Endocrine Disruptors and Hog Manure

Hog farming is a significant agricultural activity in Canada, with the size of operations expected to increase substantially in the near future. This will not only mean more pork, but also more hog-generated organic waste, which is traditionally disposed of as manure for field crops.

Source: Statistics Canada, Historical Overview of Canadian Agriculture, 1997

The concern, according to Environment Canada scientists, is that pig manure can contain high concentrations of endocrine-disrupting chemicals, including natural estrogens. These chemicals have been proven through various studies to have long-term adverse effects on the growth, development and reproduction of fish and wildlife. Runoff from fields treated with pig manure can enter adjacent streams or other bodies of water, resulting in eutrophication or even acute toxicity.

Scientists from Environment Canada's National Water Research Institute (NWRI) and Agriculture and Agri-Food Canada in Ontario joined forces earlier this year to determine the persistence of endocrine-disrupting chemicals in soil after manure application and to establish the identity, exposure and effects of chemicals entering adjacent aquatic environments. Studies completed this spring confirmed the presence of high concentrations of these chemicals in hog manure, and showed that they begin to enter nearby waterways soon after manure has been applied to fields. Studies are currently under way to isolate and identify several unknown compounds that were detected to determine if they also pose a threat to aquatic environments.

The current collaboration will be broadened to include ongoing projects among NWRI (Saskatoon), Agriculture and Agri-Food Canada and other partners in Saskatchewan. The expanded study will include determining the potential impacts of other animal wastes on aquatic organisms and possible remedial or best management practices to minimize exposure and risk to the aquatic environment.