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Revised June 1996
Captan
Trade and Other Names:
Trade names for captan include Agrox, Captal, Captec, Captol,
Captonex, Clomitane, Merpan, Meteoro, Orthocide, Phytocape,
Sepicap, Sorene, and Vancide 89. Captan may be found in
formulations with a wide range of other pesticides.
Regulatory Status:
Captan is a General Use Pesticide (GUP), though most uses of the
compound on food crops were cancelled in the U.S. in 1989. It is
categorized as toxicity class IV - practically nontoxic. However,
it bears the Signal Words DANGER or CAUTION if packaged in
concentrated form because it can be irritating to the skin and
eyes.
Chemical Class:
phthalimide
Introduction:
Captan is a nonsystemic phthalimide fungicide used to control
diseases of many fruit, ornamental, and vegetable crops. It
improves fruit finish by giving it a healthy, bright colored
appearance. It is used in agricultural production as well as by
the home gardener. A major use of captan is in apple production.
Formulation: Not
Available
Toxicological Effects:
- Acute toxicity: The rat oral LD50 for
captan ranges from 8400 to 15,000 mg/kg, indicating very
low acute toxicity [15]. The mouse LD50 is 7000 mg/kg.
Sheep showed no effect at doses of 200 mg/kg, but
experienced deaths at 250 mg/kg. The inhalation LC50
(2-hour) in mice is 5.0 mg/L [8]. Rabbits showed little
or no skin sensitization to captan, while guinea pigs
were moderately sensitive [6]. Workers exposed to high
concentrations of captan in air (6 mg/m3) experienced eye
irritation including burning, itching, and tearing. Skin
irritation also occurred in some cases [6].
- Chronic toxicity: Rats fed up to 750
mg/kg/day of Orthocide for 4 weeks had decreased food
intake and body weights [6]. No deaths occurred in pigs
given as much as 420 to 4000 mg/kg/day in the diet for 12
to 25 weeks, however, cattle given six doses of 250 mg/kg
experienced varied toxic effects, including death [6].
- Reproductive effects: Pregnant mice
exposed by inhalation to high doses of captan for 4 hours
a day during days 6 to 15 of gestation showed significant
mortality or weight loss. Fetal mortality accompanied
these effects. Mice fed 50 mg/kg/day over three
generations reproduced normally. Captan is unlikely to
cause reproductive effects in humans at usual levels of
exposure [6,8].
- Teratogenic effects: Teratogenicity
studies with rats, rabbits, hamsters, and dogs have given
both negative and positive results. However, the weight
of evidence suggests that captan does not produce birth
defects [16].
- Mutagenic effects: Although captan was
mutagenic in some laboratory tests on isolated tissue
cultures, the majority of evidence indicates that captan
is nonmutagenic [16].
- Carcinogenic effects: There is strong
evidence that captan causes cancer in female mice and in
male rats at high doses. In addition, captan is
chemically similar to two other pesticides, folpet and
captafol, that have been shown to produce cancer in test
animals. Tumors were associated with the gastrointestinal
tract and, to a lesser degree, with the kidneys. Tumors
appeared in the test animals at doses of about 300
mg/kg/day [6,8].
- Organ toxicity: Most organ-specific
effects are found in the kidneys of rats at and above
doses of 100 mg/kg/day.
- Fate in humans and animals: Studies in
several animal species have shown that captan is rapidly
absorbed from the gastrointestinal tract and is rapidly
metabolized. Residues are excreted primarily in the
urine. Rats given captan orally excreted a third in the
feces and half in the urine within 24 hours. A cow fed
small amounts in its diet for 4 days had no captan in the
milk at a 0.01 mg/L detection limit, nor could any be
detected in the urine at a 0.1 mg/L detection limit [6].
Ecological Effects:
- Effects on birds: Captan is practically
nontoxic to birds. The LD50 is greater than 5000 mg/kg in
mallard ducks and pheasants. The LD50 is 2000 to 4000
mg/kg in bobwhite quail [1]. High doses administered for
90 days to chickens caused an 80% reduction in the number
of eggs produced, but had no effect on the fertility or
hatchability of the eggs produced [6].
- Effects on aquatic organisms: Captan is
very highly toxic to fish. The LC50 (96-hour) for
technical captan ranges from 0.056 mg/L in cutthroat
trout and chinook salmon to 0.072 mg/L in bluegill [1].
The LC50 for captan in the aquatic invertebrate Daphnia
magna is 7 to 10 mg/L, indicating that the compound is
moderately toxic to this and other aquatic invertebrates
[8]. Captan has a low to moderate tendency to accumulate
in living tissue. Fish exposed for 3 days to
concentrations which would be expected in a pond
following treatment of an adjacent watershed at a rate of
1 lb/acre, had no detectable residues of captan [6].
Estimates of the bioconcentration factor range from 10 to
1000 [9].
- Effects on other organisms: Captan is
not toxic to bees when used as directed [1].
Environmental Fate:
- Breakdown in soil and groundwater:
Captan has a low persistence in soil, with a half-life of
1 to 10 days in most soil environments [6]. Captan was
not detected in field studies of its mobility at
application rates of up to 42 kg active ingredient per
hectare [9].
- Breakdown in water: Captan is rapidly
degraded in near neutral water. Half-lives of 23 to 54
hours and 1 to 7 hours have been reported at various
acidities and temperatures [6]. The effective residual
life in water is 2 weeks [15].
- Breakdown in vegetation: Captan is taken
up through leaves and roots and translocated throughout
the plant. Residual fungitoxicity remains for 23 days
after application on potato leaves, but residues were
below the detection limit within 40 days after
application [6]. Some varieties of apples, pears, lettuce
seeds, celery, and tomato seeds may be injured by captan
at high doses [1].
Physical Properties:
- Appearance: Captan is a white to buff
colored compound in the technical form. It is a colorless
crystal in its pure form [1]. The technical product has a
pungent smell.
- Chemical Name:
3a,4,7,7a-tetrahydro-2-[(trichloromethyl)thio]-1H-isoindole-1,3(2H)-dione
- CAS Number: 133-06-2
- Molecular Weight: 300.61
- Water Solubility: 3.3 mg/L @ 25 C [1]
- Solubility in Other Solvents: xylene s.;
acetone s.; chloroform v.s.; cyclohexanone v.s. [1]
- Melting Point: 178 C [1]
- Vapor Pressure: 1.3 mPa @ 25 C [1]
- Partition Coefficient: 2.7853 [1]
- Adsorption Coefficient: 200 [11]
Exposure Guidelines:
- ADI: 0.1 mg/kg/day [12]
- MCL: Not Available
- RfD: 0.13 mg/kg/day [13]
- PEL: Not Available
- HA: Not Available
- TLV: 5 mg/m3 (8-hour) [17]
Basic Manufacturer:
Drexel Chemical Company
1700 Channel Avenue
Memphis, TN 38113
- Phone: 901-774-4370
- Emergency:Not Available
References:
References for the information in this PIP can be found in
Reference List Number 10
DISCLAIMER: The
information in this profile does not in any way replace or
supersede the information on the pesticide product labeling or
other regulatory requirements. Please refer to the pesticide
product labeling.