Toxicology report confirms phosphine in Delhi zoo antelopes, likely from rodenticides used on premises
Toxicology Report Links Deaths of Chousingha at Delhi Zoo to Rodenticides
New Delhi: A toxicology report from the Indian Veterinary Research Institute (IVRI) revealed that two chousingha (four-horned antelopes) died at the Delhi zoo due to the presence of phosphines in their rumen and intestines. This finding suggests possible exposure to rodenticides, specifically aluminium or zinc phosphide.
Officials indicated that the deaths are likely connected to rodenticides. The report, dated December 18, states that samples sent to IVRI tested negative for all other common pesticides. “The samples of rumen and intestinal content were positive for the presence of phosphine and negative for HCN, nitrate-nitrite, heavy metals and commonly used pesticides. The presence of phosphine indicates exposure of animals to rodenticides,” the report noted.
IVRI also tested the animals’ feed samples and found no insecticides present. Metal phosphides, such as aluminum or zinc phosphide, are common in rat poison. These substances react with moisture and stomach acid to release phosphine gas, which is highly toxic to animals.
“This is likely the reason behind the sudden deaths. The initial post-mortem could not determine the sudden cause of death,” a zoo official stated.
Delhi zoo director Sanjeet Kumar did not comment on the report or respond to queries from HT regarding the matter. HT reported on December 16 about the deaths of the two chousingha on December 11 and 12, noting foam found near their mouths.
HT has also reviewed an internal zoo document confirming that on December 2, rodenticides, including aluminium phosphide (56% concentration) and zinc phosphide (80% concentration), were used for rat control on the premises. A zoo official confirmed this, adding that tablets were used for rodent control. “The animals may have ingested these,” the official said.
The four-horned antelope is protected under Schedule I of the Indian Wildlife Protection Act (amended), 2022. This species is native to central, south, and western India, with a small population in Nepal.
The zoo, established in 1959, houses 96 different species of animals, birds, and reptiles and covers an area of 176 acres.
Summary of Findings
| Detail | Information |
|---|---|
| Location | Delhi Zoo |
| Species | Chousingha (Four-horned Antelopes) |
| Death Dates | December 11 and 12 |
| Toxicology Report Date | December 18 |
| Rodenticides Found | Aluminium Phosphide, Zinc Phosphide |
| Zoo Established | 1959 |
| Area | 176 acres |
| Species Count | 96 |
