Bio magnification also called as food chain concentration or biological magnification or biological amplification
It is a successive increase in concentration of persistent chemicals by organisms at various trophic levels in food chain. Persistent chemicals are the chemicals that cannot be degraded in the environment and remains in environment then they are consumed by organisms through food. Simply we can say that An Accumulation of different chemical materials in organism's body slowly. Many chemicals show bio magnification such as DDT, heavy metals, pesticides.. etc.
Causes:
- Natural causes are negligible
- Releasing of sewage directly into water bodies.
- Releasing of industrial effluents directly into water bodies
- Domestic waste, biodegradable,non biodegradable material are thrown into water bodies.
- Agrochemicals: Fertilisers, insecticides, pesticides in the soil, then they finally deposited in to the water bodies.
- Radioactive materials: Radioisotopes in hospitals..etc
- Thermal pollution
- Oil spills: this also lead to marine pollution.
For example a chemical Was released into water body from Factory/oil spills/sewage..etc. That chemical is deposited in phytoplankton present in water body. Then Zooplankton consume phytoplankton. Small fish consume zooplankton. Big fish consume small fish. Humans consumer big fish. And that chemical concentration is also increased from lower animals to higher animals.
Effects:
Effects on water bodies:
- Eutrophication of lake. Due to addition of organic and inorganic nutrients path to Increasing of nutrient concentration in the water body.
- Due to eutrophication, free floating algae numbered is increased and it is known as Algal booms.
- Biological Oxygen demand is increased. That is the amount of dissolved oxygen required by the bacteria to decompose the organic waste present in water body.
Effects on human health:
Biomagnification Cause different diseases such as
Copper in water cause hypertension,
Zinc in water cause vomiting, Renal damage.
Lead(pb) cause fatigue, paralysis,
Cadmium cause ouch ouch disease,
Arsenic cause Black foot disease or Melanoma,..etc.
Let's take DDT as an example how this effects the all organisms. Dichlorodiphenyltrichloroethane (DDT) are using as a insecticide to kill mosquitoes. DDT is not biodegradable. It enters into the food chain.
After spraying DDT, it enters into the plant, then plants to animals through food chain , finally DDT is deposited in our body and cause dangerous effects such as
Immunization levels are decreased,
Estrogen and testerone activities are decreased,
In birds, eggshell become very thin so that not possible to continue next generation(hatching)..etc.
Many countries banned the usage of DDT, India banned it for agriculture usage but against mosquitoes even though large population of mosquitoes are not responding to DDT. In World-wide highest DDT% is present in Indian organisms.
Sources
- https://programs.wcs.org/india/Newsroom/Blog/ID/15443/Biomagnification--an-ever-growing-threat
- Miller ME, Hamann M, Kroon FJ (2020) Bioaccumulation and biomagnification of microplastics in marine organisms: A review and meta-analysis of current data.
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