Serious pollution levels in the Waikato River are being investigated by regional council staff.
Heavy bacterial contamination was detected by council testing almost two weeks ago. More tests were carried out yesterday to try to trace the source.
The level of e-coli, an indicator of animal or human faeces,
downstream of Cambridge was seven times the acceptable limit on April 7.
The pollution bloom is upstream of regular sampling at Narrows Bridge, which has returned even higher e-coli counts for the past year.
Council staff yesterday tried to further narrow the source of the pollution by testing "pockets" of water as they passed downstream. The testing relies on the assumption that water discharging from Karapiro dam is relatively clean.
Water scientist Bill Vant said by repeatedly testing the same water they hoped to pinpoint where it became contaminated.
He expected to have the results of yesterday's tests on Tuesday.
Meanwhile, there was a sewage discharge into the river in Hamilton yesterday. It was believed to have lasted less than an hour, but followed a spill into the river in Hamilton East last week.
Hamilton City Council water, drainage and refuse manager Leroy Leach said the city had fewer than six such incidents in a year.
- NZPA
nzherald.co.nz/environment
