The term biomagnification or biological amplification or concentration refer to the increase in concentration of non-biodegradable pollutant through successive trophic level of a food chain. The organisms of last tropic level possess high concentration of the non-biodegradable pollutant. One of the best example of biomagnification of mercury pollutant is Minimata lake of Japan. Where accumulation of pollutant in fishes through food chain was responsible for a large number of death due to Minimata disease.