Toxic algae scare in Ashley River
People are being told to avoid North Canterbury's Ashley River after potentially toxic blue-green algae were found in the water.
The Canterbury District Health Board today issued a health warning after the algae, known as benthic cyanobacteria, were found in the river.
Humans and animals, especially dogs, should avoid the river upstream of State Highway 1 until the health warning is lifted.
Canterbury medical officer of health Ramon Pink said the algae looked like dark brown or black mats and could produce toxins harmful to people and animals.
The algae occur naturally but could increase rapidly during warm weather.
Exposure to the algae could cause skin rashes, nausea, stomach cramps, and tingling and numbness about the mouth and fingertips.
Anyone who experienced such symptoms should visit their doctor immediately, Pink said.
Reticulated town water supplies were safe, but no-one should drink water from the river at any time.
"Even after boiling the water from the river, it does not remove the toxin and therefore should not be consumed," he said.
Animals that came into contact with the contaminated river should be taken to a vet immediately.
Environment Canterbury would monitor the site and advise of any changes in water quality, he said.