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Ammonia (NH3) is a colorless gas with a strong pungent odor. It is easily liquefied and
solidified and is very soluble in water. One volume of water will dissolve 1,300 volumes of
NH 3. Ammonia will react with water to form a weak base. |
Methodology: An ammonia ion-specific electrode can be used with a computer aided
titrimeter (CAT). However, Ion Chromatography is a more accurate and efficient method for
anion identification.
Ammonia concentration is usually reported as total (NH3/NH4-N) ammonia nitrogen.
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NH3 is the principal form of toxic ammonia. It has been reported to be toxic to fresh water organisms at concentrations ranging from 0.53 to 22.8 mg/L. Toxic levels are both pH and temperature dependent; toxicity increases as pH decreases and as temperature decreases. Plants are more tolerant of ammonia than animals, and invertebrates are more tolerant than fish. Hatching and growth rates of fishes may be affected while structural development changes may occur in tissues of gills, liver, and kidneys may also occur. Toxic concentrations of ammonia in humans may cause loss of equilibrium, convulsions, coma, and death.
Criteria: The un-ionized form of ammonia (NH3) should not exceed 0.05 mg/L in order to protect aquatic organisms. This is calculated from total ammonia using temperature and pH in a formula.
© 2007 Arizona Board of Regents for The University of Arizona |