Canterbury lake's toxic algae enough to kill

Canterbury lake's toxic algae enough to kill

A severe recurring algal bloom in a Canterbury lake has killed sheep, fish and household pets.

It's now so bad researchers claim drinking a single teaspoon of the green slime could kill a person.

Its thick, green and deadly -- the paint-like slime seeping on the shores of Lake Forsyth is killing stock and pets and native eels.

"People won't walk their dogs or pets around the lake because they are too scared their animal will drinks some of the water and they will die," says local fisherman Josh Bashford.

It's so toxic researchers say just one teaspoon of the algal bloom is enough to kill a child.

Ngai Tahu has teamed up with Environment Canterbury to try and improve the water quality and keep the lake alive. They have tried opening the lake to the sea numerous times to clean it out, but this year a lack of rainfall has meant the lake has become a perfect breeding ground for the poisonous algal bloom.

"Since the start of summer the lake has been at 1.8 metres and we've had such a hot, dry summer that the lake has heat up and dissolved the phosphorous of the soil," says Wairewa Marae natural resources leader Iaean Cranwell.

The lake is in the worst condition he has ever seen.

"It is a really serious issue and we take it very seriously, and it has been identified in our planning framework," says Environment Canterbury surface water science manager Tim Davie. "We are putting in place rules and regulations to try and improve the situation."

Tonight a public health warning remains in place to stay well out of the lake.