Impact of sediment characteristics on the heavy metal concentration and their ecological risk level of surface sediments of Vaigai river, Tamilnadu, India

•Distributions of heavy metals were measured for surface sediments of the Vaigai river.•Average values of PLI and PER show that sediments have moderate toxicity level.•Content of clay and organic matter raise the level of heavy metal and their toxicity.•Metal contents and their toxicity decreases in sand sized sediment samples.

The distributions of the metals (Al, Fe, Mg, Cd, Cr, Cu, Ni, Pb and Zn) were measured for the surface sediments of the Vaigai river, Tamilnadu, India. These values are compared with different standard values to assess the level of toxicity of the heavy metals in the sediments. Risk indices (CF, PLI and PER) are also calculated to understand the level of toxicity of the metals. Multivariate statistical analyses (Pearson’s correlation analysis, cluster analysis and factor analysis) are carried out to know the inter-relationship between sediment characteristics and the heavy metals. From this analysis, it is confirmed that the contents of clay and organic matter play an important role to raise the level of heavy metal contents as well as PLI and PER (level of toxicity). Heavy metal concentrations of the samples (after removing silt and clay fractions from bulk samples) show decrease in their concentrations and risk indices compared to the level of bulk samples.

Graphical abstractDendrogram shows cluster of variables. Cluster I confirms that the clay and organic matter content plays an important role to raise the level of heavy metal contents as well as PLI and PER (level of toxicity).Figure optionsDownload full-size imageDownload as PowerPoint slide