Question

Which of the following is the correct order of biomagnification of DDT in an aquatic food chain?

• A. Water- $0.003$ ppm, zooplankton- $0.5$ppm, small fish- $0.04$ppm, large fish -$2$ppm, fish eating birds-$25$ppm
• B. Water-$0.003$ppm, zooplankton-$0.04$ppm, small fish-$0.5$ppm, large fish-$2$ppm, fish eating birds-$25$ppm
• C. Water-$0.003$ppm, small fish-$0.04$ppm. zooplankton-$0.5$ppm, large fish-$2$ppm, fish eating birds-$25$ppm
• D. Water-$0.003$ ppm, fish eating birds-$25$ppm, zooplankton-$0.5$ppm, small fish-$0.04$ppm, large fish-$2.5$ppm
• E. Water-$0.003$ppm, large fish-$0.04$ppm, small fish-$0.5$ppm, zooplankton-$2$ppm, fish eating birds-$25$ ppm

Answer 1

The correct option is B Water-$0.003$ppm, zooplankton-$0.04$ppm, small fish-$0.5$ppm, large fish-$2$ppm, fish eating birds-$25$ppm

DDT is not soluble in water, so it will be least in water (0.003 ppm). It is seen that the level of DDT increases as the food chain progresses. It means, the primary consumers (zooplankton) will have more DDT concentration than the producers, the secondary consumers (small fish) will have more than primary consumers and so on. The highest concentrations will be seen in the top carnivore (fish eating bird). 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.

Hence, the correct answer is 'Water-0.003ppm, zooplankton- 0.04ppm, small fish-0.5ppm, large fish-2ppm, fish eating birds-25ppm'