The Grant County Health District reported Tuesday that toxic blue-green algae has been found in Potholes Reservoir near the Lind-Coulee boat launch and the Job Corps dike.
Warning signs have been posted on the shoreline recommending that park visitors avoid drinking lake water, swimming, wading and other water activities.
Pets also should be stopped from drinking or having contact with the water.
Fish caught in the reservoir should be well-cleaned and the guts discarded.
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When boating, avoid areas where algae scum is floating.
The toxic blooms are made up of a bacteria that grows rapidly in fresh water, sunlight and high temperatures. Blue-green algae is common in Grant County waters in summer and fall. Not all blue-green blooms are toxic, but some produce poisons that can cause serious illness.
People who come into contact with toxic blooms can experience symptoms including numb lips, tingling fingers and toes, dizziness, stomach pain, diarrhea, vomiting and skin rashes. Anyone experiencing these symptoms after being in contact with the water should seek immediate medical treatment.
Pets that come into contact with toxic algae might suddenly become sick or die.
Signs of toxic blue-green algae include the appearance of greenish or bluish paint floating on the water's surface and large numbers of dead fish, birds or other animals.
Anyone who sees algae can report it to the health district's Ephrata office at 754-6060.