What is Bioaccumulation
Bioaccumulation refers to the gradual buildup of a substance in a living organism which cannot be used or metabolized at the same rate at which it is accumulated. These substances may be heavy metals, mercury or DDT etc. It is of no concern if the accumulating substance is not harmful to the organism. However, some harmful compounds can also accumulate in the body such as mercury.
The major sources of pollutants that are accumulated in organisms are pesticides as well as automobile and industrial emissions. When the pollutant enters the water or soil it can easily enter the food chain and be a part of an organism.
The simplest example of this phenomenon is that a pollutant enters the water source where it sticks to phytoplankton; from here many of its kinds may be eaten by a zooplankton. Then if a small fish eats few such zooplanktons and then such small fishes are eaten up by a large fish. It may again be eaten up by a larger predator; in this way the toxic substance can be accumulated in the large predator. Because it was in a tiny amount when it stuck to a phytoplankton but then it magnified many times until it is accumulated in a fish. This phenomenon leads to biomagnification.
The level at which a substance is bioaccumulated depend upon the rate at which it is taken up and the rate at which it is eliminated from the organism.
Bioaccumulation may also be harmful to human life. For example saltwater animals are sometimes heavily loaded with such toxic substances like mercury which enter the human body if they are consumed.