The use of nitrogen fertilizers has not only been found to harm planet Earth, but is also linked to a wide array of human illnesses. Even if farmers stopped using fertilizers today, the nitrogen from farm fertilizers can still pollute drinking water for decades, a new study found.

Researchers from the University of Waterloo said that the levels of nitrogen concentrations in lakes and rivers will remain high for many years even if these fertilizers will be banned from being used by farmers.

"The fact that nitrogen is being stored in the soil means it can still be a source of elevated nitrate levels long after fertilizers are no longer being applied," said Professor Nandita Basu. 

In the study published in the journal Environmental Research Letters, the researchers analyzed more than 2,000 soil samples from the Mississippi River Basin. Nitrogen buildup was not seen in the upper layer of soil but was observed in about 2 to 8 inches beneath the soil surface.

The researchers believe that the buildup of nitrogen in soil not only happened because of the increased use of fertilizers but is also due to soybean cultivation and changes in tillage practices. As a result, nitrogen levels slowly accumulated in the past eight decades.

Nitrogen Fertilizers Contaminating Water For Decades

Nitrogen is often found in inorganic fertilizers that have been widely used in the United States after World War II. Since then, it has provided a cheaper source of nitrogen and other plant nutrients that have paved way for a boom in agriculture productivity.

In the 50s, nitrogen fertilizer use increased five-fold not only in the U.S. but also in other developed countries. This has led to profound changes in the environment, such as algal blooms that resulted in "dead zones" in lakes and coastal regions.  

Many farmers across the globe have been using nitrogen-containing fertilizers. This study sheds light on the impact of nitrogen on bodies of water, which are the major sources of drinking water.

Health Effects Of Nitrate Contamination

Humans frequently exposed to nitrogen fertilizers are at a higher risk of ingesting nitrate-contaminated drinking water. Nitrate is the product created by breakdown of nitrogen that accumulates in ground water under land used for planting crops. Nitrate levels are high in rivers, lakes and streams because of runoff of excess nitrogen fertilizer from agricultural fields.

Nitrate exposure has been linked to health issues among humans, specially infants. Excessive exposure to nitrates impedes oxygen transport in the bloodstream. Young infants under 4 months of age still lack the enzyme needed to correct this condition called blue baby syndrome. Nitrate contamination has also been associated with certain cancers, adverse reproductive outcomes, thyroid diseases and diabetes.

Photo : Syuzo Tsushima | Flickr

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