Idaho has many beautiful lakes and reservoirs where you can fish, boat, and swim. Most of the year these bodies of water are safe to enjoy. However, when water temperatures rise and the right type of nutrients are available, some bodies of water can produce harmful algal blooms. These can pose health risks to humans, pets, livestock, and wildlife.
What is a harmful algal bloom?
They are actually bacteria (not algae) that can produce toxins. When weather conditions are calm and there is an increase in water temperature and nutrients, they can rapidly increase in number and produce a bloom. Blooms can occur at any time, but they most often occur in late summer or early fall.
What do these blooms look like?
Harmful algal blooms can be blue, bright green, brown, or red and may look like paint or anti-freeze floating on the water. As the bloom matures, it may look like foam, scum, or mats on the surface of freshwater lakes and ponds. If you or pets or livestock swim in or drink from water that contains a bloom, the effects can be dangerous.
What are the symptoms of an exposure to a harmful algal bloom?
The most common effects are skin and eye irritation. Other more severe effects can include:
- Difficulty breathing
- Stomach pain
- Nausea
- Vomiting
- Diarrhea
- Dizziness
- Numbness and tingling in lips, fingers, and toes
If you experience mild irritation, rinse with clean water immediately. If you experience severe symptoms, you should seek medical attention.
Are the symptoms the same for animals?
Pets and livestock exposed to HABs may exhibit symptoms and conditions such as:
- Weakness
- Staggering
- Foaming at the mouth
- Difficulty breathing
- Convulsions/seizures
If your pet comes in contact with a bloom, rinse them with clean, fresh water immediately. If severe symptoms occur, call a veterinarian. In severe cases, animals may die within minutes and up to several hours after they have been exposed to harmful algal blooms. When harmful algal blooms decompose, they can also kill fish that live in the water.
How can a person reduce the risk of exposure?
- Do not go in or near water that has an unusual color, and keep children, pets, and livestock out of the water.
- Avoid any water sports such as swimming, diving, water skiing, or boating in areas with HABs.
- Do not use untreated water for drinking, bathing, cleaning, or cooking. Boiling water that has been contaminated by a HAB will not remove toxins, and it may actually cause more toxins to be released.
- Remember: “When in doubt, stay out.”
Is it safe to fish in water affected by a harmful algal bloom?
There have been no reports of people becoming sick from eating fish caught during a bloom. Information about the risk of eating fish from affected waters is limited. Even so, some studies suggest that fish fillets are less likely to contain toxins than other parts of the fish. If you decide to eat fish from affected waters:
- Remove the skin, organs, and fatty deposits from the fish
- Be careful not to cut into the organs
- Rinse the fillets with clean water before cooking
- Limit the consumption of these fish to no more than two 8-oz fillets per week
A Closer Look at Your Health airs weekly on KBOI Newsradio 670-AM in Boise Tuesday mornings at 6:50 a.m. This is a transcript of the Aug. 8, 2017 program.
Resources:
- FAQ on Harmful Algal Blooms: http://healthandwelfare.idaho.gov/Health/EnvironmentalHealth/HarmfulAlgalBlooms/tabid/2174/Default.aspx
- Location of current HAB advisories in Idaho: http://www.deq.idaho.gov/water-quality/surface-water/recreation-health-advisories/
- Information from the Centers for Disease Control and Prevention: https://www.cdc.gov/habs/index.html
- Report and view HABs near you:http://cyanos.org/bloomwatch/
DHW Voice 