Bioaccumulation.
Normally, plants and animals have the ability to get rid of some poisons out of their systems. However, certain toxic chemicals like pesticides, insecticides, methyl mercury, heavy metals such as mercury, lead, cadmium, zinc, copper, etc. tend to accumulate and remain fro longer periods in the body of organisms. This is called bioaccumulation. Once bioaccumulated at any level of the food chain, their concentration goes on progressively increasing as they pass from organism to organism along the food chain. This is called biomagnifications. Thus, these chemicals tend to accumulate in quantities far higher than their concentration in the surrounding medium. The toxic methyl mercury present in pollute water can accumulate in fishes in concentration 1000 times greater than its concentration in the water. Consumption of such fish caused ‘Minamata disease’ in Japan in 1952. Similarly, bioaccumulation of cadmium in liver, kidneys and pancreas caused a human disease called ‘Itai-Itai’ in Japan. It is a bone disease and leads to cancer of liver and lungs.
The bioaccumulation of poisonous substances is found to be very high in India. This is especially true of pesticide chemicals. This is due to the consumption of crop and vegetables treated with insecticides, contaminated water and drinks, etc.
The fallouts of nuclear fission and various radioactive substances also enter and accumulate in organisms. These are passed on human through the food chains. This is harmful and causes various health hazards e.g. genetic misbalance, tumors, Leukemia, etc.
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