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    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 
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    While the information provided is believed to be accurate according to 
    data available at the time when the sheet was compiled, neither WHO nor 
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    The issue of this document does     Ce document ne constitue pas une  
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    Part 1 - General information


    Primary use:  insecticide 
    Secondary uses:  acaricide 
    Chemical group:  organochlorine compound 
    Data sheet No. 17
    Date issued:  December 1975

    1.1   COMMON NAME:  Dieldrin (ISO)

    Identity:  A technical product containing 85% of the chemical known
    as HEOD of which the composition is: 1,2,3,4,10,10-hexachloro-6,7-
    expoxy-1,4,4a,5,6,7,8 8a-octahydro-endo-5,8-dimethanonaphthalene. 
    According to British usage, HEOD is the exo-endo isomer. Dieldrin is 
    closely related to its metabolic precursor aldrin and much of the 
    toxicological information on aldrin is referable to dieldrin. 

    Chemical Structure - Dieldrin

    Synonyms:                                        Local synonyms: 

    OMS 18

    1.2 SYNOPSIS:  An organochlorine pesticide of high mammalian toxicity 
    which can accumulate in tissues of man and animals.  The accumulation 
    of dieldrin in tissues is related to and in equilibrium with the level 
    of intake. 


    1.3.1 Physical characteristics

    The pure major ingredient HEOD is a white crystalline solid m.p. 
    176-177C; technical dieldrin is a light tan flaky solid m.p. 150C.

    1.3.2 Solubility

    Water at 25C, practically insoluble (0.1 ppm) alcohol slightly 
    soluble (5%); benzene and acetone, moderately soluble (39 and 25%).

    1.3.3 Stability

    Pure HEOD is stable in alkali and diluted acids but reacts with 
    strong acids. Compatible with most other pesticides. 

    1.3.4 Vapour pressure (volatility)

    Very low (5.4 x 10-6 mm Hg at 25C).


    1.4.1 Common formulations

    Emulsifiable concentrates, 18-20%; wettable powders, 50 and 75%; 
    dust, 2%; granules, 2 and 5%; solutions, up to 20%.  There are FAO 
    specifications for the technical material, emulsifiable concentrates, 
    dispersible powders and dusts, and a draft specification for granules. 

    1.4.2 Susceptible pests

    High contact and stomach toxicity to most insects.

    1.4.3 Use pattern

    The use pattern has changed considerably during the last few 
    years owing to restrictions in many countries. 

    Pre-harvest treatments:  treatment of soil against various 
    insects; seed treatment of grains, sugar beets, beans, leeks and 
    onions; foliar treatment of agricultural crops, fruits, nursery stocks 
    and ornamentals.  There are restrictions on these uses in many 
    countries, particularly where crops for food or animal feed are 
    involved to ensure that residue levels arising from use are no greater 
    than current FAO/WHO or local maximum residue levels. 

    Post-harvest treatments:  has been used for treatment of empty
    warehouses etc. in food storage practice.  This use has decreased and 
    is prohibited in many countries.  Dieldrin is not used directly on 
    stored commodities or for treatment of containers which may come into 
    contact with foodstuffs. 

    Other uses:  Dieldrin is used in tropical and sub-tropical 
    regions to control disease vectors and locusts:  application is usually 
    by trained personnel only.  Dieldrin is used for termite control in 
    buildings under construction and for spot treatment against other 
    domestic pests:  domestic use is no longer allowed in several 
    countries. It is used in dilute solution to preserve wood from attack 
    by boring insects and for moth-proofing wool during dyeing. 

    1.4.4 Unintended effects

    The persistence of dieldrin has led to widespread occurrence in
    tissues and hence to restrictions in its use.  It has been implicated 
    in the decline of some wildlife birds, partly by a direct effect upon 
    egg production, but more generally by causing thinning of eggshells. 


    It has been used, usually under strict control, to control
    mosquito adults, chiggers, reduviid bugs, tsetse flies.


    Limited household use, prohibited in several countries.


    Part 2 - Toxicology and risks               
    Common name:  dieldrin

    Data sheet No. 17

    Date issued:  December 1975


    2.1.1 Absorption route:  Absorbed by the intact skin as well as by
    inhalation and from the gastrointestinal tract.

    2.1.2 Mode of action:  Central nervous system stimulant producing 

    2.1.3 Excretion products:  Mainly excreted in the faeces largely as a 
    9-hydroxy derivative.  Minor metabolites are also excreted in the 
    urine.  Dieldrin is also stored in body tissues, particularly the fat, 
    and is slowly excreted. 

    2.1.4 Toxicity, single dose

    Oral:     LD50 rat (M) 46 mg/kg
                   rat (F) 46 mg/kg

    Dermal:   LD50 rat (M) 90 mg/kg
                   rat (F) 60 mg/kg

    Dermal:   LD50 rabbit 250-360 mg/kg.
    Most susceptible species:  There is no marked difference in toxicity
    among various species. 
    2.1.5 Toxicity, repeated doses
    Oral:  Daily administration of 0.625 mg/kg of dieldrin to rabbits
    adversely affected survival rate.  At 2.5 mg/kg all the animals died. 
    See also dietary studies.

    Inhalation:  No information.

    Dermal:  Rabbits in daily contact with an average of 40 mg/kg of dry
    dieldrin 2 hours per day for 5 days a week survived 50 contact periods;
    at 163 mg/kg, 4 out of 5 animals died after 9, 11, 15 and 20 contact

    Cumulation of compound:  Dieldrin is cumulative in body tissues being
    stored particularly in fat.  The level in lipids is related to the
    average level of intake.

    Cumulation of effect:  The chronic toxicity of dieldrin is due to the
    cumulation of the compound in the body.  It will only occur when the
    dieldrin level in blood, in equilibrium with the dieldrin level in fat
    exceeds a certain value.

    2.1.6 Dietary studies


    Increased mortality was observed in rats fed 125 ppm (6.25 
    mg/kg/day) or higher for 90 days.  Histological changes were observed 
    at 10 ppm (0.5 mg/kg/day) and above. 

    Dogs fed 1 ppm (0.025 mg/kg/day) of dieldrin for 15 months (the 
    lowest level fed) exhibited enlarged livers, but there were no 
    histological changes observed.  At 10 ppm (0.25 mg/kg/day) survival was 
    In another study the no effect level in the dog with respect to
    clinical or histopathological abnormalities was 0.2 mg/kg (equivalent 
    to 8 ppm in the diet). 


    The life span of mice fed 10 ppm (1.5 mg/kg/day) of dieldrin for 
    up to two years was reduced when compared to controls. 

    Non-specific hepatic cell changes and increase in liver to body-
    weight ratios were evident in rats fed 1.5 ppm (0.07 mg/kg/day) of 
    dieldrin or higher for two years.  Rats were fed dietary levels of 0.1, 
    1.0 or 10.0 ppm (0.005, 0.05, 0.5 mg/kg/day) of dieldrin for two years. 
    Symptoms (increased irritability and occasional convulsions) were only 
    observed at 10 ppm (0.5 mg/kg/day) increased liver weight and liver to 
    body-weight ratios were observed in the females only at 1.0 and 10.0 
    ppm (0.05 and 0.5 mg/kg/day) and histological liver changes were only 
    observed at 10.0 ppm (0.5 mg/kg/day). 

   Two dogs have been on a continuing dietary regime of 0.2 
    mg/kg/day for six years or longer.  The only effects observed were 
    increased serum alkaline phosphatase activity in both animals and 
    increased bromosulphthalein clearance in the male. 

    No changes in liver enzymes were observed in monkeys fed 0.5 ppm 
    (0.025 mg/kg/day) or less of dieldrin for up to six years.  At 1.0 ppm 
    (0.05 mg/kg/day) and above some increase in activity of microsomal 
    liver enzymes was evident.  No histological changes were seen. 

    2.1.7 Supplementary studies of toxicity


    For mice fed 10 ppm (1.5 mg/kg/day) of dieldrin for two years, 
    there was a significant increase in tumours which were morphologically 
    benign.  Mice were fed dietary levels of 0.1, 1.0 or 10 ppm (0.015, 
    0.15 or 1.5 mg/kg/day) of dieldrin for periods up to 132 weeks.  No 
    tumours were evident before 37 weeks at any dose level.  After this 
    time, the incidence of tumours increased with the concentration of 
    dieldrin that was fed.  Some tumours were classed as benign, the others 
    as hepatocarcinomas; the latter kind were very rare in the controls. In 
    a few cases emboli of tumour cells were found in the lungs. 

    In rats fed 20, 30, or 50 ppm (1.0, 1.5 or 2.5 mg/kg/day) of
    dieldrin there was a dose related increase in all tumours particularly 
    in the mammary and lymphatic glands.  There was no evidence of 
    malignancy.  In rats fed levels of dieldrin ranging from 0.5 to 150 ppm 
    (0.025 to 7.5 mg/kg/day), there was an increase in the number of 
    tumours when compared to a control group, but in this study, there did 
    not appear to be a dose related increase. 


     Significantly smaller litters were produced from mice fed 5 ppm 
    (0.75 mg/kg/day) of dieldrin than from a control group although 
    mortality was unaffected. 

    A diet of 2.5 ppm (0.125 mg/kg/day) or higher of dieldrin
    initially reduced the number of pregnancies and increased mortality 
    among suckling young.  In another study the maximum level of dieldrin 
    in rats which did not interfere with reproduction was 0.24 ppm in the 
    diet (0.012 mg/kg/day). 


    No teratogenic effects were observed in young sheep fed dietary
    levels of dieldrin up to 25 ppm (1 mg/kg/day). 

    2.1.8 Modifications of toxicity

          No information.
    2.2   TOXICOLOGY - MAN

    2.2.1 Absorption

    See 2.1.1. Both the oral and dermal routes have been responsible 
    for poisoning in man. 

    2.2.2 Dangerous doses

    Single:  Persons exposed to oral doses of dieldrin or aldrin which
    exceed 10 mg/kg frequently became acutely ill.  A dose of about 44 
    mg/kg of dieldrin led to convulsions in a child. 

    Repeated:  Little information.  In different countries 2% to 40% of
    men applying 0.5% to 2.5% suspensions or emulsion at the rate of about 
    1 g/m2 have developed poisoning within two weeks to 24 months after the 
    first exposure. 

    2.2.3 Observations of occupationally exposed workers

    Extensive observations on plant workers have been conducted.  No
    report of cases of fatal poisoning in aldrin and dieldrin manufacture 
    can be located.  The threshold levels of dieldrin in the blood below 
    which no symptom of intoxication has been observed is 0.20 g/ml.  The 
    half-life for dieldrin in the blood of exposed workers has been 
    estimated to be 0.73 years.  In one plant, concentrations of dieldrin 
    in the blood of workers ranged from < 0.01 to 0.44 g/ml in 1964 to 
    < 0.005 to 0.15 g/ml in 1969.  At a level of 0.15 g/ml, there was no 
    impairment of health, and no signs of enzyme induction.  Calculations 
    based on the geometric means for the two years indicated that 
    absorption was equivalent to an average oral daily intake of 802 or 
    287 g respectively. 

    2.2.4 Observations of exposure of the general population

    Total diet studies in two countries and calculations from 
    dieldrin levels in adipose tissue demonstrate an average daily dieldrin 
    intake of 7 g/man (range 2.7 to 22 g/man) (equivalent to 0.1 
    g/kg/day). This intake corresponds to a blood level of 0.0006 g/ml. 

    2.2.5 Observations of volunteers

    Male subjects were given daily doses of 0 (control), 0.01, 0.05, 
    or 0.21 mg of dieldrin for two years.  The blood and adipose tissue 
    concentration of dieldrin were found to be proportional to the daily 
    dose and it was believed that concentration equilibrium was reached in 
    the blood between the tenth and the eighteenth month and in the adipose 
    tissue between the ninth and the fifteenth month.  After 18 months, the 
    increase in blood level was slight.  All men remained in excellent 
    health and there were no clinical abnormalities.  Laboratory tests 
    revealed a slight drop in plasma alkaline phosphatase in the highest 
    dose group as the only abnormality. 

    2.2.6 Reported mishaps

    There have been no cases of mass poisoning by dieldrin.  A total
    of 13 isolated cases of fatal poisoning by aldrin and dieldrin had been 
    reported in 1965. 


    The entries in these sections are intended to draw attention to
    special risks and to give warnings of any needs for special 

   2.3.1 Fish

    Highly toxic to fish.
    2.3.2 Birds

    Toxicity to birds varies.  Fairly high (LD50 about 50 mg/kg or
    less) for several tested species.  Evidence of cumulative toxic action. 

    2.3.3 Other species

    Toxic to bees.

    Part 3 - For regulatory authorities         

    Common name:  dieldrin

    Data sheet No. 17

    Date issued:  December 1975



    (For definition of categories see introduction).  Liquid 
    formulations over 25%, category 3, and over 2.5%, category 4. Solid 
    formulations over 10%, category 4. Other formulations, category 5. 


    All formulations in categories 3 and 4

    UN classification 6.1.

    All formulations in categories 3 and 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 stored 
    in the same compartment. 

    Formulations, category 5

    Should be stored in clearly labelled leak-proof containers, out 
    of reach of children, away from food and drink. 

    3.3   HANDLING

    All formulations, categories 3 and 4

    Full protective clothing (see part 4) should be provided for 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, 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 to be required. 


    All formulations

    Containers must 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. 


    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

    Special medical examination not needed.  Warning to workers to
    contact essential. 
    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. 

    3.7   LABELLING


    All formulations, categories 3 and 4.

    Minimum cautionary statement

    "Dieldrin 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 protective gloves and 
    clean protective clothing whilst 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 their 


    Formulations, category 5.

    Minimum cautionary statement

    "This formulation contains dieldrin, 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."


    Maximum residue limits have been recommended for dieldrin by the 
    joint FAO/WHO Meeting on Pesticide Residues.  As these are subject to 
    change at annual reviews, the latest data will be found in the report 
    of the 1972 Joint FAO/WHO Meeting on Pesticide Residues. 

    Part 4 - Prevention of poisoning in man and emergency aid

    Common name:  dieldrin     

    Data sheet No. 17          
    Date issued:  December 1975

    4.1.1 General

    Dieldrin is an organochlorine pesticide of high mammalian 
    toxicity which penetrates the intact skin and is also absorbed by 
    inhalation and from the gastro-intestinal tract. Concentrated 
    formulations should be handled by trained personnel wearing protective 
    4.1.2 Manufacture and formulation  
    (A.C.G.I.H.) 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 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 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 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. 

    4.1.4 Other associated workers (including flagmen in aerial operations)

    Persons exposed to dieldrin 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 dieldrin. 
    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 but 
    not at levels of medical significance. 


    Unprotected persons should be kept out of treated areas for at
    least one day.


    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 passible 
    into a deep dry pit and the remainder washed away with large quantities 
    of water. 

    4.4.1 Early symptoms of poisoning
    Early symptoms of poisoning are headache, dizziness, nausea,
    vomiting, loss of appetite, general malaise and possibly insomnia. 
    Convulsions may occur, sometimes without the warning symptoms just 

    4.4.2 Treatment before person is seen by a physician, if these symptoms 
    follow 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. 
    Part 5 - For medical and laboratory personnel

    Common name:  dieldrin     

    Data sheet No. 17          
    Date issued:  December 1975
    5.1.1 General information

    An organochlorine pesticide of high mammalian toxicity which may 
    be absorbed through the intact skin as well as by inhalation and from 
    the gastrointestinal tract.  Its mode of action is as a central nervous 
    system stimulant producing convulsions.  It is cumulative in body 
    tissues particularly fat.  The half life in blood has been estimated to 
    be 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.  Following 
    repeated exposure a condition indistinguishable from epilepsy has been 

    5.1.3 Laboratory

    No symptoms have ever been observed where the blood level of 
    dieldrin is 0.2 g/ml or below.  Levels above this figure may therefore 
    be indicative of poisoning.  The presence of dieldrin metabolites in 
    the urine also indicates absorption.  The electro-encephalogram may 
    show specific changes:  bilateral synchronous spikes, spike and wave 
    complexes and slow theta waves. 

    5.1.4 Treatment

    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.  It may be 
    necessary to give large doses over a period of two weeks in connexion 
    with the syndrome characterized by complete loss of appetite and severe 
    weight loss.  Mechanical respiratory assistance with oxygen may be 
    required.  Calcium gluconate, 10% in 10 ml should be ingested four 
    hourly. Contraindications are oily purgatives, epinephrine and other 
    adrenegic drugs and central stimulants of all kinds. 

    5.1.5 Prognosis

    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 
    prolonged convulsions. 

    5.1.6 References of previously reported cases 
    The following reference gives methods of treatment used in cases of 
    Zavon, M. R. (1964) J. Amer. Med. Ass., 190, 595-596; 
    Hayes, W. J. jr (1963) "Clinical Handbook on Economic Poisons", U.S. 
    Dept. Hlth Educ. Wel., Publ. Hlth Ser. Pub. No. 476, pp. 49, 50, 66. 

    There are no rapid methods for determining the extent of 
    absorption of dieldrin prior to the appearance of symptoms.  Levels of 
    dieldrin in blood and the presence of dieldrin metabolites in urine 
    have been used in surveillance tests. 

    5.3   LABORATORY

    References only are given.
    5.3.1 Detection and analysis

    For the determination of dieldrin in blood, see Richardson et al. 
    (1967) ; Dale et al. (1967); and Jain et al. (1965).  Levels of 
    dieldrin in urine have also been measured (Cueto & Biros, 1967). 

    Multiresidue gas-chromatographic methods of analysis are now
    available for a number of organochlorine pesticides in food including 
    dieldrin.  The methods of the AOAC (1970, 1971, 1972; see also U.S. 
    Food and Drug Administration, 1971); de Faubert Maunder et al. (1964); 
    Wood (1969); and Abbott et al. (1969) are suitable for foodstuffs and 
    processed foods.  They allow determinations of 0.002 ppm in milk and 
    0.02 ppm in most other foods. 

    5.3.2 Other tests in cases of poisoning

    Electroencephalographic changes after poisoning by cyclodiene
    compounds are described by Hoogendam, I., Versteeg, J. P. J. & de
    Vlieger, M. (1962) Arch. environm. Hlth., 4, 86-94.


    Richardson, A. , Robinson, J. , Bush, B. & Davies, J. M. (1967)
    Determination of dieldrin (HEOD) in blood. Arch. environm. Hlth.,
    14, 703

    Dale, W. E. , Curley, A. & Hayes, W. J. (1967) Determination of
    chlorinated insecticides in human blood.  Industr. Med. Surg., 
    36, 275 

    Jain, N. C., Fontan, C. R. & Kirk, P. L. (1965) Simplified gas
    chromatographic analysis of pesticides from blood.  J. Pharm. 
    Pharmacol., 17, 362

    Cueto, C., jr & Biros, F. J. (1967) Chlorinated insecticides and
    related materials in human urine.  Toxicol. appl. Pharmacol., 10,

    "Official Methods of Analysis of the AOAC", 11th ed., 1970, 29.001

    Changes in Methods.  J. Assoc. Off. Anal. Chem., 1971, 54, 470
    Ibid., 1972, 55, 428

    U.S. Food and Drug Administration, "Pesticide Analytical Manual", 
    Vol. I, 1971, Sections 211, 212 

    de Faubert Maunder, M. J., Egan, H., Godly, E. W., Hammond, E. W., 
    Roburn, J. & Thomson, J. (1964) Clean-up of Animal Fats and Dairy 
    Products for the Analysis of Chlorinated Pesticide Residues, 
    Analyst, 89, 168 
    Wood, N. F. (1969) Extraction and Clean-up of Organochlorine Pesticide
    Residues by Column Chromatography, Analyst, 94, 399 

    Abbott, D. C., Holmes, D. C. & Tatton, J. O'G. (1969) Pesticide 
    Residues in the Total Diet in England and Wales, 1966-1967.  II -
    Organochlorine Pesticide Residues in the Total Diet.  J. Sci. Fd 
    Agric., 20, 245 

See Also:
        Dieldrin (IARC Summary & Evaluation, Supplement 7, 1987)
        Dieldrin (IARC Summary & Evaluation, Volume 5, 1974)
        Dieldrin (PIM 575)