Seasonal variations and flux of arsenic in Gomati river, Ganga alluvial plain, Northern India

Abstract

Arsenic is a naturally occurring toxic metalloid and its contamination in the hydrological system has significantly received worldwide attention in the last three decades. It is widely distributed in all the components of the environment and varies by more than four orders of magnitude ranging from <0.5 μg/l to 5000 μg/l in the natural water systems. Natural systems, with climate as the controlling mechanism, play an important role in strong geochemical fractionation with quantitative elemental transportation (Raju, 2012a). Natural systems of tropical environment are, therefore, a major concern for environmental scientists (Dissanayake and Chandrajith, 1999; Smedley and Kinniburgh, 2002). The study of fluvial time series provides the key for the understanding of elemental mobilization that controls the dissolved elemental concentration in the various components of the hydrological system (Raju 2012a). Studies have shown that dissolved As concentration in river water varies at a great extent and is mainly dependent on geology, hydrology, climate as well as various anthropogenic activities (Raju 2012b; Masson et al., 2007; Elbaz-Poulichet et al., 2006; Pettine et al., 1997; McLaren and Kim, 1995). In northern India, the Ganga Alluvial Plain (GAP) is one of the most densely populated regions of the world. It is drained by several alluvial rivers and supports nearly 500 million people. The objective of this paper is to report the seasonal variation and flux of dissolved As in the Gomati river and to understand the As mobilization for its eco-toxicological potentials in the GAP.