NEET Questions Solved


DDT content in the water of a lake that supplies drinking water to the nearby 

villages, is found to be 0.003 ppm. The kingfishers of that area were reported 

to have 2 ppm of DDT. Why has the concentration increased in these birds?

What harm will this cause to the bird population? Name the phenomenon. 

1. DDT is a non-biodegradable pollutant. It can not be utilized and excreted out from the 

body of living organisms, hence gets accumulated at different trophic


2. From water, it accumulates in phytoplanktons then to fish and finally to predatory birds.

3. Higher concentration of DDT diturbs calcium metabolism in birds

resulting in thinning of egg shells, and their premature breaking. 

This phenomenon is called biomagnification.

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