Although still open, both Marion Reservoir and Marion County Lake will be under blue-green algae warnings through this weekend and the Fourth of July holiday.

The reservoir has been under a warning for more than a month. The lake was under a less-serious watch last week but had been under a warning the week before.

Blue-green algae warnings are updated each Thursday afternoon.

Camping sites will remain available, and boat ramps will be open. However, beaches will be closed, and direct contact with lake water via swimming or skiing will be discouraged.

Anglers should limit water contact and thoroughly wash hands and arms in clean water after fishing or handling fish. Fillets are safe to eat if rinsed, but heads and organs should be discarded.

Public water supplies for Marion, Hillsboro, and Peabody all use Marion Reservoir as their source. However, treatment procedures were changed several years ago to make municipal water safe to consume even during algae blooms.

Blooms develop rapidly and may float around a lake. If there is scum or a paint-like surface, or the water appears bright green, a harmful bloom may be present.

Blue-green algae, technically known as cyanobacteria, come in several varieties, most of which release toxins when they die.

With some species, the toxins are mild irritants. With others, they are potentially fatal neurotoxins. The exact species in any bloom cannot immediately be determined.

While no humans have died in Kansas during blue-green algae blooms, many dogs have died, and human illnesses have been reported.

Symptoms in humans include sore throat, congestion, cough, wheezing, difficulty breathing, itchy or red skin, blistering, hives or other rashes, earache, agitation, headache, abdominal pain, diarrhea, vomiting, and eye irritation.