Evaluation of heavy metal contamination using environmetrics and indexing approach for River Yamuna, Delhi stretch, India

•River Yamuna (Delhi stretch) polluted with high concentrations for most of the heavy metals beyond permissible limits.•Delhi stretch is critically polluted stretch in terms of Heavy metal pollution index.•Najafgarh and Shahdara drain outlet in the river identified as the hot-spots of metal contamination.•Principal component analysis resulted in two components each having its own pollution source. The objective of the present study is to investigate the current status of heavy metal pollution in River Yamuna, Delhi stretch. The concentrations of Nickel, Cadmium, Chromium, Copper, Iron, Lead, and Zinc in water samples have been studied during December 2013–August 2015. The overall mean concentration of heavy metals was observed in the following order Fe>Cu>Zn>Ni>Cr>Pb>Cd. Correlation analysis formed two distinct groups of heavy metals highlighting similar sources. This was further corroborated by results from principal components analysis that showed similar grouping of heavy metals (Ni, Zn, Fe, Pb, Cd) into PC1 having one common source for these heavy metals and PC2 (Cu, Cr) having another common source. Further, our study pointed out two sites i.e. Najafgarh drain and Shahdara drain outlet in river Yamuna as the two potential sources responsible for the heavy metal contamination. Based on heavy metal pollution index value (1491.15), we concluded that our study area as a whole is critically polluted with heavy metals under study due to pollutant load from various anthropogenic activities.