What’s So Special About Nitrate? Implications for Water Quality in the Upper Great Plains
Ammonia synthesis, an economic means to fix nitrogen from the atmosphere, is arguably the most important technological invention of the 20th century; it allowed large-scale industrial production of explosives and nitrogen fertilizers. After World War II, the focus of nitrogen production switched from explosives to fertilizers. Today, without the large-scale use of N in agriculture, as much as 40% of the world’s population would starve due to protein deficiencies. However, as a consequence of its widespread use, nitrate has been called the most common groundwater contaminant. How does nitrate influence water quality?
On a molar basis, nitrate is only slightly less energetic than oxygen as an oxidant; however, nitrate solubility may be over 10,000 times that of oxygen in equilibrium with the atmosphere. As a result, geologic materials exposed to nitrate in groundwater may be oxidized at unprecedented rates. In this paper, I explore how the interaction of nitrate with minerals may have a profound influence on water quality in the Upper Great Plains and beyond. Examples, both actual and hypothetical, are provided to illustrate how nitrate may influence water quality in agriculture, coal mining, coal-fired power plants, and in-situ uranium leach mining.