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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 Assessment Program.

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Carbophenothion

Publication Date: 9/95

TRADE AND OTHER NAMES

Trade names for products containing carbophenothion include Trithion, Garrathion, Dagadip, R-1303(1), Endyl, Lethox (2), Nephocarp, Acarithion, and Hexathion (3).

REGULATORY STATUS

Carbophenothion is a Restricted Use Pesticide (RUP). It is for retail sale to and use only by certified applicators or people directly supervised by them. The EPA requires a 2-day safety waiting interval between application and worker reentry to fields to prevent unnecessary skin exposure (1, 4).

INTRODUCTION

Carbophenothion is an insecticide and acaricide (1, 2). A member of the organo-phosphate class of chemicals, it has a long residual activity. For this reason, it is effective against the eggs and recently hatched young of many species (6). It affects insects on contact and when consumed. It is used on citrus fruit and cotton to control aphids and spider mites. When combined with petroleum oil, it controls over-wintering mites, aphids, and scale bugs (8, 9). It is also used to control aphids, mites, suckers, and other pests on fruit, nuts, vegetables, sorghum, maize, and others. It is used to control parasites on animals. Carbophenothion is available as an emulsifiable concentrate, wettable powder, granules, and a seed treatment (9). The EPA has classified carbophenothion as Category I - highly toxic. Products containing the active ingredient bear the SIGNAL WORD: DANGER (5). Carbophenothion may enhance the toxicity of malathion and some other compounds which are processed into more toxic forms by living organisms (10).

TOXICOLOGICAL EFFECTS

ACUTE TOXICITY

Carbophenothion affects the nervous system by inhibiting chlolinesterase (3). Symptoms of poisoning include headache, blurred vision, weakness, nausea, discomfort in the chest, abdominal cramps, vomiting, diarrhea, salivation, sweating and pinpoint pupils (12, 16). It is highly toxic when eaten and nearly as toxic when absorbed through the skin.

The LD50, the dose of carbophenothion which kills half of the study animals who eat it, is 10 mg/kg for female rats, 30 mg/kg for male rats and 218 mg/kg for mice (9). The LD50 for skin exposure to carbophenothion is 27 mg/kg for female rats, 54 mg/kg for male rats, and 1,270 to 1,850 mg/kg for rabbits (8, 9, 11). The LC50, the concentration at which half of the test rats die by inhaling carbophenothion is 0.002 mg/l of air (14). Carbophenothion causes irritation to rabbit eyes, but symptoms clear within days (14).

CHRONIC TOXICITY

Reproductive Effects

A three generation study showed that a dose of 1-2 mg/kg/day of carbophenothion in the diet caused reduced birth weight, increased stillbirths, and a decreased survival to weaning in rats (7). The level at which it has no observable effect (NOEL) on reproduction is 0.5 mg/kg/day (4). The lowest dose which had an effect on reproduction (LEL) is 1.5 mg/kg/day. At this level, rat pups' survival decreased and they weighed less than normal (14).

Teratogenic Effects

Carbophenothion is not teratogenic (7).

Mutagenic Effects

No information is available. However, since carbophenothion is an organophosphate compound and most organophosphate compounds are not mutagenic, it is unlikely to be mutagenic (10).

Carcinogenic Effects

A two-year feeding study of rats showed that a dose of 4 mg/kg/day of carbophenothion, the highest dose tested, did not cause tumors (14).

Organ Toxicity

As a cholinesterase inhibitor, carbophenothion affects the activity of nerves and the brain (9, 10). Studies have shown that carbophenothion may also cause some reduction in the number of red blood cells and increased adrenal gland weights in females (10).

Fate in Humans and Animals

Carbophenothion is absorbed through the skin very quickly. It penetrates rat skin in less than an hour (8). It is excreted from the body rapidly. The majority is excreted in urine and feces within 72 hours. Almost none is retained in tissue (15).

ECOLOGICAL EFFECTS

Effects on Birds

Carbophenothion is highly toxic to many birds (3). The LD50 is 5.6 mg/kg for European starlings, 29-35 mg/kg for the Canada goose, 121 mg/kg for mallard ducks, and 56.8 for Japanese quail. The LC50 for Japanese quail who consume carbophenothion in their diet is 4,434 ppm (8).

Effects on Aquatic Organisms

Carbophenothion is highly toxic to fish, crustaceans, marine organisms and amphibians (3, 6). The LD50 is 56 ppb for rainbow trout and 13 ppb for bluegill sunfish, 0.47 ppb for pink shrimp and 17 ppb for sheepshead minnow. Preliminary data show that Carbophenothion may accumulate in some species of minnow (4).

Effects on Others (Nontarget species)

Carbophenothion is highly toxic to bees. It is also highly toxic to wildlife, including upland game birds (3, 4). Leaf damage may occur to Delicious apples and injury also has been reported on grapefruit, kumquat, and citron from exposure to carbophenothion. It may injure ferns and a few sensitive rose varieties, especially in warm, moist conditions (6, 9).

ENVIRONMENTAL FATE

Breakdown of Chemical in Soil and Groundwater

Carbophenothion persists in soils for longer than 6 months (8). Preliminary data indicate that it is relatively immobile in sandy loam soils (4).

Breakdown of Chemical in Surface Water

No information currently available.

Breakdown of Chemical in Vegetation

A ten day waiting period between treatment with carbophenothion and application of dinitro compounds is recommended because the combination may damage plant leaves (6).

PHYSICAL PROPERTIES AND GUIDELINES

Carbophenothion in the pure form is a yellow-brown liquid with a mild mercaptan-like odor. It is non-corrosive and relatively stable to hydrolysis and to temperatures up to 80 degrees C (9).

Physical Properties:

CAS #: 786-19-6
Chemical Name: S-[[(p-chlorophenyl)thio] methyl] O,O-diethyl phosphorodithioate
Water solubility: 0.34 ppm at 20 degrees C (8)
Solubility in other solvents: Miscible in most organic solvents including alcohols, ethers, toluene, benzene, xylene, ketones, and mineral and vegetable oils (9)
Boiling point: 82 degrees C

Exposure Guidelines:

ADI: 0.0125 mg/kg/day (13)
NOEL: 1.1 mg/kg/day (rat)(13)

BASIC MANUFACTURER

ICI Americas, Inc.
Agricultural Products
New Murphy Road
Wilmington, DE 19897
Telephone: 302-886-1000 or 800-323-8633

Review by Basic Manufacturer:

Comments solicited: October, 1994
Comments received:

REFERENCES

  1. Ware, G. W. 1986. Fundamentals of Pesticides - A Self Instruction Guide, Second edition. Thomson Publications. Fresno, CA.
  2. Sine, Charlotte, (ed.). 1992. Farm Chemicals Handbook '92. Meister Publishing Company. Willoughby, OH.
  3. Briggs, Shirley. 1992. Basic Guide to Pesticides. Hemisphere Publishing. Washington, DC.
  4. Walker, M. M. and L. H. Keith. 1992. EPA Fact Sheet Database. Lewis Publishers. Ann Arbor, MI.
  5. Meister, R.T. 1994. Farm Chemicals Handbook '94. Meister Publishing Company. Willoughby, OH.
  6. Thomson, W. T. 1983. Agricultural Chemicals Book I Insecticides. Thomson Publications. Fresno, CA.
  7. Hayes Jr., Wayland. 1982. Pesticides Studied in Man. Williams and Wilkins Publishers. Baltimore, MD.
  8. Smith, G. J. 1993. Toxicology & Pesticide Use in Relation to Wildlife: Organophosphorus & Carbamate Compounds. C.K. Smoley. Boca Raton, FL.
  9. The Agrochemicals Handbook, Third Edition. 1994. Royal Society of Chemistry Information Systems, Unwin Brothers Ltd., Surrey, England.
  10. Hayes Jr., Wayland, and E. R. Laws, Jr., (eds.). 1991. Handbook of Pesticide Toxicology Volume 1. Academic Press, Inc. New York, NY.
  11. Budavari, Susan, (ed.). 1989. The Merck Index, Eleventh Edition. Merck and Company Incorporated. Rahway, NJ.
  12. Miller, Darcy (ed.). 1985. Crop Protection Chemicals Reference. Chemical and Pharmaceutical Publishing Corporation. NY, NY.
  13. U.S. Environmental Protection Agency. 1984. Pesticide Fact Sheet Carbophenothion No.25. U.S. EPA Office of Pesticides and Toxic Substances. Washington, DC.
  14. U.S. Environmental Protection Agency. Toxchem No. 165. CORE grade/Document # 003469 and 003730. Document Accession no. 250969 and 00036074. U.S. EPA. Washington, DC.
  15. Menn, J. J., J. R. DeBauand & J. B. McBain. 1976. "Recent Advances in the Metabolism of Organophosphorus Insecticides" in Federation Proceedings, Vol. 35 No. 14.
  16. U.S. Department of Health and Human Services. 1993. Hazardous Substance Data Base. HHS. Washington, DC.