Beaches closed on northern Lake Champlain

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(Host) Public health authorities in Canada have closed beaches in northern Lake Champlain because of toxic algae blooms. In Vermont, officials are keeping a close eye on water quality but so far have not issued health warnings. VPR’s John Dillon reports.

(Dillon) The shallow waters in Missisquoi Bay on northern Lake Champlain are a breeding ground for a dangerous form of plant life. Blue algae are microscopic organisms that can produce a toxin that’s dangerous to people and animals. On the Quebec side of the lake, the algae has multiplied to form a heavy, soup-like scum on the water. Quebec has told swimmers to stay out of Missisquoi Bay until further notice.

In Vermont, scientists collect samples of lake water to look for algae concentrations. State toxicologist Bill Bress says the Health Department will warn the public if the toxin levels reach the guidelines set by the World Health Organization.

(Bress) “So on our side of Missisquoi Bay we haven’t reached that level yet. We’re at the level where the counts are increasing of the blue green algae but the toxin level is still low. But if we have an extended heat wave, the algae will probably increase to the point where we will be doing public notification.”

(Dillon) Last year, two dogs died after drinking water from Missisquoi Bay. Officials last year told swimmers to avoid areas where the blue-green algae scum has accumulated.

Mary Watzin is a University of Vermont scientist who leads the lake research project. She says people need to look out for water that’s thick with algae.

(Watzin) “When you begin to see that visible surface scum of algae, that’s where we’ve seen the really high toxic concentrations. That’s why we tell folks watch for the scum, and if you see scum forming – and you’re particularly likely to see that forming on the shoreline – those are the areas you need to be careful.”

(Dillon) The algae blooms are aggravated by the high levels of nutrients, such as phosphorus, that flow into the water from farm run-off and city streets. Scientists believe the situation is worse on the Canadian side because the prevailing wind in the summer blows from south to north, and it probably pushes the algae on to the Quebec shoreline.

For Vermont Public Radio, I’m John Dillon in Montpelier.

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