Your Dog's Poop and Pee Is Worse for the Environment Than You Think

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Your dog’s turds may be more harmful to the great outdoors than you thought.

That’s the conclusion of a new report from scientists in Belgium on the environmental impact of urine and feces from dogs. Researchers at Ghent University studied the chemical composition of soil adjacent to footpaths in four different nature reserves—ground where dogs were most likely to poop and pee—and found that the dirt contained harmful levels of nitrogen and phosphorus.

These two elements are often found in dog foods, and they can kill some plants while allowing others, such as nettles and hogweed, to thrive. They can also drive out wildlife species that depend on such plants for food.

The research estimated that the total amount of nitrogen and phosphorus excreted by Europe’s 87 million dogs is similar to what is produced by the continent’s industrial agriculture and car traffic.

“We were surprised by how high the nutrient inputs from dogs could be,” said Pieter De Frenne, a professor at Ghent University, who led the research. “Atmospheric nitrogen inputs from agriculture, industry, and traffic rightfully receive a lot of policy attention, but dogs are entirely neglected in this respect.”

Researchers found that picking up and taking away a dog’s poop removed most of its phosphorus deposits, but the significant nitrogen pollution from urine is, naturally, harder to take away. And the study also found that high levels of nitrogen and phosphorus from dogs can persist even three years after dogs are banned from an area.

Rob Stoneman, director of landscape recovery at the Wildlife Trusts, told the Guardian: “Nature reserves are special places for nature conservation, where wildlife and fragile habitats are protected. Obviously poo is a part of nature, but dog poo contains nutrients which can damage the ecology of vulnerable habitats. Wherever you walk your dog, it is important to pick up, bag, and bin poo, to ensure the continued protection of these wild areas for us all to enjoy.”