WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE
ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
ET L'AGRICULTURE
VBC/DS/75.14
ORIGINAL: ENGLISH
DATA SHEETS ON PESTICIDES No. 14
June 1975
MEVINPHOS
It must be noted that the issue of a Data Sheet for a
particular pesticide does not imply endorsement of the pesticide by
WHO or FAO for any particular use, or exclude its use for other
purposes not stated. While the information provided is believed to
be accurate according to data available at the time when the sheet
was compiled, neither WHO nor FAO are responsible for any errors or
omissions, or any consequences therefrom.
The issue of this document does Ce document ne constitue pas une
not constitute formal publication. Il ne doit faire
publication. It should not be l'objet d'aucun compte rendu ou
reviewed, abstracted or quoted résumé ni d'aucune citation sans
without the agreement of the l'autorisation de l'Organisation
Food and Agriculture des Nations Unies pour
Organization of the United l'Alimentation et l'Agriculture
Nations or of the World Health ou de l'Organisation Mondiale de
Organization. la Santé.
MEVINPHOS
Part 1 - General information
CLASSIFICATION
Primary use: insecticide
Secondary uses: acaricide
Chemical group: organophosphorus compound
Data sheet No. 14
Date issued: June 1975
1.1 COMMON NAME: Mevinphos (ISO)
Identity: 2-methoxycarbonyl-1-methylvinyl dimethyl phosphate,
the technical material contains at least 60% of the cis isomer.
Synonyms
Phosdrin<F;S>³<F;>
1.2 SYNOPSIS: an organophosphorus pesticide of very high mammalian
toxicity. It may be absorbed from the gastrointestinal tract, by
inhalation and through the intact skin.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics: the technical material is a
pale yellow to orange liquid b.p. 99-103°C at 0.03 mm Hg.
1.3.2 Solubility: highly soluble in water in all proportions,
also alcohols, ketones, and chlorinated aromatic hydrocarbons.
Practically insoluble in hexane.
1.3.3 Stability: moderately stable in neutral solution which
remains effective biologically after standing for seven days.
The technical product is hydrolysed in aqueous solution with a
half-life of 120 days at pH 6, 35 days at pH 7 and 1.4 hours at
pH 11. Corrosive to brass, cast iron, mild and some stainless
steels. Relatively non-corrosive to copper, monel, nickel and
aluminium. Diffuses slowly through polythene. Incompatible with
alkaline pesticides and fertilizers.
1.3.4 Vapour pressure (volatility): 2.9 x 10-3 mm Hg at
21°C.
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY
1.4.1 Common formulations
Water solution, 25%; emulsifiable concentrates, 10-50%; granules,
1-5%; wettable powder, 10%; aerosols.
There are draft FAO specifications for the technical material and
emulsifiable concentrates.
1.4.2 Susceptible pests
Highly effective against most insects and mites.
Although not persistent, the high initial kill gives
relatively long protection. The cis-isomer is about
100 times as insecticidal as the trans-.
1.4.3 Use pattern
Mevinphos has been used to control many pests on a wide
range of crops, but its main uses are against vegetable
pests and aphids, leaf rollers and mites in fruit. Owing
to its rapid loss by volatilization and degradation from
treated plants, it is most used shortly before harvest.
In a number of countries, officially approved pre-harvest
intervals for outdoor application at rates up to 0.5
kg/ha are in the range of 1-4 days for many crops.
1.4.4 Unintended effects
Toxic to most animal species but hazard from rec ended
use is slight owing to rapid breakdown. Non-recommended
uses as an avicide are known to have killed domestic
animals and wildlife. Does not accumulate in soil and no
ill effects on soil micro-organisms have been reported.
Not phytotoxic when used as recommended, although some
crops may be sensitive to solvents used in certain
formulations.
1.5 PUBLIC HEALTH PROGRAMMES
Not used in public health.
1.6 HOUSEHOLD USE
Mevinphos is too toxic for household use.
MEVINPHOS
Part 2 - Toxicology and risks
Common name: mevinphos
Data sheet No. 14
Date issued: June 1975
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption route: absorbed by the skin as well as by
inhalation and from the gastrointestinal tract, as well as by
inhalation and through the intact skin.
2.1.2 Mode of action: cholinesterase inhibition.
2.1.3 Excretion products: excretion takes place rapidly as
dimethylphosphoric acid in urine.
2.1.4 Toxicity, single dose
Oral: LD50 rat (M) 6.1 mg/kg
(F) 3.7 mg/kg
Demal: LD50 rat (M) 4.7 mg/kg
(F) 4.2 mg/kg
Dermal: LD50 rabbit 4.7-33.8 mg/kg
Most susceptible species: not known.
2.1.5 Toxicity, repeated doses
Oral: see dietary studies
Dermal: no information
Inhalation: no information
Repeated administration by any route will result in progressive
reduction of cholinesterase.
Cumulation of compound
Mevinphos does not accumulate in body tissues and is excreted
rapidly in the urine as dimethyl-phosphoric acid. Only hydrolysis
products were found in the milk of treated cows.
Cumulation of effect
Repeated exposure to sub-lethal amounts may reduce cholinesterase
activity to hazard levels.
2.1.6 Dietary studies
Short-term: In rats which were fed 0.32, 0.8, 20 or 5.0 ppm
(0.016, 0.04, 0.1 or 0.25 mg/kg/day) for up to 12 weeks the no-
effect level with respect to erythrocyte cholinesterase activity
was 0.8 ppm (0.04 mg/kg/day). A concentration in the diet
greater than 5 ppm (0.25 mg/kg/day) was required to cause a
significant reduction in the cholinesterase activity of the
plasma or brain.
In dogs which were fed 0.3, 1.0, 2.5, 5.0, 75 or 200 ppm of
mevinphos in their diet (0.0075, 0.025, 0.125, 1.875 or 5.0
mg/kg/day), signs of intoxication were evident at 75 ppm (1.875
mg/kg/day). The no effect level with respect to erythrocyte
cholinesterase was 1 ppm (0.025 mg/kg/day).
2.1.7 Supplementary studies of toxicity
No information.
2.1.8 Modifications of toxicity
No information.
2.2 TOXICOLOGY - MAN
2.2.1 Absorption
See 2.1.1. The dermal route is an important route of absorption
with mevinphos.
2.2.2 Dangerous doses
Single: The dangerous dose of mevinphos for man is unknown.
However, animal experiments and poisoning cases arising from
occupational exposure show that it is very small.
Repeated: No information.
2.2.3 Observations of occupationally exposed workers
Most observed cases of poisoning have been isolated and have been
occupational in origin. In one year in one location in the
Americas, of 287 cases of poisoning by organophosphorus
pesticides, 34 were caused by mevinphos which was second only to
parathion as the most common cause of poisoning by this class of
compound.
2.2.4 Observations on exposure of the general population
With correct use in agriculture, the general population will not
be exposed to hazardous amounts of mevinphos.
2.2.5 Observations of volunteers
No information.
2.2.6 Reported mishaps
Six children in one location in the Americas were poisoned by
wearing unwashed jeans that had been contaminated by mevinphos.
Approximately 8 months previously the trousers had been
transported on a truck loaded with mevinphos. The insecticide
had spilled fr= a punctured container.
2.3 TOXICITY TO NON-MAMMALIAN SPECIES
2.3.1 Fish
Toxic to fish and crustaceans.
2.3.2 Birds
Highly toxic to birds.
2.3.3 Other species
Toxic to bees and other pollinators. Toxic to wildlife
generally. Not harmful to soil micro-organisms.
In all species, there is little hazard from recommended use owing to
rapid decomposition.
MEVINPHOS
Part 3 - For regulatory authorities
Common name: mevinphos
Data sheet No. 14
Date issued: June 1975
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY
(for definition of categories, see introduction)
Liquid formulations over 20%, category 2; liquid formulations
over 2%, category 3; all others, category 4.
Solid formulations over 20%, category 3; all others, category 4.
3.2 TRANSPORTATION AND STORAGE
All formulations
Should be transported and stored in clearly labelled impermeable
containers under lock and key, secure from access by unauthorized
persons and children. No food or drink should be stored in the
same compartment.
3.3 HANDLING
All formulations
Full protective clothing (see part 4) should be used by those
handling the compound. Adequate washing facilities should be
available at all times during handing and should be close to site
of handling. Eating, drinking and smoking should be prohibited
during handling and before washing after handling.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINERS
All formulations
Container must either be burned or crushed and buried below
topsoil. Care must be taken to avoid subsequent contamination of
water sources. Decontamination of containers in order to use them
for other purposes should not be permitted.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
All formulations
Pre-employment medical examination of workers necessary. Workers
suffering from active hepatic or renal disease should be excluded
from contract. Pre-employment and periodic cholinesterase test
for workers desirable. Special account should be taken of the
workers' mental ability to comprehend and follow instructions.
Training of workers in techniques to avoid contact essential.
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT
All formulations
Pilots and loaders should have special training in application
methods and early symptoms of poisoning, and must wear a suitable
respirator. Use of flagmen not recommended. Flagmen, if used,
should wear protective clothing and be located well away from the
dropping zone.
3.7 LABELLING
All formulations
"POISON"
(skull and cross bones insignia)
"Mevinphos is an organophosphorus compound which inhibits
cholinesterase. It is a very toxic substance. Contact with the
skin, inhalation of dust or spray, or swallowing may be fatal.
Wear protective gloves, clean protective clothing, and a
respirator of the organic-vapour type when handling this
material. Bathe immediately after work. Ensure that containers
are stopped under lock and key. Empty containers must be
disposed of in such a way as to,prevent all possibility of
accidental contact with them. Keep the material out of reach of
children and well away from foodstuffs, animal feed and their
containers.
"In case of contact, immediately remove contaminated clothing and
wash the skin thoroughly with soap and water; for eyes, flush
with water for 15 minutes.
"If poisoning occurs, call a physician. Atropine and pralidoxime
are specific antidotes and repeated doses may be necessary.
Artificial respiration may be needed."
3.8 RESIDUES IN FOOD
Maximum residue levels
The Joint FAO/WHO Meeting on Pesticides Residues (1972) has
recommended the following limits:
Broccoli, Brussel sprouts, cabbage, cauliflower, collards... 1 ppm
Cherries, strawberries...................................... 1 ppm
Apples, grapes, peaches, lettuce, spinach................... 0.5 ppm
Cucumbers, tomatoes, apricots, citrus fruit, pears.......... 0.2 ppm
Carrots, beans, onions, pears, potatoes, turnips............ 0.1 ppm
Melons...................................................... 0.05 ppm
MEVINPHOS
Part 4 - Prevention of poisoning in man and emergency aid
Common name: mevinphos
Data sheet No. 14
Date issued: June 1975
4.1 PRECAUTIONS IN USE
4.1.1 General
Mevinphos is an organophosphorus pesticide of very high toxicity.
It penetrates the intact skin and is also absorbed by inhalation
and from the gastrointestinal tract. Most formulations should be
handled by trained personnel wearing protective clothing.
4.1.2 Manufacture and formulation
T.L.V.
(A.C.G.I.H.) 0.1 mg/m3; (USSR)
Formulation should not be attempted without advice from the
manufacturer.
Closed systems and forced ventilation may be required to reduce
as much as possible the exposure of workers to the chemical.
4.1.3 Mixers and applicators
When opening the container and when mixing, protective
impermeable boots, clean overalls, gloves and respirator should
be worn. Mixing, if not mechanical, should always be carried out
with a paddle of appropriate length. When spraying tall crops or
during aerial application a respirator should be worn as well as
an impermeable hood, clothing, boots and gloves. The applicator
should avoid working in spray mist and avoid contact with the
mouth. Particular care is needed when equipment is being washed
after use. All protective clothing should be washed immediately
after use, including the insides of the gloves. Splashes must be
washed immediately from the skin or eyes with large quantities of
water. Before eating, drinking or smoking, hands and other
exposed skin should be washed.
4.1.4 Other associated workers (including flagmen in aerial operations)
Persons exposed to mevinphos and associated with its application
should wear protective clothing and observe the precautions
described above in 4.1.3 under "mixers and applicators".
4.1.5 Other populations likely to be affected
With good agricultural practice subject to 4.2 below, other
populations should not be exposed to hazardous amounts of
mevinphos.
4.2 ENTRY OF PERSON INTO TREATED AREAS
Unprotected persons should be kept out of treated areas for at
least one day.
4.3 SAFE DISPOSAL OF CONTAINERS AND SPILLAGE
Residues in containers should be emptied in a diluted form into a
deep pit taking care to avoid contamination of ground waters.
Decontamination of containers in order to use them for other
purposes should not be permitted.
Spillage of mevinphos and its formulations should be removed by
washing with 5% sodium hydroxide solution and then rinsing with
large quantities of water.
4.4 EMERGENCY AID
4.4.1 Early symptoms of poisoning
Early symptoms of poisoning may include excessive sweating,
headache, weakness, giddiness, nausea, vomiting, stomach pains,
blurred vision, slurred speech, and muscle twitching. Later
there may be convulsions, coma, loss of reflexes and loss of
sphincter control.
4.4.2 Treatment before person is seen by a physician, if these symptoms
appear following exposure
The person should stop work immediately, remove contaminated
clothing and wash the affected skin with water and soap, if
available, and flush the area with large quantities of water. If
swallowed, vomiting should be induced if the person is conscious.
In the event of collapse, artificial respiration should be given,
bearing in mind that if mouth-to-mouth respiration is used, vomit
may contain toxic amounts of mevinphos.
MEVINPHOS
Part 5 - For medical and laboratory personnel
Common name: mevinphos
Date sheet No. 14
Date issued: June 1975
5.1 MEDICAL DIAGNOSIS AND TREATMENT OF CASES OF POISONING
5.1.1 General information
An organophosphorus pesticide of very high acute toxicity which
is easily absorbed through the intact skin as well as by
inhalation and from the gastrointestinal tract. It acts by
inhibiting acetyl cholinesterase. Continued exposure to low
amounts may inhibit blood cholinesterases to dangerous levels.
5.1.2 Symptoms and signs
Initial symptoms of poisoning may include excessive sweating,
headache, weakness, giddiness, nausea, vomiting, stomach pains,
blurred vision, slurred speech and muscle twitching. More
advanced symptoms of poisoning may be convulsions, coma, loss of
reflexes and loss of sphincter control.
5.1.3 Laboratory
The most important laboratory finding is reduction in activity of
blood cholinesterases. Urinary levels of organic phosphorus
containing metabolites should also be able to be used as a
measure for exposure. Neither method is specific for mevinphos.
5.1.4 Treatment
If the pesticide has been ingested, unless the patient is
vomiting, rapid gastric lavage should be performed using 5%
sodium bicarbonate, if available. For skin contact, the skin
should be washed with soap and water. If the compound has
entered the eyes, they should be washed with isotonic saline.
Persons without signs of respiratory inefficiency but with
manifest peripheral symptoms should be treated with 2-4 mg of
atropine sulfate and 1000-2000 mg of pralidoxime chloride or 250
mg of toxogonin (adult dose) by slow intravenous injection. More
atropine may be given as needed. Persons with severe
intoxication with respiratory difficulties, convulsions and
unconsciousness should immediately be given atropine and a
reactivator. In such severe cases 4-6 mg of atropine sulfate
should be given initially followed by repeated doses of 2 mg at
5-10 minute intervals. The patient's condition, including
respiration, blood pressure, pulse frequency, salivation and
convulsions should be carefully observed as a guide to further
administration of atropine. If the patient is cyanotic,
artificial respiration should be given first, then atropine
sulfate. The airways should be kept free and artificial
respiration should be applied, if required, preferably by
mechanical means. If necessary intubation should be performed.
Contraindications are morphine, barbituates, phenothiazine
tranquillizers and central stimulants of all kinds.
5.1.5 Prognosis
If the acute toxic effect is survived and adequate artificial
respiration has been given if needed, the chances of complete
recovery are good. However, in very severe cases, particularly
if artificial respiration has been inadequate, prolonged anoxia
may give rise to permanent brain damage.
5.1.6 References of previously reported cases
Case histories and general methods for treatment are given in:
Hayes, W. J. Jr. Clinical Handbook and Economic Poisons, U.S.
Public Health Ser. No. 476, Revised 1963, pp 18-23, 38-39.
See also Safe Use of Pesticides in Public Health (1967) Wld Hlth
Org. techn. Rep. Ser. No. 356, pp 58-59
For reports of individual cases of poisoning see:
Warren, M. C., Conrad, J. P., Bocian, J. J. and Hayes, M.
(1963) J. Amer. Med, Assoc., 184, 266-268
Bell, A., Barnes, R. and Simpson, G. R. (1968) Med, J. Aust.,
1, 178-180
5.2 SURVEILLANCE TESTS
Test Normal Hazard Symptomatic
level* level* level*
Plasma cholinesterase 100% 50% variable
Erythrocyte cholinesterase 100% 70% usually < 40%
* expressed as percentage of pre-exposure activity
Urinary levels of ether-extractable organic phosphorus should
also be able to be used to determine the degree of exposure.
5.3 LABORATORY METHODS
References are given only.
5.3.1 Detection and assay of compound
It is unlikely that unchaged mevinphos will be detectable in
human tissue after exposure. Determination of levels of blood
cholinesterase (see 5.3.2 below) should be used in cases of
suspected poisoning.
The multi-residue gas-chromatographic method of Abbott et al.
(1970) is satisfactory for determining levels of mevinphos in
foodstuffs. Other methods have been reviewed by FAO/WHO (1973).
5.3.2 Other tests in cases of poisoning
Levels of cholinesterase in the blood, particularly plasma,
provide the most useful diagnosis of poisoning. See:
Michel, N. O. (1949) J. Lab Clin. Med., 34, 1564-1568 Ellman,
G. L., Courtney, K. D., Andres, V.-, Jr. and Featherstone, R. M.
(1961) Biochem. Pharmacol., 7, 88-95
Urinary levels of other extractable organic phosphorus (Mattson &
Sledak, 1960) or dimethyl phosphate and phosphorothionate (Shafik
& Enos, 1969) can also be used to determine exposure.
REFERENCES
Abbot, D. C., Crisp, S., Tarrant, K. R. & Tatton, J. O'G., Pesticide
Residues in the Total Diet in England and Wales, 1966-1967. III.
-Organophosphorus Pesticide Residues in the Total Diet, Pestic.
Sci., 1970, 1, 10
FAO/WHO, 1973 Evaluation of some pesticide residues in food, FAO/AGP:
1972/M/9/1; WHO/1973, p. 413
Mattson, A. M. & Sledak, V. A., Ether-extractable urinary phosphates in
man and rats derived from malathion and similar compounds, J.
agr. Fd Chem., 1960, 8, 107
Shafik, M. T. & Enos, H. F., Determination of Metabolic and Hydrolytic
Products of Organophosphorus Pesticide Chemicals in Human Blood
and Urine, J. agric. Fd Chem., 1969, 17, 1186