Swimmers warned over river's E. coli levels

Swimmers are being warned to stay out of the Foxton River Loop, which connects to one of the country's most polluted waterways, because of faecal contamination.

Horizons Regional Council has issued a "red alert" for the river, and is advising swimmers to stay out of the water because of high E. coli levels.

E. coli is harmful in high concentrations, which indicate that the water has been contaminated with either human or animal faeces.

Policy and consent manager Richard Munneke said people who swam in the river could experience upset stomachs or diarrhoea.

Horowhenua District Council chief executive David Ward said the E. coli had not come from the council's sewage plant at Foxton.

Tests at the plant had shown a count of 36 E. coli per 100 millilitres of effluent at the point where effluent was discharged, while the council's consent for the plant allowed up to 550.

However, 200 metres downstream from that point, tests had shown a level of 2300 E. coli.

Rivers are considered unsafe for swimming once E. coli levels go beyond 550.

Mr Munneke said the regional council believed the faeces had come from ground runoff and dairy farms in the area. A combination of weather conditions would also have contributed, because the tests were taken after a dry spell and then a few days of rain.

Lower water levels could have also increased E. coli concentrations, he said.

The Foxton River Loop connects to the Manawatu River, which was rated the most polluted of 300 waterways in Australia, New Zealand, Europe and North America by the Cawthron Institute research centre in November.

The council would not be following up the reading with dairy farmers, Mr Munneke said, but was taking a "longer term" approach to the problem of contaminated waterways through its One Plan.

The policy aims to introduce more comprehensive resource consent conditions for farms.

- © Fairfax NZ News