Heavy metal distribution, fractionation, metal pollution and environmental risk assessment in surface sediment of Narmada River, India

Abstract

ABSTRACT Owing to the rapid industrial and socioeconomic development, the heavy metal concentration in the river is gradually increasing, it has the potential to threaten the aquatic environment and mankind. The present investigation deals with the quantification and fractionation of heavy metals from the sediments of the Narmada River. The presence of these heavy metals can be toxic to human health and aquatic life, therefore different pollution indices were evaluated to identify the degree of threat that might be imposed by these contaminants in the surface water and sediment. In this context, risk assessment code (RAC), hazard quotient (HQ), hazard index (HI) and total cancer risk (TCR) were calculated to examine the risk of heavy metal contamination on the human being. The important heavy metals and their concentration (in mg/kg, dry weight) have followed the following order, Fe > Al > Mn > Cr > Cu > Ni > Zn > Pb > Cd. Pollution indices classified the surface sediments under the uncontaminated to moderately contaminated category; the major responsible heavy metals for different pollution levels were Cr, Mn, Cu and Pb. The RAC identified Mn and Cd as potential heavy metals which may cause a high risk to aquatic organisms. HQ, HI and TCR values confirmed no human health risk. However, the Cr concentration present in surface sediments might cause cancer via ingestion in children. The insights obtained from this study shall aware and encourage the competent legislative bodies to plan an appropriate regular monitoring campaign and take necessary measures to improve the health of the river.