● DDT is one of the Organochlorine pesticides.
● The chemical formula of DDT is C14H9Cl5.
● It is colourless, odorless and tasteless crystaline compound.
● It is highly hydrophobic.
● It affects our central nervous system, gastro-intestinal and respiratory system.
● It is soluble in organic solvent but insoluble in water.
● Austria chemist Othmar Zeidler first synthesized the DDT.
● DDT has been sold in the market under the trade name like Anofex, chlorophenothane, dinocide, neocidol, etc.
These compounds are available as:
- Dusting powder
● It is used as insecticides in agriculture.
● Gamma benzene hexachloride is used as a scabicide for the treatment of scabies.
● It is also used as pediculocide for eradication of head lice. It is available as topical ointment, cream, or lotion. Some Indian brand names include Bexarid (Shalaks), Gab (Gufic), Gamaric (Euphonic), Scaboma (Glenmark), and Ultrascab (Perch).
- The fatal dose of DDT is 15 to 30 gm.
- DDT is considered “highly toxic”(LD50: 51 to 500 mg/kg).
Absorption, metabolism and excretion
● Organochloride compounds such as DDT are absorbed through skin, inhalation and through gastrointestinal tract.
● Most of the compounds are metabolized slowly in the body and remains in tissues, especially in fatty tissues for prolonged duration.
● These compounds are metabolized in liver and are excreted in urine, feces and milk.
Mode of action
● DDT and analogues affect the sodium channel and sodium conductance across the neuronal membrane especially of the axon.
● They also alter the metabolism of serotonin, noradrenaline and acetylcholine.
● DDT has the capacity to induce the drug-metabolising enzymes of the liver.
● Most of these agents cause liver necrosis and they are potent enzyme inducers.
●Evidence suggests an important role of benzoquinones in the hepatotoxicity of chlorinated hydrocarbons as opposed to traditional epoxides.
● Cytochrome P450 appears to be associated with covalent protein binding of reactive metabolites.
Sign and Symptoms
- Hyperaesthesia or paresthesia of mouth and face.
- Wheezing, if aspiration or inhalation occurs.
- Renal failure
- Exposure of DDT for prolonged duration may result in cumulative toxicity characterized by-
- weight loss
- Pseudotumor cerebri
- Abnormal mental changes
- Thrombocytopenic purpura
● Skin -The affected part should be washed thoroughly with copious water.
● Ocular-copious eye irrigation with normal saline or tap water is effective.
● Ingestion -Gastric lavage and administration of activated charcoal is administered.
● Oxygen administration.
● Ventilator assistance
● Maintain vital parameters, hydration, and urine output.
● Convulsions should be controlled with judicious use of diazepam or lorazepam.
● Hyperthermia should be managed in usual way.
● Arrhythmias can be managed with lidocaine.
● Hyperthermia should be managed aggressively with cooling.
● Supportive measures—special attention must be paid to the airway and breathing, and adequate circulation should be maintained.
● Haemodialysis and haemoperfusion have not been proven effective.
- Epinephrine may exacerbate ventricular arrhythmias.
- Oil based fluid/food/cathartic.
Post mortem findings
- Insecticide like smell
- Froth at mouth and nostrils
- Congestion of organs
- Pulmonary edema
- Cerebral edema
● Abdominal radiograph may reveal the presence of certain organochlorines which are radiopaque.
● Organochlorines such as DDT can be detected in serum, adipose tissue, and urine by gas chromatography.
● Blood chlorinated hydrocarbon levels are not clinically useful following acute exposure. For most compound they reflect cumulative exposure over a period, of months or years rather than recent exposure.
● Measurement of organic halogen compounds in urine is suggested as an indicator of exposure. Sensitivity is as low as 1 mcg of organic halogen per 100 ml of urine.
Medico legal aspects
● Accidental poisoning may occur in farmers while spraying in the fields or opening the lid of the containers.
●Suicidal poisoning is also common with this insecticide.
● Homicidal is rare as it is difficult to mask the smell of insecticide but has been reported.
- Dr. K.S. Narayan Reddy. The essential of forensic medicine and toxicology.34th edition.
- VV Pillay. Modern medical toxicology.4th edition.
- R.K.Sharma. Concise textbook of forensic medicine and toxicology. 3rd edition.