Human poo pollutes lagoon
It is not just duck and dog poo making Palmerston North’s Hokowhitu Lagoon dirty.
High counts of the bacteria E coli of the human type have been recorded in the former oxbow of the Manawatu¯ River.
The results have prompted a city council investigation into where it is coming from.
Meantime, the Kiwi Canoe Polo Club will continue to train and compete there, warning players to keep their mouths closed when they go under.
Council water and waste services manager Robert van Bentum said the type of contamination was confirmed by Horizons Regional Council in June after complaints from people claiming to have become sick after coming in contact with the water.
The elevated levels of E coli created significant health risks, he said.
Van Bentum said contamination had previously been identified in ‘‘safe swim spot’’ regional monitoring.
Levels spiked at almost eight times the trigger for a red alert, especially after heavy rain.
The reserve was popular with dog walkers, and attracted ducks and other water fowl, so evidence of their droppings was expected.
But the samples showed the most significant source was human.
The contamination could come from anywhere within the 250-hectare catchment, but checks would begin at The Chalet, the nearest possibility where wastewater could be leaking into the stormwater.
Kiwi Canoe Polo Club committee member Colleen Sheldon welcomed the investigation.
She said the club was aware of the risks, and followed guidelines from the Public Health Service.
Members were advised to keep their heads above water, avoid swallowing water, to wash their hands and face after contact, and avoid getting any open cuts or wounds wet in the lagoon.
Van Bentum said the search for the human E coli source would involve monitoring up to 15 stormwater discharge points at the lagoon.
Part of a programme to search the wider stormwater networks for leaks or cross connections would focus on the lagoon catchment.
‘‘We are trying to find where that high level of human bacteria is coming from.
‘‘We are trying to find where that high level of human bacteria is coming from.’’ Robert van Bentum Council water and waste services manager
‘‘It is clearly a concern, and officers are taking this seriously, but there is still quite a lot of detective work to be done.’’
He said staff would report back to councillors during 2019 on progress. We might be lucky.
‘‘We might find the source quickly. Or we might still be looking.’’
The council’s sport and recreation committee yesterday rejected Cr Brent Barrett’s proposal to include monitoring of contamination from heavy metals in the lagoon.
Van Bentum said a simple sample could be included, but testing as extensive as that proposed for finding the source of the bacteria contamination would add significant cost.
Cr Susan Baty said the lagoon was not a swimming pool, and everyone who grew up in Palmerston North knew it was full of duck and dog poo and not to go in there.
Barrett said the council could not assume everybody knew that.
‘‘It does concern me we might be taking a slightly cavalier approach to public health.’’