Surface water quality assessment with reference to trace metals in River Mahanadi and its tributaries, India

Trace elements (As, Cr, Cu, Cd, Hg, Fe, Pb, Ni, and Zn) in surface water of Mahanadi River and its tributaries were measured in order to investigate their geospatial metal distribution and extent of contamination. The study was designed to make water quality comparisons with local and global average values. As the river and its contributing tributaries flow through a diverse geologic, topographic, hydrologic, and industrial region, a large catchment area comprising 17 inter-distant water quality sites was chosen. A total of seventy-five water samples were analyzed for the concentration of trace metals in dissolved phases using atomic absorption spectrophotometer. The contamination factor data suggest that several metals had higher concentrations than acceptable and permissible limits prescribed by World Health Organization. Principal component analysis reveals the relationships between metal groups, viz. Ni, Cr, Cu, and Fe, and Hg, Pb, and Cd, and Zn and As. It indicates a difference in the sources of their origin. Further, Pearson’s coefficient analysis revealed a strong and specific intermetal relationships among studied metals. The statistical analysis points toward various industrial wastes and municipal wastes as primary contributing factors for most of the excess dissolved metals in the Mahanadi River.