Birds a key cause of fecal contamination at Lake Winnipeg beaches
E. coli advisories in place for rest of summer at Gimli, Winnipeg Beach and Sandy Hook beaches
Eight beaches in Manitoba have permanent advisories for the summer after testing positive for fecal contamination — and birds flying overhead could be partly to blame.
Summer-long warnings are in effect at Hnausa Beach, Spruce Sands Beach, Sandy Hook Beach, Winnipeg Beach, Milne Beach, West Grand Beach, East Grand Beach and Gimli Beach after tests showed a spike in Escherichia coli (E. coli) in July and August well above the threshold considered optimal for swimming water.
"What we found on Lake Winnipeg is E. coli is really driven by the wind and wave processes on the water," said Elaine Page, manager of the water quality management section with Manitoba Sustainable Development.
E. coli indicates feces from warm-blooded animals is present.
A large study by Manitoba Water Stewardship in 2004 analyzed DNA to try and trace the origins of the E. coli. Researchers found 73 per cent of the E. coli in bathing water was from animals — only eight per cent was from humans.
Further tests showed gulls and terns were the largest contributor.
Page said E. coli from bird poop leaches down into the sand where the bacteria can reproduce in the moist, nutrient-rich environment, creating a cesspool-like reservoir.
When northerly winds blow in, as they frequently do, waves create what's called a swash zone where the lake pulls in the bacteria into the water.
E. coli spikes typically only last a short time after a wavy day — when the water settles, E. coli counts can drop dramatically.
The province's goal or "recreation water quality objective" is fewer than 200 E. coli organisms per 100 millilitres of lake water, or about seven tablespoons. Anything more is considered risky enough to warrant a publicly posted warning at the beach urging swimmers to avoid drinking lake water, to wash their hands before eating and to avoid swimming altogether if they are sick or if they have an open wound or cut.
The presence of E. coli in the water can mean other pathogens and bacteria are potentially floating around too — like Staphylococcus aureus and Pseudomonas aeruginosa which can cause ear, nose, eye and throat infections and Salmonella which can cause a bad stomach flu.
E. coli spike at Gimli Beach
Gimli saw some of the highest peaks of E. coli this summer of all 20 lakes tested weekly for E. coli.
On July 11, the province found 2,290 organisms per 100 ml or 11 times the guideline at the town's beach and on Aug. 1 found 1,339 organisms per 100 ml or 6.5 times the guideline.
Gimli mayor Randy Woroniuk said his town has a bit of a love-hate relationship with the birds. On the one hand, visitors come to the quaint Icelandic enclave to see birds like pelicans, eagles, osprey and piping plover and on the other, there's no ignoring the impact squawking gulls have on the water quality.
They flock to the beach in huge numbers to snack on minnows and food scraps left by humans.
"This is just an attractive place for birds," said Woroniuk, who is also a retired conservation officer. "You come here in the spring and fall this is full of Canada geese. We have a marsh just south of us and wetlands surrounding us."
While the province monitors lake water quality, like all beaches not located in a provincial park, it's up to the municipality to keep beaches clean.
A few years ago, Gimli installed a fake eagle by the volleyball nets to try and scare away marine birds.
Woroniuk said it worked for a time but eventually birds got used to it. The town has since focused prevention: combing the beach regularly to turn over the sand which can help kill off the E. coli and encouraging people to stop feeding birds.
"It doesn't help our problem. The best thing is to stay away from the birds. Try not to interact with them," the mayor said.
Humans play a part too, mayor says
He is certain humans and cattle farms have part to play in Gimli's E. coli levels too, perhaps more than what the province's DNA study showed.
When Woroniuk describes the lake, he recalls a diagram he once saw at a presentation with a toilet superimposed on the map.
"Lake Winnipeg is at the bottom of everybody's watershed," he said. "We draw right from the Rocky Mountains, right from South Dakota, way into northwestern Ontario … that's a contributing factor also."
The province maintains that E. coli in Winnipeg sewage or in farm runoff from the United States dies before it reaches Lake Winnipeg because sunlight kills the bacteria within two days.
"I've heard different scientists say it doesn't contribute that much, I personally don't believe it because I've seen the phosphorus levels rise," said Woroniuk. "We all need to take our responsibility and become part of the solution."
Gimli has done its part by building a water treatment plant just over a decade ago, the mayor added.
Last August, the federal and provincial government pledged $6 million each to help fund an $18 million expansion of Gimli's water treatment plant.
Still today, there remain parts of the municipality like Sandy Hook that rely on aging septic tanks. On Aug. 1, Sandy Hook Beach saw the highest peak of E. coli so far this summer at 3,957 E. coli organisms per 100 ml sample.
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