Ammonia occurs in water as either ionized Ammonium (NH4) or unionized Ammonia (NH3) resulting from leachate or run-off from agriculture, degredation of organic matter, or a build up of waste products within the water. Even in low concentrations, Ammonia can be harmful if absorbed by aquatic animals, invertibrates or plants.
Measurement and control of Ammoniacal Nitrogen is necessary to maintain sewage treatment performance. On-site determination is important to ascertain that nitrification is adequate and biological treatment satisfactory. High levels of Ammonia in groundwater and flooded properties indicates contamination by raw sewage.