Monday 10 May 2021Media release3 minutes to read
Canterbury DHB’s Community and Public Health unit has issued a health warning for the Cust Main Drain at Skewbridge Road.
The warning follows a high cover of potentially toxic algae (benthic cyanobacteria), as well as detaching mats, being found in the Cust Main Drain.
People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.
People are advised to treat every low-flowing river cautiously, check for the presence of benthic cyanobacteria and avoid contact.
Dr Cheryl Brunton, Canterbury Medical Officer of Health, says the algae look like dark brown to black mats and can produce toxins harmful to people and animals.
“Gathering of mahinga kai such as watercress/pūwhā should be avoided as exposure to the algae may cause skin rashes, nausea, stomach cramps, tingling and numbness around the mouth and fingertips.
“If you experience any of these symptoms, visit your doctor immediately, also let them know if you’ve had contact with dark brown/black algal mats or water in this area,” Dr Brunton says.
Pets that show signs of illness after coming into contact with algal mats should be taken to a vet immediately.
People and animals should remain out of the waterways until the warnings have been lifted.
Environment Canterbury is monitoring the sites and the public will be advised of any changes in water quality.
Facts about cyanobacteria:
For further information visit
Or contact Community and Public Health on (03) 364 1777:
For more information about Mahinga Kai:
Page last updated: 19 August 2021
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