E X T O X N E T
Extension Toxicology Network
A Pesticide Information Project of Cooperative Extension Offices of
Cornell University, Michigan State University, Oregon State University, and
University of California at Davis. Major support and funding was provided
by the USDA/Extension Service/National Agricultural Pesticide Impact
Publication Date: 9/93
TRADE OR OTHER NAMES
Some trade names include Bay 30130, Cekupropanil, Prop-Job, Chem-Rice,
DPA, Strel, S 10145, Vertac, Dropaven, Propanilo, Supernox, Erban, FW-734,
Herbax, Propanex, Riselect, Stampede, Stam-F-34, Stam M-4, Surcopur, Surpur
and Wham EZ.
Products containing propanil must bear the signal word "Warning" (4).
Propanil is an acetanilide postemergence herbicide with no residual
effect. It is used against numerous grasses and broad-leaved weeds in rice
(1, 4). It is available as emulsifiable concentrates, liquid and dry
flowable, low volume, and ultra low volume (ULV) formulations (4).
Propanil is toxic by ingestion and slightly toxic by dermal absorption
(7). It is readily absorbed into the body through ingestion, inhalation or
dermal exposure. It may cause central nervous system (CNS) depression. CNS
effects include headache, dizziness, drowsiness, and confusion. Other
symptoms include dark urine and blood (from the formation of methemoglobin),
acetanilide in the urine, chills, cyanosis (also from methemoglobin), and
jaundice. Death from respiratory failure may occur. Eating propanil may
result in a burning sensation and irritation of the mouth, throat and gut,
accompanied by gagging, coughing, nausea or vomiting. Ingestion may also
cause stupor, dizziness, fever, drowsiness and blue lips and fingernails (2).
Inhalation of vapors can irritate the nose and throat and cause drowsiness,
slurred speech, headache, nausea, dizziness, stupor and unconsciousness (2).
Cardiac patients are especially susceptible to the toxic effects of the
acetanilide group of herbicides (11).
Propanil has caused chloracne and hyperkeratinosis (thickening and
roughening of the skin) in unprotected factory workers. Sensitization,
irritation and dermatitis are possible (3, 11). Repeated contact can cause
irritation with drying, splitting or cracking of the skin (2).
Propanil is very irritating to the eyes (2). It will cause irritation,
conjunctivitis, photophobia (bright light is painful) and even severe lesions
if splashed in the eye (12).
A person who attempted to commit suicide by drinking a 35% solution of
propanil became disoriented, vomited repeatedly and had a sore, swollen
stomach. Their conjunctiva (the tender membrane under the eyelids) became
yellowed (jaundice) (JPN. J. Accident. Med. Assoc. 28(1):37-41. 1980).
The amount of a chemical that is lethal to one-half (50%) of experimental
animals fed the material is referred to as its acute oral lethal dose fifty,
or LD50. The oral LD50 for propanil in rats is 367 to 2500 mg/kg, 360 mg/kg
in mice, and 1,217 mg/kg in dogs. The dermal LD50 in rabbits is greater than
5,000 mg/kg (3, 4). The lethal concentration fifty, or LC50, is that
concentration of a chemical in air or water that kills half of the
experimental animals exposed to it for a set time period. The inhalation LC50
for propanil in rats is greater than 1120 mg/m3 (7).
In a 2-year study, a dietary level of 1600 ppm caused a decrease in
growth and a relative increase in the weight of the spleen and liver in female
rats and of the testes in males. The NOEL for this study was 400 ppm (19
mg/kg/day). In a 2-year study with dogs, a dietary level of 4,000 ppm
depressed growth in spite of increased food intake. The only other change
detected was a slight increase in the relative weight of the heart. The NOEL
for this study was 600 ppm (12.6 mg/kg/day) (3).
Repeated overexposure to propanil can cause liver damage and blood
In a 3-generation study, male and female rats were fed propanil for 11
weeks before the parent generation was mated. Dietary levels as high as 1,000
ppm had no effect on fertility, gestation, viability or lactation (3).
No evidence of teratogenic effects was observed in studies with rats and
In vitro tests (with isolated cells in culture and bacterial cells) show
propanil and some of its breakdown products to be mutagens (11). The Ames
test, tests on mammalian cell cultures, and a cytogenetic assay on mice
failed to show mutagenic effects (9).
No evidence of carcinogenicity was observed in long-term studies of mice
and rats (9).
Several organs are affected by propanil and its metabolites. Liver and
kidney damage are likely after long-term exposure. Dermatitis (rashes) and
sensitization (allergies) are possible. High doses may produce anemia because
of the formation of methemoglobin.
In a 2-year feeding study with rats, high doses of propanil caused a
decrease in growth and a relative increase in the weight of the spleen and
liver in females and of the testes in males. In a 2-year study with dogs high
doses caused a slight increase in the relative weight of the heart (3).
Repeated overexposure to propanil can cause liver damage and blood changes
Fate in Humans and Animals
When propanil was fed to a cow for 4 days, 1.4% of the total dose was
recovered in the feces, but none was detected in the urine or milk (3). This
suggests that propanil is absorbed into the bloodstream through the
gastrointestinal tract and, that once in the bloodstream, propanil is
metabolized by the body. Propanil is lipid (fat) soluble. The liver breaks
down propanil to aniline derivatives. These metabolites are responsible for
the methemoglobin formation (11). Excretion is through the urine.
Effects on Birds
Propanil is slightly to moderately toxic birds. The oral LD50 for
technical propanil (88% active ingredient) in bobwhite quail is 196 mg/kg.
The 8-day dietary LC50 for technical propanil in bobwhite quail is 2,861 ppm,
and in mallard ducks is 5,627 ppm (9).
Effects on Aquatic Organisms
Propanil is toxic to aquatic invertebrates such as crayfish, worms and
snails, and to fish (2, 5). The 96-hour LC50 for technical propanil (88%
active ingredient) in bluegill sunfish is 3.7 to 5.36 ppm, and 2.3 ppm in
rainbow trout (4, 9). The 48-hour LC50 for technical propanil in Daphnia
magna, a small freshwater crustacean, is 0.14 mg/l (9). All contamination of
streams and lakes with propanil should be avoided.
Effects on Other Animals (Nontarget species)
Propanil appears to have very low toxicity to mammals. Only information
on lab animals such as rabbits, rats and dogs was found.
Breakdown of Chemical in Soil and Groundwater
Although propanil is soluble in water and it absorbs only weakly to soil
particles (Koc = 188 g/ml), its rapid breakdown in soil practically eliminates
the potential for groundwater contamination (6). Propanil is rapidly broken
down in the soil by micro-organisms (Menzie. Metab. Pesticides 1969). Its
half-life in the soil is from 1-3 days under warm, moist conditions (2, 6).
Fungi use it as a carbon source. Bacteria produce highly colored by-products
such as tetrachloroazobenzene.
Breakdown of Chemical in Water
Propanil will break down in water. Streams and lakes should not be
contaminated with propanil.
Breakdown of Chemical in Vegetation
Within a plant, propanil is moved from the leaves to the growing shoots,
then back to other leaves. It is a contact herbicide. Crop plants such as
rice completely metabolize propanil (2). Carry over of herbicidal activity to
subsequent crops is not likely. The use of propanil with other pesticides
such as the organophosphorous compounds can kill even desirable plants because
these plants can no longer metabolize the propanil (10).
PHYSICAL PROPERTIES AND GUIDELINES
Propanil is a white to brown crystalline solid with a mild offensive odor
(7). The technical product is brownish, crystalline solid or a dark, oily
liquid, with a melting point of 88 to 91 degrees C. It is stable in emulsion
concentrates, but is hydrolyzed in extremely acid or basic conditions (3, 4).
Propanil is stable under normal temperatures and pressures, but it may pose a
slight fire hazard if exposed to heat or flame. It poses a fire and explosion
hazard in the presence of strong oxidizers. Thermal decomposition of propanil
will release toxic oxides of nitrogen and carbon and toxic and corrosive fumes
of chlorides (7).
Propanil is incompatible with a number of pesticides. Combination of
propanil with carbamates or organophosphates will kill most plants. At least
two weeks should pass between the application of either of these two classes
of pesticides and the application of propanil (8). The toxic effects of
propanil to mammals and fish are also increased by these combinations (11).
Propanil should not be applied with liquid fertilizers.
Occupational Exposure Limits:
No occupational exposure limits have been established for propanil by
OSHA, NIOSH or ACGIH. Rohm and Haas Company recommends a TWA of 5 mg/m3 and
an STEL of 10 mg/m3 (7).
|CAS #: ||709-98-8
|Specific gravity: ||1.25 at 25 degrees C (2)
|Solubility in water: ||225 ppm at 25 degrees C
|Solubility in other solvents: ||Propanil is soluble in benzene and highly soluble in methanol (14).
At 25 degrees C, it is more than 25% soluble in hexalene glycol, isopropyl alcohol, methyl ethyl ketone, toluene and xylene (2).
|Melting point: ||91 - 93 degrees C (196 - 199 degrees F) (13).
|Flash point: ||100 degrees C (4)
|Vapor pressure: ||negligible (7); 9 x 10 to the minus 5 mm Hg at 60 degrees C (5); 2.6 x 10 to the minus 7 mbar (4)
|Koc: ||188 g/ml (6)
|Density: ||1.054 at 25 degrees C/15.6 degrees C (Spencer. guide to chem. in crop prot. 1982)
|Chemical class/use: ||amide herbicide; aniline derivative
Rohm and Haas Co.
Independence Mall West
Philadelphia, PA 19105
Review by Basic Manufacturer:
Comments solicited: October, 1992
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