1. KTH-International Groundwater Arsenic Research Group, Department of Land and Water Resources Engineering, Royal Institute of Technology, Teknikringen 76, SE-100 44 Stockholm, Sweden
2. Department of Chemistry, University of Kalyani, Kalyani 741 235, West Bengal, India
3. School of Geosciences, The University of Sydney, Sydney, NSW 2006, Australia
4. Department of Geology and Geophysics, Indian Institute of Technology-Kharagpur, Kharagpur-721 302, West Bengal, India