Environmental activists have long criticized pharmaceutical use by hog farmers and veterinarians in treating swine disease, saying pharmaceuticals are being overused and errantly contaminating the environment. But new research from the University of Guelph has shown that environmental contamination from antibiotics does not pose appreciable risks to soil and aquatic organisms.
Prof. Paul Sibley of the Department of Environmental Biology and Prof. Keith Solomon of the Centre for Toxicology have wrapped up six years of research examining the use of pharmaceuticals in the Canadian hog and cattle industry. They’ve determined that the pharmaceuticals represent negligible environmental risk if used as instructed.
“It’s good news for producers, veterinarians and pharmaceutical companies,” says Sibley. “We’ve found evidence that suggests there’s little risk to soil and aquatic biota from using pharmaceutical products, so there’s little need to be concerned.”
Pharmaceuticals first raised concerns when they were detected in the environment more than a decade ago. It was thought they could cause contamination through simple routine practices such as manure spreading. Animals administered antibiotics excreted them through feces or urine, which was then applied to land and could cause damage to soil systems or migrate into nearby waterways.
But was this true? To find out, the research team simulated real-life scenarios in the laboratory and field to study pharmaceutical toxicity. They applied pharmaceuticals directly to soil and water to simulate field exposure. This direct exposure would be similar to an actual worst-case scenario, making it a good test of potential risks, says Sibley. In toxicity, safety (or risk) is often measured as the difference between what is found in the environment and what the pharmaceutical’s toxicity is known to be, he says.
In most experiments, he found that the toxicity effects of pharmaceuticals were in the milligram- to gram-per-litre range. That was significantly higher than the nanogram- to microgram-per-litre range typically detected in soil and water for pharmaceuticals.
Sibley says the long duration of some of the studies helped to accurately assess changes in contamination levels and toxicity over time, ultimately leading to a stronger conclusion that supports environmental safety.
“It’s comforting to know that levels of antibiotics in the environment don’t seem to be posing a problem. We’ve tested aquatic, vertebrate, fish and soil communities, and the evidence clearly indicates little cause for concern.”
He says there’s been a strong push by consumers and activists over the last decade to reduce pharmaceutical use on pig farms. Programs such as the Canadian Quality Assurance are helping to inform farmers about proper protocols and how to manage the antibiotics given on the farm. The program also helps with traceability should contamination occur.
“I hope this research still encourages pharmaceutical companies, veterinarians and producers to be more efficient with their antibiotic treatments but, at the same time, eases any thoughts of potential negative environmental effects.”
This research was funded by the Canadian Pork Council through the Livestock Environmental Initiative, the Canadian Cattlemen’s Association and the Canadian Network of Toxicology Centres.
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