Spatial distribution and Anthropogenic imprints of La, Ce, Pr, Nd and Sm in Alluvium Sediments of Gangetic Plain, India

The primary study is based on anthropogenic imprints of Light Rare Earth Elements (LREE) such as La, Ce, Pr, Nd and Sm, which have become emerging contaminants due to their widespread use in high technologies in recent years. The main objective of present research is to investigate the spatial distribution and anthropogenic imprints of these elements in river sediments of the Gangetic Plain. In the Gomati River, there is a distinct downstream increase in the concentration of LREE, from 339 to 1349 μg/g, identified in the biotite of the mica-rich bedload sediments. Total average LREE content in suspended sediments of the Gomati (192.3 μg/g), the Sai (229.0 μg/g) and the Hindon (495 μg/g) rivers were observed to be higher than that of the Upper Continental Crust (131.6 μg/g), Average Sediments (122.9 μg/g), World Major Rivers Suspended Sediments (148.9 μg/g) and Post-Archean Australian Shale (166 μg/g). The Hindon River’s suspended sediment from highly urbanized centers at Ghaziabad (1519 μg/g) and Greater Noida (1377 μg/g) represented the extreme LREE levels. The Geo-accumulation index (Igeo) shows a toxicity trend in these sediments: Ce>Pr> La>Sm>Nd. Modern anthropogenic processes are responsible for the LREE enrichment in suspended river sediments, of nearly an order of magnitude higher than in the rivers of the Gangetic Plain. The increasing concentrations of these elements indicate the anthropogenic activities around rivers in urban centers and need for high- level research in the future to monitor them.