ABSTRACT
A total of 423 TWs were surveyed for platform color and concentration of As, iron (Fe) and Mn in TW water over an extensive area of 100 km2 in Chakdaha block, West Bengal, India (23.02-23.12°N; 88.5-88.6°E) (Fig. 1). The color of
1 INTRODUCTION
Millions of hand-pumped Tubewells (TWs) have been installed over the past few decades, predominantly through community initiatives as well as governments to shift drinking water source from surface water to groundwater. Most of these TWs are installed in the shallow aquifers with depth ranging between 10-50 m, where the concentrations of dissolved Arsenic (As) have been reported to be the highest (Bhattacharya et al. 2011; von Brömssen et al. 2007; Chatterjee et al. 2010). Consequently several millions of people, living in this region, are estimated to be exposed with As in drinking water above World Health Organization (WHO) drinking water guideline of 10 μg/L (van Geen et al. 2003; Kapaj et al. 2006; Chakraborti et al. 2008; Polya & Charlet 2009). Recently dissolved Manganese (Mn) in drinking has also been
the TW platform was assigned in the field and latter in the laboratory it was further verified by looking into the picture of TW platform captured by a Kodak C183, 14 MP, digital camera equipped with 3X optical zoom. Prior to groundwater sampling, each TW were purged for few minutes and collected samples were acidified on-site by 7M nitric acid (HNO3) (1% v/v, Suprapur®, Merck) to preserve the metals in solution until analyses of As, Fe and Mn in the laboratories of Kalyani University.
