Warning Lake Waiparera toxins may be harmful

OUT OF BOUNDS: Swans were enjoying themselves on Lake Waiparera last week, but it's now out of bounds for people and dogs.PHOTO/PETER JACKSON

A Far North dune lake has been declared potentially toxic to people and animals.

Authorities have erected a sign at Waiharara's Lake Waiparera, warning that potentially toxic bacteria in the water may be harmful to people and animals who come into contact with it.

Northland DHB and the Far North District Council have erected a sign warning against swimming, sailing, water skiing, fishing and drinking the water, noting that any bodily contact could result in skin or eye irritation. Swallowing the water could result in illness, and internal organs of fish, where toxins could accumulate, should be removed before cooking.

Bushland Trust chairman Kevin Matthews said the toxins, which could cause serious health issues for people, would potentially be fatal to dogs.

It is believed that testing has yet to identify the particular algal bloom responsible for the problem, but Mr Matthews, who was critical of authorities' lack of response, said the lake had become "pretty smelly", which would hopefully put people off swimming in it.

The lake's eastern shore was was one of only a handful of approved freedom camping sites in the Far North, which potentially heightened the risk, he added, although the district council's failure to maintain it made it singularly unattractive. Much of the land around the lake was privately owned or DoC-managed, however, and wasn't fenced.

The lake, Mr Matthews said, faced a number of major issues, including the high numbers of swans and Canada geese that fed there, defecating in the water and transferring eel grass from Rangaunu Harbour.

"They move between the lake and the harbour," he said, "and oxygen weed is rampant thanks to the high nutrient levels."

The problem had been exacerbated by the lowering of the lake's outlet (to Rangaunu Harbour) some years ago, which had drained some of the wetlands that had previously served as a buffer, he said.

"People were blaming the butchery [at Waiharara] for the smell, but it was the lake," he said.

The situation was even more serious given that Waiparera and Ngatu were the only two dune lakes that were still publicly accessible, and it was time for adjacent land owners to give some serious thought as to what they wanted and were prepared to do.

Meanwhile the lake was taking on an increasingly toxic look with every passing day. And Mr Matthews was not impressed with the size or positioning of the warning sign. "It's A4-size, and hiding under a big macrocarpa tree."