Acephate - Chemical Profile 4/85
CHEMICAL NAME: O,S-Dimethyl acetylphosphoramidothioate (56)
DEC INGRED. CODE:
TRADE NAME(S): Orthene, Ortran (56)
FORMULATION(S): 75% soluble powder (56)
TYPE: Organophosphate insecticide
BASIC PRODUCER(S): Chevron Chemical Co./Ortho Div.
940 Hensley Street
Richmond, CA 94804
STATUS: General use
PRINCIPAL USES: Foliage systemic and contact insecticide for insects on
flowers, vegetables, trees, and shrubs (1).
Tolerances and labels now exist for use on celery, head lettuce,
bell peppers, dry and succulent beans, cotton, soybeans, and mint.
Labelled for cockroach control (spot treatment only) in residential and
industrial buildings (except food handling establishments), and insect
control in forests, tobacco, and on ornamentals (56).
Field trials from 1969-1972 show Orthene to be very effective
against aphids, bagworms, cankerworms, tent caterpillars, gypsy moth,
lace bugs, leaf miners, leaf rollers, leafhoppers, mealybugs, oak moth,
sawflies, pine tip moths, thrips, webworms and other insects attacking
ornamentals, trees and turf. Excellent activity has also been
demonstrated against nuisance pests such as roaches, spiders, crickets,
ticks and clover mites (17g).
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C4 H10 NO3 P S (62)
MOLECULAR WEIGHT: 183.2 (62)
PHYSICAL STATE: Colorless solid (technical grade, purity 80-90%)
MELTING POINT: 82-89 C (technical grade) (62)
VAPOR PRESSURE: 226 uPa at 24 C (technical grade) (62)
SOLUBILITY: At room temperature c. 650 g/l water (technical
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: None established
NIOSH RECOMMENDED LIMIT: None established
ACGIH RECOMMENDED LIMIT: None established
A. ACUTE TOXICITY
DERMAL: LD50 = >2000 mg/kg (rabbit, technical);
>10250 mg/kg (rabbit, Orthene 75% SP) (17g).
No irritation or sensitization observed in Guinea
ORAL: LD50 = 945 mg/kg (male rat, technical); 866 mg/kg
(female rat, technical); 361 mg/kg (mouse,
technical); 1494 mg/kg (rat, Orthene 75% SP) (17g).
INHALATION: The vapor pressure of Orthene is low. Tests in
the rat also showed that the vapor toxicity was
low. Four hour exposure to vapors showed no
morbidity or mortality in rats and cholinesterase
values were normal (technical) (17g).
EYES: Slight conjunctival irritation but no corneal opacity
or iritis was observed. Eyes appeared normal after 1
week (rabbit, technical) (17g).
Moderate irritation and slight iritis after 24 hours;
eyes normal after 7 days; no corneal opacity
observed. Dilute sprays were not irritating (rabbit,
Orthene 75% SP) (17g).
B. SUBACUTE AND CHRONIC TOXICITY:
In 2-yr feeding trials: dogs showed depression of cholinesterase
at 100 mg/kg diet (maximum dose level) but no other significant effect;
rats showed depression of cholinesterase but no effect on weight gain or
pathological effect at 30 mg/kg diet. No teratogenic, mutagenic or
carcinogenic effect was observed (62).
90-day Subacute Oral Toxicity in Rats: Feeding Orthene Technical
for 90 days at dietary levels up to 300 ppm revealed no abnormalities
in weight gain, food consumption, survival, blood and urologic studies,
gross and microscopic pathology or organ weights and ratios (17g).
90-Day Feeding Study in Beagle Dogs: Levels up to 100 ppm caused
no significant effects other than depression of cholinesterase (Orthene
One-year Feeding Study in Beagle Dogs: Dietary levels up to 100
ppm for one year showed no significant differences in the various
parameters studied except for depression of RBC cholinesterase activity
at the 100 ppm level. No gross and histopathologic changes related
to ingestion of the chemical were noted (Orthene Technical) (17g).
IV. ENVIRONMENTAL CONSIDERATIONS
Some hazard to birds, fish, and beneficial insects. Hazardous to
honeybees. Biological magnification unlikely. Do not apply to
American elm, flowering crab apple, sugar maple, or huckleberry (1).
Toxicity to Fish: The 96-hr. TL50 is greater than 1000 ppm for
rainbow trout, 2050 ppm for bluegill, 1725 ppm for large-mouth black
bass, 2230 ppm for channel catfish, 6650 ppm for mosquito fish
(Gambusia) and 9550 ppm for goldfish (17g).
Toxicity to Birds: Acute Oral LD50 of Orthene Technical:
350 mg/kg for mallard ducks, 140 mg/kg for ringneck pheasants and
852 mg/kg for chickens (17g).
Approximate Residual Period: 10-15 days as systemic; does not
translocate to new growth. Short life in soil (1).
V. EMERGENCY AND FIRST AID PROCEDURES
The chemical information provided below has been condensed
from original source documents, primarily from "Recognition and
Management of Pesticide Poisonings", 3rd ed. by Donald P. Morgan,
which have been footnoted. This information has been provided in
this form for your convenience and general guidance only. In
specific cases, further consultation and reference may be required
and is recommended. This information is not intended as a sub-
stitute for a more exhaustive review of the literature nor for the
judgement of a physician or other trained professional.
If poisoning is suspected, do not wait for symptoms to develop.
Contact a physician, the nearest hospital, or the nearest Poison
FREQUENT SYMPTOMS AND SIGNS OF POISONING BY ORGANOPHOSPHATE PESTICIDES
Symptoms of acute poisoning develop during exposure or within 12
hours (usually within four hours) of contact. headACE, DIZZINESS,
WEAKNESS, INCOORDINATION, MUSCLE TWITCHING, TREMOR, NAUSEA, ABDOMINAL
CRAMPS, DIARRHEA, and SWEATING are common early symptoms. Blurred or
dark vision, confusion, tightness in the chest, wheezing, productive
cough, and PULMONARY EDEMA may occur. Incontinence, unconsciousness
and convulsions indicate very severe poisoning. SLOW HEARTBEAT,
salivation, and tearing are common. TOXIC PSYCHOSIS, with manic or
bizarre behavior, has led to misdiagnosis of acute alcoholism. Slowing
of the heartbeat may rarely progress to complete sinus arrest.
RESPIRATORY DEPRESSION may be fatal. Continuing daily absorption of
organophosphate at intermediate dosage may cause an INFLUENZA-LIKE
ILLNESS characterized by weakness, anorexia, and malaise (25).
SKIN CONTACT: Bathe and shampoo victim with soap and water if there
is any chance that skin and hair are contaminated (25).
INGESTION: If victim is alert and respiration is not depressed,
give Syrup of Ipecac, followed by 1-2 glasses of water to induce
vomiting. Adults (12 years and over): 30 ml; children: 15 ml (25).
NOTES TO PHYSICIAN:
Administer ATROPINE SULFATE intravenously, or intramuscularly, if IV
injection is not possible.
In MODERATELY SEVERE poisoning: Adult dosage: 0.4-2.0 mg repeated
every 15 minutes until atropinization is achieved: tachycardia (pulse
of 140 per minute), flushing, dry mouth, dilated pupils. Maintain
atropinization by repeated doses for 2-12 hours or longer depending on
severity of poisoning. Dosage for children under 12 years: 0.05 mg/kg
body weight, repeated every 15 minutes until atropinization is
achieved. Maintain atropinization with repeated dosage of 0.02-0.05
SEVERELY POISONED individuals may exhibit remarkable tolerance to
atropine; two or more times the dosages suggested above may be needed.
Administer PRALIDOXIME (Protopam (TM)-Ayerst, 2-PAM) in cases of severe
poisoning in which respiratory depression, muscle weakness and
twitchings are severe.
Adult dosage: 1.0 gm intravenously at no more than 0.5 gm per minute.
Child's dose (under 12 years): 20-50 mg/kg (depending on severity of
poisoning) intravenously, injecting no more than half the total dose
per minute. Dosage of pralidoxime may be repeated in 1-2 hours, then
at 10-12 hour intervals if needed. In very severe poisonings, dosage
rates may be doubled (25).
VI. FIRE AND EXPLOSION INFORMATION
To be developed.
Compatible with most insecticides and fungicides but must not be
mixed with alkaline materials such as lime sulfur or Bordeaux (1).
VIII. PROTECTIVE MEASURES
To be developed.
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
X. LITERATURE CITED
1. Harding, W.C. 1979. Pesticide profiles, part one: insecticides
and miticides. Univ. Maryland, Coop. Ext. Serv. Bull. 267.
8a. Thomson, W. T. 1976. Agricultural chemicals - book 1:
insecticides, acaricides, and ovicides. Revised ed. Thomson
Publ., Indianapolis, IN. 232 pp.
17g. Chevron Chemical Company, Ortho Division. 1973. Experimental
data sheet: Orthene insecticide. Moorestown, NJ.
25. Morgan, D.P. 1982. Recognition and management of pesticide
poisonings, 3rd ed. U.S. Environmental Protection Agency,
Washington, DC. 120 pp.
56. Farm Chemicals Handbook, 70th ed. 1984. R. T. Meister, G. L.
Berg, C. Sine, S. Meister, and J. Poplyk, eds. Meister
Publishing Co., Willoughby, OH.
62. The Pesticide Manual: A World Compendium, 7th ed. 1983. C.R.
Worthing, ed. The British Crop Protection Council, Croydon,
England. 695 pp.