Water polution - blue-green algae

What are blue-green algae?

Though often referred to as algae, blue-green algae are not algae at all, but types of bacteria called cyanobacteria. They are normally present in bodies of water. This type of bacteria thrives in warm, nutrient-rich water. When conditions are right, the blue-green algae can grow quickly forming “blooms.” Certain varieties of blue-green algae can produce toxins that are linked to illness in humans and animals.

What do blue-green algal blooms look like?

Blue-green algal blooms are often described as looking like pea soup or spilled green paint. However, blooms aren’t always large and dense and can sometimes cover small portions of the lake with little visible algae present. Blooms can also produce a swampy odor when the cells break down.

What are harmful algal blooms?

Blue-green algae blooms are harmful when they produce toxins that can make humans and animals sick. Most blooms are not harmful. You can't tell by looking at a bloom if it is harmful or not.

When do harmful algal blooms occur?

Blue-green algae prefer warm, calm, sunny weather and water temperatures higher than 75°F. Blooms usually occur during summer and early fall, but can occur other times of the year, if conditions are right. 

What are the possible health effects?

You can become sick if you swallow, have skin contact with, or breathe in airborne water droplets while swimming, boating, waterskiing, tubing, bathing, or showering in water that has harmful algae or if you drink water that contains algal toxins. If you become sick, you might experience vomiting, diarrhea, rash, eye irritation, cough, sore throat, and headache. Symptoms generally begin hours to two days after exposure.