Nitrate contamination of soil and water: Implications for ecosystem functions and human health

Human-induced changes in the global nitrogen (N) cycle have resulted in more than doubling the amount of reactive N in the environment, posing significant threats to ecosystem functions and human health. The world’s rising population and subsequently increasing demands for water and food security have led to more chemical N fertilizers being employed, and more organic N sources such as animal manures and sewage sludge many-fold. This has resulted in a rising amount of N in terrestrial and aquatic environments, mainly in the form of nitrate (NO3). Nitrate contamination of surface and groundwater has raised serious concerns for ecosystem functions and people’s health, and is linked to a number of United Nations’ stipulated sustainable development goals (SDGs). Excess NO3 in groundwater causes a variety of diseases in humans and animals but especially of concern are conditions affecting human infants, who suffer more and when they are exposed to higher NO3 in drinking water. Considering the deleterious effects of excess NO3 in drinking water, many techniques including water treatment and legislative/regulatory measures have been introduced to tackle NO3 contamination issues in surface and groundwater but to date mostly in the world’s advanced economies.