By PETTI FONG
Tuesday, November 21, 2006
Two million residents of Greater Vancouver have been advised to boil their cloudy water after heavy rainfall created mudslides in the region's reservoirs, the widest water warning in Canadian history.
Health officials said tap water is unsafe for drinking, brushing teeth or washing fruits and vegetables after the mudslides increased the risk of bacteria and viruses infecting the water supply. The risks can't be minimized by disinfectants such as chlorine _ hospitals, seniors homes and schools have been told to use only bottled or boiled water.
"This is a precautionary measure," said Dr. Patricia Daly of Vancouver Coastal Health. "We are telling people don't drink tap water. Either boil it or drink bottle water."
Dr. Perry Kendall, the province's chief health officer, said one concern is that the water supply could contain viruses, such as the norovirus and the E. coli bacteria, both of which can lead to diarrhoea.
"The turbidity is very high and when it washes the topsoil, it can get contaminated with a lot of different things that you don't want contaminating your water, such as wild animal feces," Kendall said.
The advisory could last for weeks until the water supply clears. In 2000, people living in the Ontario town of Walkerton had to boil or buy their water for seven months after their supply was found to be unsafe. At least seven people died and more than 2,300 were sickened by E. coli found in it.
In British Columbia's case, there was an intense period of heavy rainfall for 15 hours straight _ that caused a runoff into the three watersheds that supply water for about 2 million people.
"The very heavy storms we've experienced, for some unknown reason, concentrated a lot of rain in our watersheds," said Paul Archibald, division manager of water supply for the Greater Vancouver Regional District.
He said 37 slides in 24 hours created the muddiness in the water, a mixture of sandy gravel and the more problematic clay, which has fine sediment that could take weeks to wash out.
Watershed officials are adding more chlorine to increase the amount of disinfectant in the water and are releasing the water supply into the reservoir to dilute its turbidity.
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