Characterisation of Metals in Water and Sediments of Subarnarekha River along the Projects’ Sites in Lower Basin, India

The Subarnarekha River is one of the most important east flowing rivers of India. The river in West Bengal and Odisha is site for the Subarnarekha Barrage Project and Kirtania port respectively. The major objectives of the present study were to investigate the pre-projects level of heavy metals in water and sediments of the Subarnarekha River along the projects’ sites. Water and Surface sediments collected from six locations were analysed for Fe, Zn, Cu, Pb, Ni, Cd, Mn and Cr with Atomic Absorption Spectrophotometer. Contamination factor, Contamination degree, Pollution load index (PLI) and Geo-accumulation index (Igeo) were used to assess the degree of accumulation of heavy metals in the sediments. The important findings of the study are: (1) Ficklin plot classified all water samples into near neutral low metal class; (2) A close relationship was obtained between organic carbon and metal content in river bed sediments; (3) All sampling sites displayed PLI values ≥ 0 but < 1; (4) Igeo values for metals at the sampling sites were ≤ 0. The results indicated river water and bed sediments to be unpolluted and ecologically suitable and sustainable. Absence of major anthropogenic influence in the region was primarily found to be responsible for the unpolluted nature of water and sediments. This study can be used as reference to monitor the status of quality of water and sediments during ongoing projects and post-projects scenario.