The concentration of polychlorinated biphenyls (PCB, an organochloride contaminant) in many fish populations has been declining, since a ban on their production was instituted in the late 1970s. PCBs remain a potential problem, however, because they are lipophilic and are known to biomagnify. Based on this knowledge,
What type of fish expected to be safest for human consumption?

Piscivorous fish species (i.e., which eat other fish)

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Benthivorous fish species (i.e., which eat invertebrates on the lake bottom)

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Small (young) fish

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Fish species with high fat content

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Solution

The correct option is C Small (young) fish
Heavy metals and persistent pesticides (e.g., organochlorine of chlorinated hydrocabons like DDT) pass into food chain and increase in amount per unit weight of organisms with the rise in trophic level due to their accumulation in fat, This phenomenon is called biomagnification. Therefore, lower the trophic level of fish (such as small fish), lesser will be the biomagnification and hence safer it will be for consumption.

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