITY, COMA, DEATH.

CHLORBROMURON WAS TESTED FOR /SRP: INDUCTION/ OF CHROMOSOME ABERRATIONS & INHIBITION OF SEED GERMINATION IN BARLEY. FREQUENCIES OF ABERRANT CELLS WAS 8.06%. CHLORBROMURON INDUCED ... ABERRATIONS LIKE ETHYLENIMINE.

For more Non-Human Toxicity Excerpts (Complete) data for CHLORBROMURON (6 total), please visit the HSDB record page.

PHOTODECOMPOSITION UNDER FIELD CONDITIONS IS NOT EXPECTED TO CONTRIBUTE SIGNIFICANTLY TO DISSIPATION OF CHLORBROMURON.

The rate constant for the vapor-phase reaction of chlorbromuron with photochemically produced hydroxyl radicals has been estimated as 1.0X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1,SRC). This corresponds to an atmospheric half-life of about 1.5 days at an atmospheric concn of 5X10+5 hydroxyl radicals per cu cm(1,SRC).