A research team at the Indian Institute of Technology Guwahati has unveiled a low-cost, natural process capable of removing toxic lead from contaminated water, offering a potentially scalable solution to one of the world’s most persistent environmental threats.
Details of the work, published in the Journal of Hazardous Materials, were led by Prof. Debasish Das of the Department of Biosciences and Bioengineering, together with Dr. Abhijeet Mahana and Prof. Tapas K. Mandal of the Department of Chemical Engineering. The scientists relied on cyanobacteria, photosynthetic microorganisms found in nature, to extract lead from polluted water without the use of expensive synthetic chemicals.
Lead contamination remains a global public-health concern, affecting more than 800 million children worldwide, including an estimated 275 million in India. The metal enters water bodies through industrial discharge, agricultural runoff, and ageing pipelines, and can persist for decades. Its impact on human health is severe, leading to neurological, cardiovascular, kidney, and developmental disorders.
Conventional treatment systems depend heavily on costly chemicals or synthetic adsorbents that often introduce secondary pollution. Seeking an alternative, the IIT Guwahati team turned to bioremediation, a natural method by which microorganisms remove harmful substances from the environment. The researchers identified a light-dependent cyanobacterial species, Phormidium corium NRMC-50, and found that the exopolysaccharides (EPS) it produces were the most efficient agents for lead removal.
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Laboratory results showed that EPS could remove up to 92.5 per cent of lead from contaminated water. “This approach uses very little energy and can be scaled without complex infrastructure,” said Prof. Das. “Preliminary estimates indicate it could reduce treatment costs by 40–60% compared to conventional methods, with equal or better effectiveness. Its eco-friendly nature makes it ideal for industries and municipalities seeking affordable solutions.”
The researchers noted that cyanobacteria can also capture a wider range of pollutants, including pesticides, dyes, and industrial chemicals. Metals absorbed during the process may later be recovered to produce biochar, bioplastics, or biofuels, increasing the sustainability and economic value of the method.
Cyanobacteria require only sunlight, carbon dioxide, and limited nutrients to reproduce, making them an energy-efficient and renewable alternative to synthetic treatment systems. The IIT Guwahati team plans to scale the project from laboratory settings to a pilot-scale system capable of handling real-world wastewater conditions.
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