Warm sunny days can lead to algae blooms in South Sound lakes. Blue-green algae reproduce rapidly when the combination of sunlight, temperature and nutrients are right. Within a few days a clear lake, pond or ditch can become cloudy with algae growth. This is an algae bloom. At times, the algae will float to the surface and can form thick scum near the shoreline.
If you visit a lake and notice a bright green color or thick scum along the shore, stay out of the water. Some blue-green algae produce toxins that can cause illness in humans and kill pets, fish, and other animals.
When an algae bloom is occurring in a lake, take these simple precautions:
If the water looks bad, dont swim in it. Find another place to swim. If your water supply is lake water, use an alternate supply. Boiling and algicides are not effective treatments.
Keep children, pets, and livestock away from the water. Pets are the most susceptible to algae-related illness because they tend to both drink water and then lick the scum off their fur or paws. Children are also vulnerable because they have less body weight and may accidentally swallow more water than adults. Get proper medical or veterinary attention right away if you, your children, pets, or livestock have signs of poisoning. Blue-green algae can produce nerve toxins and liver toxins. Signs of neurotoxin poisoning usually appear within 15-20 minutes after ingestion. In animals, signs include weakness, staggering, difficulty breathing, convulsions and death. In people, signs may include numbness of the lips, tingling in fingers and toes, and dizziness. Algae can also cause skin rashes. It may be hours or days before signs of liver poisoning appear. Liver toxins can cause abdominal pain, diarrhea and vomiting in humans, and death in animals. Some activities are OK in lakes with algae blooms. Boating is fine, but avoid areas where algae is visible. Rinse boats and trailers before going to another lake. On lakes with severe algae blooms, it is best to practice catch and release when fishing, since a recent state Department of Ecology study has shown that algae toxin can accumulate in fish tissue. Remember to wash your hands after fishing.
Determining if a bloom is toxic requires special testing. Moreover, testing only provides information on that single sample, at a particular moment of time. Even the scientific experts have not yet solved the mystery of why, when, and how algae turn toxic. In other words, there is no way to predict when, or if, an algae bloom will be toxic. If the water at your favorite beach looks bad, dont swim in it.
For current information on lake closures, check the Thurston County Public Health and Social Services Department website at www.co.thurston.wa.us/health/ehadm/swimming/swimming_index.html. To report an algae bloom, call 360-867-2626, (TDD line 360- 867-2603).
Dr. Diana T. Yu is the Health Officer for Thurston and Mason counties. Reach her at 360-867-2501 or firstname.lastname@example.org or @yu4health on Twitter.