Question

Which organisms in a food chain consisting of algae, copepods (small crustaceans), small fish, large fish, and ospreys (fish-eating birds of prey) would have the highest concentrations of DDT in their tissues?
(A) Algae
(B) Copepods
(C) Small fish
(D) Ospreys

Answer 1

Hint:DDT is a pesticide and thus a toxin, so it can undergo the process of biomagnification. Through this process toxicity in each trophic level is maximum at the highest trophic level. Biomagnification can be reduced by reducing the use of chemicals and restricting such chemical-based substances to enter water bodies.
Step by step solution:
Biomagnification is the accumulation of a chemical by an organism as a result of exposure to both food and water, resulting in a concentration that is higher than what would have been expected from equilibrium and higher than what would have occurred with only water exposure.
In contrast to home sewage, wastewater from sectors like petroleum, paper manufacture, metal extraction and processing, chemical manufacturing, etc., frequently contains. Especially dangerous compounds are heavy metals (defined as Items with a density greater than 5 g/cm3 like mercury, lead, cadmium, copper, and other heavy metals) and a range of organic compounds. A few hazardous chemicals, which are frequently present in industrial wastewater, can be amplified biologically by the aquatic food chain. A few hazardous chemicals, which are frequently present in industrial wastewater, can be amplified biologically by the aquatic food chain.
The term "biomagnification" describes an increase in the poison at progressively higher trophic levels. This occurs because a creature acquired a poisonous chemical that cannot be metabolised or eliminated, thus it is transferred to the trophic level above that. Both mercury and DDT are well-known for this behaviour. DDT biomagnification in a marine food web. That is in a way that raises the DDT concentration at trophic levels; for example, if it starts at 0.003 ppb (ppb = parts per billion) in water 25 ppm in fish-eating birds or parts per million via means of biomagnification. High DDT concentration can disturb calcium metabolism in birds which can lead to thinning of eggshells. So, the maximum concentration of DDT is at the highest trophic level which is in ospreys.
So, option (D) is correct.
Note: Sewage discharged from households does not lead to biomagnifications but still it can lead to serious health complications, which can also lead to the eutrophication of the lake.