Zinc phosphide

ZINC PHOSPHIDE

  • Zinc phosphide is used as a rodenticide.
  • Zinc phosphide has a disagreeable odour but not to the rodents.
  • Under acid conditions, it liberates phosphine gas, which is highly inflammable and toxic.
  • Phosphine gas is used as a grain fumigant.
    • Zinc phosphide is absorbed from the stomach.
    • It is directly irritant to the gut and causes vomiting.
    • Phosphine gas at the acid pH in the stomach causes acute toxicosis.
    • In humans inhalation of phosphine causes dyspnoea, hypotension, bradycardia, nausea and vomiting.
    • Phosphine gas blocks cytochrome oxidase and this in turn reduces energy production.
    • There is also increase in reactive oxygen species resulting in peroxidation and other cellular oxidative damage.
  • Clincal signs
    • Clinical signs include anorexia, lethargy; vomiting of blood, increase in rate and depth of respiration, abdominal pain, bloat, ataxia, weakness, prostration, gasping, convulsions, coma and death in 3 to 48 hors.
    • Dogs show symptoms of mad dog running – aimless running, howling and yelling, snapping of teeth, tremors and extensor rigidity seizures.
    • Lesions include pulmonary congestion, oedema, pleural effusion, subpleural haemorrhage, congestion of liver and kidney, gastroenteritis and acetylene like odour in the vomitus or stomach contents.
    • Zinc levels in the blood, liver, and kidneys may be increased.
    • No specific treatment is available.
    • Sodium bicarbonate can be administered to alter the pH so as to reduce the conversion of zinc phosphide to phosphine gas.
    • Gastric emptying and lavage with 5% sodium bicarbonate, calcium gluconate and 1/6Molar sodium lactate is useful.
    • Intravenous dextrose can be administered to control kidney and liver disorders.
Last modified: Sunday, 30 October 2011, 9:56 AM