Ammonia

an inorganic form of nitrogen, is contained in fertilizers,
septic system effluent,
and animal wastes. It is also a product of bacterial
decomposition of organic
matter. Ammonia NH3-N (NH3-N) becomes a concern if high levels
of the un-ionized form are
present. In this form NH3-N can be toxic to aquatic organisms.
The presence of
un-ionized ammonia is a function of the NH3-N concentration,
pH, and
temperature. Conversion of NH3-N to nitrite nitrogen by
nitrification requires
large quantities of oxygen which can kill aquatic organisms due
to the lowered
dissolved oxygen concentrations in water. NH3-N concentrations
are reported
in mg/L NH3-N.