Impacts of Blue Green Algae on Human Health

Blue green algae, or cyanobacteria, occur naturally in lakes and streams. These microscopic organisms can grow abundantly in warm, shallow water with plenty of sunlight. The water often becomes discolored with rafts of floating algae visible on the surface. The State of Delaware, however, advises that blue green algae toxins have been found in waters with no visible disturbances. Thus, people should be aware of the health effects associated with this algae and take necessary precautions.

Effects from Inhalation

• According to the New York Department of Health, people are at risk for inhaling airborne blue green algae while swimming, bathing or showering in contaminated water. Water recreational activities such as jet skiing, canoeing and sailing also put people at risk for inhalation exposure. Governmental reports across the nation, including from California, New York and Delaware, show that people who have inhaled blue green algae-laden water have experienced asthma- and flu-like symptoms. These symptoms include runny nose, hives, watery eyes and sore throat. Skin irritation and respiratory tract inflammation may also occur.

Ingestion Effects

• Water ingestion during swimming, diving and recreational sports activities puts people at high risk of exposure to blue green algae toxins. This same risk exists when people wash their dishes in or ingest untreated surface water and consume fish or shellfish from contaminated bodies of water. Adverse effects of such exposure include gastrointestinal upsets, experienced as diarrhea, nausea, vomiting and abdominal pain. The potential for severe systemic effects also exists, and David Stone and William Bress of the Oregon State Public Health Department and Vermont Department of Health state people have previously suffered liver failure, neurologic damage and death after blue green algae ingestion. Kidney damage may occur as well.

Dermal Impacts

• According to the Oregon State Public Health Department, skin reaction is one of the most common effects from blue green algae exposure. The risks for this exposure are moderate and exist primarily during canoeing, rowing, sailing and kayaking. Dermal exposure may also occur during fishing. Allergic effects could ensue, particularly in the form of skin rashes and blisters where contact was made. If a person touches her eyes or mouth after contact with blue green algae, vision disturbances or blisters may form in those areas as well.

Unconfirmed Effects

• According to the New York Department of Health, little information is known about the health effects of continued exposure to low levels of blue green algae. Long-term drinking of untreated surface waters with blue green algae may lead to increased risks of liver cancer. This relationship, however, is not yet confirmed. Some people may also be particularly sensitive to even minute concentrations of blue green algae, experiencing mild symptoms similar to allergic reactions. Those symptoms include skin, eye and throat irritation.

Ways to Avoid Exposure

• People can take measures to reduce their risks of exposure to blue green algae. The California Department of Public Health, for example, recommends that people avoid drinking any untreated sources of water. This can also protect people from exposure to other microbes that may negatively impact health. The best way to minimize recreational risks is to avoid body contact with blooms of blue green algae. Parents are advised to take particular caution with children, as their small body weight may put them at greater risk for adverse health effects. Pets should also be kept from water contaminated by blue green algae.