"In May 2000, around half of Walkerton’s 5,000 residents fell severely ill and seven people died when cow manure washed into a well. The extent of the water pollution in the small Canadian town was concealed from the public, people drank from their taps and the result was ruined lives.
For academic microbiologist Joan Rose, who has observed water pollution outbreaks around the world, it was the worst that she had ever experienced.
“It affected me the most. Walkerton is a small small farming community. The people there were very gracious. Two pathogens came in to their water supply. They did not know children would die, or would suffer kidney failure and be on on dialysis for the rest of their lives. I saw what it did to people. I saw the pain.”
Walkerton was one of Canada’s worst-ever pollution incidents but there are hundreds of similar incidents every year around the world, albeit mostly less serious, says Prof Rose, who is laboratory director in water research at Michigan State University.
Most come from people drinking water contaminated with sewage, she says. “In the US there are 12-18m cases of human water-borne diseases a year. In developing countries it is possible that one in three hospital cases may be due to contamination of water. We do not know exactly how bad it is but 1.5 billion people do not have access to adequate sewage treatment.”