A WARNING for people to avoid contact with water in the Mindarie marina remains in place.
The Department of Health issued the advice on December 16 after testing of the water revealed it contained red tide algae, which can cause a red or brown discolouration and surface scum in the water.
Environmental health acting director Stan Goodchild said the algal bloom had not dissipated, so recreational activities including swimming, kayaking, fishing and crabbing in the waters should be avoided.
Pets should also be kept away.
Mr Goodchild said contact with the algae could cause skin irritation, possibly leading to severe dermatitis, and ingestion of affected water may cause severe illness and liver damage.
“Anyone who comes in contact with algal scum should rinse it off with clean water and seek medical attention if they feel unwell,” he said.
“Further samples will be taken early in the new year by the Department of Water for testing.”
The City of Wanneroo will oversee and maintain installation of standard health warning signage around the marina and collect a water sample once the visual appearance of the bloom disappears.
Signage will remain in place until sampling shows no potential health effects.
Marina director of operations David Bornmann previously said stand-up paddleboard and flyboarding activities would not operate while the water was affected.