For Immediate Release
Friday, July 18, 2025 | 5:00 p.m. | Windsor-Essex County
The Windsor-Essex County Health Unit (WECHU) is issuing a precautionary notice to residents based on initial laboratory results of a blue-green algae bloom in the Ruscom River in the area of Trepanier Road and Lakeshore Road 129. While initial chemical analysis does not show the presence of Microcystin related toxins within the samples collected, toxicity may increase due to the algae identified in the bloom. Residents on the municipal drinking water system can continue to drink the water. Routine water testing is done by the municipal water treatment plant and at this time there are no concerns.
Blue-green algae (cyanobacteria) are microscopic organisms that occur naturally in freshwater lakes, ponds, rivers and streams in the late summer and early fall. They are usually present in low numbers but can rapidly increase in warm, shallow, undisturbed surface water that gets a lot of sun. When this happens, they can form blooms that discolour the water or produce floating scum on the surface of the water. These blooms can make the water appear bluish-green, can form solid looking clumps, and may contain toxins, called microcystins, that can be dangerous to human and animal health.
Contact with microcystins can produce negative health effects in humans such as skin and eye irritations and if ingested can lead to headaches, fever, diarrhea, abdominal pain, nausea, and vomiting.
“As a reminder, wind and water conditions may move the blue-green algae bloom towards other areas. Residents and visitors are urged to take a cautious approach and protect themselves, their children, and their pets from potential health risks,” says Dr. Aloosh, Medical Officer of Health, Windsor-Essex County Health Unit.
Residents that use wells or cisterns that draw water directly from the Ruscom River in the area of Trepanier Road and Lakeshore Road 129 (such as private cottages with wells) are advised not to drink the water unless they are routinely testing for microcystins using a licensed lab and results show levels less than 1.5 ppb.
For more information on blue-green algae blooms, please visit the Health Unit website at https://www.wechu.org/drinking-water-small-drinking-water-systems-beaches/blue-green-algae-bloom.