High-Arsenic Groundwater in the Southwestern Bengal Basin Caused by a Lithologically Controlled Deep Flow System

M. R. Khan, H. A. Michael, B. Nath, B. L. Huhmann, C. F. Harvey, A. Mukherjee, I. Choudhury, M. Chakraborty, M. S. Ullah, K. M. Ahmed, S. L. Goodbred, P. Schlosser, B. C. Bostick, B. J. Mailloux, T. Ellis, A. van Geen