The Minnesota Pollution Control Agency is asking swimmers to be aware of algae-ridden lakes and foul-smelling water this holiday weekend after toxins from the blue-green blooms hospitalized a child and killed two dogs near Alexandria, Minn., last month.
Although not all algae are harmful, poisonous blooms typically look like pea soup, green paint or floating mats of scum. Officials warn that the clusters often emit a strong stench like cow manure.
"With the intermittent periods of rain, followed by high temperatures, blue-green algal blooms will be common on many lakes throughout Minnesota for the remainder of this summer," Steve Heiskary, an MPCA scientist, said in a statement.
A young boy was swimming in Alexandria's Lake Henry in June when he was exposed to the noxious plant and hospitalized, said MPCA's Detroit Lakes spokesman Dan Olson. Researchers took samples of the water a few days later, confirming the presence of the dangerous blue-green algae. The boy made a full recovery.
Before the Lake Henry beach opened for the season, "water advisory" signs were hung in the swimming area warning visitors to stay away if the water looks like spilled green paint.
Olson said it's difficult to say whether there are more outbreaks of the blooms this summer compared to previous years because Minnesota lakes are not regularly tested for it.
Blue-green algae forms when extra nutrients like phosphorus seep into bodies of water — often as a result of agricultural practices. In most cases, the blooms are "self-limiting due to weather conditions and don't persist," Olson said, adding that algae regularly disperse in wind and lower temperatures. Conditions change so quickly that it's difficult to track an outbreak, which is why officials urge vacationers to be wary.
Olson said the Lake Henry incident is the first case of human exposure he's heard of.
