Health experts are warning against swimming and diving at Lake Bonney until further notice.
People at the Barmera Riverlands can still enjoy the lake by boating, fishing, canoeing and rowing, but are advised to take extra care not to ingest the water.
Most recent samples taken from Lake Bonney on Thursday 29 December showed elevated levels of potentially harmful blue green algae. Up until this test, unaffected parts of the lake, especially around the jetty, were deemed safe to swim in.
Direct contact with the water may cause local irritation to the skin, eyes, ears, nose and mouth and accidentally swallowing algae-affected water can lead to illness.
Anyone who has been swimming at Lake Bonney should closely monitor for symptoms - especially in children and pets.
These symptoms can include nausea, diarrhoea, vomiting and abdominal cramps.
About 1 in 10 people may also develop a rash or skin irritation, which usually goes away after washing the area.
If you have been in the water at Lake Bonney and you start feeling unwell, seek help. Consult with your GP and say you may have been exposed to blue green algae.
Pets are particularly vulnerable and should be kept out of the water. Algae may also stick to their fur, giving them a higher exposure.
Fish caught in the lake should be cleaned and gutted thoroughly before being eaten.
Algal blooms are naturally occurring, and appear during low rainfall, low water flows, and ongoing warm weather conditions.
Quotes attributable to SA Health Principal Water Quality Adviser, Dr David Cunliffe
The water in Lake Bonney has been tested regularly since blue green algae blooms were found last week.
If you're up in the Riverland, please don't swim or dive in Lake Bonney, don't drink the Lake water and keep your pets and kids well clear.
And if you are exposed, keep an eye on your health. If you start showing symptoms, make sure you get medical help.
We're continuing to monitor the Lake and test for algae levels, and will work with relevant agencies so that hopefully people can get back in the water soon.
