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    WORLD HEALTH ORGANIZATION             FOOD AND AGRICULTURE
                                          ORGANIZATION
    ORGANISATION MONDIALE DE LA SANTE     ORGANISATION POUR L'ALIMENTATION
                                          ET L'AGRICULTURE

                                          VBC/DS/77.21
				          ORIGINAL:  ENGLISH




    DATA SHEETS ON PESTICIDES No.  21

    December 1976

    DDT





         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.


      

    Part 1.  General Information  

          CLASSIFICATION:

          Primary use:     Insecticide
          Secondary use:   None
          Chemical group:  Organochlorine compound
          Data Sheet:      No. 21
          Date issued:     December 1976

    1.1   COMMON NAME - DDT (ISO)

    1.1.1 Identity: 2,2-bis-(p-chlorophenyl)-1,1,1-trichloroethane

          Structure

    1.1.2 Synonyms                 Local synonyms

          Chlorophenothane

          Dicophane

          Dichlorodiphenyltrichloroethane

          OMS-16

    1.2   SYNOPSIS: A persistent organochlorine pesticide of moderate 
          mammalian toxicity.  No ill effects have been observed in 
          personnel exposed for many years both in its manufacture and field 
          use.  It accumulates in body fat to a plateau level related to 
          absorption.  It is cumulative in the natural enviroranent. 
          
    1.3   SELECTED PROPERTIES

    1.3.1 Physical characteristics: Technical DDT is of variable 
          composition and may consist of 11 or more compounds of 
          which the pp'-isomer of DDT contributes 63-77%, the 
          op'-isomer 8-21% and the oo'-isomer 0.1-1.0%. Pure pp'-
          DDT is a white crystalline solid of melting point 108.5-
          109°C. The technical material, however, takes the form of 
          a white or cream coloured waxy solid or amorphous powder 
          of indefinite mp. 

    1.3.2 Solubility

          Practically insoluble in water.  Moderately soluble in 
          hydroxylic and polar solvents and in petroleum oils. 
          Readily soluble in most aromatic and chlorinated solvents. 

    1.3.3 Stability

          Dechlorinated at temperatures above its melting point 
          into a non-insecticidal ethylene derivative, a reaction 
          catalysed by ferric and aluminium chloride and by UV 
          light.  In solution it is readily dehydrochlorinated by 
          alkalis or organic bases, otherwise it is stable being 
          unattacked by acid and alkaline permanganate and by 
          aqueous acids and alkalis.  With technical DDT 
          dehydrochlorination may proceed at temperatures as low 
          as 50°C. 

    1.3.4 Vapour pressure (volatility)
          pp'-isomer 1.9 x 10-7 mm Hg at 20°C

    1.4   AGRICULTURE, HORTICULTURE AND FORESTRY

    1.4.1 Common formulations

          Wettable powders, dusts, aerosols, emulsifiable 
          concentrates.  Concentrations of solid and liquid 
          formulations are mostly between 20% and 25%. 

    1.4.2 Susceptible pests

          In agriculture and horticulture for control, where 
          permitted, of susceptible pests (e.g. cutworms, 
          leafhoppers, leatherjackets, midgets, millepedes, 
          mushroomflies, thrips, sandflies, wasps, weevils, 
          whiteflies, woodlice). 

    1.4.3 Use pattern

          Cotton, 2 quarts of 25% emulsifiable concentrate (e.c.) 
          in sufficient water to give good cover per acre; 
          brassicae 56 lbs 5% dust per acre, cornborer in maize, 3 
          quarts 25% e.c. in 10 gallons applied at 15 gallons per 
          acre. 

    1.4.4 Unintended effects

          It should not be used on curcubits and certain barley 
          varieties as damage may occur.  It should also not be 
          used on permanent and temporary grass for grazing, 
          silage or hay, brassicae seed crops, peas, beans and 
          bush fruit. 

    1.5   PUBLIC HEALTH PROGRAMME

          Still widely used in public health programmes where the vector is 
          not resistant.  The predominant use is for residual indoor 
          application against anopheline mosquitos in malaria control 
          programmes using 5% w.d.p. applied at 1-2 g/m2. 

          In tsetse fly control, 25% e.c. has been applied as a residual 
          insecticide on vegetation. Until recently, DDT was used 
          extensively for blackfly (Simulium) control being introduced into 
          streams at 0.1-1 mg/l using 20-25% e.c. As a general mosquito 
          larvicide 1.25-5% e.c. is used. 

    1.6   HOUSEHOLD USE

          Active against most household pests, including ants, cockroaches, 
          house-flies, mosquitos, bedbugs and fleas, etc.  Some strains of 
          insect species have developed resistance.  Bedbugs 5% spray, also 
          for fleas, ticks, wasps 5% to 10% dust. 

    Part 2.  Toxicology and risks      

      Common name:  DDT
      Data Sheet:    No. 21
      Date issued:  December 1976

    2.1   TOXICOLOGY - MAMMALS

    2.1.1 Absorption route: Absorbed from the gastrointestinal tract 
          and by inhalation.  It may also be absorbed by the 
          intact skin when in oily solution. 

    2.1.2 Mode of action: Central nervous system stimulant producing 
          hyperactivity and tremor; convulsions may occur but are 
          less common than with other organochlorine pesticides. 

    2.1.3 Excretion products: Intact DDT is found in fatty tissues 
          along with its metabolites DDD and DDE.  DDD may be 
          further metabolised to DDA and excreted in urine. 

    2.1.4 Toxicity, single dose:

          Oral:    LD50     Rats (M and F) 250 mg/kg

          Dermal:  LD50     Rata  250-500    mg/kg  in oil
                                   3000     mg/kg    as powder
                              Rat (F) 2510  mg/kg  as powder

          Dermal:  LD50     Rabbita   300  mg  kg  in oil
                            2820  mg/kg   as powder

              Most  susceptible  species:   rat

                   a Sex not stated.

    2.1.5 Toxicity, repeated dose

          DDT administered as a 10% solution in kerosene at 100
          mg/kg/day orally to five rabbits proved fatal in six 
          days.  Similarly 200 mg/kg was fatal to five guineapigs 
          and five rats in 12 and 14 days respectively when dosed 
          under the same conditions. 

          Dermal: Rats treated with 200 mg/kg/day in kerosene were 
          severely affected, with some fatalities after 14 days. 

          Inhalation: Exposure of rats to a concentration of 1000 
          ppm DDT in air for two hours a day caused some deaths 
          after 4-10 exposures. 

          Cumulation of compound:

          DDT and its metabolites accumulate in body fats and 
          other tissues, either as pp'-DDT, DDD or DDE.  Under 
          normal circumstances a plateau level is reached where 
          intake and storage are in equilibrium with excretion, 
          therefore the amount stored in fat will remain constant 
          as long as exposure remains constant.  Central nervous 
          stimulation is related to brain level of DDT; this may 
          be reached by a single acute dose or by smaller repeated 
          doses. 

     

    2.1.6 Dietary studies

          Short-term: 2000 ppm in rats gave a 50% kill in 
          nine days.  600 ppm was tolerated for 14 weeks but was 
          100% fatal after 52 weeks.

          Long-term:  250 ppm produced no toxic effects over one year
          in rats. However, dietary feeding as low as 5-10 ppm has 
          been reported to produce slight hepatic cell enlargement
          especially centrolobularly and increased cytoplasmic 
          oxvphilia.  At higher doses, 500 and 1000, ppm focal 
          necrosis, atrophy and hydropic degeneration were observed. 

    2.1.7 Supplementary studies of toxicity

          Carcinogenicity:

          DDT has been shown to be carcinogenic in a two-
          generation life span study.  (CF 1 mice) at 2,
          10, 50 and 250 ppm, all levels increased tumour 
          incidence in females and two highest levels in 
          males.  While early work of DDT suggested that it 
          might be tumorigenic in rats, no convincing 
          evidence of carcinogenicity to this species has 
          been provided.  The significance of the finding in 
          mice for man cannot yet be assessed.  No increased 
          incidence of tumours has been observed in 
          formulators and spraymen exposed to excessive 
          quantities of DDT for 20 or more years (see 2.2.3).

         Teratogenicity:

          DDT has been shown not to be teratogenic in rats in 
          a three-generation study at dose levels of 20 and 
          200 ppm DDT.  The number of pregnancies and 
          fertility were unaffected at these dose levels.  
          Survival of offspring during weaning at 200 ppm was 
          reduced. 

          Mutagenicity:

          DDT caused moderate mitotic inhibition at 20-50 
          µg/ml in an in vitro test using a kangaroo rat 
          cell line culture.  At 10 µg/ml pp'-DDT, 
          chromosome aberrations and damage were observed in 
          22.4% of cells.  Test in mice to determine whether DDT
          produces dominant lethal mutations proved negative. 

    2.1.8 Modification of toxicity

          The chronic toxicity of DDT has been shown to increase 
          in association with lowering of the protein content of 
          the fat. 

    2.2   TOXICOLOGY - MAN

    2.2.1 Absorption: (see 2.1.1)

          Only massive ingestion (accidental or suicidal) has 
          given rise to cases of poisoning. 

    2.2.2 Dangerous doses

          Single: 10 mg/kg produces illness in some but not all 
          subjects. 16 mg/kg or above will cause convulsions.  
          Dosages as high as 285 mg/kg have been taken without 
          fatal results.  Estimated lethal dose for man 500 mg/kg 
          and in kerosene solut4ion 150 mg/kg. 

          Repeated: Exposure to an aerosol mist containing 80 mg 
          DDT in a room of 113 m3 on five consecutive days 
          for two hours twice a day gave no evidence of toxic 
          effects. 
     
    2.2.3 Observations of occupationally exposed workers

          Over 150 persons with heavy and prolonged occupational 
          exposure to DDT in manufacturing plants have been 
          subjected to exhaustive medical examinations.  The only 
          relevant findings were increased storage and excretion 
          of DDT and its metabolites and a mild stimulation of 
          microsomal enzymes of the liver. 

          Extensive observations of spraymen heavily exposed both 
          with and without protective clothing have revealed no 
          evidence of ill effects with regard to the clinical 
          examination, blood picture and urine tests. 

          Spraymen recruited from areas where the normal diet is 
          of a poor nutritional standard have shown no 
          predisposition to poisoning with DDT. 

    2.2.4 Observations on exposure of the general population

          Food is the main source of exposure and due to its low 
          biodegradability and high lipophilic properties, traces 
          of DDT (and its analogues) are found in adipose tissue.  
          The mean levels vary from country to country (in recent 
          years, 2.3-21.3 ppm, expressed as total DDT), while age, 
          sex, race and social class have been described as 
          important demographic variables influencing the 
          frequency distribution of DDT residue in the general 
          population.  Accumulation in other tissues is markedly 
          smaller, and is proportional to their neutral fat 
          content. 

          A high degree of safety of DDT for the general 
          population is indicated by the studies on people 
          occupationally exposed (2.2.3) and volunteers (2.2.5). 

    2.2.5 Observations in volunteers

          Exposure to 1 mg DDT/3 m3 for 1 h/day for six days 
          produced no untoward effects.  Oral dosage with 500 mg 
          in olive oil gave no toxic effect and 11 mg/kg (770 mg 
          total) pure DDT in 25 cc olive oil gave no subjective 
          signs, tremor, twitching or EEG abnormalities.  Twenty-
          four volunteers ingested technical or p,p'-DDT at rates 
          up to 35 mg per man per day for 21.5 months. They were 
          then observed for an additional 25.5 months and 16 were 
          followed up for five years.   Storage of DDT and DDE and 
          excretion of DDA were proportional to dosage.  The fat of
          those receiving technical insecticide at the highest rate 
          contained 105 to 619 ppm of DDT when feeding stopped.  The 
          average dosage of p,p'-DDT administered in this study was 
          555 times the average intake of all DDT-related compounds by
          19-year-old men in the general population and 1250 times 
          their intake of p,p'-DDT.  Since no definite clinical or 
          laboratory evidence of injury by DDT was found in this 
          study, these factors indicate a high degree of safety of 
          DDT for the general population. 

    2.2.6 Reported mishaps

          In spite of the prolonged exposure of the entire 
          population of the world and the heavy occupational 
          exposure of a substantial number, the only reported 
          poisoning cases were due to intentional or accidental 
          ingestion.  In most of these cases only moderate nervous 
          symptoms were observed and convulsions were rare. 

    2.3   TOXICITY TO NON-MAMMALIAN SPECIES

    2.3.1 Fish: Harmful

    2.3.2 Birds: Moderately toxic

    2.3.3 Other species: Harmful to bees.

    Part 3.  For regulatory authorities        

    Common name:  DDT

    Data Sheet:   No. 21

    Date issued:  December 1976

    RECOMMENDATIONS ON REGULATION OF COMPOUND

    3.1   RECOMMENDED RESTRICTIONS ON AVAILABILITY

          (for definition of categories, see introduction)

          Formulations of 10% and above and all liquid formulations over 2% 
          - category 4. Formulations below 10% - category 5. 

    3.2   TRANSPORTATION AND STORAGE

          Formulations in category 4

          Should be transported or stored in clearly labelled rigid leak-
          proof containers and away from containers of food and drink.  
          Storage should be under lock and key and secure from access by 
          unauthorized persons and children. 

          Formulations in category 5

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

    3.3   HANDLING

          Formulations in category 4

          Protective clothing should be used by those handling concentrates.  
          Adequate washing facilities should be available close at hand. 
          Eating, drinking and smoking should be prohibited during handling 
          and before washing, after handling. 

          Formulations in category 5
      
          No special facilities other than those needed for handling of any 
          chemicals need be required. 

    3.4   DISPOSAL AND/OR DECONTAMINATION OF CONTAINER

          Containers containing residues 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

          Formulations in category 4

          Pre-employment medical examination desirable.  Workers suffering 
          from active hepatic or renal disease should be excluded from 
          contact.  Monitoring of DDT levels in fat, gives little or no 
          indication of degree of acute exposure. 

          Formulations in category 5
      
          Warning of workers to minimize contact essential.
        
     
    3.6   ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT

          Pilot and loaders should have special training in application 
          methods. 

    3.7   LABELLING

          Formulations in category 4

          Minimum cautionary statement

          This formulation contains DDT, a toxic substance which is 
          poisonous if swallowed.  Keep the material out of the reach of 
          children and well away from foodstuffs, animal feed and their 
          containers. 

          Formulations in category 5

          Minimum cautionary statement

          DDT is an organochlorine insecticide.

          Keep the material out of the reach of children and well away from 
          foodstuffs, animal feed and their containers. 
                    
    3.8   RESIDUES IN FOOD

          Maximum residue limits for DDT have been recommended by the Joint 
          FAO/WHO Meeting on Pesticide Residues. 

    Part 4.  Prevention of poisoning in man and emergency aid 


    Common name:   DDT

    Data Sheet:    No. 21

    Date issued:   December 1976

    4.1   PRECAUTIONS IN USE

    4.1.1 General

          DDT is a moderately toxic organochloride 
          insecticide which is slowly metabolised and stored 
          in body tissues and can act as both an acute and 
          chronic poison.  It can be absorbed by mouth, by 
          inhalation of dust and also through the intact skin 
          when in an oil-based formulation.  It is important 
          that concentrated formulations be washed 
          immediately from the skin and eyes. 

    4.1.2 Manufacture and formulation

          TLV

          (ACGIH) 1 mg/m3 (USSR) 0.1 mg/m3.  Although 
          volatility is low, vapour and dust should be 
          controlled preferably by mechanical means.  
          Protective equipment for the skin and respiratory 
          protection is advisable. 

    4.1.3 Mixers and applicators

          When opening the container and when mixing care 
          should be taken to avoid contact with the mouth and 
          eyes.  If necessary a facial visor and gloves 
          should be worn.  Mixing, if not mechanical, should 
          always be carried out with a paddle of appropriate 
          length. 

          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 DDT and associated with its 
          application should 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 DDT. 

    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

          Spillage of DDT and its formulations should be removed by washing 
          with large quantities of water. 

    4.4   EMERGENCY AID

    4.4.1 Early symptoms of poisoning

          Early symptoms may include parasthesia (tingling) of the 
          tongue, lip and parts of the face, in severe cases 
          extending to the extremities.  The patient may have a 
          sense of apprehension and disturbance of equilibrium, 
          dizziness, confusion and a characteristic tremor.  In 
          severe poisoning, convulsions occur. 

          More general symptoms include headache, nausea and 
          fatigue.  Sensitivity to touch and pain are exaggerated 
          in areas in which parasthesia is evident. 

    4.4.2 Treatment before person is seen by a physician, if these 
    symptoms appear following exposure

          Remove contaminated clothing and wash the affected skin 
          with water and soap and flush the area with large 
          quantities of water. 

          If swallowed, vomiting should be induced if the person 
          is conscious.  Patient should be calmed and kept in 
          quiet, shaded conditions until medical help arrives. 

    Part 5.  For medical and laboratory personnel

    Common name: DDT

    Data sheet:  No. 21

    Date issued: December 1976

    5.1   MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING

    5.1.1 General information

          DDT is an organochlorine insecticide of moderate 
          toxicity.  It is absorbed from the gastrointestinal 
          tract and by inhalation.  It may also be absorbed 
          through the intact skin, more especially in the case of 
          oil-based formulations.  Cases of poisoning reported 
          only after massive ingestion.  Its mode of action is by 
          stimulation of the CNS.  It is slowly metabolized and 
          eliminated from the tissues and may be stored in body 
          fat. 

    5.1.2 Symptoms and signs

          Symptoms of poisoning may include headache, nausea and 
          vomiting, weakness, dizziness and confusion, 

          disturbances of equilibrium, parasthesia and a 
          characteristic tremor.  In more severe poisoning 
          convulsions occur. 

    5.1.3 Laboratory

          Measurement of blood or fat levels of DDT and urine 
          levels of DDA will confirm absorption of DDT but will 
          not necessarily reflect degree of poisoning.  High 
          levels of DDT and its metabolites will be found in 
          body fats, these levels may continue to increase after 
          acute dosage, when symptoms of poisoning have abated.  
          Treatment should never be deferred pending the results 
          of a laboratory test. 

    5.1.4 Treatment

          If the pesticide has been ingested, 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.  There 
          is no specific antidote and treatment must be 
          symptomatic.  Soluble barbiturate, diazepam or 
          paraldehyde should be used to calm patient and control 
          convulsions. 

    5.1.5 Prognosis

          If the acute toxic effect is survived the chances of 
          complete recovery are good with great improvement within 
          24-48 hours after ingestion. 

    5.1.6 References of previously reported cases

          Case histories and general methods for treatment are 
          given in: 

          1. Cunningham & Hill (1952) Pediatrics, 9, 745

          2. Dreisbach, R. H. (1974) Handbook of poisoning, pp. 
             91-93, 8th ed.  Lange Med.  Pub., Los Altos, 
             California 

          3. Hayes, W. J. jr (1963) Clinical handbook of 
             economic poisons, US Public Health Service Publ.  
             No. 476 revised 

          4. Von Oettingen (1955) The halogenated hydrocarbons,
             toxicity and potential dangers, US Dept of Hlth 
             Educ. and Welfare 

     
    5.2   SURVEILLANCE TESTS

          There are no readily available techniques to determine the degree 
          of exposure prior to the appearance of symptoms. 

    5.3   LABORATORY METHODS

    5.3.1 Detection and assay of compound

          The analysis of blood, urine and faeces is of extreme 
          importance when studying transport and elimination of 
          p,p'-DDT and p,p'-DDT-derived metabolites.  The 
          examination of urine is of particular interest because 
          p,p'-DDA, a predominant metabolite of p,p'-DDT, is 
          excreted by this route.  Excretion levels of this 
          metabolite have been established as sensitive indicators 
          of exposure to p,p'-DDT (Durham et al., 1965).  A rapid 
          sensitive gas chromatograhic procedure for the analysis 
          of this metabolite was developed as a dual analytical 
          procedure to determine DDT and its polar and non-polar 
          metabolites in human urine (Cranmer et al., 1969).  
          Utilizing electrolytic conductivity, or micro-
          colormetric detection, the procedure can be readily 
          adapted for the exclusive determination of p,p'-DDA 
          excretion levels. 

    5.3.2 Other tests in cases of poisoning

          Liver function.


                                 REFERENCES

    Cranmer, M. F., Carroll, J. J. & Copeland, M. F. (1969) Determination 
    of DDT and metabolites including DDA in human urine by gas 
    chromatography, Bull. Environ. Contamin. & Toxicol., 4, 214 

    Cueto, C., Barnes, A. G. & Mattson, A. M. (1956) Determination of DDA 
    in urine using an ion exchange resin, J. Agr. Food Chem., 4, 943 

    Durham, W. F., Armstrong, J. F. & Quinby, G. E. (1965) DDA excretion 
    levels, Arch. Environm. Health, 11, 76 








    See Also:
       Toxicological Abbreviations
       Ddt (ICSC)
       DDT (JECFA Evaluation)
       DDT (PIM 127)
       DDT (FAO Meeting Report PL/1965/10/1)
       DDT (FAO/PL:CP/15)
       DDT (FAO/PL:1967/M/11/1)
       DDT (FAO/PL:1968/M/9/1)
       DDT (FAO/PL:1969/M/17/1)
       DDT (Pesticide residues in food: 1979 evaluations)
       DDT (Pesticide residues in food: 1980 evaluations)
       DDT (Pesticide residues in food: 1984 evaluations)
       DDT (JMPR Evaluations 2000 Part II Toxicological)