A blue-green algae bloom has caused an advisory to be issued for Pine Lake.The advisory from Alberta Health Services was issued on Aug. 21 and is still in effect. It suggests people take the precautions of not drinking the lake water, to avoid swimming or wading in it and to not touch any algae along the shoreline. The same is suggested for children and animals.“When we issue an advisory we do so because there's a lot of algae in the lake and the algae's producing a toxin that can be harmful,” said Dr. Deena Hinshaw, a medical officer of health for the central zone with AHS.The advisory said contact or ingesting water with toxins in it could result in skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea and vomiting and/or diarrhea. The symptoms usually appear within one to three hours and are gone within one to two days according to the advisory.Rebecca Rooney, a research associate at the University of Alberta in the Department of Biological Sciences, said high levels of exposure over a short period of time can lead to liver problems, but low levels of exposure over a long time carry their own dangers.“It's a suspected cancer agent,” Rooney said. Rooney was one of the authors on a recent paper about high microcystin concentrations only occurring when the nitrogen-to-phosphorus rate is low in nutrient rich Canadian lakes, in the September issue of the Canadian Journal of Fisheries and Aquatic Sciences. Samples from Pine Lake were included in the study but the specific microcystin levels weren't identified in the paper.Rooney explained microcystins are the toxins produced by some kinds of blue-green algae.She said there's some uncertainty over what causes some blue-green algae to produce the toxins.“We suspect it's related to environmental triggers,” she said, adding there are lots of theories as to what those environmental triggers are.Blue-green algae blooms are triggered when the nitrogen-to-phosphorus level is low. She said the algae thrive on more phosphorus in the water because they can take nitrogen out of the air.Rooney explained that nutrients that get into the water from things like fertilizer help cause the algae to bloom.“This is a problem across Canada and a bit more in the prairies,” she said. She said there's more nutrients in the soil and more farming in general across the prairies.She and Hinshaw both emphasized that in general water stewardship can help prevent algae blooms. Examples given include farmers ensuring fertilizer doesn't run off and cottage owners and other lake users making sure human waste products don't end up in the water.“These are the kinds of things that can be done to try and prevent the algae in the first place,” Hinshaw said.Rooney said World Health Organization guidelines suggest drinking water only if the microcystin rate is one microgram per litre or below. She said the Canadian guideline for swimming in the water is 20 micrograms of microcystins per litre or less.Hinshaw said the advisory will likely remain in place until the end of the season. She said even once the algae disappears, the toxins remain in the water for some time.Boiling the water won't remove the toxins either, Hinshaw said.
