Short notes about biological magnification
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Biological magnification
Pesticides are used on a large scale to protect crops from various diseases and pests. When these pesticides enter the soil, they are absorbed by plant parts with minerals and water from the soil. These chemicals can enter water sources as a result of rains, furthermore into the bodies of aquatic animals and plants, hence into the food chain. As these chemicals cannot be disintegrated, at each of the tropic levels, they keep getting accumulated, wherein most of the accumulation occurs at the top carnivore’s level. This is termed as biological magnification where there is increase in the concentration of harmful pollutants with each increasing tropic level.
For instance, high DDT concentration in a pond saw the producers (phytoplankton) to have a DDT concentration of 0.04 ppm. As these phytoplankton were consumed by zooplankton – the consumers, the concentration of DDT in the bodies of zooplankton was noted to be 0.23 ppm. When this in turn is consumed by small fish, more of DDT gets collected in their bodies. Consequently, the large fish (top carnivore) feeding on different small fish tend to have the maximum concentration of DDT.