Nitrates

Nitrate in Rural Groundwater

High reported levels of Nitrate in groundwater have been an issue in Mid Canterbury for over 25 years.

In relatively shallow wells below meat processing plants, the levels have exceeded 20ppm in effected wells.

Four meat processing plants near Ashburton have historically contributed to significant documented evidence of elevated Nitrate in groundwater.

In 1994 two children were hospitalised as a result of the well on a property on the seaward boundary of the CFM plant at Fairton, being contaminated with Nitrate, reported at above 20ppm. This well and others below other local meat processing plants to the north and east of Ashburton had negatively affected water quality in the resulting plumes of recorded Nitrate testing.

Fast forward to the advent of intensive dairying in Canterbury and other areas, for the number of wells effected in a significantly increased area, to have exponentially increased, with widespread elevated levels of Nitrate.

Nitrate is colourless, odourless and tasteless so many people are unaware of its presence but a simple inexpensive water analysis will reveal the level present in a groundwater sample. There is a loose three-way connection between bacteria, Nitrate and other agricultural chemicals – they are all applied to the land surface and will leach into underground aquifers, so if one is present, the others may also be.

Increased awareness of the known negative health risks associated with Nitrate, which converts into a carcinogenic compound (N-nitroso) after ingestion, is slowly becoming more acknowledged. Traditionally, Nitrate poisoning in babies (Methemoglobinaemia) and pregnant women has been under-reported but the sheer volume of wells and families affected is increasing.

A 2018 Danish report correlated documented evidence from a very substantial long-term study that proves an increased incidence of colo-rectal (CRC) or bowel cancers associated with Nitrate, in drinking water at a very low level. The dramatically lower trigger point reported is noteworthy.

New Zealand has one of the highest incidents of colo-rectal or bowel cancers worldwide.

Based on drinking water quality analyses at public waterworks and private wells between 1978 and 2011, the study calculated nitrate exposure for 2.7 million Danish adults, 5,994 of which were found to have CRC.

During that time the Danish researchers found nearly 6000 cases of colo-rectal cancer within the study group.The research was a major work which involved collecting data from 2.7 million adults for 23 years.

They looked at the risk of cancer in relation to the level of nitrate exposure in the drinking water supplies of these people and they found the risk was around 16 percent higher in the most exposed group.

 A big surprise was the level of risk was elevated in comparatively low levels of nitrate - a level that's described as .87 parts per million - this is approximately one tenth of the level that's currently the recommended exposure level across the globe.

New Zealand has a Maximum Acceptable Value (MAV) of 11.3ppm

Point of Use (POU) water treatment is ideal for Nitrate reduction and other agricultural chemicals to provide safeguarded water in individual homes for all water used for food preparation, cooking, drinking and especially for making baby formula.

It is predominantly the water entering your body that is of greatest concern, so the water purifier is installed in the kitchen. The in-coming cold water is directed through a sediment then carbon pre-filter before passing through the RO membrane with a pore size of .0005 of a micron which is 80,000 times smaller than the smallest visible dot–so molecular separation of the totally dissolved solids. (Smallest visible size is about 40 micron)

The rejected waste water is washed away to the kitchen drain and the purified water to a reservoir tank with approx 10-12 Litre capacity. There is a separate dispensing tap mounted into the kitchen bench top by the sink. A Water Quality Monitor is installed as part of the tap, so the rejection rate of contaminants is available with the press of a button, for continuous information. The RO membrane is capable of producing up to 50 American GPD on demand.

The Reverse Osmosis process has international acceptance as a proven and very effective option to safeguard water to be used domestically for food preparation, cooking, drinking and for making baby formula.

Testing and certification by the American NSF International against NSF/ANSI Standard 58 for the reduction of the claims specified on the Performance Data sheet, report an average reduction of 87% for Nitrate from influent water challenge concentration of 27ppm Nitrate and 86% reduction for 30ppm combined Nitrate +Nitrite (as N)

We understand some health professionals have taken particular notice of the recent Danish study which reported a very much lower level of Nitrate correlated with increased cancer rates, than the current MAV in the Drinking Water Standards for NZ.

  • Sue Kelly Water Systems Ltd was established in Ashburton and now operating in Christchurch, have specialised in water treatment for over 25 years.
  • Nitrate levels in groundwater are increasing.
  • Because Nitrate/Nitrite in water is invisible, many people are not aware of the presence of these chemicals in ground water, or the resulting negative health implications.
  • A simple inexpensive test can be arranged for any water sample.
  • Most water filters do not remove Nitrate.
  • The correct technology in an under bench water purifier is extremely effective in dramatically reducing Nitrate levels to safeguard water for domestic use.
  • Approx. 80+% rejection rate along with other agricultural chemicals.


  • H & E, ASHBURTON
    ‘I had the water tested for bacteria and it came back clear but our symptoms were persisting. After almost two months at the address and no answers I decided to pay the money and have further tests done on the water. Our test came back showing that our water was very high in Nitrates – the level was 16. It also showed our water was very hard. We installed a Reverse Osmosis system for our drinking water and the transformation in our daughter has been remarkable. We watched her eczema literally disappear from her body. My symptoms of nausea and lack of appetite have also disappeared. This is just our experience. For us changing our water has brought about a dramatic improvement in our health issues. Nitrates were an issue that I was completely unaware of. We are now into our 3rd week of being healthy and happy’.
    H & E, ASHBURTON