FACT SHEET ON CYANOBACTERIA (“BLUE-GREEN” ALGAE) BLOOMS IN BURLINGTON

FACT SHEET ON CYANOBACTERIA (“BLUE-GREEN” ALGAE) BLOOMS IN BURLINGTON

Yesterday (7/12/21), Burlington Parks, Recreation & Waterfront saw visual indications of cyanobacteria at multiple beaches, resulting in closures. Given understandable public concern and interest in the state of our beaches and water infrastructure, we want to offer some information on “algae-blooms.”

CYANOBACTERIA (“BLUE-GREEN” ALGAE) BLOOM CLOSURES

• Parks, Recreation and Waterfront conducts visual inspections of the beaches everyday during recreation season
• Upon the presence of cyanobacteria (“blue-green algae”), a beach will be closed
• Beaches are re-opened when there is no longer a physical presence of cyanobacteria and an on-site toxin screening is negative.

PUBLIC HEALTH & BLOOMS

• You and your pets should avoid the water when there is presence of cyanobacteria.
• The City’s drinking water intake is ~ 2500’ off shore and 30’ below the water surface – an area where blooms are less likely to occur.
• As part of a cyanotoxin monitoring program through the Department of Health, the City’s Raw and Finished Drinking Water are screened weekly for microcystin, one of the toxins that can be associated with cyanobacteria blooms. Vermont’s action level (0.16 micrograms/liter) is more stringent than the EPA’s threshold of 0.30 micrograms/liter.  
• For more information, please visit the Vermont Department of Health cyanobacteria site at https://www.healthvermont.gov/health-environment/recreational-water/cyanobacteria-blue-green-algae

CITY INFRASTRUCTURE & BLOOMS

• We understand the public’s concern about these blooms
• Burlington has had no Combined Sewer Overflows (CSO) so far in 2021, even in light of some recent heavy downpours. The current health of our wastewater & stormwater system is attributable to major upgrades completed in 2021 at all 3 wastewater treatment plants and an abundance of green infrastructure projects that have reduced combined sewer stormwater inputs over recent years. There is more to come to build an even more resilient system.
• While we continue to work on reducing CSOs in order to minimize bacteria inputs into the Lake, acute CSO’s alone have not significantly increased the input of bloom-causing nutrients into Lake Champlain.
• Blooms are a longer term challenge all of the Lake Champlain Basin must work through, and are the result of long-term, wide scale nutrient inputs from all land use sectors. Wastewater sources account for approximately 3-6% of this load.

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13 July 2021