E. coli traces prompt continued boil water order for White Rock, B.C.

By Tamsyn Burgmann in Vancouver, 24 Aug 2010, Canadian Press

WHITE ROCK, B.C. - A massive water tank in suburban Vancouver is being drained of its 1.2 million litres in an effort to pinpoint and flush E. coli contamination that's led to an indefinite boil-water order for about 20,000 residents.

People living in White Rock and south Surrey have been advised to boil any water for drinking, cleaning food or brushing teeth for at least one minute after routine monthly testing last week first identified the problem.

"E. coli is a bacteria that is only found in the gut of warm-blooded animals," said Dr. Elizabeth Brodkin, medical health officer for the Fraser Health Authority.

"When you find it in drinking water it means, by definition, that there has been contamination by fecal material."

A massive testing and cleansing project is now underway, as operator Epcor can not assure the water's safety until clear test samples are produced for at least three consecutive days. After last week's initial result, a follow-up Friday also came back positive.

Testing was clear over the weekend, but three positive samples Monday led to an extension of the boil water advisory that will last until at least the weekend.

Those samples helped Epcor trace the contamination to one particular three-metre-tall reservoir partially buried in the earth on White Rock's northern border.

"Once we get it emptied we're going to go in and we're going to do an extensive, detailed investigation on the inside," said David Rector, Epcor's director of water services.

"We're looking at potential roots where something could come in and hopefully we find something."

Although no cracks have been spotted on the outer tank, it's possible a small animal or bird might have infiltrated, Rector said.

Even if nothing obvious is found, the container will be disinfected before being refilled. Then testing will begin again.

The draining process is usually completed every five years, with the last routine cleaning happening three years ago.

No illnesses related to the contamination have been reported, but the health authority is monitoring the situation closely. Brodkin said symptoms of infection could range from upset stomach to vomiting or even bloody diarrhea.

She noted that sickness could look different in different people because E. coli indicates the presence of potentially a long list of bacteria, viruses or parasites.

Health authority policy is that a single positive sample, as obtained Thursday, requires a second positive test before a boil-water order is issued. That's why residents weren't notified until late Friday.

"If the contamination is at relatively low levels, it may be the detection of E. coli in the water is intermittent," Brodkin said. "This is why we don't just turn the tap back on based on a single sample."

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