WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
DATA SHEETS ON PESTICIDES No. 41
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.
Primary use: Insecticide
Secondary use: Acaricide
Chemical group: Organochlorine Compound
Date issued: April 1979
1. GENERAL INFORMATION
1.1 COMMON NAME:
A material containing not less than 95% of 1,2,3,4,10,10-hexachloro,
In the convention of the American Chemical Society, the
configuration is endo-exo.
An organochlorine pesticide of high mammalian toxicity which
accumulates in the tissues of man and animals.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics
HHDN is a white, crystalline, odourless, solid, m.p. 104 to 104.5°C.
Technical aldrin is a tan to dare brown solid, melting range 49 to
Practically insoluble in water (0.027 mg/litre at 25-29°C).
Moderately soluble in petroleum oil. Readily soluble in acetone,
benzene and xylene.
Stable to heat, alkali and to mild acids; oxidizing agents and
strong acids attack the unchlorinated ring. It can also be
1.3.4 Vapour pressure
2.31 x 10-5 mmHg at 20°C.
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY
1.4.1 Common formulations
Emulsifiable concentrates 240-480 g/litre; epichlorhydrin added to
delay corrosion and inhibit dehydrochlorination. Wettable powders
40-70% - urea added to prevent dehydrochlorination by certain
carriers. Dysts 2.5-5%. Seed dressings and granules.
1.4.2 Pests mainly controlled
Effective against a wide range of insect species, notably cabbage
root fly, hop root, weevil, leatherjackets, narcissus bulb fly,
wireworm and other soil insects, strawberry beetle and grasshoppers.
1.4.3 Use pattern
Used against pests which occur in soil and attack plants below
ground level or at ground level. Major crops treated are maize,
sorghum, small grain, cereals, potatoes, beet vegetables, tobacco,
cotton and sugar cane.
1.4.4 Unintended effects
1.5 PUBLIC HEALTH PROGRAMME
No recommended use.
1.6 HOUSEHOLD USE
Aldrin is too toxic for household use.
2. TOXICOLOGY AND RISKS
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption route
Absorbed by the intact skin as well as by inhalation and from the
gastrointestinal tract. Organic solvents such as xylene and edible
and other vegetable oils enhance the rate of absorption of the
toxicant into the body.
2.1.2 Mode of action
Central nervous system stimulant producing convulsions.
2.1.3 Excretion products
After absorption aldrin is rapidly epoxidized to dieldrin (Data
Sheet No. 17) and only for a short time may it be demonstrable in
blood or body fat.
Dieldrin is stored in body tissues, particularly body fat and is
slowly excreted. It is mainly excreted as hydrophilic metabolites in
the bile and faeces. A few minor metabolites are also excreted in
2.1.4 Toxicity, single dose
Oral: LD50 rat (M): 38-54 mg/kg
LD50 rat (F): 46-67 mg/kg
LD50 dog: 65-95 mg/kg
Dermal: LD50 rat: 98 mg/kg
LD50 rabbit: 600-1250 mg/kg
2.1.5 Toxicity, repeated doses
Oral: See dietary studies.
Inhalation: No information.
Dermal: Dry aldrin was applied daily to the skin of rabbits for 2
hours on each of 50 days over a period of 10 weeks. The minimum
lethal doses were 35-123 mg/kg.
Cumulation of compound: Aldrin is stored as dieldrin in body
tissues; its chronic toxicity is related to the level of dieldrin in
the body; the level of dieldrin in adipose tissue is related to
intake and reaches a plateau level if intake is steady.
2.1.6 Dietary studies
Short-term: Groups of 12 rats (6 males and 6 females) were fed
diets containing 0.5, 2.5, 75, 150 mg aldrin/kg diet for three
months. The liver weight was increased at the two higher dosages and
the mortality rate was increased at the 150 mg/kg level only. Dogs
were more susceptible than rats to the toxic effects of aldrin.
Diets that contained aldrin in concentrations of 10, 25 or 50 mg/kg
fed 5 or 6 days of each week, induced fatalities in mongrel dogs
after periods of feeding ranging from several days to three months.
Groups of four beagle dogs fed dietary concentrations of 1.0 and
3.0 mg/kg aldrin survived 15.6 months. Increased liver weights were
observed at the dietary levels of 3.0 mg/kg aldrin. Minor liver cell
changes were seen in males and females fed aldrin at 3.0 mg/kg diet.
Groups of three rabbits were given dosages of aldrin of 0.625, 1.25,
2.5, 5.0 and 10.0 mg/kg body weight per day, i.e. equivalent to
approximately 20.6, 82.5, 165 and 330 mg/kg diet. There were no
observable effects at the 1.25 and 0.625 levels. Dosages of
2.5 mg/kg body weight and above were fatal.
Long-term: When fed for two years to rats (in groups of 40 males
and 40 females) at concentrations of 2.5, 12.5 or 25.0 mg/kg diet,
aldrin showed no significant effect on mortality of rat or growth
rate. Non-specific changes in hepatic cells were recorded in all
experimental groups. In another two-year study, groups of 12 male
and 12 female rats were fed concentrations of 0.5, 2, 10, 50, 100
and 150 mg aldrin/kg diet. Survival was markedly decreased among
rats fed 50 mg/kg and above. Histopathological changes in the liver
were observed at 10 mg/kg. The 0.5 mg/kg level was assumed to be the
lowest showing an effect. Groups of mongrel dogs (12 males and 12
females) were fed aldrin at daily dosages of 0.2, 0.5, 1.0, 2.0, 5.0
and 10.0 mg/kg diet for up to two years. Dogs fed 0.5 mg/kg and
higher dosages showed gross toxic effects, including loss of weight
and convulsions and died progressively earlier with increasing dose
levels. Histopathological changes were seen in the liver, kidney and
bone marrow of the dogs fed 1.0 mg/kg. No effect, either gross or
microscopic was seen in dogs receiving 0.2 mg/kg.
2.1.7 Supplementary studies of toxicity
Carcinogenicity: Since aldrin is converted to dieldrin all chronic
effects are due to dieldrin. Neither aldrin nor dieldrin have
produced malignant tumours in rats, dogs and monkeys at tolerated
dose levels in long-term feeding studies. In mice, however,
long-term feeding studies have shown the development of liver
tumours, some of which may present malignant characteristics. The
incidence of liver tumours shows a direct relationship to the level
Reproduction studies, including teratology: Rats fed aldrin or
dieldrin at concentrations of 2.5, 12.5 and 25.0 mg/kg diet over
three consecutive generations, each generation being bred twice,
showed no significant difference from controls in reproductive
capacity. Increased litter mortality was noted, especially in the
group receiving 12.5 and 25.0 mg/kg. No teratogenic effects were
2.1.8 Modification of toxicity
2.2 TOXICOLOGY - MAN
See 2.1.1. The greatest hazard is by absorption through the intact
2.2.2 Dangerous doses
Single: Persons exposed to oral doses which exceed 10 mg/kg body
weight frequently become acutely ill. The lethal dose of aldrin for
an adult man is estimated to be about 5 g.
Repeated: From observations on occupationally exposed workers it
has been concluded that intoxication due to repeated or prolonged
absorption of aldrin and dieldrin is not observed when the levels of
dieldrin in the blood are below 0.2 mg.
2.2.3 Observations of occupationally exposed workers
Extensive observations on plant workers have been conducted. No
fatal poisoning in aldrin manufacture has been reported. Aldrin and
dieldrin exposed workers, with blood levels of 0.105 mg dieldrin,
showed no sign of enzyme induction. This no-effect level has been
calculated to be approximately equivalent to a daily intake of at
least 1224 mg/man/day.
2.2.4 Observations on exposure of the general population:
Total diet studies in two countries and calculations from dieldrin
levels in adipose tissues and also in blood, demonstrate an average
combined aldrin/dieldrin intake of 7 µg/man (equivalent to
0.1 µg/kg/day). This intake corresponds to a blood level of 600 mg.
2.2.5 Observations on volunteers
See Data Sheet No. 17.
2.2.6 Reported mishaps
There have been no cases of mass poisoning by aldrin or dieldrin.
2.3 TOXICITY TO NON-MAMMALIAN SPECIES
Varies in severity from harmful to highly toxic.
Toxic but toxicity varies considerably.
2.3.3 Other species
Toxic to wildlife in general.
3. FOR REGULATORY AUTHORITIES - RECOMMENDATIONS OF REGULATIONS OF
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY
(for definition of categories, see introduction)
Liquid formulations over 25%, category 3; liquid formulations above
2.5%, category 4; solid formulations above 10%, category 4, all
other formulations, category 5.
3.2 TRANSPORTATION AND STORAGE
All formulations; Categories 3 and 4, United Nations
Classification 6.1 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 stored in the same compartment.
Formulations, Category 5 - Should be stored in clearly labelled
leakproof containers, out of reach of children, away from food and
All protective clothing (see part 4) should be used by all handling
of the compound. Adequate washing facilities should be available at
all times during handling and should be close to the site of
handling. Eating and drinking and smoking should be prohibited
during handling and before washing after handling.
Formulations, Category 5 - No facilities other than those needed
for the handling of any chemical need be required.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINER
All formulations - Containers 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 Categories 3 and 4 - Pre-employment medical
examination of workers and regular special examination advisable.
Special account should be taken of the workers' mental ability to
comprehend and follow instructions. Training of workers in
techniques to avoid contact essential.
Formulation, Category 5 - Warning of workers to minimize contact
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. Use of flagmen not recommended. Flagmen, if used, should
wear overalls and be located well away from the dropping zone.
All formulations, Categories 3 and 4 - Minimum cautionary statement
Aldrin is a toxic substance and may cause convulsions. It is
poisonous if swallowed. It may be absorbed through the skin or
inhaled as dusts or mists. Avoid skin contact; wear hand protection
and clean protective clothing while using 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
Formulation; Category 5 - Minimum cautionary statement - This
formulation contains aldrin, 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 aldrin have been recommended by the Joint
FAO/WHO Meeting on Pesticide Residues. These are subject to change
at annual reviews.
4. PREVENTION OF POISONING IN MEN AND EMERGENCY AID
4.1 PRECAUTIONS IN USE
Aldrin is an organochlorine pesticide of high mammalian toxicity
which penetrates the intact skin; it may also be absorbed by
inhalation and by the gastrointestinal tract. Concentrated
formulations should be handled by trained personnel wearing
4.1.2 Manufacture and formulation
T.L.V.; (ACGIH) 0.25 mg/m3, (USSR) 0.01 mg/m3. 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 respirators should be worn.
Mixing, if not mechanical, should always be carried out with a
paddle of appropriate length. 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 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. Although not
usually used on tall crops, if these are sprayed or during aerial
applications, a face mask should be worn as well as an impermeable
hat, overall, 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 gloves.
4.1.4 Other associated workers (including flagmen in aerial
Persons exposed to aldrin 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, and subject to 4.2 below, other
populations should not be exposed to hazardous amounts of aldrin.
Total diet studies in two countries have demonstrated that the
intake of aldrin and dieldrin is well below the hazard level.
Detectable levels of dieldrin are found in the fat of the general
population, some of which may be due to absorption of aldrin.
4.2 ENTRY OF PERSONS INTO TREATED AREAS
Unprotected persons should be kept out of treated areas for at least
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 ground waters.
Decontamination of containers in order to use them for other
purposes should not be permitted. Spillage should be removed as much
as possible into a deep dry pit and the remainder washed away with
large quantities of water.
4.4 EMERGENCY AID
4.4.1 Early symptoms of poisoning
Early symptoms of poisoning are headache, dizziness, nausea,
vomiting, loss of appetite, general malaise, and possibly insomnia.
Later, convulsions may occur.
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 the area with large quantities of water. If
swallowed, vomiting should be induced, if the person is conscious.
5. FOR MEDICAL AND LABORATORY PERSONNEL
5.1 MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING
General information - An organochlorine pesticide of high toxicity
which may be absorbed through the intact skin as well as by
inhalation and from the gastrointestinal tract. It is rapidly
epoxidized to dieldrin in the human body. The made of action is
similar to that of dieldrin and consists of central nervous system
stimulation producing epileptiform convulsions. It is stored in body
tissues, particularly in the fat, as dieldrin. The half-life of
dieldrin calculated from the decrease in blood levels after
cessation of exposure is 0.73 years.
5.1.2 Symptoms and signs
Early symptoms of acute poisoning include headache, nausea,
vomiting, general malaise and dizziness. With more severe poisoning,
clonic and tonic convulsions occur with or without the symptoms just
mentioned. Coma may or may not follow the convulsions.
Hyperexcitability and hyperirritability are common findings. The
clinical syndrome of intoxication is indistinguishable from epilepsy
and therefore history of exposure is important.
No symptoms have ever been observed when the blood level of aldrin/
dieldrin is 0.2 mg/litre or below levels above this may therefore be
indicative of poisoning. The presence of aldrin metabolites in the
urine also indicates absorption. The electroencephalogrammay show
specific changes: bilateral synchronous spikes, spike and wave
complexes and slow theta waves.
If the pesticide has been ingested, gastric lavage should be
performed with 2-4 litres of tap water followed by saline purgatives
(30 g sodium sulfate in 250 ml of water). Barbiturates (preferably
phenobarbitone or pentobarbitone) or diazepam should be given IM or
IV in sufficient dosage to control restlessness or convulsions.
Mechanical respiratory assistance with oxygen may be required.
Calcium gluconate, 10% in 10 ml should be injected 4 hourly.
Contraindications are oily purgatives, epinephrine and other
adrenergic drugs and central stimulants of all kinds. It is
advisable to continue large doses of phenobarbitone over a longer
period since it may prevent a post-convulsive syndrome of loss of
appetite and weight loss and by stimulating the oxydative enzyme
system of the liver, increases the rate of excretion.
If the convulsions are survived, the chances of complete recovery
are good. However, in very severe cases, there is a possibility of
permanent brain damage secondary to continued anoxia resulting from
5.1.6 References of previous reported cases
The following reference gives methods of treatment used in cases of
poisoning: Zavon, M. R. (1964) J. Amer. Med. Assoc., 190,
595-596. See also, Hayes, W. J. jr (1963) Clinical handbook on
economic poisons, Environmental Protection Agency, p. 49, 50, 66.
5.2 SURVEILLANCE TESTS
There are no rapid methods for determining the extent of absorption
of aldrin prior to the appearance of symptoms. Levels of
aldrin/dieldrin in blood and the presence of aldrin metabolites in
urine have been used in surveillance tests. Workers continuously
exposed can be satisfactorily monitored by the regular determination
of the dieldrin level in the blood which, to prevent intoxication,
should not exceed 0.2 µg/ml.
5.3 LABORATORY METHODS
5.3.1 Detection and assay of compound
References only are given.
Due to rapid epoxidation of aldrin to dieldrin in the liver, only
dieldrin needs to be determined in the blood.
Determination of dieldrin in blood is carried out by gas
chromatography, using an electrocapture detector as described by
Richardson et al. (1967). Levels of dieldrin in urine have also been
measured by Cueto et al. (1967). A number of multi-detection systems
are available for the detection and determination of residues of
aldrin in food, along with residues of other compounds. The methods
are sensitive to about 0.002 ppm of aldrin in milk and 0.02 ppm in
most other foods. Anon. (1966), Porter (1972).
5.3.2 Other tests in cases of poisoning
Electroencephalographic changes after poisoning by cyclodiene
compounds are described by Hogendam, I. (1962).