Toxic Virginia Lake closed to public

By ANNE-MARIE EMERSON
VIRGINIA Lake is closed until further notice.
Wanganui Mayor Michael Laws and council staff decided yesterday afternoon to close access to the lake after scientists advised it was suffering from a toxic cyanophyte bloom.
Mr Laws said the lake now posed a significant health risk, and the public should stay well clear of the lake's water. He said the bloom appeared to be unrelated to the recent algal bloom plaguing the lake.
Cyanophyte bloom can cause skin irritations in both children and adults, and has the potential to poison and kill small mammals such as cats and dogs.
Mr Laws said the council had environmental scientists working on the problem.
"Our first priority is to find out the specific toxicity of what we're dealing with.
"We need to act quickly, but until we know exactly what we're dealing with, we don't know how [the bloom] will be treated."
Mr Laws said it was frustrating that a solution to deal with the algal bloom had been decided upon, only to have a new problem surface.
"Now we're dealing with a different kettle of fish, and we have to start again."
Wanganui District Council infrastructure manager Julian Reweti said the reason for the sediment being disturbed was unclear, but one possible explanation was recent seismic activity.
"On Wednesday, the sediment on the bottom of the lake began to 'boil'. This mixed the lake up and changed the nutrient compound of the water.
"This will feed the [algal bloom] and take even more oxygen out of the lake."
Mr Reweti said the lake was releasing hydrogen sulphide and ammonia gases.
He said yesterday's rain diluted the sediment but also dispersed it across the lake.
A nearby resident who was walking his dog by the lake on Wednesday evening said he saw an "amazing coloured substance coming out of it".
"This fluorescent green sludge was collecting at the lake's edge."
The man said he had never seen anything like it at Virginia Lake.
Virginia Lake aviary manager Darryl Greeks said the health of the birds at the lake was of concern, particularly the nine white swans, whose wings are pinioned.
"The other birds can fly away, but the white swans can't."
Last night, Mr Greeks and Wendy McGhie, parks and recreation manager, managed to capture a breeding pair of white swans, who were housed in the aviary overnight.
Mr Greeks said the birds' situation would be reassessed today and if necessary all nine would be relocated.
"But if we relocate them, that's the end of this year's breeding season."
Mr Greeks said he understood five dead ducks were found at the lake yesterday, along with a number of dead fish.
Only the walk around the perimeter of the lake is closed. The upper walk, the footpath, the winter gardens, aviary and cafe were all open as usual.