Question

Biomagnification of DDT in aquatic food chain from $0.003$ ppb in water to fish eating birds would be

• A. $100$ ppm
• B. $50$ ppm
• C. $25$ ppm
• D. $2$ ppm

Answer 1

The correct option is C $25$ ppm

DDT (Dichlorodiphenyltrichloroethane) is an organochlorinated compound that is stable in nature. It is highly soluble in the fats of the living organism and so, it shows persistence in the food chain. It is seen that the level of DDT increases as the food chain progresses. It means, the primary consumers will have more DDT concentration than the producers, the secondary consumers will have more than primary consumers and so on. The highest concentrations will be seen in the top carnivore. This is because the consumers at the successive trophic level consume more than the previous level to fulfil the energy requirements. Due to this, DDT keeps on accumulating in the successive trophic levels in higher concentrations. This process is called the biomagnification.

0.003 ppb in water, 0.04 ppm in zooplankton, 0.5 ppm in small fish, 2 ppm in large fish, 25 ppm in large fish eating bird.

Hence, the correct answer is '25 ppm'