May 28, 2020 - A water sample taken last week has shown us that the algae bloom in Shawnigan Lake is a non-toxic bloom, and is due to extreme biodiversity of different types of algae present in the lake at this time. The presence of algae in the water is causing different taste and odour issues that many residents were experiencing or may continue to experience this week. In discussions with the microbiologist from the laboratory where the sample was tested, we learned that many lakes in BC are experiencing the same algae issues this time of year from the nutrient loading that results from early spring rains. Typically tastes and odours related to high algae levels only last a short period of time (one or two weeks), and we expect these aesthetic issues to dissipate very soon, if they haven’t already.
May 21, 2020 - We have received a number of inquiries from customers of the CVRDs Shawnigan Lake North water system regarding a metallic taste and odour associated with the drinking water which originates from Shawnigan Lake. We understand that many similar concerns have been expressed to other water utilities serving the Lake area and to Island Health.This type of problem has come up a number of times in summers in the past and has been determined to be the result of an algae bloom in the lake water.
A water sample has been taken by CVRD staff and sent to a lab for analysis. This will confirm the algae species involved. Results are expected in about a week.
In prior summers the primary algae present has been a brown algae which does not present any risk to health. Some customers have inquired whether the algae could be blue-green algae which may be toxic. Blue-green algae is favoured where the water is warm, shallow and rich in nutrients particularly phosphorus. Due to the high level of replacement of existing water with runoff occurring in Shawnigan Lake, these conditions are not prevalent. In the past lab testing of samples have shown only very low levels of blue-green algae constituting no risk to human health. So there is nothing to indicate the algae to be blue-green algae. However this is expected to be confirmed by the lab testing which will be made publicly available on our website and shared with Island Health.
There is no simple treatment such as boiling or filtering that would remove the toxins if the algae were blue-green algae. The only precaution would be to not drink the water until testing results are available.
Should you have any further questions please call the Engineering Services Department at 250-746-2530.