Toxic algae mats found earlier than usual in Taranaki rivers

• Exposed mats of potentially toxic cyanobacteria have been found in four rivers
• The mats are a health risk for both humans and pets
• Contaminated water may cause nausea, vomiting, diarrhoea and abdominal pain
• In serious cases it can cause liver or kidney damage

Taranaki residents are being urged to be cautious around rivers, after potentially toxic cyanobacteria was detected earlier in the season than usual.

Taranaki Regional Council found exposed mats of cyanobacteria in four rivers - the Manganui, Waingongoro, Kaupokonui and Waiwhakaiho Rivers - raising health concerns for both swimmers and pets.

Cyanobacteria, also known as blue-green algae, is a naturally occurring algae that often grows in rivers on rocks as thick brown or black mats.

It has the potential to release toxins that can pose significant health risks to both humans and animals.

When these mats become exposed on the edges of rivers, they can have a distinctive, unpleasant smell, often described as musty or swampy.

If people saw these mats, it was safest to stay out of the water and keep a close eye on children and pets, Water quality scientist Angela Collins said.

"Children are at greater risk because their smaller body size means they need to ingest less toxin to become seriously ill, while dogs may be attracted to the musty smell.

"This is earlier than we typically expect to find cyanobacteria in our rivers and is likely due to the drier winter we had - heavy rainfall and high water flow help to flush cyanobacteria."

The council was closely monitoring cyanobacteria levels at selected rivers and lakes as part of its Can I Swim Here? programme, which began this week and will run until March.

"As we kick off the programme, we want to remind the public of the risks posed by cyanobacteria and encourage everyone to be mindful when planning a swim - especially in the rivers where we've found the mats," Collins said.

Alongside cyanobacteria, water is tested for E. coli at freshwater sites and enterococci at coastal sites, both of which were indicators of possible faecal contamination.

Any time water didn't look or smell right, it was safest to stay out, Collins said.

If members of the public come into contact with water contaminated with cyanobacteria, they were advised to wash it off with clean water as soon as possible.

If ingested, contaminated water may cause nausea, vomiting, diarrhoea, abdominal pain and, in more serious cases, liver or kidney damage.

If members of the public experience any of these symptoms, they should contact their doctor immediately.

District councils were responsible for warning signage at swim spots and Te Whatu Ora Health New Zealand was responsible for decisions on when to issue public health warnings.

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