Editing Nitrification (section)

==Environmental concerns==
[[File:Nitrification Process Tank.jpg|thumb|Nitrification process tank at a [[sewage treatment]] plant]]
Nitrification inhibitors are also of interest from an environmental standpoint because of the production of nitrates and [[nitrous oxide]] from the nitrification process. Nitrous oxide (N<sub>2</sub>O), although its atmospheric concentration is much lower than that of CO<sub>2,</sub> has a [[global warming potential]] of about 300 times greater than carbon dioxide and contributes 6% of planetary warming due to greenhouse gases. This compound is also notable for [[Catalysis|catalyzing]] the breakup of ozone in the [[stratosphere]].<ref>{{cite journal|doi=10.1017/S1466046607070482|title=Environmental Review: The Potential of Nitrification Inhibitors to Manage the Pollution Effect of Nitrogen Fertilizers in Agricultural and Other Soils: A Review|journal=Environmental Practice|volume=9|issue=4|pages=266–279|year=2007| vauthors = Singh SN, Verma A |s2cid=128612680}}</ref> Nitrates, a toxic compound for wildlife and livestock and a product of nitrification, are also of concern.

Soil, consisting of [[polyanion]]ic clays and [[silicates]], generally has a net anionic charge. Consequently, ammonium (NH<sub>4</sub><sup>+</sup>) binds tightly to the soil, but nitrate ions (NO<sub>3</sub><sup>−</sup>) do not. Because nitrate is more mobile, it [[Leaching (agriculture)|leaches]] into groundwater supplies through [[agricultural runoff]]. Nitrates in groundwater can affect surface water concentrations through direct groundwater-surface water interactions (e.g., gaining stream reaches, springs) or from when it is extracted for surface use. For example, much of the drinking water in the United States comes from groundwater, but most wastewater treatment plants discharge to surface water.

Among wildlife, amphibians (tadpoles) and freshwater fish eggs are most sensitive to elevated nitrate levels and experience growth and developmental damage at levels commonly found in U.S. freshwater bodies (<20&nbsp;mg/l). In contrast, freshwater invertebrates are more tolerant (~90+mg/l), and adult freshwater fish can tolerate very high levels (800&nbsp;mg+/l).<ref>{{cite journal | vauthors = Rouse JD, Bishop CA, Struger J | title = Nitrogen pollution: an assessment of its threat to amphibian survival | journal = Environmental Health Perspectives | volume = 107 | issue = 10 | pages = 799–803 | date = October 1999 | pmid = 10504145 | pmc = 1566592 | doi = 10.2307/3454576 | jstor = 3454576 }}</ref> Nitrate levels also contribute to [[eutrophication]], a process in which large algal blooms reduce oxygen levels in bodies of water and lead to death in oxygen-consuming creatures due to anoxia. Nitrification is also thought to contribute to the formation of [[photochemical]] smog, ground-level ozone, [[acid rain]], changes in [[species diversity]], and other undesirable processes. In addition, nitrification inhibitors have also been shown to suppress the oxidation of methane (CH<sub>4</sub>), a potent [[greenhouse gas]], to CO<sub>2</sub>. Both [[nitrapyrin]] and [[acetylene]] are shown to be potent suppressors of both processes, although the modes of action distinguishing them are unclear.