DELIVERED
Dairy wastewater flowing from an irrigator on an Orini farm, raising the risk of nitrates entering the groundwater. Greenpeace says the regional council should do more to warn people about the risks of drinking nitrate-laden spring water (file photo).
The regional council should do more to warn people about the risks of drinking nitrate-laden groundwater in rural Waikato areas, environmental group Greenpeace says.
But the council’s science manager, Mike Scarsbrook, says they are closely monitoring the issue and advising water suppliers and the public.
The comments follow a report on nitrate issues in groundwater presented to the council’s environmental performance committee this month.
It included five years of monitoring a 110-person regional network of water resources for the state of the environment (SOE) and an additional 80 water resources for local or national schools.
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The latter are not currently used for drinking water, but the SOE wells could be.
The technically complex report said nitrates “frequently” exceeded drinking water guidelines, with medians above the maximum acceptable level at just over 1 in 10 (11%) SOE sites. The highest concentrations were associated with horticulture and dairy farming.
Those highest levels were in the Pukekohe, Pukekawa and Matamata areas.
Christel Yardley/Stuff
The regional council says it will provide clear information about the nitrate content in wells.
The report said high concentrations in drinking water could lead to “blue baby syndrome,” which can cause serious problems in infants around adequate blood oxygenation. Other colon cancer and reproductive risks have also been linked to elevated nitrate levels.
Greenpeace senior campaigner Steve Abel said that people in rural Waikato who consume groundwater are especially at risk and wanted the council to do more to warn the public of potential problems.
He disputed the way the council’s report framed the issue, suggesting it underestimated potential risks compared to national and international warnings about the potential impacts of relatively lower nitrate levels.
“The regional council has a duty of care.”
delivered/greenpeace
A Greenpeace protest over the use of synthetic nitrogen fertilizers (file photo).
Scarsbrook said the council had provided information about the state of the environment, which it had done through the report, and that it was available to water suppliers.
He also said landowners with the SOE wells on their properties were informed about nitrate levels so they could make an informed choice about how to use it.
“There have been instances where we have helped a landowner identify an alternative groundwater source where they were concerned about water quality,” Scarsbrook said.
He said the SOE wells with nitrate levels above the maximum acceptable levels (MAV) were not being used for public supply.
Abel said that about 80% of New Zealanders had access to low-nitrate water, but about 138,000 – mostly in rural areas – faced a higher risk of consuming water.
He claimed that “hundreds of domestic water supplies in Waikato” could have nitrate levels exceeding levels considered potentially harmful to reproductive health.
Abel said the regional council has “an absolute duty to warn those communities about the potential health risks and do something about it.”
Information from the office of the prime minister’s chief scientific adviser says that up to 14% of the population can obtain drinking water from unregistered facilities where nitrate levels are often not tested.
It said evolving evidence of a “possible relationship” between nitrates, colon cancer and reproductive outcomes in New Zealand should be followed.
“Regular testing of nitrate levels in drinking water is important for families with formula-fed infants who use private groundwater wells or wells.”