June 30, 2006
As of June 28, recreational water quality was excellent at all beaches monitored by Manitoba Water Stewardship including beaches on Lake Winnipeg, Lake Manitoba, Lake Dauphin, in the Whiteshell and Birds Hill areas, and others.
On Lake Winnipeg, water quality is presently within recreational water quality guidelines at all 18 beaches monitored including Victoria (at the beach and the Red Cross dock) Albert, Hillside, Lester, West Grand, East Grand, Patricia, Grindstone, Black Point, Gull Harbour, Sandy Bar, Hnausa, Spruce Sands, Gimli, Sandy Hook, Winnipeg and Matlock beaches.
Levels of Escherichia coli (E. coli) bacteria were briefly above the recreational water quality guideline at Winnipeg Beach on June 26 but quickly returned to below guidelines by June 28. Exceedance of the guideline of 200 E. coli/100 ml was likely caused by weather conditions when high winds and waves led to bacteria being washed out of beach sand and into the water. On Lake Winnipeg, weather and lake level information appear to be good predictors of E. coli bacteria levels. Strong northerly winds that cause waves and push water levels higher tend to cause E. coli bacteria levels to increase. When calmer weather returns, E. coli bacteria levels typically fall quickly to below guideline levels.
Results for all beaches across Manitoba are posted as they become available on Manitoba Water Stewardship’s website at http://www.gov.mb.ca/waterstewardship.
Extensive sampling for E. coli in beach sand and water on Lake Winnipeg is underway again this year and follows from the work done in 2003, 2004 and 2005.
Extensive research has shown that wet sand underlying a number of Lake Winnipeg beaches contains E. coli bacteria that can be washed into beach water when water levels rise and flood beaches.
Advanced testing known as DNA ribotyping is being used to identify sources of contamination. Results over the last several years indicate that approximately 50 per cent of the sand and water samples could be attributed to shorebirds and geese, while 36 per cent of the samples could not be matched to a source. Only seven per cent of the samples could be attributed to human activity.
Recent studies of Lake Winnipeg beaches indicate that levels of E. coli bacteria can fluctuate daily and that elevated levels are typically short term and quickly fall back below guideline levels. Although the risk of illness is small, advisory signs help to remind bathers of additional precautions they can follow to reduce the risk of bather-related illness at beaches where E. coli levels fluctuate regularly. Since bacteria levels can fluctuate daily, the advisory signs will remain posted for the duration of the summer.
Advisory signs were posted at Winnipeg Beach on June 28 and at Hnausa, Spruce Sands and Sandy Bar beaches on June 2.
Most swimmers will not become ill when E. coli bacteria levels are elevated above the recreational water quality guideline. However, the possibility of illness increases with rising levels of bacteria.
Manitobans can safely enjoy the province’s plentiful beaches and are advised to keep a few things in mind when at the beach:
- avoid swallowing lake water when playing or swimming;
- wash your hands before handling food;
- avoid swimming with an open cut or wound, or if you’re experiencing illness; and
- reduce exposure to the lake water if water levels are high and the wind is coming from the north.
Algae Blooms
An algae bloom was noted in Pelican Lake on June 16. The concentration of an algae toxin, microcystin-LR, was above Manitoba’s proposed recreational water quality guideline of 16 micrograms per litre. In the meantime, the algae bloom has dissipated and the lake has been re-sampled to determine the current concentration of microcystin-LR. Results are pending, but it is expected the concentration of microcystin-LR will be well below the recreational water quality guideline.
An algae bloom was also noted on June 27 at Killarney Lake. The bloom had dissipated by June 29. While toxin levels are expected to be below the recreational water quality guideline, microcystin-LR results are pending.
Algae are a sign of a healthy lake since they provide food and oxygen for many aquatic life forms. However, too much algae will form floating clumps or scums, and can cause water-quality problems for drinking water and recreation. During bloom conditions, the water sometimes looks like thick pea soup and may emit a strong, unpleasant odour.
Algae blooms can contain toxins that can be harmful to the liver or nervous system if large amounts of water are ingested. Drinking water containing algae can also cause an upset stomach and diarrhea, and external exposure to algae blooms has been reported to cause skin irritation.
In the absence of a severe algal bloom, recreational activities are considered safe. However, if large amounts of green scum are visible in the water, it is advisable to:
- avoid swimming or other contact with the water;
- not drink the water – boiling or chlorination will not make the water safe;
- prevent pets and livestock from drinking along the shoreline; and
- not eat fish from the lake that appear unhealthy
The City of Winnipeg’s public drinking water supply is routinely monitored for the presence of microcystin-LR. Over the past several years, microcystin-LR has not been detected by the City of Winnipeg.
Manitobans should be aware that summer is the most common time of year for algae blooms on Manitoba beaches. Optimum circumstances for algae growth include clear and calm water conditions and warmer temperatures.
Beach Safety
One of the most important things to think about when enjoying Manitoba’s beaches is safety. A safety tip to remember is to know your swimming limitations and stay within them. Don’t try to keep up with more experienced or stronger swimmers.
Lake Winnipeg Facts
On average, Lake Winnipeg is about 12 metres deep but at a point off the northeast shore of Black Island, the lake reaches its maximum depth of about 36 metres.
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