If the amount of methaemoglobin in the blood does not exceed 50% of the total haemoglobin, the fish usually survive. Totally different authors often come to contradictory conclusions, and normally fail to offer a definitive rationalization of both the mechanism of nitrite poisonous action on fish or the modifying results of various environmental elements. In normal cardio circumstances, ammonia is oxidized to nitrite and then to nitrate by two separate bacterial actions.
The primary sources of nitrate pollution of floor waters is the usage of nitrogenous fertilizers and manures on arable land resulting in diffuse inputs, and the discharge of sewage effluents from therapy works. They’re present in low concentrations in all surface waters. Nitrites as a