AIMAN AMERUL MUNER/Stuff
Yvonne Lane, from Mosgiel, fills up water bottles at the Morven Hall for members of her family she is staying with in the Morven area.
Emergency drinking water supplies have been delivered to parts of the Waimate District as measured nitrate levels have risen past the Drinking Water Standards Maximum Acceptable Value (MAV).
Approximately 615 residents on the Lower Waihao Rural (including Waikakahi East) Water Scheme have been advised not to drink the water after the increased levels were detected by the Waimate District Council on Saturday.
Council has now placed water tanks at the Glenavy Hall and Morven Hall to ensure safe drinking water is available to all scheme users. The tanks will remain as an alternative source until the issue is resolved. A third supply at Victoria Park potable water tap on Hillary Street in Waimate is also available.
The council first advised residents on Saturday of the increased nitrate levels nearing the MAV of 50mg/L (milligrams per litre) and that it was expected to rise further.
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The council’s chief executive Stuart Duncan, on Wednesday said nitrate levels were exceeding the MAV by 1.3 mg/L at 51.3 mg/L of nitrate-NO3.
“At this level of nitrates, treatment is the only option at the moment. Council does have preliminary plans for a denitrification plant,” Duncan said.
“Elevated nitrate levels near 50mg/L (milligrams per litre) of nitrate NO3 (MAV) have been detected at the source of the water supply following recent weather events and are likely to rise further,” council has advised consumers.
“These have the potential to cause health issues, with an increased level of risk to pregnant women and infants under six months of age. The risk to a healthy adult is low but caution is advised.”
Water for the scheme is drawn from a “shallow bore next to the Waitaki River, six kilometres upstream from Glenavy”.
AIMAN AMERUL MUNER/Stuff
A water tank with emergency drinking supplies sits outside Morven Hall in the Waimate District after nitrate levels rose past the maximum acceptable value in the Lower Waihao Rural (including Waikakahi East) Water Scheme.
The council is also warning residents that the usual method of boiling of water does not remove nitrates.
Until nitrate concentrations return to compliant levels, the council has advised consumers to access drinking water from the tanks at the hall or the source in Waimate.
The council said they continuously monitor nitrates within the supply to ensure that prolonged exposure is managed.
“It is important to note, the rise in nitrate levels is primarily due to environmental factors and recent weather events. This is not due to a failure of the water scheme itself.”
The council said it will not be testing for nitrates at individual consumer points of supply/storage tanks.
However, the council does carry out online nitrate monitoring via telemetry at the source, and independent lab testing as well, so this situation is closely monitored at all times.
The council said, due to the environmental nature of this event, they are unable to confirm a timeframe for the nitrate concentrates to return to previous levels, but will monitor the situation closely and advise of any developments immediately.
Council, when asked whether it had found any other reasons for the elevated nitrate levels, apart from the weather, directed inquiries to Environment Canterbury. ECan has been approached for comment.