Victoria, BC - The Do Not Consume Advisory for the Highland Drinking Water System remains in effect due to a toxin in St Mary Lake produced by a blue-green algal bloom.
Regulatory Limits for Microcystin
Currently, there are no Provincial or Federal regulations to guide health authorities about acute (daily) exposure limits for microcystin. The regulations provide only chronic (lifetime) exposure limits. Given that algal blooms are not usually long in duration (and in the absence of acute limits), Dr. Richard Stanwick, Chief Medical Health Officer, Vancouver Island Health Authority, advised the CRD to issue the Do Not Consume Advisory as a precaution until the toxin either disappeared or the treatment process was confirmed to consistently remove or destroy the toxin.
Use of Tap Water During the Advisory
Some residents have expressed concern about how to use their tap water during this advisory. Residents are advised not to consume the water (because ingestion is the primary problem) but can continue to use it for bathing, showering and brushing teeth. With the relatively low microcystin concentrations being observed in St Mary Lake and in the Highland Drinking Water System, this is consistent with information provided by Health Canada and the World Health Organization.
It is suggested that residents be cautious about information obtained from unofficial sites on the internet about algal toxins in drinking water. Often, that information does not identify the type of toxin or provide concentrations and worse case scenarios (such dramatic blooms in farm ponds or developing countries) are cited.
The latest lab results show that the microcystin level in St Mary Lake is declining.
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For additional information, please contact:
Ted Robbins, CRD Water Management 250-360-3061 Cell 250-217-908
Stewart Irwin, CRD Water Quality250-474-9603 Cell 250-727-5995