Bengal arsenic, an archive of Himalaya orogeny and paleohydrology

Holocene groundwater in many districts of the West Bengal and parts of Bangladesh are enriched in arsenic enhancing poisoning effect on humans. One of the main problems to depict the source of arsenic is that this element is very mobile and can be easily removed and recombined from the source during alteration processes, transport and mobilization in sediments. The Ganga-Brahmaputra river system mainly contributed to the buildup of the Bengal fan, which is considered one of the largest modern deltas of the world, then the possible source of the As has probably to be search within the Himalayan belt. We propose that the Indus-Tsangpo suture zone dominated by arc-related rocks and more particularly by large volume of serpentinites enriched in…