Ammoniacal nitrogen is a measure for the amount of ammonia, a toxic pollutant often found in landfill leachate and in waste products, such as sewage, liquid manure and other liquid organic waste products
- It can also be used as a measure of the health of water in natural bodies such as rivers or lakes, or in man made water reservoirs. The term is used widely in waste treatment and water purification systems.
- Major organic forms of nitrogen include proteins, amino acids, DNA, and RNA.
- Ammonia is toxic to fish and humans. The toxicity is decreased with lower alkalinity and increases with higher alkalinity as ammonium is converted to ammonia
Source: Wikipedia, https://en.wikipedia.org/wiki/Ammoniacal_nitrogen#Structure_and_Basic_Chemical_Properties