Shellfish sewage warning signs go up in Bay of Islands

By TONY GEE

Signs were erected yesterday near Opua in the Bay of Islands warning people that shellfish may be contaminated with human sewage at nearby Okiato Pt.

The signs, in English and Maori, were put up by Northland Health.

The region's medical officer of health, Dr Jonathan Jarman, said people collecting shellfish at Okiato Pt had a right to know that there was a risk of contamination from properties with failing septic tank effluent drainage fields.

"It's highly likely some human sewage is intermittently leaking into the harbour at Okiato Point," Dr Jarman said.

A consultant's report to the Far North District Council said soil at the point was unsuitable for septic tank systems.

At least 12 properties have been identified with failing systems.

But a residents and ratepayers group says there is no conclusive proof that effluent or contaminated groundwater is going into the sea.

Bruce Howell, chairman of the Okiato and Te Wahapu Residents and Ratepayers' Association, said that although up to 20 tanks may need treatment there had been no confirmed cases of contaminated water leaching into the harbour.

If faults were found in systems, property owners would fix them before any new system was installed.

Another report, from an engineer, sent to the council yesterday is understood to confirm that existing septic tank waste water treatment at Okiato needs upgrading and that it falls short of required standards.

The latest report recommends exit filters for tanks of less than 3000 litres and installing water reduction measures to reduce the volume of waste water going into effluent fields.

The report also recommends installing individual or shared secondary treatment systems on most properties.

A council spokesman said yesterday the report was being considered by technical staff who would provide further recommendations for a solution to the council's next works committee meeting.

Far North District Council chief executive Clive Manley previously said that options for a long-term solution to fix failing fields in coastal locations such as Okiato Pt would probably involve reticulation.

Dr Jarman said everyone knew there was a problem. "The question is what is the best way to fix it."

Several illnesses can be transmitted by shellfish contaminated with sewage.

There have been outbreaks of disease related to Bay of Islands shellfish in the past few years.

These include a hepatitis A outbreak which affected 14 people involved in collecting contaminated mussels from Moturoa Island in 1999.

Traces of the Norwalk gastroenteritis virus were recorded in 1994, 1999 and again last year in several Auckland restaurants, being linked to contaminated oysters from the Waikare Inlet.

Dr Jarman said that although the council was to be congratulated on what it had done so far in trying to resolve the problems at Okiato Pt, he was disappointed it had decided not to warn shellfish gatherers about the possible risk of faecal contamination.

"Shellfish is a staple food item for many people in the Bay of Islands and they are especially important for local Maori."

Dr Jarman said the council was required to take all necessary steps to abate a nuisance identified as likely to be offensive or a health risk under the Health Act.

nzherald.co.nz/environment