Question

How does pollution relate to biological magnification?

Answer 1

Bio magnification is the increase in the concentration of pollutant at each trophic level. It is commonly seen in aquatic food chains where animals are found in water and water acts as a source of pollutant.

Complete answer:
Biomagnification is the increase in the concentration of the substance that is toxic to the individual at the successive trophic level in the food chain. It happens because pollutants are accumulated in an organism but cannot be excreted by the body so they pass to the next trophic level which feeds on them.
Bio magnification is the accumulation of toxic pollutants by various organisms within a food chain. It is mainly seen in mercury or pesticide like DDT.
There is a lot of environmental pollution happening in the present day, where industrial waste or other pollutants like heavy metals are released into the rivers, lakes and ocean.
If there is any pollutant like heavy metals entering the rivers there are large aquatic lives and this aquatic life includes zooplankton, aquatic plants and animals where those zooplanktons and plants absorb the water, so by that heavy metal and other toxins enter those organisms. And these aquatic organisms are taken as food by small tiny fishes and other aquatic life and these tiny fishes are eaten by the bigger fishes and large birds and animals or humans. So these toxins used to accumulate and increase in the concentration in tissues of those animals. So they move up in the food chain in a progressive manner because organisms of one trophic level are food for organisms of another trophic level. The main cause of the increase in biomagnification occurs due to persistence, where the substance cannot be broken down by the environmental process. At the same time the concentration of substance increases as they move up a food chain.

Some effects of Biomagnification:
-DDT obstructs calcium metabolism found in birds which can cause decrease of egg shells and their premature cracking and death of bird population.
-Selenium accumulates in plants growing on selenium rich soil which result in stunted growth in plants, loss of appetite in animal grazing in such plants.
-Bio magnification of fish results in Minamata disease in Japan leading to numbness of limbs, lips etc.

Note: The various causes of biomagnification are:
-Industrial activities: Industries and factories release high amounts of toxic substances into soil, rivers.
-Agriculture: Farming leading to increase in nutrients and heavy metals because of high use of fertilizers etc.
-Organic contaminants: Manures and bio solids which are processed contain various contaminants.