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This study reports the distribution of Cr, Ni, Cu and Pb in waters, sediments, macrophytes and fish of the Yamuna River’s patch in Delhi (India). This is one of the most polluted stretches of rivers in the world. Water from this river is used fosr irrigation, industrial and domestic purposes, including drinking water. The effects of season and anthropogenic practices were identified. Almost zero dissolved oxygen and high levels of lead and phosphate indicate the polluted state of the aquatic system. The enrichment factors in sediments (with respect to reference site) vary in the range of 0.60–82.9% (Cr), 1.40–90.5% (Ni), 1.00–85.3% (Cu) and 3.80–86.6% (Pb). The toxic effects due to Ni and Pb could frequently be visible in aquatic life as their values fall above the probable effect level (36 mg Kg−1 for Ni and 91.3 mg Kg−1 for Pb). The metal contents in the macrophyte (Eichhornia crassipes) and the fish (Oreochromis niloticus) generally increase in the summer season. Cu and Pb accumulate preferenti...

In this study, the fractionation and ecotoxic potential of Cr, Ni, Cu and Pb in water and sediments of the river Yamuna (Delhi stretch) is presented. The river water is used for various purposes such as irrigation, industrial, domestic and drinking. The investigations suggest that the availability of metals in water follows the sequence Ni>Cr>Pb>Cu whereas a different pattern (Pb>Cu>Ni>Cr) is observed in sediments. Statistically significant spatial variations are indicated by two-way ANOVA in different geochemical forms of the metals and physicochemical parameters of water and sediments of the river Yamuna. Principal component analysis (PCA) suggests a similar source for all four metals probably from the sewage from municipal drains. PCA also indicates some independent sources of Cu and Pb. The hot spots were identified using hierarchical cluster analysis considering bioavailable forms of the metals in water and sediments as objects and the sampling sites as variables. Risk assessment code analysi...

The speciation pattern of heavy metals namely chromium, nickel, copper and lead in water and sediments of an urban lake system of high ecological significance was studied. The total available metal (dissolved) in water follows the sequence Ni>Cr>Pb>Cu. However, a different pattern Pb>Cu>Ni>Cr is observed for total available metal (metal in non-residual phases) in sediments. Significant spatial variations are observed in different geochemical forms of the metals as indicated by two-way ANOVA. This is attributed to localized anthropogenic activities. The anthropogenic parameters of water not only show statistically significant correlations among themselves but also positively correlate with the particulate forms of Cr, Cu and Pb. The total available forms of copper and lead correlate with the organic content of the sediments. Principal component analysis (PCA) separates the metals into three groups: I (Cr); II (Ni); III (Cu and Pb). The polluted sites were identified using hierarchical cluster analysis. Risk assessment code (RAC) analysis indicates low to medium risk due to Cr at most of the sites. However, Ni, Cu and Pb pose medium to high risk. But Pb at a few sites presents very high risk (RAC > 50%).