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Nitrate down the water well

Nitrate has been a problem for more than 50 years. Low levels are not unsafe

Nitrate in groundwater has been a recognized problem since a “blue- baby” was related to a nitrate-contaminated farm well in Iowa in the 1940s. A farmer took a sick baby to hospital. The baby was okay soon, but got sick again as soon as it was returned to the farm. On the third visit, the farmer brought along sample of the water and said, “Test it. Our food is okay, it must be the water.” The water was found to be highly nitrate contaminated and also had microbiology problems.

That resulted in the discovery of the same problem in many parts of the world, including Saskatchewan and Manitoba. (It isn’t found as often in Alberta — they have fewer shallow-dug or bored wells).

A 1948 survey of 2,000 Saskatchewan farm wells found 31 per cent to have nitrates above the accepted limit. That was before any significant nitrogen fertilizer was used and before intensive livestock operations.

Sampling for nitrates in Saskatchewan

My first experience with soil nitrate was in 1970. We rigged up a soil coring truck to retrieve cores to a depth of 6.1 metres (20 feet). We sampled ordinary farmland, grassland and irrigated land that had higher nitrogen rates for only a few years. We also sampled continuous fallow land between the rows of trees at the Forestry Farm then located just east of Saskatoon (it is now the Forestry Farm Park and Zoo).

Grassland had almost no nitrate, farmland a bit more and the irrigated land was too “new” to have accumulated much. But the continuous fallow at the Forestry Farm had considerable nitrate below the root zone of crops.

The nitrate topic seems to come back in the spotlight about every 20 years or so and is now much in the news. “Johnnie come latelies” do a water well survey and find 20 to 30 per cent of wells to have nitrate above 10 ppm nitrate-nitrogen and declare a problem: “All that fertilizer we are pouring on is polluting our groundwater.”

Sorry folks, but 31 per cent of 2,000 wells sampled in Saskatchewan in 1948 were above the limit.

If you enter the words “nitrate groundwater” into Google it takes 0.26 seconds to return 2.8 million hits. Mind boggling to this old fossil.

To be honest, agriculture must admit that a lot of nitrate in the environment is due to farming, including organic farming, especially if the organic farming involves a lot of manure and summerfallow. In native Prairie condition a nitrate molecule was a rare beast. As soon as organic nitrogen was mineralized to nitrate, a plant root was sitting in wait to suck it up. Just breaking the prairie sod was enough to change the nitrogen cycle. Before farming, the only nitrate would have been associated with buffalo concentrations or very small areas that had been inhabited by humans for an extended time.

In 1993 hydrogeologist Bill Meneley (1933 to 2000) and I did an extensive literature search on groundwater nitrate and gathered up all available data on the topic in Western Canada — all the way from the Manitoba/Ontario border to the west coast of B.C. It was done for the then Western Canada Fertilizer Association, now the Canadian Fertilizer Institute. The report is long since out of print but a PDF is still available at the Canadian Fertilizer Institute website. Find it at www.cfi.ca (click on “elibrary” then “publications,” then look for “Fertilizer Groundwater Nitrate”).

Nitrate Contamination levels

Let’s look at seriously nitrate-contaminated wells versus slightly contaminated aquifers.

The last baby death from a nitrate contaminated well that I know of was in South Dakota in 1987. The account of that death in the medical literature was as chilling as the 1948 account of an example near Regina, Sask. But the South Dakota well had 150 ppm nitrate-nitrate and the Saskatchewan example had 275 ppm. Both had bacteria contamination as well.

Most of the highly contaminated farm wells were shallow dug or bored wells — often in the barnyard — and always with a poor or no well seal at the surface. Nitrate was literally pouring down the side of the well casing.

There is a growing body of evidence that shows that slightly elevated nitrate levels in water are not a problem. In the past couple of years I have read two books that suggest that the 10 ppm nitrate-nitrogen limit is not right.

In the meantime, society is spending huge amounts of money to strip out small quantities of nitrate.

Nitrate is a well problem, not an aquifer problem. Individual wells can be contaminated at a level to be lethal but aquifers are contaminated at a very much lower level. England used 20 ppm nitrate-nitrogen as the limit for many years with no problems recorded. They reverted back to the 10 ppm limit presumably based on political pressure from the European Union rather than facts.

It seems to me to be another case of “the emperor has no clothes.” Nobody wants to blow the whistle.

About the author

Columnist

Les Henry

J.L.(Les) Henry is a former professor and extension specialist at the University of Saskatchewan. He farms at Dundurn, Sask. He recently finished a second printing of “Henry’s Handbook of Soil and Water,” a book that mixes the basics and practical aspects of soil, fertilizer and farming. Les will cover the shipping and GST for “Grainews” readers. Simply send a cheque for $50 to Henry Perspectives, 143 Tucker Cres., Saskatoon, Sask., S7H 3H7, and he will dispatch a signed book.

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