Researchers from IIT Varanasi and Institute of Engineering and Technology (IET) Lucknow have developed cost-effective absorbents made of commonly available guava leaf biomass, mango barks and bagasse to treat arsenic contaminated water, which has become a threat to over 22 lakh people in the country.
According to doctors long-term exposure to arsenic in drinking water and food can lead to cancer and skin lesions and has been associated with the incidence of diabetes.
According to the researchers led by Devendra Mohan, Markandeya, S Dey and SB Dwivedi from IIT Varanasi and SP Shukla from IET, Lucknow , the guava leaf biomass, mango bark and bagasse were collected within the campus of IIT, Varanasi.
Extensive laboratory investigations were conducted to evaluate the adsorptive capability of low cost adsorbents prepared from the three products for adsorption of Arsenic, said the researchers in their study published in the latest journal of Current Science.
The results are significant given that several technologies that are available now for the treatment of arsenic contaminated water amongst which the most common techniques are oxidation/precipitation/ filtration, coagulation/electro-coagulation/co-precipitation, ion exchange resin, membrane techniques like ultra/nano-filtration/reverse osmosis/electrolysis, etc.
Some of these require high cost, high-tech operation and maintenance and regeneration (feasible partially) and also create sludge disposal problems. Membrane-based techniques also need high initial as well as operation and maintenance costs along with rejection of water in sizeable quantities. The other limitation associated with most of the conventional treatment
During the past few decades, arsenic has gradually been identified around the world as one of the most toxic substances in water and wastewater, which weakens the immune system and threatens human health.
Human activities resulting in arsenic in groundwater are mainly owing to arsenical pesticides, fertilizers, desiccants, preservatives, dust from the burning of fossil fuels and disposal of industrial and animal wastes, etc.
Certain severe diseases faced by humans due to consumption of arsenic contaminated water include cancers of liver, lungs, skin, kidney and bladder; pigmentation changes, hyperkeratosis, neurological and gastrointestinal disorders, muscular weakness, bone marrow problems, cardiovascular problems, etc.
At least 10 states in India are affected by arsenic contamination of groundwater and seven of them — West Bengal, Jharkhand, Bihar, Uttar Pradesh, Assam, Manipur, and Chhattisgarh — have reported contamination levels that are above the permissible limit of 10 micrograms per litre (µg/L).
State-wise, West Bengal leads in Arsenic contamination with 9,756 areas affected, followed by Assam with 4,416 areas affected. Not just India, but the presence of Arsenic in water is a huge problem worldwide. It is now recognised that at least 140 million people in 50 countries have been drinking water containing arsenic at levels above the WHO provisional guideline value of 10 g/L.
Apart from Arsenic, other toxic chemicals like Fluoride and Chlorine are also present in tap water in high amounts.