Laboratory diagnosis of zinc phosphide poisoning

Zinc phosphide, a readily-available rodenticide, poses a significant risk for intoxication in animals. Animals have been poisoned by ingesting treated bait or the carcasses of poisoned rodents. Toxicity is due to the liberation of phosphine gas in the stomach. Clinical signs include central nervous system excitation, depression and vomition. Similarities of clinical signs with other central nervous system toxicants make the diagnosis difficult without a specific diagnostic test. The procedure outlined in this paper detects phosphine liberated from zinc phosphide by the addition of hydrochloric acid as well as the phosphine previously generated by contact with stomach acid.