Heavy metals are defined as metals with relatively high densities, noted for its potential toxicity. It occurs naturally in the earth crust, widely found in soil, water, sediments and even in the organism at optimum concentration.
But rapid human activities such as mining, discharge of untreated industrial waste in rivers, vehicle emissions etc., has increased its concentration relatively. Apart from this, the use of fertiliser, ageing water supply infrastructures, treated woods and microplastics are also responsible for the increased concentration of heavy metals in soil and water.
According to research conducted by the central water commission, India’s 42 rivers have at least 2 toxic heavy metals beyond the permissible limit. Ganga, India’s national river is found to be polluted with five heavy metals namely chromium, copper, nickel, lead and iron.
Metals like lead, Mercury, cadmium, and arsenic are in the WHO lists of 10 chemicals of major public concern. India’s poor automobile recycling and scrappage policy are also paving way for the addition of these toxic metals in soil.
Heavy metals are non-biodegradable and cause biomagnification (means it’s concentration gets increases when it enters the food chain). Majority of heavy metals are toxic even at low concentration and are capable of entering the food chain.
The concentration of toxic metals in grain and vegetables grown in contaminated soils have increased at an alarming rate. These metals can enter plants, animal, and human tissues via inhalation, diet and manual handling. They can bind and interfere with the functioning of vital cellular components.
Even acute exposure to arsenic results in encephalopathy, vomiting and diarrhoea. Chronic exposure is more detrimental which may lead to diabetes, cancer, and hypopigmentation.
Heavy metal pollution is a major concern for the people living on the bank of the river because they use this water as a major source of their livelihoods, such as for drinking, cooking and irrigation. Curative measures using conventional physical and chemical methods are uneconomical and generates a large volume of chemical wastes. But the use of microbial absorbents is eco-friendly and cost-effective.
Hence it is an effective alternative for the treatment of the heavy metal contaminated environment. There is also a need for awareness among people so that they can protect themselves from these toxic metals which is silently killing them.
Article by Pranav Khatri