Question

With the help of a flow chart, show the phenomenon of biomagnification of DDT in an aquatic food chain. [3]

Answer 1

Biomagnification refers to increase in concentration of the toxicant at successive trophic levels. This happens because a toxic substance accumulated by an organism cannot be excreted or metabolised, and is thus passed on to the next higher trophic levels. [1]Fig: Biomagnification of DDT in an aquatic food chain [1]

Figure shows biomaginification of DDT in an aquatic food chain. Suppose if we consider the concentration of DDT to be 0.003 ppb in water, it can reach 25ppm in fish eating birds through biomagnification. [1]