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29/01/2022 7:29 pm
Topic starter
Which of the following causes biomagnification?
(a) SO2
(b) Mercury
(c) DDT
(d) Both (b) and (c)
1 Answer
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29/01/2022 7:31 pm
Correct answer: (d) Both (b) and (c)
Explanation:
Biomagnification refers to increase in concentration of the toxicant at successive trophic level. This phenomenon is well known for DDT and Hg. In an aquatic food chain concentration of DDT is 0.003 ppb (parts per billion) in water but it can ultimately reaches 25 ppm in fish eating birds through biomagnification. Highest DDT deposition shall occur in birds or sea gull.
High concentration of DDT disturb calcium metabolism in birds which causes:
(i) Thinning of egg shell.
(ii) Their premature breaking of egg shell.
Thus eventually causing decline in bird population.