Coming to a mailbox near you, a not-to-be-missed offer from Greenpeace Aotearoa: have your drinking water supply tested for nitrate contamination - for free – through a mail-in service.
This offer follows what Greenpeace describes as "the success of free, in-person testing days during winter 2021".
The mail-in service overcomes any Covid restrictions and it's free for drinking water from private bores.
The blurb starts with a non-controversial sentiment - that everyone should be able to trust that the water from their tap is safe to drink.
But it's followed by the statement that "nitrate contamination is linked to bowel cancer and preterm birth and is caused by synthetic nitrogen fertiliser and too many cows".
In my opinion, these "links" do not stand up to scientific scrutiny.
The perpetuation of the health links is similar to repeated statements about the Covid vaccination not having been tested, when in fact, it has been subject to more examination than any vaccination in history.
Activists hope for the Snark syndrome to work – that if something is said three times it will be believed.
In the nitrate-in-drinking-water case, alarmist methods are being used to try to move New Zealand to "organic, regenerative agriculture" without understanding the implications.
In my opinion, Forest and Bird is equally confused and the Green Party wants organic production systems because it thinks they mean greener, more sustainable food products.
The evidence indicates more environmental impact, such as nitrate loss, per unit of food production (or per mouthful) for organic systems than conventional.
Literature searches should have revealed that the Canterbury Plains leak nitrogen.
When nothing is grown and no animals are present, this leakage has been measured at 170 kg/ha per year.
Soil organisms break down the organic matter that is important in soil quality and release nitrogen as well as carbon dioxide.
Scientists from Plant and Food Research have reported that over a 13-year period of fallow (plant-free, animal-free and not cultivated), soil micro-organisms decomposed organic matter at approximately 1.5 tonnes of carbon (almost 3 tonnes of organic matter) per hectare a year, releasing nitrogen, which was then vulnerable to loss through leaching in rainfall because no plants were present to take it up.
The searches should also have shown that some of the bores in Canterbury have been high in nitrate for decades, well before the advent of the dairy boom.
As an example, a bore at Halswell Junction Road had a nitrate-N of 0.4 in 1961, 4.0 in 1977 and 3.7 in 1990.
A bore at Waterholes Road, Templeton had a nitrate-N concentration of 8.2 in 1977 and 8.5 in 2014.
Cows have increased on the Plains since the 1990s; increase in human activity started before that.
The activist research should also have shown that drinking water bores across the country show evidence of human contamination.
Dr Jacqueline Rowarth. Photo / Supplied
Research results published by ESR (Environmental and Scientific Research, one of the Crown Research Institutes) in 2019 reported that 83 per cent of bores sampled in the national survey contained caffeine and 42 per cent contained carbamazepine.
Caffeine is a stimulant loved by humans and carbamazepine is an anti-convulsant medicine used in epilepsy and neuropathic pain in humans (and cats and dogs).
The presence of these substances indicates human contamination possibly due to leaking septic tanks.
As septic tanks also leak nitrate, it is logical to deduce that at least some of the nitrate being measured in bores came from humans via septic tanks.
The fact that nitrate has been high in some bores since before the advent of dairy on the Plains, supports the deduction.
In addition, the research should have shown that the World Health Organisation has not linked nitrate in drinking water to colorectal cancer or preterm births, despite rigorous reading of scientific literature.
Further, a recent ESR report showed that nitrate in drinking water is less than 10 per cent of dietary nitrate intake. And more research would have revealed that nitrate in beetroot, kale and many other vegetables is associated positively with health.
Listen to Rowena Duncum interview Dr Jacqueline Rowarth on The Country below:
But the offer of free-drinking water testing is real, and you might then wonder about the source of funds to pay for the testing (and courier service).
Community and Public Health NZ (Canterbury District Health Board) states that it is important to use a laboratory that has been approved by the Ministry of Health to carry out the analysis required.
Prices for nitrate analysis range from $11 plus GST to $30.
The request-your-free-sampling-kit website states that "Information from testing results is important to researchers including those at Otago University who want to better understand nitrate contamination. If you consent, we will confidentially share your data with researchers."
• Dr Jacqueline Rowarth, Adjunct Professor Lincoln University, is a farmer-elected director of DairyNZ and Ravensdown. The analysis and conclusions above are her own. jsrowarth@gmail.com
