Geo-accumulation and enrichment of trace metals in sediments and their associated risks in the Chenab River, Pakistan

In this study the level of toxic metals (Mn, Zn, Pb, Cd, Co, Cu) was determined in sediment samples from the Chenab River, Pakistan. The potential toxicity of studied metals was determined by evaluating enrichment factor (EF), geo-accumulation index (I-geo) and metal pollution index (MPI). Considering the spatial distributional patterns, the metal concentrations were higher at Trimmu Headwork site followed by Pujnad, Khanki, Marala and Qadirabad Headwork sites. Unusual higher concentrations in the deeper sediments were observed, suggesting a historical deposition of the investigated metals in the area. The I-geo and EF values revealed that sediments in this study were considerably polluted by Cd and Pb and moderately polluted by other metals. Evaluation of metal toxicity based on mean probable effect concentration PEC quotient confirmed that the Chenab River is seriously contaminated with Cd and Pb. Results of the spatial distribution pattern revealed that rapid industrialization and urbanization nearby the study area were probable sources of metal pollution. Proper measures should be taken by industrial units to ensure appropriate treatment of wastewater before disposing the toxic effluents into nearby tributaries. Government authorities must ensure strict enforcement of the National Environmental Quality (NEQ) standards of municipal and industrial effluents to save the Chenab River from further degradation. (C) 2016 Elsevier B.V. All rights reserved.