Three thousand pigs can produce as much waste as a town of 10,000 people. With all that liquid manure comes the unmistakable smell. But beyond the stench, pig manure poses real risks, says Bill Paton. The biologist at the University of Brandon explains to CBC's Bob Carty that pig manure contains high amounts of phosphorus, nitrogen, ammonia, growth hormones and antibiotics, which are harmful to people and the environment.

Phosphate spurs algae growth in rivers and lakes, which robs the water of oxygen thus killing fish and other organisms. Excess nitrogen can lead to blue baby syndrome (toxic shock that can kill babies). Ammonia has been linked to thyroid disorders. Since liquid pig manure is sprayed as fertilizer on fields, it can cause respiratory problems. Despite these growing health concerns, Manitoba has some of the most lax environmental regulations in the country, says professor Paton.

• The use of pig manure as fertilizer is a common farming practice. Manure contains three major nutrients: nitrogen, phosphorous and potassium, which add valuable organic matter to the soil. It is common practice to spread manure on land near the barns. The problem occurs with over-fertilized soil unable to absorb any more manure.

• Currently (2004) no sewage-style purification of pig manure is required. There are provincial and municipal guidelines restricting the spreading and storage of pig manure but there is no enforcement in place to ensure that these guidelines are met.

Medium: Radio
Program: This Morning
Episode: Troubled Waters
Broadcast Date: Feb. 12, 2001
Host: Shelagh Rogers, Producer: Bob Carty
Guest(s): Bill Paton
Duration: 4:51