Lake Conditions—Part 2
Algal blooms are not only unsightly, but may contain cyanobacteria capable of producing toxins that in high concentration can kill animals and, depending on the concentration, can sicken people. Dogs, in particular, are vulnerable.
What is the recreational condition of our lakes?
EPA has just completed studies to find out. They measured the concentrations of:
- Microcystin, a toxic substance produced by algae
- Blue-green algae (cyanobacteria)
- Chlorophyll, the green pigment found in plants and algae
Here are the results for Minnesota, Wisconsin and nationally.
Microcystin appeared in 30 percent of the nation’s lakes measured in deep water and 50 percent of Minnesota lakes (but levels were very low). Minnesota independently found that near shore concentrations were higher than mid-lake samples. None of the lakes in the Upper Midwest had microcystin in the high or moderate risk range. However, both cyanobacteria and chlorophyll counts were present at moderate risk range. Minnesota and Wisconsin exceeded the national average for moderate risk from cyanobacteria.
I end with an anecdote. A veterinarian friend of mine told of a visit to a client’s sick dog who ran into a lake to drink water. In the process he lapped up blue-green toxin. My friend said he had never seen such a gruesome death in his life. In the space of just a few hours, blue-green algae, so tiny you’d need a microscope to see them, caused the death of an animal vastly larger in size.
Beware of pea-soupy lakes.