How does water that looks perfectly clean contain dangerous levels of arsenic? Even after decades of research and treatment technologies, why does arsenic exposure remain a drinking-water problem?

In this episode of The Water Data Podcast, hydrogeologist Prof. Abhijit Mukherjee joins host Veena Srinivasan to trace the arsenic story across the Bengal and Ganga-Brahmaputra aquifer systems.

In the conversation, Veena and Abhijit explore how arsenic naturally occurs in sediments, why the geology and geochemistry of the Bengal Delta allow it to enter groundwater, and how microbial activity, iron minerals, and changing chemical conditions underground influence its mobilization.

The conversation also examines how large-scale pumping can change groundwater flow and potentially mix water between aquifer layers, making apparently simple rules about "safe" and "unsafe" groundwater much harder to apply.

Abhijit argues that arsenic treatment itself is not necessarily the biggest challenge. Filters need to be maintained, contaminated filter media must be safely disposed of, drinking-water sources must be monitored, and solutions have to work after researchers and engineers leave.

Veena and Abhijit also discuss arsenic in irrigated agriculture and the unequal vulnerability to exposure. This episode asks a larger question: when the science of a water problem is reasonably well understood, what prevents that knowledge from becoming safe water for everyone?

The Water Data Podcast is hosted by Veena Srinivasan and produced by WELL Labs.

The Water Data Podcast is a talk show on the science, systems, and stories of water, hosted by Veena Srinivasan.

For all references and further readings related to the episode, visit https://welllabs.org/wdp-abhijit-mukherjee/

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Recording by Nabina Chakraborty and Nanditha Gogate. Video editing by Srisabari Varaguna Pandian. Graphics and artwork by Aparna Nambiar. Audio mixing and mastering by Vijay Doiphode. Podcast production and management by Nabina Chakraborty and Pavan Srinath.