1 June: Greenpeace says that "a big part of the problem for Cantabrians concerned about water safety is that the local regulator - Environment Canterbury (ECan) - is still in denial, and misleading the public about how bad the nitrate contamination problem is."

The statement follows a response by ECan’s Tim Davie to new research showing that it would take up to 11,000 litres of water to dilute pollution from the production of 1 litre of dairy milk on the Canterbury plains - and that groundwater supplies are on on a trajectory to being "undrinkable" with nitrate concentrations double that of the current acceptable drinking standard.

Nitrate in drinking water is a known risk for Blue Baby Syndrome and is linked to colorectal cancer and birth defects.

Monday night on Newshub, Mr Davie - ECAN’s Director of Science - responded to the stark groundwater contamination warnings by saying that "it [the environmental footprint of farming] is heading in the right direction", despite ECan’s own data showing that 68% of monitored groundwater wells are very likely to have increasing nitrate trends, while another 5% are likely increasing for nitrate contamination. Already 8% of groundwater sites exceed drinking water standards.

Davie has previously argued against scientific information showing worsening water quality in the region.

"Mr Davie’s statements go against ECan’s own data showing that three quarters of groundwater wells are worsening for nitrate contamination," says Greenpeace’s Senior Campaigner Steve Abel.

"ECan’s downplaying of the enormous impact of dairy intensification in Canterbury over the last 30 years - during which time the nitrate problem has vastly worsened - is frankly chilling," says Abel. This followed Mr Davie’s comments earlier in the day on RNZ Midday Report where he said, "What we’re seeing is the result of 150 years of agricultural production across the Canterbury Plains - it’s not just a recent intensification that’s causing the rise."

Over the past 30 years the Canterbury dairy herd increased tenfold from 113,000 to 1.2 million cows (1990-2019), and synthetic nitrogen fertiliser use increased seven fold nationally (693% from 1990-2019). The number of wells exceeding safe drinking standards in Canterbury has also risen sevenfold - from 1% in 1992 up to 8% in 2021.

The Ministry for the Environment states that 80% of leached nitrate comes from livestock urine and most of that - 65% of it - comes from dairy cows. Based on StatsNZ data from 2017, In order of magnitude, the biggest contributors to leached nitrate are dairy urine (129,000 tonnes), beef urine (37,000 tonnes), and synthetic nitrogen fertiliser (31,000 tonnes).

"The problem is too many cows and too much synthetic nitrogen fertiliser and the science showing that is undeniable."

Greenpeace is calling on Central Government to act.

"Right now government is reviewing the framework for protecting sources of human drinking water and needs to recognise the primary sources of nitrate are leachate from cow urine and synthetic nitrogen fertiliser and institute catchment-wide management including phasing out of synthetic fertiliser and lowering stocking rates," says Abel.

Scientists warn that 100 cases of colorectal cancer and 40 deaths per year in New Zealand could be attributable to nitrate in drinking water - and rural people on groundwater are most at risk.

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