Sources of Nitrogen contamination:
Nitrogen contamination in the form of nitrate (NO3-) and ammonia (NH3) occurs as a result of agricultural runoff from fertilizer or animal waste. It is highly soluble and easily percolates through the soil, contaminating aquifers. This excess nitrate poses a problem since it leads to eutrophication in streams and has some averse health effects in humans.
Nitrogen contamination also exists in the form of nitroaromatic compounds such as nitrobenzene, nitrophenol, nitrotoluene, and nitrobenzoate which are used in the industrial manufacture of pesticides, explosives, dyes, pharmeceuticals and plastics.
Trinitrotoluen (TNT)
Health problems:
Nitrate ingestion can cause blue-baby syndrome (methaemoglobinemia) since nitrate-reducing bacteria in the intestine produce nitrite which bind with hemoglobin in blood. This inhibits the red-blood cells from transporting oxygen to tissue cells. Nitroaromatics are also highly toxic as they are mutanagenic, and carcinogenic.
Why use bioremediation?
Bioremediation of nitrogenous pollution is not a new idea; the decontamination of nitrate and ammonia pollution by bacteria is a major part of the nitrogen cyle. In fact, wastewater treatment plants take advantage of this biological process all the time to remove nitrogenous pollution from water via aeration tanks - we simply don't usually label this process as bioremdiation. Furthermore, wastewater treatment is an example of ex situ treatment since the contaminated media is transported to a different location for remediation. While this treatment is effective, it requires expensive machinery and pump systems. Thus much current research is investigating potential strategies for in situ remediation.
Atlas (1998); Spiro (2003)