Lake near Waverly supporting potentially toxic algae

The problem in the lake was discovered last summer when two blue-green algae blooms were detected. Avenue of the Saints Lake is adjacent to U.S. Highway 218 and managed by the Bremer County Conservation Board.

The blooms are the result of flooding in previous years, according to the conservation district. High water deposited nutrient-rich sediment, which accelerated algae growth.

Blue-green algae is a common, free-floating plankton that exists in nearly all surface water impoundments, according to officials. The algae grows in warm water rich with nutrients such as phosphorus or nitrogen. If environmental conditions are right, the cyanobacteria can spread quickly and form blooms that look like a layer of scum on the water's surface.

In Iowa, blue-green algae blooms usually appear in June and could last until October.

Some blue-green algae produce a toxin after dying, which can produce allergic reactions in some people. Consequently, officials are urging caution for those using Avenue of the Saints Lake.

Skin-to-water contact with a moderate concentration of toxin may result in a rash and itching. Ingesting water with a high concentration could result in stomach cramps, vomiting, diarrhea, fever, headache and muscle or joint pain. If those symptoms appear, contact a physician.

Animals that consume large quantities of blue-green algae may become extremely ill and could die.

The algae does not kill fish or affect the flesh of fish. The World Health Organization, however, does advise eating fish in moderation taken from waters where blue-green algae blooms and avoiding the fish's liver and kidney, where toxins accumulate.

Authorities will monitor the lake throughout the summer, but they say no feasible way exists to control the algae blooms.

A multi-agency program is under way to reduce the amount of nutrients entering the lake. However, a significant amount of time is required to reduce nutrient concentrations, and existing sediment may act as a reservoir food source for the cyanobacteria.

For information, call the Bremer County Soil and Water Conservation District at (319) 353-4037 ext. 3.