- Skip Navigation

Note: This message is displayed if (1) your browser is not standards-compliant or (2) you have you disabled CSS. Read our Policies for more information.

Addressing Concerns About Blue-Green Algae

July 23, 2010: State Reports High Levels of Blue-Green Algae at Reservoirs and Lakes July 23, 2010: State Reports High Levels of Blue-Green Algae at Reservoirs and Lakes

INDIANAPOLIS-The Indiana State Department of Health cautions Hoosiers of possible high levels of blue-green algae, also known as Cyanobacteria, at many of Indiana's reservoirs and lakes.

Blue-green algae are organisms that grow and live in brackish or fresh waters. They can grow quickly and can increase in abundance with increased temperature, sunlight, and nutrients. Blue-green algae gets its name because of the visual appearance of the water as they live near the surface of rivers, streams, lakes and reservoirs.

"We recommend people use caution when swimming, skiing, or participating in other recreational water activities," said Jennifer House, DVM, veterinary epidemiologist at the Indiana State Department of Health. "Avoid coming into direct contact with the algae and try to avoid swallowing water if at all possible."

Exposure to a blue-green algae during recreational activities such as swimming, wading, and water-skiing can lead to rashes, skin, eye irritation, and other uncomfortable effects such as nausea, stomach aches, and tingling in fingers and toes.

Currently, there are nine reservoirs throughout the state being monitored for blue-green algae. At this time, the majority of the reservoirs that are being tested do have algae levels above that which would be considered high enough for the probability of causing health effects.

While there are no U.S. standards regulating algal cell counts, the World Health Organization designates risk categories for recreational contact with water. At present, standard water treatments prevent algal toxins from affecting drinking water, but it may adversely impact recreational users of the reservoir, like swimmers, tubers, and jet skiers who have skin contact or may swallow large amounts of untreated water.

As every lake, river or other type of waterbody in the state cannot be tested, all swimmers and boaters should be careful in all recreational waters during this time of the year. Precautionary measures include avoiding contact with visible algae and swallowing water while swimming.

Dr. House says it is always a good idea to take a bath or shower with warm, soapy water after coming in contact with untreated water in ponds and lakes, especially before preparing or consuming food. She also recommends people never drink, cook, or shower with untreated water from lakes, ponds, or streams. Pets and livestock should also not be allowed to swim in or drink untreated water from these sources. If you should experience any symptoms after water recreational activities, please contact your doctor.

For more information and testing results on the locations that have been sampled, please visit the Web site,