Organophosphate

Organophosphate

Main Industries and Occupations at Risk

  • Horticulture–gardeners, greenhouse workers;
  • Agriculture–garden pest control operators, farmers;
  • Vector control operators;
  • Formulation and manufacture of organophosphates, e.g., insecticide sprays;
  • Laboratory workers analysing organophosphates;
  • Packing and redistribution of organophosphates.

Note: OP may be commonly used in the homes.

Common OP used in Singapore are:

  • Basudin 60
  • Dichlorvos
  • Dimethoate
  • Dipterex
  • Diazinon
  • DDVP (2,2, Dichlorovinyl 0, 0-Dimethyl Phosphate)
  • Fenthion
  • Malathion
  • Parathion
  • Rogor
  • Tamaron
  • Temephos

Toxic Effects

  • Acute Poisoning
    • Onset is prompt but may be delayed up to 12 hours;
      • Central Nervous System, e.g., anxiety, dizziness, headache, sleeplessness, confusion, coma, convulsions;
      • Respiratory, e.g., dyspnoea, chest tightness, bronchospasm, bronchial hypersecretion, pulmonary oedema;
      • Gastrointestinal, e.g., salivation, nausea, vomiting, abdominal colic, diarrhoea, pancreatitis;
      • Ocular, e.g., lacrimation, miosis, blurring of vision;
      • Muscular, e.g., fasciculations, cramps.
    • Chronic Poisoning – Non-specific, e.g., headache, quick onset of fatigue, disturbed sleep, anorexia;
      • Central and Autonomic Nervous System, e.g., nystagmus, tremors,  failing memory, disorientation;
      • Peripheral Nervous System e.g. paresis, neuritis, paralysis.
    • Note: Organophosphates (OP) are readily absorbed through the skin.

Medical Examinations

Indications:

  • Any occupational exposure to organophosphates

Types of Tests and Frequency of Examinations:

  • Pre-placement medical examination: within three months of exposure
    • Clinical examination shall include a detailed medical and work history with emphasis on the central and autonomic nervous systems
    • Tests:
      • i. Plasma cholinesterase estimation.
  • Periodic medical examinations: every 6 months
    • Clinical examination shall include a detailed medical and work history with emphasis on the central and autonomic nervous systems