|Chemical Abstract Number (CAS #)||
||EPA Method 645|
Link to the National Library of Medicine's Hazardous Substances
Database for more details
on this compound.
|Use|| HERBICIDE FOR CONTROL OF ANNUAL BROADLEAF WEEDS & ANNUAL
SELECTIVE PREEMERGENCE HERBICIDE THAT CONTROLS GRASSES &
BROADLEAF WEEDS SUCH AS CARPETWEED, CHICKWEED, KNOTWEED,
LAMBSQUARTERS, PIGWEED, PURSLANE, & SMARTWEED.
Control of annual grasses and some broad-leaved weeds in cotton, potatoes, sweetpotatoes,
tomatoes, vegetables, capsicums, okra, soya beans, groundnuts, tobacco, pome fruit, stone fruit,
citrus fruit, bush fruit, strawberries, forestry nurseries, and ornamental plants, shrubs, and trees.
Plant growth regulator
|Consumption Patterns|| HERBICIDE, OF WHICH APPROXIMATELY 52% IS USED ON FIELD CROPS
AND 48% ON VEGETABLE CROPS (1975)
|Apparent Color|| WHITE ; CRYSTALS FROM ETHYL ACETATE ; WHITE PRISMS ; Colorless
|Odor|| NO APPRECIABLE ODOR
|Melting Point|| 134.5 TO 135.5 DEG C
|Molecular Weight|| 239.34
|Density|| 1.17 @ 23.3 DEG C
|Environmental Impact|| Diphenamid will be released in the environment during it use as a herbicide. If released to
soil, the loss of diphenamid will occur primarily due to biodegradation. Loss of diphenamid from
soil due to volatilization and photolysis should not be important. Diphenamid is expected to have
a moderate mobility in soils. Depending on soil characteristics and rainfall, the persistence of
diphenamid in soil may be 3-8 months. If released to water, the major process for the loss of
diphenamid is probably biodegradation. Hydrolysis, photolysis, bioconcentration, and
volatilization should not be important processes in water. Diphenamid will be found completely
adsorbed to particulate matter in the atmosphere and may be removed by dry and wet deposition.
Partial removal of diphenamid will also occur as a result of dry and wet deposition. The
applicators of the herbicide and farm workers are the most likely people for exposure to
diphenamid by inhalation and dermal routes.
|Environmental Fate|| TERRESTRIAL FATE: Diphenamid has an estimated Koc of 210 and therefore would
be expected to leach moderately in soil. Biodegradation is the primary degradative pathway for
loss of diphenamid from soils(1-2). The persistence of diphenamid in soil will depend on the soil
type, moisture content and the temperature of soil . Under warm, moist conditions, the average
persistence of diphenamid after application at recommended rates is 3-6 months . At higher
application rates and under low rainfall or colder temperatures, diphenamid may persist in soil
longer than 6 months(5-6). The rate of biodegradation increases moderately in soils that have
been previously treated with diphenamid. Diphenamid is non volatile and appears to be stable in
AQUATIC FATE: Neither hydrolysis(1-2) nor photolysis by sunlight(3-4) should be important
for the degradation of diphenamid in water. Based on its ability to undergo biodegradation in
soil , biodegradation should be the most important process for diphenamid in water. A
Koc value of 210(6) indicates that diphenamid may be moderately adsorbed to suspended solids
and sediment in water. The estimated BCF value of 27(6) indicates that bioconcentration of
diphenamid in aquatic organisms will not be important.
ATMOSPHERIC FATE: Based on a vapor pressure of 3X10-8 mm Hg , diphenamid should be
present mostly in the particulate form in air, but a small amount may be present in the vapor
phase(2,SRC). Based on an estimation method , vapor phase diphenamid may be removed from
the atmosphere with a half-life of 10.6 hrs due to reaction with photochemically produced
hydroxyl radicals. Partial removal of particulate diphenamid from the air may occur by dry
deposition. Both vapor and particle phase diphenamid may be partly removed from the
atmosphere by wet deposition.
|Drinking Water Impact|| GROUNDWATER: Diphenamid was not found in 678 ground water samples taken from
676 locations . It was detected at a concn 6000 ug/l in a groundwater sample from CA .
Diphenamid was also detected at a concn 43 ug/l in ground waters under a suspected spill site in a
rural area in Ontario,Canada .