Why test for Ammonia?
Ammonia is highly soluble in water. One volume of water will dissolve 1 300 volumes of NH3. Ammonia reacts with water to form a weak alkaline.
Most Ammonia in the environment comes from fertilizers (sometimes in the form of Ammonium salts such as Sulfate and Nitrate. Large amounts are used in the production of nitric acid, urea and Nitrogen compounds. It is found in ice and refrigerated plants. It is used in household cleaning to remove carbonate from hard water. Since Ammonia is a decomposition product from urea and protein, it is found in wastewater. Many water treatment processes add ammonia to form monochloramine as part of the disinfection process. Aquatic life also contribute to ammonia levels in a stream.
NH3 is the principle form of toxic Ammonia. It has been reported toxic to fresh water organisms at concentrations of 0.53 to 22.8 mg / litre. Toxic levels are both pH and temperature dependent. Toxicity increases as pH decreases and also as temperature decreases.
Fish exposed to low levels of Ammonia are more susceptible to bacterial infections, have low growth and are stressed. Tissue changes in their gills, liver and kidneys may also occur. Ammonia is a killer when present in higher concentrations and many unexplained losses have been caused by Ammonia. Toxic concentrations of Ammonia in humans may cause loss of equilibrium, convulsions, coma and death.
Criteria in South Africa:
Ammonia levels in ponds and fish tanks should be zero. When it is present, the fish in the system should not be fed until the problem is corrected. In small systems, a water change will help and in larger ponds, a 0-20-0 fertilizer may help.
1.0mg / litre for discharge of effluent water to rivers
10.0mg / litre for discharge of effluent water to other areas
* DWA – Requirements for the Purification of waste water or effluent, Act No. 991 – 18 May 1984
< 1.5 mg / litre Ammonia as N
* SANS 241-1: 2011 Drinking Water Standards