Question

In a highly pesticide polluted pond, which of the following aquatic organisms will have the maximum amount of pesticide per gram of body mass?
a. Lotus
b. Fishes
c. Spirogyra
d. Zooplanktons

Answer 1

Concentration of toxins, pesticides in tissues of organisms at successively higher levels in the food chain is called biomagnification. It is also known as biological amplification or biological magnification. It affects the food chain. The organism higher in the food chain is most affected by it.

Complete answer:
Biomagnification is the concentration of toxins in the tissues of the organisms. The contaminants consist of mercury, arsenic, pesticides such as DDT.

DDT was overly used by humans as a pesticide in 1960. It is a classic example to understand biomagnification. DDT affected the bald eagles which were higher in the food chain. It was absorbed by the organisms which were hunted by bald eagles, such as, fishes and slowly the DDT started accumulating in eagles’ bodies. The accumulated DDT in their bodies made them fragile, sterile and caused the bird population to dwindle. Thereafter, DDT was banned in 1972.

Just like DDT, mercury is also a common example of a substance that biomagnifies. Mercury is a natural occurring substance in oceans but in small quantities. Although, human interference with the environment caused it to increase. Mercury is absorbed by algae and then consumed by zooplanktons, zooplanktons are then consumed by small fishes and small fishes are consumed by large fishes. When humans consume these high in mercury fishes, they get ill from mercury poisoning.

It is a matter of concern because it has profound effects on humans, animals and other organisms. It may lead to neurological effects in infants such as mental retardation and other conditions such as cancer and organ failure is also possible due to biomagnification.

Hence, the correct answer is option (b).

Note: Biomagnification can be prevented by not dumping oil and human waste in water bodies, ban of toxic pesticides, do not flush pills or any other medications.
Biomagnification is not only caused by DDT or mercury. Some other common examples are including cyanide used in gold leaching, selenium and other heavy metals.