What substances are used to poison rats in the city? - briefly
Anticoagulant rodenticides such as bromadiolone, brodifacoum, and difenacoum are the most widely used, complemented by acute agents like zinc phosphide and strychnine in some municipal programs. These chemicals act by disrupting blood clotting or inducing rapid toxicity, allowing effective control of urban rat populations.
What substances are used to poison rats in the city? - in detail
Urban rodent control relies on a limited set of chemical agents formulated as baits. The most widely applied categories are anticoagulants, vitamin‑D derivatives, phosphides, and neurotoxins. Each class has a distinct mechanism, potency, and regulatory status.
Anticoagulant baits contain compounds that disrupt blood clotting, causing internal hemorrhage after a single lethal dose. Common products include:
- Warfarin – first‑generation, requires multiple feedings, relatively low toxicity to non‑target species.
- Bromadiolone – second‑generation, effective after a single ingestion, high potency, long biological half‑life.
- Brodifacoum – second‑generation, extremely toxic, single‑feed lethal dose, persistent in tissues.
- Difenacoum – second‑generation, similar to bromadiolone, used where resistance to first‑generation agents is documented.
Vitamin‑D based baits use cholecalciferol to induce hypercalcemia, leading to renal failure. The compound is absorbed rapidly, and lethal doses are achieved with a single bite. It poses lower secondary‑poisoning risk because mammals metabolize excess calcium more efficiently than rodents.
Phosphide baits employ zinc phosphide or aluminum phosphide. In the acidic environment of the stomach, these salts release phosphine gas, which disrupts cellular respiration. Zinc phosphide is favored for outdoor applications due to its stability in bait matrices; however, it is highly toxic to wildlife and domestic animals if accessed.
Neurotoxic baits contain bromethalin, a mitochondrial uncoupler that causes rapid loss of motor coordination and death within hours. Bromethalin is effective against anticoagulant‑resistant populations but carries a higher risk of accidental poisoning because its toxicity is not mitigated by the rodent’s metabolic pathways.
Regulatory agencies typically restrict the use of second‑generation anticoagulants and phosphides to licensed pest‑control operators. Formulations are often combined with attractants such as grain, peanut butter, or meat derivatives to ensure consumption by the target species. Bait placement follows a grid pattern, with stations spaced 10–20 m apart in high‑density infestations, and stations are inspected weekly for consumption and replenishment.
Secondary poisoning considerations dictate that baits with lower persistence (e.g., warfarin, cholecalciferol) are preferred in areas where predatory birds or domestic pets may encounter dead rodents. Conversely, when resistance is confirmed, second‑generation agents are deployed under strict supervision, and carcass removal is mandated to limit trophic transfer.
Overall, effective urban rat eradication depends on selecting the appropriate active ingredient based on resistance profiles, non‑target exposure risk, and compliance with local pesticide regulations.