E X T O X N E T
Extension Toxicology Network
A Pesticide Information Project of Cooperative Extension Offices of
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University of California at Davis. Major support and funding was provided
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Pesticide
Information
Profile
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Sodium chlorate
Publication Date: 9/95
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TRADE OR OTHER NAMES
The active ingredient sodium chlorate is found in a variety of commercial
herbicides. Some trade names for products containing sodium chlorate include
Atlacide, Defol, De-Fol-Ate, Drop-Leaf, Fall, Harvest-Aid, Kusatol, Leafex,
and Tumbleaf. The compound may be used in combination with other herbicides
such as atrazine, 2,4-D, bromacil, diuron, and sodium metaborate (1, 2, 3, 4).
REGULATORY STATUS
Sodium chlorate is not a restricted use pesticide. Check with specific
state restrictions which may apply. Products containing the active ingredient
sodium chlorate must bear the Signal Word "Warning" on their label (4).
INTRODUCTION
Sodium chlorate is a non-selective herbicide. It is considered phytotoxic
to all green plant parts. It can also kill through root absorption. Sodium
chlorate may be used to control morningglory, Canada thistle, johnsongrass and
St. Johnswort (3, 5). The herbicide is mainly used on non-crop land for spot
treatment and for total vegetation control on roadsides, fenceways, ditches,
etc. Sodium chlorate is also used as a defoliant and desiccant for cotton,
safflower, corn, flax, peppers, soybeans, grain sorghum, southern peas, dry
beans, rice and sunflowers (1, 5). If used in combination with atrazine, it
increases the persistance of the effect. If used in combination with 2,4-D, it
improves performance of the material. Sodium chlorate has a soil-sterilant
effect. Mixing with other herbicides in aqueous solution is possible to some
extent, so long as they are not susceptible to oxidation (1)
Sodium chlorate comes in dust, spray and granule formulations. There is a
risk of fire and explosion in dry mixtures with other substances, especially
organic materials, i.e. other herbicides, sulphur, powdered metals, strong
acids, etc. (1). Marketed formulations contain a fire depressant (2).
TOXICOLOGICAL EFFECTS
ACUTE TOXICITY
The acute oral LD50 for sodium chlorate in rats ranged between 1,200-
7,000 mg/kg (1, 2, 3, 4, 6). The compound was a mild skin irritant in rabbits
(6). The dermal LD50 was 500 mg/kg over 24 hours (4, 6, 7). The oral LD50 was
7,200 mg/kg for rabbits (6). The acute toxicity values for mice were 8,350
mg/kg for the oral toxicity and 596 mg/kg for the intraperitoneal LD50 (6).
Another study found sodium chlorate to have an oral LDlo of 700 mg/kg for
dogs; and an oral LDlo of 1350 mg/kg for cats (6).
A single dose of 5-10 g/person of sodium chlorate can prove to be fatal
in adults, as can a single dose of 2 g/child in small children. Another source
reported that a dose of 15 to 30 g/person may be fatal to humans (5).
Irritation of the skin, eyes, and mucous membranes has been noted (1, 2, 3).
Symptoms of oral ingestion of sodium chlorate include abdominal pain, nausea,
vomiting, diarrhea, pallor, blueness, shortness of breath, unconsciousness and
collapse (3, 6).
CHRONIC TOXICITY
Chronic exposure may render lack of appetite and weight loss, as well as
all those symptoms listed under acute exposure to sodium chlorate. A prolonged
chronic exposure to inhalation of sodium chlorate may cause mucous membrane
irritation (6).
Reproductive Effects
No information was available.
Teratogenic Effects
No information was available.
Mutagenic Effects
No information was available.
Carcinogenic Effects
No carcinogenic effects were noted for sodium chlorate (6).
Organ Toxicity
Sodium chlorate may affect blood cells and damage kidneys. Acute exposure
to the compound may damage the liver. The kidney tubules may be severely
damaged without producing detectable methemoglobinemia. Repeated ingestion of
small doses may cause anorexia and weight loss (6).
Fate in Humans and Animals
No information was found.
ECOLOGICAL EFFECTS
Effects on Birds
The long-term toxicity of sodium chlorate to birds resulted in reduced
egg production and fertility (8).
Effects on Aquatic Organisms
Sodium chlorate is considered non-toxic to fish. The possible 48-hour
LC50 for various species of fish was 10,000 mg/l (1).
Effects on Other Animals (Nontarget species)
Sodium chlorate is considered non-toxic to bees (1). Toxicity to animals
may occur if they feed on freshly treated areas. This chemical has a salty
taste and salt-hungry animals may eat enough to become poisoned (5).
ENVIRONMENTAL FATE
Breakdown of Chemical in Soil and Groundwater
The duration of residual activity for sodium chlorate in soil was 3-4
months after using 1,000 liters of a 1% solution/ha (1). Sodium chlorate may
persist in soil for 6 months to 5 years, depending on rate applied, soil type,
fertility, organic matter, moisture, and weather conditions. Toxicity in soil
is decreased considerably by a high nitrate content, alkaline conditions, and
high soil temperatures. Decomposition of the compound occurs more readily in
moist soils above 70 degrees F (5).
Breakdown of Chemical in Surface Water
No information was available.
Breakdown of Chemical in Vegetation
Plants absorb sodium chlorate through both roots and leaves. The
herbicide is carried downward through the xylem since it kills the phloem
tissue. It also increases the rate of respiration, decreasing catalase
activity, and depleting the plant's food reserves. Chlorate-injured plants are
more susceptible to frost. Sodium chlorate is 30-50 times more toxic to plants
than sodium chloride (table salt) (5).
PHYSICAL PROPERTIES AND GUIDELINES
Physical Properties:
| CAS No.: | 7775-09-9 (1) |
| Chemical name: | Sodium chlorate |
| Chemical Class/Use: | Non-selective contact herbicide; defoliant, dessiccant, harvest aid (4) |
| Specific gravity: | 2.490 at 15 degrees C (3) |
| Solubility in water: | In water at 0 degrees C, 79 g/100 ml; at 100 degrees C, 230 g/100 ml (1, 2, 3) |
| Solubility in other solvents: | In 90% alcohol, 1.6 g/100 g (1); soluble in ethanol and glycerol (2) |
| Melting point: | 248 degrees C (1, 2, 3); 478-502 degrees F (6) |
| Decomposition temperature: | 300 degrees C (1) |
| Vapor pressure: | Zero (1) |
BASIC MANUFACTURERS
Drexel Chemical Co.
2487 Pennsylvania St.
Memphis, TN 38109
Fax: 901-774-4666
Telephone: 901-774-4370
Review by Basic Manufacturer:
Comments solicited: October, 1994
Comments received: December, 1994
Wilbur-Ellis Co.
320 California Street
San Francisco, CA 94104
Fax: 415-772-4011
Telephone: 415-772-4000
Emergency: 209-226-1934
Review by Basic Manufacturer:
Comments solicited: October, 1994
Comments received:
REFERENCES
The Agrochemicals Handbook. 1983. The Royal Society of Chemistry, The
University, Nottingham, England.
Worthing, C. R. (ed.). 1983. The Pesticide Manual: A World Compendium.
Seventh edition. Published by The British Crop Protection Council.
Herbicide Handbook of the Weed Science Society of America. 1989. Sixth
edition. Champaign, IL.
Farm Chemicals Handbook. 1994. Meister Publishing Co. Willoughby, OH.
Thomson, W. T. 1992. Agricultural Chemicals. Book II: Herbicides.
Thomson Publications, Fresno, CA.
OHS Database. 1993. Occupational Health Services, Inc. 1993 (August)
MSDS for Sodium chlorate. OHS Inc., Secaucus, NJ.
U.S. Environmental Protection Agency. 1986. Office of Pesticides. TOX
Oneliners -- Sodium chlorate. May, 1986.
Briggs, S. A. 1992. Basic Guide to Pesticides: Their Characteristics
and Hazards. Hemisphere Publishing Corp., Washington, Philadelphia, London.
Disclaimer: Please read
the pesticide label prior to use. The information contained at this web
site is not a substitute for a pesticide label. Trade names used herein
are for convenience only; no endorsement of products is intended, nor is
criticism of unnamed products implied. Most of this information is historical
in nature and may no longer be applicable.
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