Environment Algae bloom isn't as bad as last year, according to tests

B9

Derwin Gowan
Telegraph-Journal

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ST. GEORGE - People can safely swim in Lake Utopia this summer "so far," a provincial health official said at a public information session this week.

The latest test results from the lake indicate that people can jump in without the water making them sick, Region 2 medical officer of health Dr. C. Scott Giffin said at the open house event in St. George.

However, people should use "common sense" if they see a blue-green "algal bloom" in Lake Utopia or any other body of water, he said.

Giffin issued an advisory about swimming in Lake Utopia last summer after people reported blue-green algae forming scum on the water. Later tests showed that the algae produced toxins which could make people sick.

The provincial environment department organized the information session at St. Mark's Anglican Church to bring people up to date on the status of the lake this summer and efforts since last year to understand the problem.

The government cannot monitor all lakes and even at Lake Utopia, which it does monitor, the government can only you tell the public the results from the latest samples once the laboratory finishes testing them.

"My main message is people have to use their common sense. If they see a bloom and the water looks murky and looks bad they shouldn't swim in it. That common sense has served quite well," Giffin said.

The swimming advisory on Lake Utopia, a popular recreation water body in the St. George area, upset many people last year.

Algae in a lake feeds on phosphorous and nitrogen. Adding these elements beyond the lake's "carrying capacity" will cause the algae to "bloom" into a visible scum, especially when summer sunshine hits it.

The officials came to the church hall to talk about efforts since last year to reduce the amount of phosphorous going into Lake Utopia - and to understand where it comes from.

Lake Utopia drains into the Magaguadavic River through a natural channel about two kilometres long called the Canal.

When the Magaguadavic River rises beyond a certain level, the water flows back up the Canal, complicating any attempt to understand what happens in the lake.

Don Fox, the environment department's water quality specialist, explained the results of a study over the past year showing that about 600 kilograms of phosphorous flows up the Canal from the Magaguadavic River into Lake Utopia, just balancing the 600 kilograms that come down the Canal from the lake into the river.

"This implies that the lake was not able to flush any excess phosphorus in the November 2007 to October 2008 period. The average long-term flushing rate is in the order of three years," the study concluded.

Sources of phosphorous in Lake Utopia include the Cooke Aquaculture salmon hatchery, septic systems from cottages, possibly agricultural run-off from blueberry fields, maybe from sunken logs, sawdust and other debris left over from forestry operations many years ago, among other things.

One person noted that in the Second World War military airplanes based at Pennfield used Cannon Ball Island in Lake Utopia for target practice.

The non-governmental organization Eastern Charlotte Waterways set up at table at the open house, explaining its program to deal with cottage owners over septic systems, the chemicals they might use on their lawns and proper landscaping to minimize shore-front erosion.

Sources of phosphorous coming up the Canal from the Magaguadavic River could include another Cooke Aquaculture hatchery on Linton Stream, which drains Digdeguash Lake above the Utopia Canal. It could also come from a commercial cranberry bog further upriver, or other agricultural, residential, industrial and other activity from as far away as the Magaguadavic headwaters in York County.

Some people questioned the effect of the hydroelectric dam at St. George, which J. D. Irving, Limited operates.

The Environment Department found in its study that the dam might influence the reverse flow of the Canal, company spokeswoman Mary Keith said in an email Friday.

However, the company knows of no science showing that the current dam impacts blue-green algal blooms in Lake Utopia, she said.

The study found that excessive nutrients, not the dam, causes the algal blooms, Keith said. The company wants to operate the dam to the highest environmental standard based on good science, she said.

The volume of phosphorous coming from the effluent pipe at the Cooke Aquaculture hatchery in the lake dropped by 75 per cent from last year, Troy Lyons, the environment department's aquaculture approvals officer, said at the open house.

The company accomplished this partly by switching to a low phosphorous feed, Lyons said.

The company just got the report from an engineering study it commissioned on the wetlands around the hatchery, Cooke Aquaculture spokeswoman Nell Halse said Thursday. The company expects to do work at the wetlands this year.

Solid waste from the hatchery goes into tanks which trucks take to treatment plants elsewhere, she said.

Cooke Aquaculture has a permit to put up to 400 kilograms of phosphorous into Lake Utopia each year, but only 11 kgs of the element came out the hatchery effluent pipe by mid-July this year, Lyons said. He does not expect the total to go past 20 kgs by the end of 2009.

Scientists have no idea how much phosphorous anyone can safely add to Lake Utopia because, given the current state of research, nobody knows how much is already there, Lyons said.