|Chemical Abstract Number (CAS #)||
||EPA Method 627|
Link to the National Library of Medicine's Hazardous Substances
Database for more details
on this compound.
|Use|| SELECTIVE PRE-EMERGENCE HERBICIDE
Controls annual grasses and broadleaf weeds in seeded alfalfa, birdsfoot trefoil, ladino clover, red
clover, direct-seeded lettuce, peanuts, transplant air cured (burley, dark) tobacco, established turf.
Control of annual grasses and some annual broad-leaved weeds in groundnuts, cucumbers,
chicory, endives, field beans, french beans, lentils, lucerne. Applied pre-emergence, with soil
|Apparent Color|| YELLOW-ORANGE CRYSTALLINE SOLID
|Odor|| NO APPRECIABLE ODOR
|Boiling Point|| 148-149 deg C @ 7 mm Hg
|Melting Point|| 65-66.5 DEG C
|Molecular Weight|| 335.32
|Sensitivity Data|| Benefin may cause skin sensitization reactions in certain individuals.
MAY BE IRRITATING TO SKIN & EYES.
|Environmental Impact|| Benefin will be released in the environment during its manufacture and use as a herbicide.
If released to soil, the loss of benefin should occur due to biodegradation, photolysis and
volatilization. Half-lives of benefin in soil range from 0.7-4 months. Benefin is expected to have
low mobility in soils. The major pathways for the loss of benefin from water may be
biodegradation, photolysis and volatilization. Bioconcentration of benefin in aquatic organisms
should be important. Reaction with photochemically produced hydroxyl radicals may be important
for the loss of vapor phase benefin in the atmosphere. The half-life of benefin due to this reaction
has been estimated to be 3.1 hrs. Partial removal of benefin will also occur as a result of dry and
wet deposition. Applicators of benefin and farm workers are the most likely people for exposure
to benefin by inhalation and dermal routes.
|Environmental Fate|| WHEN SOIL TREATED WITH BENEFIN WAS FLOODED WITH WATER,
BENEFIN DECOMP RAPIDLY. ONLY 4.6% WAS DETECTABLE AFTER 16 DAYS. THE
MAJOR DEGRADATION PRODUCTS WERE BENEFIN WITH ONE NITRO GROUP
REDUCED; WITH BOTH NITRO GROUPS REDUCED; & WITH BOTH NITRO GROUPS
REDUCED PLUS REMOVAL OF BOTH ALKYL GROUPS. FIVE OTHER METABOLITES
WERE DETECTED. THESE CMPD CONSTITUTED LESS THAN 5% OF THE TOTAL
RADIOACTIVITY. EXTRACTABLE POLAR PRODUCTS WERE OBSERVED &
BELIEVED TO BE AROMATIC AMINE CONDENSATION PRODUCTS. UNDER
AEROBIC CONDITIONS, BENEFIN DEGRADATION IN SOIL WAS SLOWER.
/STRUCTURAL FORMULAS OF DEGRADATION PRODUCTS GIVEN IN SOURCE
BENEFIN DECOMP RAPIDLY IN SOIL UNDER DEFINED ANEROBIC CONDITIONS,
WITH APPROX 5% DETECTABLE AFTER 16 DAYS. UNDER DEFINED AEROBIC
CONDITIONS, 50% OF THE ORIGINALLY INCORPORATED BENEFIN WAS
DETECTABLE AFTER 120 DAYS & ONLY 12.1% AFTER 352 DAYS. IDENTIFIABLE
DEGRADATION PRODUCTS WERE THE DEALKYLATED, REDUCED & OXIDIZED
DERIVATIVES OF BENEFIN & AN UNIDENTIFIED POLAR MIXT.
Duration of residual activity in soil is about 4-8 months.
TERRESTRIAL FATE: Biodegradation, volatilization and photolysis may all play significant
roles for the loss of benefin from soils . A Koc value of 9000 indicates that benefin should
remain strongly adsorbed in most soils and leaching of benefin from most soils should not be
important(3,SRC). The persistence of benefin in soil will depend on the soil type, moisture
content and the temperature of soil . The persistence of benefin under field use conditions may
be close to a year .
AQUATIC FATE: Based on studies in soil, photolysis by sunlight and biodegradation may be
important for the degradation of benefin in water(1,SRC). Based on an estimation method and
a Henry's Law constant value of 2.91X10-4 atm cu m/mole estimated from the ratio of vapor
pressure and water solubility , the volatilization half-life of benefin from a model river of
depth 1 m flowing at a current speed of 1 m/sec and a wind speed of 3 m/sec would be 10.8
hrs. A Koc value of 9000 indicates that benefin may be strongly adsorbed to suspended
solids and sediment in water. The BCF values of 2160 and about 2000 estimated from
regression equations and a log Kow value of 4.69 and a water solubility of 0.1 mg/l
indicates that bioconcentration of benefin in aquatic organisms will be an important environmental
ATMOSPHERIC FATE: Based on a measured vapor pressure of 6.6X10-5 mm Hg at 25 deg
C , benefin should exist both in the particulate and in the vapor phase in air(2,SRC). Based on
an estimation method(3-4), vapor phase benefin may be removed from the atmosphere with an
estimated half-life of 3.1 hrs due to reaction with photochemically produced hydroxyl
radicals. Partial removal of particulate benefin from the air may occur by dry
deposition. Both vapor and particle phase benefin may be partly removed from the
atmosphere by wet deposition.