| Chemical Abstract Number (CAS #) |
101428
|
|---|
| CASRN |
101-42-8 |
|---|
| Synonyms | Fenuron |
|---|
Urea, N,N-dimethyl-N'-phenyl- | 1,1-Dimethyl-3-phenylurea | N,N-Dimethyl-N'-phenylurea |
| Analytical Method |
EPA Method 632 |
|---|
| Molecular Formula | C9H12N2O |
|---|
Link to the National Library of Medicine's Hazardous Substances
Database for more details
on this compound. |
| Use | Weed and brush killer.
Control of woody plants and deep rooted perennial weeds, particularly on non crop land. Often
used in combination with chloropropham to extend the weed spectrum and range of crops.
|
|---|
| Apparent Color | White, crystalline solid; Colorless crystalline solid; Colorless crystals
|
|---|
| Melting Point | 133-134 deg C
|
|---|
| Molecular Weight | 164.21
|
|---|
| Density | 1.08 at 20 deg C/20 deg C
|
|---|
| Sensitivity Data | Non-irritating to skin
|
|---|
| Environmental Impact | Fenuron may be released to the environment primarily during its use as a herbicide. If
released to the atmosphere, degradation of vapor-phase fenuron by reaction with photochemically
produced hydroxyl radicals (estimated half-life of 2.3 hrs) will be important. Photolysis may be
important and particulate-phase fenuron will be removed from air via dry deposition. If released to
soil, biodegradation will be the primary fate process. A complete degradation half-life of 2.2-4.5
months was measured for fenuron in soil. Photolysis may be important on soil surfaces exposed to
sunlight. Adsorption to soil will not be important. In water, volatilization, adsorption to sediment,
hydrolysis and bioconcentration in aquatic organisms will not be important. Biodegradation is
expected to be the primary fate process and some photodegradation may occur. Workers may be
exposed via dermal contact and inhalation of dust.
|
|---|
| Environmental Fate | TERRESTRIAL FATE: In soil, enzymic and microbial degradation involves step by step
N-demethylation.
TERRESTRIAL FATE: The complete degradation of fenuron in soil has been experimentally
determined to be 4.5 months at 15 deg C and 2.2 months at 30 deg C . Biodegradation will be
the primary fate process in soil . Measured Kocs of 27 and 43 indicate that adsorption to
soil will not be important. A visible change in color occurred within 2 hours when paper
saturated with fenuron was exposed to sunlight suggesting that some fenuron may be removed
from soil surfaces via direct photolysis.
AQUATIC FATE: After 2 weeks, approximately 20% of 10 ug/L fenuron remained in raw river
water samples exposed to sunlight and artificial fluorescent light . Biodegradation is expected to
be the primary fate process in aquatic ecosystems(2,SRC). Measured Kocs of 27 and 43
indicate that adsorption of fenuron from the water column to sediment and suspended material
will not be important. An estimated BCF of 6 indicates that fenuron will not
bioconcentrate in fish. A visible change in color occurred within 2 hours when paper
saturated with fenuron was exposed to sunlight suggesting that some fenuron may be removed
from water via direct photolysis. Volatilization from water will not be important(7) based
on a low Henry's Law constant of 1.68X10-10 atm-cu m/mole at 25 deg C(6,SRC).
ATMOSPHERIC FATE: Based on a measured water solubility of 4,027 mg/L at 25 deg C
and an estimated Henry's Law constant of 9.71X10-10 atm-cu m/mole at 25 deg C , the vapor
pressure of fenuron can be estimated to be 1.81E-5 mm Hg at 25 deg C. This vapor
pressure value suggests that fenuron will exist in the vapor and particulate phases in the ambient
atmosphere . Vapor-phase fenuron is rapidly degraded in the ambient atmosphere by reaction
with photochemically formed hydroxyl radicals; the half-life for this reaction in air can be
estimated to be about 2.3 hrs(4,SRC). A visible change in color occurred within 2 hours when
paper saturated with fenuron was exposed to sunlight suggesting that fenuron may be removed
from the atmosphere via direct photolysis. Particulate-phase fenuron is removed via dry
deposition.
|
|---|
| Drinking Water Impact | SURFACE WATER: Fenuron was qualitatively detected in river water .
|
|---|
