Due animal poisons become non-toxic after being metabolized?

Asked November 6, 2018, 9:17 AM EST

We frequently hear about secondary poisoning when a scavenger eats an animal that's been killed by poison. Is the secondary poisoning caused by surplus poison within the dead animal (assuming there is undigested poison that remains) or is the poison, which actually killed the dead animal, still lethal for other animals which may consume it as they scavenge the dead animal's organs? I imagine the answer may be yes, in that there's most likely always surplus or unmetabolized poison which remains in the dead animal. In chemistry we frequently see that a compound's radical is delivered to a reaction and enters into the reaction which changes its properties, however, that's not the case for a catalyst which emerges unchanged from the expedited reaction it has caused.

Los Angeles County California wildlife

1 Response

The way I look at it, primary poisoning occurs when an animal dies due to ingestion of a toxicant. That can be a toxicant placed in the environment, or an unmetabolized toxin still in a victim. For example, there used to be severe secondary hazards from strychnine poisoned ground squirrels. The squirrels died quickly from strychnine poisoning, but died with active toxicant still in their cheeks and gut. Then a coyote or other animal eating the squirrel would ingest the toxicant and be affected. The coyote was still eating the poison directly, even though it was in its prey.

There are toxicants that retain their toxicity after ingestion and metabolism (https://en.wikipedia.org/wiki/Secondary_poisoning). A number of anticoagulants fit this category. http://npic.orst.edu/factsheets/rodenticides.html

https://www.epa.gov/rodenticides/rodent-control-pesticide-safety-review

For more specific information on pesticides registered in your state, contact your local Cooperative Extension office.