Also see the rebuttal at the foot of this article.
By Guy Trafford
Despite a large cross-over of fishers being farmers and vice versa, the relationship between Fish & Game and farming, particularly dairy farming has not been a happy one.
It was Fish & Game who were the first to tag dairy farmers with the label “dirty dairying” and began the national pastime of putting dairy farming under scrutiny at seemingly the expense of anything else. Much of the facts they roll out are correct; what seems to be lacking is a sense of balance and providing credit to those who are leading the way to improved environmental management. Yes, there is a problem and yes dairy farming (among others) have largely contributed to it. But just remember, water quality as an issue has only surfaced in the last twenty five years, at least in Canterbury anyway, and the focus has gone on to it in more detail in about the last fifteen. So given the size and relative importance of agriculture to the economy it is not surprising that it is taking time to turn the ship around.
The latest article to come out of Fish & Game is yet another piece that appears to lack any balance and makes implications that, at least by ECan’s data, appear to be wrong. The article reeks of scaremongering despite the Fish & Game chief executive declaring that it’s not.
It states that Canterbury water nitrate levels are increasing and are predicted to get worse.
Reading the 2016 Ecan report it alludes to, it says no such thing. It does say that, at 2016, 23% of wells surveyed had increased their nitrate levels, over the previous 10 years. 10% had decreased and 67% had remained the same. It did not predict future trends. In fact (2018) ECan’s latest’s report states “All but one water quality attribute showed more Canterbury sites were improving than degrading over the past 10 years (with a probability of 67% or greater)” and the one that didn’t show improvement was turbidity.
The heading of the article is “Canterbury water testing raises health concerns”.
The supposed driver for the Fish & Game concerns is a Danish report which has found that colon cancer can increase by 15% when exposed to drinking water with nitrate levels over 9.7mg per litre of water when compared to those with access to water with a 1.3mg per litre of water. Fish & Game then go onto say that they worked with Dr Mike Joy to conduct a survey and he found over half had nitrate levels of 3.7mls per litre, nothing like the 9.7 in the Danish study, although to be fair the study did say that over 4mg per litre the potential for increased colon cancer did exist, but no figure was given.
Fish & Game state “One of the world’s largest ever studies on the impacts of nitrates in drinking water in Denmark confirmed that nitrate levels above 3.87 mg/1000ml substantially increases the risk of colorectal cancer (CRC).” I would be happy to be corrected but I could find no such reference.
What the study does state is that “We found statistically significant increased risks at drinking water levels above 3.87 mg/L, well below the current drinking water standard of 50 mg/”. To a researcher, and Dr Joy would be well aware of this, “statistically significant” means that it is unlikely to be a random result but the value is likely to be less than 5% certainly not “substantially increases”.
When it comes to the impact upon trout, obviously anything other than high quality water is less than desirable. However nitrate toxicity for trout is exceedingly low; arguably of more concern is the impact upon our native species which according to a 2014 NIWA study are more vulnerable and trout have also had a fair bit to do with their state.
It is also a pity that there was not more detail about where the water samples came from as the article says they came from across the Canterbury Plains from samples provided by concerned Cantabrians “and from sampling of public water supplies at sports grounds and public facilities”. I would feel more comfortable if the samples came from an unbiased group and knew more about the various sources.
From what I can glean and certainly compared to international standards Cantabrians should feel more reassured about their water quality rather being increasingly concerned.
My intention is not to try and pretend there is not a problem and water quality certainly does need to improve especially when it gets into the rivers. But some balance needs to be brought to the discussion rather than try to create a beat-up for another agenda and to say that the article wasn’t a “scare mongering”… come-on.
As if to prove a point that there is a substantial movement to improve the environmental footprint on most dairy farms, Matamata dairy farmer Tracy Brown won the sustainability Superstar Award at the Sustainable Business Network Awards. Selected from across all businesses, not just agriculture. The award was for Brown’s activity in promoting the sustainability cause and she is a founding member of the Piako Catchment Forum and Mangapapa Catchment Care Group. She and husband Wynn's farm 'Tiroroa' is an environmental award-winning property and they frequently hosts groups to explain what dairy is doing to be more sustainable. The supreme winner was the City Rail Link project in Auckland just to show the diversity of the contestants.
The following rebuttal has been received from Fish & Game:
Re. The recent article titled “Guy Trafford reviews the latest claims on Canterbury water quality by Fish & Game and finds misrepresented sources, misquoted facts, and no transparency around samples selected”
In the article Guy said: “Fish & Game state One of the world’s largest ever studies on the impacts of nitrates in drinking water in Denmark confirmed that nitrate levels above 3.87 mg/1000ml substantially increases the risk of colorectal cancer (CRC).” I would be happy to be corrected but I could find no such reference.
I’m not sure why Guy had trouble finding 3.87 as it in the abstract, here is the line from the abstract of the 3.87 mg/L, well below the current drinking water standard of 50 mg/L.”“We found statistically significant increased risks at drinking water levels above
Where Guy has gone wrong is that he doesn’t realise the difference between the scales for nitrate (NO3-) which is used in the Danish study and Nitrate Nitrogen NO3-N as used in our study and used in the figures he quotes from Environment Canterbury (ECAN) reports and is the usual nitrogen species used in New Zealand. They are both measuring the same thing but on a different scale because of molecular weights (seebelow).
What this means is that the 50 mg/l drinking water standard quoted from the Danish paper is identical to our New Zealand and Word Health Organisation limit for human health of 11.3 mg/l nitrate nitrogen (50 multiplied by 0.22 = 11.3 using the table below).
Thus, the 3.87 mg/l that is the trigger value for increase in the chance of cancer in the abstract of the Danish paper is in New Zealand parlance 0.87 mg/l NO3-N. This means that around 90% of the samples we gathered in Canterbury exceeded that number.
Further in response to Guys implication that our sample was biased; the latestfrom ECAN shows that half of the wells they monitor have values greater than 3mg/l NO3-N (three times or more higher than the Danish cancer number) so our numbers fit well with their survey, they don’t break down the less than three so can be more accurate.
Guy Trafford responds:
It appears that my lack of in-depth chemistry knowledge has got me into trouble and it appears that the data as used by the Fish & Game article does pose reason for concern.
I know this as I received a rather detailed response from both Mike Joy and the Fish & Game CEO Martin Taylor. This highlighted a couple of things to me. One was that I have a bit to learn around the various types of nitrates and on this count got it wrong (see below). So guilty as charged over that error in interpretation: “Where Guy has gone wrong is that he doesn’t realise the difference between the scales for nitrate (NO3-) which is used in the Danish study and Nitrate Nitrogen NO3-N as used in our study and used in the figures he quotes from Environment Canterbury (ECAN) reports and is the usual nitrogen species used in New Zealand. They are both measuring the same thing but on a different scale because of molecular weights (see table below). “
It was perhaps unfortunate that more clarity over the use of a different basis of measurement was not included in the article if better appreciation of the sampling was the aim. One of the principles impressed upon me as a student was to always consider the audience and while I will admit to deficiencies around chemistry (and many other things). I don’t consider myself hugely out of step with plenty of others and if my interpretation was flawed (and it was) then perhaps I wasn’t the only one. So, on that point I accept; an apology is in order and given.
However, I still stand by what I said about a lack of balance and a misuse of information in the broader picture.
Every-one knows that agriculture and particularly dairying have a negative impact upon the environment and I am not a huge fan of it. But I also am aware that large strides have been taken both in actions and attitudes and plenty of work is being continued to be done to try and mitigate impacts further.
Farming families have invested immense amounts of sweat and tears as will as capital and are not going to disappear so working with the industry and recognising gains made may be a more productive way forward.
A difficulty farming faces is that food retailers (supermarkets) are committed to providing consumers with the cheapest food available and the consumer welcomes this. This attitude runs at odds with the consumer then wondering why we have this move to corporate farming with many of the negative attributes that go with it. They want it both ways but fail to see what and where the cost is.
I find it ironic that this conversation is being had with Fish & Game which after agriculture are probably one of the sectors which have had negative impacts upon native water species. It appears Government is also viewing the impact of trout in less than favourable eyes as a bill is before Parliament to aid in the protection of native fish species. Quoting the F&G site “The Indigenous Freshwater Fish Amendment Bill aims to provide better protection for indigenous fish such as galaxids, whitebait, eels, bullies, torrent fish, mudfish and other species. But the Bill also poses a serious threat to trout and angling. It allows trout and salmon to be removed from particular rivers and lakes, even if they are significant trout and salmon fisheries.” Needless to add Fish & Game view this bill as threatening and are encouraging members to contest it. So perhaps farming and Fish & Game do have some things in common.