methoxychlor (Marlate)
methoxychlor
CHEMICAL NAME: 2,2-bis(p-methoxyphenyl)-1,1,1-trichloroethane (56)
DEC INGRED. CODE:
TRADE NAME(S): Marlate, Flo Pro Mc Seed Protectant, Chemform (dis-
continued), Moxie (discontinued), Prentox, Double-M
(56).
FORMULATION(S): Wettable powders, emulsifiable concentrates, oil
solutions, dusts, flowables (56).
TYPE: Organochlorine insecticide
BASIC PRODUCER(S): Hopkins Agricultural Chemical Co.
P.O. Box 7532
Madison, WI 53707
Kincaid Enterprises, Inc.
P.O. Box 671
Nitro, WV 25143
Prentiss Drug and Chemical Co., Inc.
21 Vernon St.
CB 2000
Floral Park, NY 11001
STATUS: General use
PRINCIPAL USES: Widely used because of its long residual action
against many species of insects and its low toxicity to humans and
warm-blooded animals. For control of certain insect pests on fruit and
shade trees, vegetables, dairy and beef cattle, home gardens, and
around farm buildings (except poultry houses). (An excellent
replacement for DDT where application may constitute a hazard to
warm-blooded animals or susceptible plants. It is rarely phytotoxic,
and injury is usually negligible even on DDT-susceptible crops such as
cucurbits) (56).
I. EFFICACY
Important Pests Controlled: Houseflies, lice, ticks, weevils, stored
grain beetles, leafhoppers, Japanese beetles, armyworms, codling moths,
plum curculio, spittlebugs, scale (crawlers), lygus bugs, and many
others (8a).
Aphids and mites are not controlled (8a).
II. PHYSICAL PROPERTIES
MOLECULAR FORMULA: C16 H15 Cl3 O2 (62)
MOLECULAR WEIGHT: 345.7 (62)
PHYSICAL STATE: Colorless crystals (pure compound); gray powder
(technical product, contains 88% or more of
methoxychlor and 12% or less of related isomers)
(62).
ODOR: Pungent (34c)
MELTING POINT: 89 C (pure ); 77 C (setting point, technical product)
(62).
SOLUBILITY: 0.1 mg/l water at 25 C (technical product) (62).
III. HEALTH HAZARD INFORMATION
OSHA STANDARD: 15 mg/m3 averaged over an 8-hr. work shift (14).
NIOSH RECOMMENDED LIMIT: None established
ACGIH RECOMMENDED LIMIT: TWA (Time Weighted Average): 10 mg/m3 (15c).
TOXICOLOGY
A. ACUTE TOXICITY
DERMAL: Application to skin of rabbits of 2820 mg (in dimethyl
sulfoxide) produced no symptom (62).
ORAL: LD50 = 6000 mg tech./kg (rat) (62)
B. SUBACUTE AND CHRONIC TOXICITY:
In 1-yr feeding trials no toxic effect was observed in dogs
receiving 300 mg/kg daily; in 2-yr trials in rats there was no effect at
200 mg/kg diet, but some reduction in growth occurred at 1600 mg/kg diet
(62).
Lehman (1952) found that a dietary level of 100 ppm (equivalent to
350 mg/man/day) for two years was the lowest dosage producing no
symptoms, although tissue change was absent at 200 ppm and appeared only
at levels of 500 ppm or higher. Tegeris and associates (1966) found that
dogs fed 1 gm/kg per day for 6 months lost weight. At 2 gm/kg most
animals died within nine weeks. Pigs were more resistant (15b).
Although some liver tumors were observed in rats fed up to 2000 ppm
in the diet, it is not possible to evaluate adequately the
carcinogenicity of methoxychlor due to inadequate reporting of these
data; three other feeding studies produced no evidence of carcinogenesis.
In mice given 5 mg orally over 3 days and in rats given 20 mg there was a
uterotrophic effect manifested as a marked increase in weight of the
uterus (14).
IV. ENVIRONMENTAL CONSIDERATIONS
Little or no hazard to birds, fish and beneficial insects.
Relatively nonhazardous to honey bees. Biological magnification
unlikely. Considered to be nonphytotoxic (1).
Toxic to fish and bees (8a).
Approximate Residual Period: Several weeks on plant surfaces; over 1
year on bark; long residual in soil and water (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
Control Center.
FREQUENT SYMPTOMS AND SIGNS OF POISONING BY ORGANOCHLORINE PESTICIDES
APPREHENSION, EXCITABILITY, DIZZINESS, HEADACHE, DISORIENTATION,
WEAKNESS, PARESTHESIAE, muscle twitching, tremor, tonic and clonic
CONVULSIONS (often epileptiform), and unconsciousness are the major
manifestations. Soon after ingestion, nausea and vomiting commonly
occur. When chemicals are absorbed dermally, apprehension, twitching,
tremors, confusion, and convulsions may be the first symptoms.
Respiratory depression is caused by the pesticide and by the petroleum
solvents in which these pesticides are usually dissolved. Pallor
occurs in moderate to severe poisoning. Cyanosis may result as
convulsive activity interferes with respiration (25).
SKIN CONTACT: Bathe and shampoo the victim vigorously with soap
and water if skin and hair have been contaminated (25).
INGESTION: If victim is alert and gag reflex is not depressed,
give Syrup of Ipecac to induce vomiting (adults and children 12 years
and older: 30 ml; children under 12: 15 ml), followed by 1-2 glasses
of water (25).
INHALATION: If a person breathes in large amounts of methoxychlor,
move the exposed person to fresh air at once (14).
EYE CONTACT: Wash with lots of water for at least 15 minutes.
Seek medical attention, if necessary (34c).
NOTES TO PHYSICIAN:
CONTROL CONVULSIONS. DIAZEPAM (VALIUM (TM)) is a valuable
anticonvulsant.
Adult dosage: 5-10 mg (1-2 ml) slowly, intravenously (no faster than
one ml per minute) or give total dose intramuscularly (deep). Repeat
in 2-4 hours if needed.
Dosage for children under 6 years or 23 kg in weight: 0.1 mg/kg (0.02
ml/kg) intravenously, no faster than half the total dose per minute, or
give total dose intramuscularly (deep). Repeat in 2-4 hours if needed.
Persons suffering SEVERE PROTRACTED CONVULSIONS may require additional
anticonvulsant medication. Agents that have been used successfully in
the past are pentobarbital (Numbutal (TM)), phenytoin (Dilantin (TM)),
thiopental (Pentothal (TM)), and succinylcholine (Anectine (TM)).
If the victim is NOT FULLY ALERT, empty the stomach immediately by
INTUBATION, ASPIRATION, and LAVAGE, using isotonic saline or 5% sodium
bicarbonate. Because many pesticides are dissolved in petroleum
distillates, emesis and intubation of the stomach involve a serious
risk that solvent will be aspirated, leading to chemical pneumonitis.
DO NOT give epinephrine or other adrenergic amines, because of the
enhanced myocardial irritability induced by chlorinated hydrocarbons
(25).
VI. FIRE AND EXPLOSION INFORMATION
Nonflammable (34c).
VII. COMPATIBILITY
Generally compatible but do not mix with lime or alkaline materials
(1). Reacts with strong oxidizers such as chlorine and permanganates
(34c).
VIII. PROTECTIVE MEASURES
STORAGE AND HANDLING: Protect containers from damage. Store in cool,
dry area away from fire hazard and out of direct sunlight (34c).
PROTECTIVE CLOTHING: Wear splash-proof goggles and impervious gloves,
apron and boots (34c).
PROTECTIVE EQUIPMENT: For levels up to 150 mg/m3 use a chemical
cartridge respirator with dust, mist and fume filter, including
pesticide respirator meeting these requirements, a supplied-air
respirator, or self-contained breathing apparatus.
For levels up to 750 mg/m3 use the above with full facepiece or
gas mask with organic vapor canister with dust, fume and mist filter,
including pesticide respirators meeting these requirements. For levels
up to 7500 mg/m3 use a powered air-purifying respirator with
high-efficiency filter and organic vapor cartridge including pesticide
respirators meeting these requirements, or a Type C supplied-air
respirator in a positive pressure or continuous flow mode (34c).
IX. PROCEDURES FOR SPILLS AND LEAKS
IN CASE OF EMERGENCY, CALL, DAY OR NIGHT
(800) 424-9300
PESTICIDE TEAM SAFETY NETWORK/CHEMTREC
Persons not wearing protective equipment and clothing should be
restricted from areas of spills until cleanup has been completed.
If methoxychlor is spilled, the following steps should be taken:
1. Ventilate area of spill.
2. Collect spilled material in the most convenient and safe manner
and deposit in sealed containers for reclamation, or for disposal
in a secured sanitary landfill. Liquid containing methoxychlor
should be absorbed in vermiculite, dry sand, earth, or a similar
material.
Waste disposal method: Methoxychlor may be disposed of in sealed
containers in a secured sanitary landfill (14).
X. LITERATURE CITED
1. Harding, W.C. 1979. Pesticide profiles, part one: insecticides
and miticides. Univ. Maryland, Coop. Ext. Serv. Bull. 267.
30 pp.
8a. Thomson, W. T. 1976. Agricultural chemicals - book 1:
insecticides, acaricides, and ovicides. Revised ed. Thomson
Publ., Indianapolis, IN. 232 pp.
14. U. S. Department of Health and Human Services, National Institute
for Occuptational Safety and Health. 1981. Occupational
health guidelines for chemical hazards. F. W. Mackinson, R.
S. Stricoff, L. J. Partridge, Jr., and A. D. Little, Inc.,
eds. DHHS (NIOSH) Publ. No. 81-123. Washington, DC.
15b. American Conference of Governmental Industrial Hygienists. 1971.
Documentation of the threshold limit values for substances in
workroom air with supplements for those substances added or
changed since 1971, 3rd ed., 4th printing (1977). Cincinnati,
OH. 484 pp.
15c. American Conference of Governmental Industrial Hygienists. 1984.
TLVs: threshold limit values for chemical substances and
physical agents in the work environment and biological exposure
indices with intended changes for 1984-85. Cincinnati, OH.
116 pp.
25. Morgan, D.P. 1982. Recognition and management of pesticide
poisonings, 3rd ed. U.S. Environmental Protection Agency,
Washington, DC. 120 pp.
34c. New York State Department of Health, Bureau of Toxic Substances
Management. 1981. Chemical fact sheet: methoxychlor.
Albany, NY.
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.
4/10/85
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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