B.C. gov. bans use of rodenticides over concerns about food chain seepage

Rodenticide Photo by Shutterstock/Gallinago_media

B.C. is changing its approach to rodent management.

On October 28, the province’s Ministry of Environment and Climate Change announced that it is permanently banning the widespread sale and use of second-generation anticoagulant rodenticides (SGARs).

These are chemical agents designed to kill rodents by preventing their blood from clotting, causing internal bleeding. Rodenticide poisons have become the default strategy worldwide for handling rodent problems, but they come with a number of side effects.

The B.C. government implemented an 18-month ban on SGARs in July 2021 to further understand the poison’s effects. After public consultations and consultations with experts, the government decided to make the ban permanent starting January 21, 2023, when the temporary ban expires.

SGARs are often mixed with an attractant, such as peanut butter, and baited inside small black boxes. The chemicals are highly toxic to all types of wildlife, and there have been cases where animals other than rats and mice have been poisoned, such as squirrels, cats, and even dogs.

The B.C. government is concerned about secondary poisoning. The deadly chemicals can last in the rodent’s tissues for up to 24 months, even after death. Any predator that eats an infected rodent is at risk of secondary poisoning.

Between 1988 and 2003, scientists collected 164 B.C. owls to test for rodenticide. The study found that 70 per cent of the owls had detectable liver residues of at least one anticoagulant rodenticide. The study did note, however, that only six of the owls died from rodenticide poisoning. The rest died from other circumstances.

Secondary poisoning from rodenticide is most common among raptors, but it has also been found in other predators, such as coyotes and foxes. There is concern among experts that predators are dying through secondary poisoning and effectively allowing rodent populations to thrive and spread diseases contagious to humans.

Despite the risks associated with SGARs, the government is making exceptions to the ban. To balance the need to protect wildlife, while protecting the delivery of essential services, the government said that agricultural operators and essential service providers, such as hospitals, grocery stores, and even telecommunication services, will be allowed to continue purchasing SGARs. The SGARs can only be purchased and used by a licensed pesticide applicator.

Before using SGARs, the pesticide applicator must identify the species of rodent and monitor the population size to assess the risk. After using SGARs, they must properly dispose of the dead rodents, so that they don’t pose a threat to other wildlife. Vendors can only sell SGARs to licensed applicators and they must keep track of all sales for at least three years.

Tips for deterring rodents

  • prune excessive vegetation where rodents might nest
  • ensure doors and windows are flush with their frames
  • plug any holes with steel wool (mice can fit through a hole the size of a dime and rats a hole the size of a quarter)
  • keep all attractants, such as food and compost, in sealed bins

Not everyone agrees with these exceptions, though. B.C.’s Society for the Prevention of Cruelty to Animals (SPCA) said that all anticoagulant rodenticides should be banned. The organization noted that compliance with proper SGARs use has been lax in the past. In 2019, provincial officers conducted 311 SGARs inspections. Only 39 per cent of those inspected complied with proper protocols. The organization is concerned that this type of misuse could continue.

SPCA also pointed out that first-generation anticoagulant rodenticides (FGARs) are still legally available for use. These products are slower-acting and less potent than SGARs, but can still pose a poisoning risk to wildlife.

Instead, SPCA is advocating for more humane rodent management strategies, such as prevention.

“The BC SPCA is committed to supporting the transition from rodenticides to more humane pest control strategies,” the organization said in a statement, “and is working with municipal staff to ensure there is a sustainable plan for their communities.”

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