Ammonia in the pond water is a by-product of
metabolism by animals and bacterial
Decomposition of organic matter such as wasted
food, faeces, dead planktons etc.
In water, ammonia nitrogen occurs in two Forms,
un-ionized ammonia and ammonium ion (NH4).
Un-ionized ammonia is determined By total
ammonia concentration, ph, and water
temperature and to a lesser extent on salinity.
It is considered more toxic form of ammonia due
to its ability to diffuse readily across cell
Membrane, hence should be less than 0.1 ppm.
A given concentration of un-ionized ammonia
Is more toxic when dissolved oxygen
concentrations are low.
0.02-0.05 mg/litre Safe concentration
0.05-0.4 mg/litre Sub lethal effect
0.4-2.5 mg/litre Lethal effect
Take 5 ml of water sample
Add 1ml of trisodium nitrate
Add 1ml of phenol nitro phosphate
Add 1ml of sodium hyphochlorite
Cover it with aluminium soil
Keep at dark room for 2 hrs
Observe it under spectro photometer at 630
Maintaining sufficient level of Dissolved
periodic partial removal of algal blooms
water exchange and addition of Liming
agents such as hydrated lime or quick lime
Add zeolite to absorb obnoxious gas
Nitrite is an intermediate product in
biological oxidation of ammonia to nitrate, a
process called nitrification
Nitrite is highly toxic to fish as it oxidizes
hemoglobin to form methemoglobin, which is
incapable of transporting oxygen.
Nitrite toxicity is affected by water pH and
the presence of chloride and calcium ions.
Toxicity increases with increasing pH and
decreases with increasing calcium and
Optimum level of nitrite is less than 0.25
Optimum level can be maintained by
effective removal of organic waste, adequate
aeration, correct application of fertilizer &
feed and use of biofertilizer to accelerate
Take 50 ml of water sample
Add 0.5 ml of sulphuramide solution
Then 0.5 ml of diamine solution
Obeserve the OD value at 543 nm
Correct stocking,feeding and fertilization
practices should be maintained
Pond should kept well oxygenated
Biofilteration should be done through special
filters by conversion of nitrite to harmless