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
Ansar 138, Arsan, Bolls-Eye, Broadside, Check-Mate, Cotton Aide HC,
Moncide, Montar, Phytar, Phytar 138, Phytar 600, Rad-E-Cate 25, Dilic,
Silvisar 510, Sylvicor.
Products containing cacodylic acid must bear the signal word
Cacodylic acid is an arsenical non-selective contact herbicide
which will defoliate or desiccate a wide variety of plant species (6).
It is used as a cotton defoliant and for lawn renovation, for weed
control in non-crop areas such as around buildings, near perennial
ornamentals, along fence rows, and in forest management. Its phytotoxic
properties are quickly inactivated upon contact with the soil (2).
Cacodylic acid is available in concentrated solution formulations (3).
Cacodylic acid is toxic by inhalation and moderately toxic by
ingestion. It is absorbed into the bloodstream more readily through
inhalation than through ingestion or dermal exposure (4). Arsenate,
from the metabolism of cacodylic acid, slows the production of energy by
The symptoms of subacute poisoning with arsenicals may include a
salty taste, burning in the throat, colicky pains in the stomach and
intestines, and garlicky odor of the breath, urine and sweat. In
persons exposed to sufficient arsenical dust, the onset of illness is
usually characterized by difficult or short breath, with pain in the
chest, followed by nausea and diarrhea. Severe arsenic poisoning causes
headache, dizziness, vomiting, profuse and watery diarrhea, followed by
dehydration, electrolyte imbalance, gradual fall in blood pressure,
stupor, convulsions, general paralysis, and possible death within 3 to
14 days (2, 4). Decreased peripheral circulation (blanching or flushing
of the skin, especially of the fingers), cirrhosis of the liver, atrophy
of the bone marrow, kidney damage, and loss of sensory and motor
functions have also been reported. About six weeks after exposure,
white bands may appear across the toe and finger nails (4, 5, 12).
Cacodylic acid is irritating to skin or eyes (4). Product
formulations may be irritating, depending on their acidity or
alkalinity. Blistering or conjunctivitis may occur (10, Grant. Tox. of
the Eye 1974).
Breathing the spray mist is a common means of exposure to cacodylic
acid (1). Fires may produce irritating and/or poisonous gases if
cacodylic acid is burned (8).
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 cacodylic acid in rats is
644 to 830 mg/kg (2, 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 cacodylic acid in rats is 3900 mg/m3 (4).
Signs of chronic arsenic poisoning include loss of appetite, weight
loss, weakness, nausea, alternating diarrhea and constipation, colic,
pain and tenderness in the limbs (usually starting in the fingers or
toes), dermatitis, abnormal changes in skin color, loss of hair,
giddiness and headache. Prolonged exposure may cause gradual mental and
physical deterioration. There may be disturbances of sight, taste,
smell and bladder function (4). Prolonged or repeated exposure of the
skin to arsenicals may cause dermatitis. Prolonged eye contact may
cause conjunctivitis and has caused eruptions of eyelids, conjunctiva
and even the cornea. Repeated exposure to low levels of arsenic may
produce increased tolerance for arsenic (4).
Feeding lab animals large amounts of cacodylic acid for extended
periods of time has decreased fertility. Male rats fed 226 mg/kg for 3
weeks showed reduced sperm production (2).
Oral doses to pregnant rats and mice have produced toxic effects
and developmental changes in the embryos (4).
No information found. for mammals. Cacodylic acid does have an
effect similar to colchicine, a chemical used to induce multiplication
of the number of chromosomes in plants (6).
Exposure to arsenic has been associated with increased incidence of
skin and other cancers (4). It may cause lung carcinomas (cancer) (5).
No information was found on carcinogenic effects of cacodylic acid.
Cacodylic acid affects a variety of organ systems. The kidney,
liver, heart, digestive tract, and central and peripheral nervous
systems are all targets. Arsenic will accumulate in finger or toe
nails, skin and hair (4, 5).
Fate in Humans and Animals
Most arsenicals including cacodylic acid are readily absorbed into
the bloodstream when ingested. It is metabolized (broken down) in the
liver. It accumulates in the skin, finger/toe nails and hair which also
serves as a means of excretion (5).
Effects on Birds
No information found.
Effects on Aquatic Organisms
Cacodylic acid presents a low toxicity hazard to most fish (6).
The LC50 for cacodylic acid in bluegill sunfish is 1000 ppm (0.1% of the
Effects on Other Animals (Nontarget species)
Arsenic causes skin rashes in some animals, such as pigs and
buffalo. Cacodylic acid is toxic to bees in the 100-1,000 ppm range (6).
The lowest dose (LCLO) that will kill a mouse is 500 mg/kg. The LCLO in
dogs is 1 g/kg (NIOSH RTECS Online File #83/8304).
Bioaccumulation is unlikely because cacodylic acid is not
persistent in the environment.
Breakdown of Chemical in Soil and Groundwater
Cacodylic acid is quickly inactivated upon contact with the soil by
adsorption to soil particles and ion exchange (2, 7). Soil
microorganisms degrade most of the cacodylic acid in the soil (6, 11).
Cacodylic acid is practically non-volatile and is not decomposed by UV
Arsenic competes with phosphorus in the soil. It forms insoluble
salts with chromium, silver nitrate or other metals. 15-80% of the
cacodylic acid in the soil will disappear in 8 months.
Breakdown of Chemical in Water
Run-off from fire control or dilution water may cause pollution of
surface waters (8). However, contamination of streams and lakes from
proper use of cacodylic acid is unlikely (11). Contamination of forest
streams is unlikely when cacodylic acid is used to thin forests (Bull.
Environ. Contam. Tox. 30 (3):309- 16.1983). Information on groundwater
contamination was not found.
Breakdown of Chemical in Vegetation
Arsenic, from the metabolism of cacodylic acid, is tightly bound in
the foliage (leaves) of plants (6, Bull. Environ. Contam. Tox. 30
(3):309-16.1983). The arsenicals are poisons to cell division in plants
Phosphorous can affect the phytotoxicity (ability to harm plants)
of arsenic. Phosphorous can free the arsenic from the soil, but also
will compete with the arsenic for uptake into the plant (6).
PHYSICAL PROPERTIES AND GUIDELINES
Cacodylic acid is a colorless crystalline solid with an offensive
odor (2, 4). It is not flammable and is stable under normal
temperatures and pressures. It will not ignite, but may burn if exposed
to heat or flame. Thermal decomposition may release toxic oxides of
arsenic and carbon (4). Since cacodylic acid is hygroscopic (it can
pull moisture out of the atmosphere), it should only be stored in
airtight containers which are kept closed and away from moisture (4).
Cacodylic acid is mildly corrosive and will cause damage to zinc, tin
and aluminum (2, 7). It is very dangerous to mix cacodylic acid with
active metals such as iron, aluminum, or zinc (11). Do not store
cacodylic acid near fertilizers, seeds, insecticides or fungicides (1).
Occupational Exposure Limits:
|0.5 mg (as) /m3 OSHA TWA (2)
|0.2 mg (as) /m3 ACGIH TWA (2)
|CAS #: ||75-60-5
|Specific gravity: ||>1.1 (4)
|Solubility in water: ||66.7g/100 ml. Forms water soluble sodium and potassium salts (2); 83% at 22 degrees C (4)
|Solubility: ||cacodylic acid is insoluble in ethyl ether. At 20 degrees C, its solubility in alcohol is 20.6g/100g (2). It is soluble in ethanol and acetic acid (4).
|Boiling point: ||>392 degrees F (>200 degrees C) (4)
|Melting point: ||378 degrees F (192 degrees C) (4)
|Flash point: ||nonflammable
|Chemical class/use: ||organo-arsenical herbicide
Drexel Chemical Co.
PO Box 9306
2487 Pennsylvania St.
Memphis, TN 38109
Review by Basic Manufacturer:
Comments solicited: October, 1992
Meister, R.T. (ed.) 1987. Farm Chemicals Handbook. Willoughby,
OH: Meister Publishing Co.
WSSA Herbicide Handbook Committee. 1983. Herbicide Handbook of
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Publishing Company, Willoughby, Ohio. 4 Occupational Health Services,
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