WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE
ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
ET L'AGRICULTURE
VBC/DS/80.43
ORIGINAL: ENGLISH
DATA SHEETS ON PESTICIDES No. 43
March 1980
JODFENPHOS
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.
CLASSIFICATION:
Primary use: Insecticide
Secondary use: Acaricide
Chemical group: Organophosphorus compound.
Date issued: March 1980
1. GENERAL INFORMATION
1.1 COMMON NAME:
Jodfenphos (ISO), iodofenphos in French
1.1.1 Identity:
O-(2,5-dichloro-4-iodophenyl) O,O-dimethyl phosphorothioate
1.1.2 Synonyms:
Iodofenphos Alfacron(R)
Nuvanol(R) C 9491
OMS-1211 ENT 27408
Local synonyms:
1.2 SYNOPSIS:
An organophosphorus insecticide and acaricide of low mammalian
toxicity, used for the protection of stored products and in public
health. It is active after metabolism.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics
Colourless crystals with a mild odour, m.p. 76°C.
1.3.2 Solubility
At 20°C, practically insoluble in water (2 mg/l): soluble in
ketones, aromatic hydrocarbons and aliphatic chlorinated
hydrocarbons: slightly soluble in alcohols and aliphatic
hydrocarbons.
1.3.3 Stability
Relatively stable in weakly acid, neutral and weakly alkaline media,
unstable in strongly acid and alkaline media.
1.3.4 Vapour pressure
8 x 10-7 mmHg at 20°C.
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY
No recommended use.
1.5 PUBLIC HEALTH PROGRAMME
1.5.1 Common formulations
50 g/kg dust, 200 ml/l emulsifiable concentrate (EC), 500 g/kg
wettable power (WP), 500 ml/l liquid suspension = flowable (FW).
1.5.2 Susceptible pests
Effective against a wide range of insect pests in public hygiene
including cockroaches, sucking lice, bugs, flies and mosquitos,
fleas, and mites and ticks.
1.5.3 Use pattern
Mainly used against livestock pests and vectors, applied as dust for
the control of ectoparasites, as emulsion against mosquito larvae
and mites, as residual sprays against flies and mosquitos, and as
ULV spray against flies and mosquitos (larvae and adults).
1.5.4 Unintended effects
No information.
1.6 HOUSEHOLD USE
1.6.1 Common formulations
See 1.5.1.
1.6.2 Susceptible pests
Jodfenphos is effective against a wide range of insect pests in the
household, such as silverfish, earwigs, cockroaches, psocids, ants,
wasps, beetles, moths, flies, mosquitos, fleas, mites and spiders.
1.6.3 Use pattern
Aerosols and emulsions are suitable for the control of crawling
household pests as well as for long-lasting protection, e.g. against
silverfish, carpet beetles and coddling moth. Dust is applied
against ants, cockroaches and silverfish.
1.6.4 Unintended effects
No information.
1.7 PROTECTION OF STORED PRODUCTS
1.7.1 Common formulations
See 1.5.1.
1.7.2 Susceptible pests
Jodfenphos is effective against various insect pests in stored
products such as psocids, beetles, weevils, moths and mites.
1.7.3 Use pattern
Emulsions are used in surface clean-out sprays. Wettable powders and
flowable formulations are used as residual surface sprays against
various pests, such as moths, beetles, weevils and mites.
1.7.4 Unintended effects
No information.
2. TOXICOLOGY AND RISKS
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption route
May be absorbed from the gastrointestinal tract, by the intact skin
and by inhalation.
2.1.2 Mode of action
An organophosphorus cholinesterase inhibitor.
2.1.3 Excretion products
In mammals, jodfenphos is rapidly eliminated, mainly in the urine
(82% of the administered dose after 24 hours). The main excretion
products are acid metabolites: phosphorus acid, dimethyl phosphoric
acid, monomethyl phosphoric acid, dimethyl phosphorothioic acid and
desmethyl - jodfenoxon.
2.1.4 Toxicity, single dose
Oral: LD50 rat (M & F): 2100-3000 mg/kg
LD50 dog (M & F): 3000 mg/kg
Dermal: LD50 rat (M & F): 2150 mg/kg
2.1.5 Toxicity, repeated doses
Oral: Female rats fed 4.5 mg technical grade jodfenphos daily for
90 days showed no effect or clinical symptoms. See also 2.1.6
Dietary studies, short-term.
Dermal: Male and female rabbits exposed to 300 mg technical
jodfenphos (micronized) daily for 21 days showed no effect or
clinical symptoms.
Inhalation: LC50 (rats) 246 mg/m3. Male and female rats were
exposed to technical grade jodfenphos 6 hours daily for 19 days. The
animals showed mild clinical symptoms typical of organophosphorus
poisoning and slightly reduced cholinesterase activity.
Cumulation of compound: Does not accumulate in body tissues to any
significant extent.
Cumulation of effect: Repeated exposure may produce cumulative
inhibitory effect on cholinsterase.
2.1.6 Dietary studies
Short-term: In a 91-day study, body weights of male rats fed
500 mg jodfenphos/kg diet were consistently lower than female
controls and rats of both sexes. Haematological parameters were
within normal range. Marginal inhibition of erythrocyte
cholinersterases was observed at 50 mg/kg and marked inhibition at
500 mg/kg. Plasma cholinesterase was significantly inhibited at both
intake levels. Erythrocyte and plasma cholinesterases returned to
normal or near normal activity during the 4-week recovery period. At
autopsy, there were no gross pathological changes that could be
attributed to ingestion of the chemical. The no-effect level was
5 (mg/kg)/day. In another 91-day study with dogs fed 15, 150 and
1500 mg/kg diet, all test generally lost weight. Food consumption
was reduced in the 1500 mg/kg group. Plasma cholinesterase was not
affected at 15 mg/kg but was inhibited significantly at 150 mg/kg.
There was no effect on erythrocyte cholinesterase at 15 mg/kg,
marginal inhibition at 150 mg/kg and significant inhibition at
1500 mg/kg. Brain cholinesterase was significantly inhibited at
150 mg/kg and 1500 mg/kg. Inhibited erythrocyte and plasma enzyme
returned to normal during the 4-week recovery period. At autopsy, no
organs showed any change attributable to jodfenphos. The no-effect
level was 15 (mg/kg)/day.
Long-term: No information.
2.1.7 Supplementary studies of toxicity
Carcinogenicity: No information.
Teratogenicity: Pregnant female rats were treated from day 6
through 15 of pregnancy with 0.0, 6.5, 20, 65 and 200 (mg/kg)/day
jodfenphos. No gross malformations nor any increased incidence of
abnormalities were observed in the offspring and their weight at
term was normal despite the distinct toxic effects in a number of
treated mothers at high doses.
Mutagenicity: Jodfenphos showed no mutagenic effect on
streptomycin-dependent
Escherichia coli SD4 strain by the paper disc method.
Delayed neurotoxicity: Hens received 2000 mg/kg technical grade
jodfenphos orally, twice at an interval of 3 weeks (LD50);
histopathological examinations showed no neurotoxic effects.
2.1.8 Modification of toxicity
No information.
2.2 TOXICOLOGY - MAN
2.2.1 Absorption
May be absorbed from the gastrointestinal tract, by inhalation or by
the intact skin.
2.2.2 Dangerous doses
Single: Not known.
Repeated: Not known.
2.2.3 Observations of occupationally exposed workers
Jodfenphos has been applied as a residual indoor spray for adult
mosquito control. There have been no complaints attributable to
exposure to the pesticide recorded among the baggers and operators
who sprayed jodfenphos for 8 days.
2.2.4 Observations on exposure of the general population
In a malaria control trial in a village of 1819 inhabitants in
Nigeria, whole blood cholinesterase levels were unaffected among
exposed villagers and no complaints were received.
2.2.5 Observations of volunteers
No information.
2.2.6 Reported mishaps
None.
2.3 TOXICITY TO NON-MAMMALIAN SPECIES
2.3.1 Fish
Jodfenphos has a medium to high toxicity to fish and water fleas
(Daphnia spp.). Those fish living in potential mosquito breeding
places can normally tolerate the recommended dosage for control of
mosquito larvae of 0.1 mg a.i./l, but this rate should not be
exceeded. On other water organisms such as algae, saltwater
crustaceans and snails there was no effect at a concentration of
0.1 mg/l.
2.3.2 Birds
Slightly toxic to birds.
2.3.3 Other species
Toxic to bees.
3. FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON REGULATION OF
COMPOUND
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY
(For definitions of categories, see introduction).
Liquid and solid formulations above 10%: category), 4
Other formulations: category 5
3.2 TRANSPORTATION AND STORAGE (UN classification 6.1)
Formulations in category 4 - Should be transported or stored in
clearly labelled, rigid and leakproof containers, under lock and
key, secure from access by unauthorized persons and children. No
food or drink should be transported or stored in the same
compartment.
Formulations in category 5 - Should be transported or stored in
clearly labelled, leakproof containers out of reach of children,
away from food and drink.
3.3 HANDLING
Formulations in category 4 - Protective clothing should be used
for those handling the compound. Adequate facilities should be
available at all times during handling and should be close to the
site of handling. Eating, drinking and smoking should be prohibited
during handling and before washing after handling.
Formulations in category 5 - No facilities other than those needed
for handling of any chemical may be required.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINER:
Containers may be decontaminated. Decontaminated containers should
not be used for food and drink. If not decontaminated, emptied
containers should be burned or crushed and buried below topsoil.
Care must be taken to avoid subsequent contamination of water
sources.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
Formulations in category 4 - Pre-employment medical examination of
workers desirable. Workers suffering from active hepatic or renal
disease should be excluded from contact. Pre-employment and periodic
cholinesterase tests 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.
Formulations in category 5 - No special cholinesterase test for
workers necessary. Warning of workers to minimize contact essential.
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT
All formulations - Pilots and loaders should have special training
in application methods and recognition of early symptoms of
poisoning and must wear a suitable respirator. Flagmen, if used,
should wear overalls and be located well away from the dropping
zone.
3.7 LABELLING
Formulations in category 4 - Minimum cautionary statement:
Jodfenphos is an organophosphorus compound which inhibits
cholinesterase. It is poisonous if swallowed. It may be absorbed
through the skin or inhaled as a dust or mist. Avoid skin contact;
wear protective gloves, and clean protective clothing when handling
the material. Wash thoroughly with soap and water after using. Keep
the material out of reach of children, and well away from
foodstuffs, animal feed and their containers. If poisoning occurs,
call a physician. Atropine and pralidoxime are the specific
antidotes and artificial respiration may be needed.
Formulations in category 5 - Minimum cautionary statement: This
formulation contains jodfenphos, a toxic substance which is
poisonous if swallowed. Keep the material out of reach of children
and well away from foodstuffs, animal feed and their containers.
3.8 RESIDUES IN FOOD:
Maximum residue limits for jodfenphos have not yet been considered
by the WHO/FAO Meeting on Pesticide Residues.
4. PREVENTION OF POISONING IN MAN AND EMERGENCY AID
4.1 PRECAUTIONS IN USE
4.1.1 General
Jodfenphos is an organophosphorus pesticide of low mammalian
toxicity. It penetrates the intact skin and is also absorbed by
inhalation of dust and spray mist, and from the gastrointestinal
tract. Highly concentrated formulations should be handled by trained
personnel wearing protective clothing.
4.1.2 Manufacture and formulation
No TLV values have been recommended. 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 indoors, a face mask 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 washed
after every use, including the insides of gloves and boots. 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 jodfenphos and associated with its application
should wear clean overalls and observe the precautions described
above in 4.1.3 under "Mixers and applicators".
4.1.5 Other populations likely to be affected
With correct use in agriculture and public health, the general
population should not be exposed to hazardous amounts of jodfenphos.
4.2 ENTRY OF PERSONS INTO TREATED AREAS:
The general population should be kept out of treated areas for at
least one day.
4.3 DECONTAMINATION OF SPILLAGE AND CONTAINERS:
Residues in containers should be emptied in a diluted form into a
deep pit taking care to avoid contamination of groundwaters. The
empty containers may be decontaminated by rinsing two or three times
with water and scrubbing the sides. An additional rinse, should be
carried out with 5% sodium hydroxide solution which should remain in
the container overnight. Impermeable gauntlets should be worn during
the work and a soakage pit should be provided for the rinsings.
Decontaminated containers should not be used for food and drink.
Spillage of jodfenphos 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
These 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 soap and water, if
available, and flush 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 jodfenphos.
5. FOR MEDICAL AND LABORATORY PERSONNEL
5.1 MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING
5.1.1 General information
Jodfenphos is an organophosphorus pesticide of low toxicity which
may be absorbed from the gastrointestinal tract as well as by
inhalation and through the intact skin. It acts by inhibiting
acetylcholinesterase. Continuous exposure to low amounts may inhibit
blood cholinesterase to hazard levels.
5.1.2 Symptoms and signs
Initial symptoms o£ 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 could also be used as a measure of exposure.
Neither method is specific for jodfenphos.
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 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
at the same time as 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, barbiturates,
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 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
None.
5.2 SURVEILLANCE TESTS
Test Normal level* Action level* Symptomatic level*
Plasma cholinesterase 100% 50% Variable
Erythroctye cholinesterase 100% 70% Usually < 40%
Urinary levels of ether extractable organic phosphorus may also be
used to determine the degree of exposure.
5.3 LABORATORY METHODS
References only are given.
5.3.1 Detection and assay of compound
Residues of jodfenphos are determined by GLC using electron-capture
of a phosphorus specific flame photometric detector. Particulars of
the methods can be obtained from Ciba-Geigy Ag, Basle, Switzerland.
5.3.2 Other tests in cases of poisoning
Levels of cholinesterase in the blood, particularly plasma, provide
the most useful diagnosis of poisoning:
*Expressed as percentage of pre-exposure activity.
Michel, N. O. (1949) J. Lab. Clin. Med., 34, 1564
Ellman, G. L. et al. (1961) Biochem. Pharmacol., 7, 88
Urinary levels of ether extractable organic phosphorus (Mattson &
Sledak, 1960) or dimethyl phosphate (Shafik & Enos, 1969) can also
be used to determine exposure.
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