Temporal Variations in Dissolved Elemental Compositions in the Ganga River at Rishikesh, Uttaranchal

A number of studies have been carried out and published in recent times on the major elemental compositions and isotopic geochemical aspects on the Ganga River, thus generating a wealth of information. The immense data confirmed the control of Himalayan Rivers, Ganga and Brahmaputra, on changing isotopic signatures of sea waters through geologic time. In a first ever attempt to monitor and study temporal variations in chemical composition of river water, at a particular location in the Ganga River in the Himalayas, we present information collected at a single location of the Ganga River in its initial stages (Rishikesh), studied daily over a four week period during non-monsoon season in the year 2004. The temporal variations in major water quality parameters have been inferred. The variations in chemical compositions at different periods of the day show variations indicating variable chemical weathering rates. The 84 samples collected and analysed for 13 chemical parameters and reported here, have thus generated a strong database for further studies. The variable compositions indicate the dissolution of rocks at different rates and hence there is a strong need to characterize the dissolution rates of various lithologies in river basins.