Toxins persisting in Waipoua River

WAIRARAPA NEWS

It is hoped the latest flush of rain will wash out toxic algal mats in the Waipoua River.

Regional council and district council staff are keeping warning signs up after they found persistent algal mats, with more expected warm weather on the way.

Greater Wellington environmental scientist Summer Warr said warnings will stay in place until the next check.

"There was actually still quite a lot of algae around after that fresh so the signs were left up," she says.

They had someone check the situation on Monday, but the water was too high to see if there was any algae left.

Henley Lake dog walkers are also being warned not to let their dogs off their leads around the lake until Masterton District Council advises it is safe to do so.

This follows the discovery of potentially deadly toxins related to the decay of algal bloom, says parks and recreation manager Grant Hathaway.

"A health warning was issued today and signs have been put up at the lake. While we are not sure how dangerous the toxins are, it would be wise to keep pets leashed near the lake edge and to keep people out of the water too," he said.

Preliminary results showed high concentrations of cyanobacteria, which produce toxins that are harmful to humans and animals if swallowed or through contact with skin.

"Exposure to cyanobacteria may cause symptoms such as skin rashes, nausea, tummy upset and tingling and numbness around the mouth or tips of fingers. If you or your pets experience symptoms after contact with contaminated water, contact your doctor or vet immediately," Mr Hathaway said.

Mr Hathaway said the council will continue to monitor the lake during summer and the public will be advised of any changes in water quality.