Explanation:

The term bio-magnification refers to the increase in the concentration of non-degradable pollutants as they pass through food chain.
For example, spraying a marsh to control mosquitoes will cause trace amounts of DDT to accumulate in the cells of microscopic aquatic organisms, the plankton, in the marsh. In feeding on the plankton, filter-feeders, like clams and some fish, harvest DDT as well as food.