Blue-Green Algae, also known as cyanobacteria, can produce toxins that threaten
people and their pets. These algae are common in Burlington Bay, but generally
do not reach the high density, or bloom conditions necessary for toxin production.
However, north of Burlington Bay, in Missisquoi Bay there have been substantial
algal blooms and toxin concentrations have exceeded levels of concern.
Blue-green algae populations are closely monitored in Burlington Bay in the
summertime, and if bloom conditions develop, public health officials are
notified. Although there is no cause for alarm, it is important to be aware
of the possible effects that algal blooms can have on humans or animals.
What causes an Algal Bloom ?
The main cause of the algal bloom is an excess amount of phosphorus and other
nutrients in the water. These nutrients can come from several different sources,
sewage or wastewater discharges, and stormwater runoff that carries pet waste,
fertilizer, sediments, and other materials into the lake.
Blue-Green Algae Effects on Humans and Animals:
Some of the symptoms that can result from exposure to blue-green algae include
abdominal pain, rashes, and eye irritations. These symptoms are generally
not long lasting and usually go away within a week.
There has only been one reported death from algal toxins in the United States.
This dealth occurred in Wisconsin, and was the result of a highly unusual
exposure to an intense bloom in a farm pond.
Pets are at greater risk of getting seriously ill from algal toxins because
they will drink lake water even when it is very green. Dogs also commonly
lick their fur clean after swimming in the lake, and in the process can ingest
large quantities of harmful algae if a bloom is occurring.
What Should I do?
If the lake water looks green or blue-green, and there are visible accumulations
of algae, or scums at the surface, it is prudent to stay out of the water.
Because dogs will not avoid water on a hot day no matter what the condition,
it is important to keep your pets leashed and away from the water. If your
pet does take a swim, hose the animal off with fresh water when it comes
out of the lake and be sure not to let the animal lick itself clean.
If you have a camp that draws water directly from the lake, do not use the
water for drinking or bathing if there is visible algae in the water. Listen
to the news for any warnings about conditions in the lake. The Vermont Department
of Health can test your water for the presence of toxins in the event that
a bloom does occur.