Guwahati: Researchers at IIT Guwahati have developed an eco-friendly method to remove lead from contaminated water using cyanobacteria, commonly known as blue-green algae, a move they said could offer a sustainable option to improve water quality.According to the Central Ground Water Board (CGWB), 20% to 30% of groundwater samples tested across major Indian cities exceed the safe limits prescribed by the World Health Organisation.IIT Guwahati on Wednesday said the study presents an environmentally friendly approach to tackling lead-contaminated water. In the study, a research team led by Prof. Debasish Das of the Department of Biosciences and Bioengineering identified cyanobacteria that can absorb lead from polluted water. The algae are commonly found in village ponds, lakes, reservoirs, paddy fields and other slow-moving freshwater bodies.The researchers found that exopolysaccharides (EPS), a sticky, sugar-rich substance in the algae, showed the highest lead absorption capacity. “In our recent study, we found that EPS organism can remove lead (66.2%), one of the most toxic heavy metals, from polluted water,” Prof. Debasish Das said.The findings were published in the Journal of Environmental Chemical Engineering in a paper co-authored by Prof. Debasish Das, Prof. Tapas Kumar Mandal of the Department of Chemical Engineering and Dr. Abhijeet Mahana, Postdoctoral Fellow at IIT Guwahati.To determine how EPS absorbs lead, the team used multiple techniques to analyse the material’s composition and its interaction with lead. They found that naturally occurring chemical groups in the material bind lead particles, aiding removal from contaminated water, and that blue-green algae can change its chemical composition to capture lead.“Though there are multiple conventional water treatment methods, which use chemical precipitation, membrane filtration or ion exchange processes, they are often expensive, consume large amounts of energy, and generate secondary pollutants. Due to such limitations, researchers around the globe are working towards finding an environmentally friendly and renewable alternative for this problem,” IIT Guwahati said.
