August 04, 2006
As of Aug. 2, recreational water quality was excellent at all beaches monitored by Manitoba Water Stewardship including beaches on Lake Winnipeg, Lake Manitoba, 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 (Beach and 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 above the recreational water quality guideline at West Grand Beach and Gimli Beach on July 28 but quickly returned to below guidelines. 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.
Levels of E. coli bacteria were also above the recreational water quality guideline at Lynch’s Point on Lake Manitoba on July 28 but returned to below guidelines by Aug. 1. Historically, elevated levels of E. coli bacteria have occasionally been observed at Lynch’s Point but 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 humans.
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 Gimli Beach on July 30, at Oak Lake, Pelican Lake (South Beach) and Lynch’s Point on July 29, at West Grand Beach on July 1, at Winnipeg Beach on June 28, at East Grand Beach on June 7, 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 swimming with an open cut or wound, or if you’re experiencing illness;-
stay away from the water if you are experiencing digestive or intestinal problems;-
avoid swallowing lake water when playing or swimming;-
wash your hands before handling food; and-
on Lake Winnipeg, reduce exposure to the lake water if water levels are high and the wind is coming from the north.Algae Blooms
On Lake Winnipeg, algae blooms were noted at Grindstone, Gull Harbour, Sandy Hook, Hillside and Victoria (Red Cross Dock) beaches on July 31. The concentration of an algae toxin, microcystin-LR, was well below Manitoba’s proposed recreational water quality guideline of 16 micrograms per litre at all five beaches.
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 produce 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.
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. Ensure that young children and weaker swimmers wear a properly-sized lifejacket or personal floatation device. But remember, a lifejacket or personal floatation device is not a replacement for supervision.
Lake Winnipeg Facts
During the week of July 27 to Aug. 2, staff from Manitoba Water Stewardship participated in the science cruise of The Namao on Lake Winnipeg. Staff collected water samples from the north basin of Lake Winnipeg and while some algae blooms were observed, concentrations of an algae toxin, microcystin-LR, were below detection.
- 30 -