Livestock Antibiotics Pose Minimal Environmental Risk, Study Finds

September 13, 2007 - News Release

Antibiotics used on livestock pose minimal environmental risk in Canada, according to a new University of Guelph study.

Prof. Paul Sibley, Department of Environmental Biology, and Prof. Keith Solomon, Centre for Toxicology, recently completed a six-year study examining the use of pharmaceuticals in the Canadian hog and cattle industry. They found that pharmaceuticals don't pose appreciable risks to soil and water if used as instructed.

“We’ve found evidence that suggests there’s little risk to soil and aquatic biota from using pharmaceutical products," said Sibley.

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.

To determine whether these concerns were valid, Sibley, Solomon and a team of researchers simulated real-life scenarios in the laboratory and field to study the toxicity of pharmaceuticals. 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, said Sibley.

After applying the pharmaceuticals, the researchers tested the soil, soil life, water and aquatic life in the area to measure the level of toxicity. They also measured concentrations of antibiotics at several locations on the Grand River watershed heavily populated with livestock.

In both studies, they found the level of antibiotics detected was "significantly" lower than the amount required to elicit toxic responses and was therefore likely to pose negligible environmental risk, said Sibley.

The long duration of some of the studies, which ran up to 60 days, helped the researchers accurately assess changes in contamination levels and toxicity over time, ultimately leading to a stronger conclusion that supports environmental safety, he said.

“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.”

Paul Sibley
Department of Environmental Biology
519-824-4120, Ext. 52707

Keith Solomon
Centre for Toxicology
519-824-4120, Ext. 58792

For media questions, contact Communications and Public Affairs: Lori Bona Hunt, 519-824-4120, Ext. 53338, or Deirdre Healey, Ext. 56982.

University of Guelph
50 Stone Road East
Guelph, Ontario, N1G 2W1