Assessment of pollution and sources of heavy metals in the sediments of the Shitalakhya river, Bangladesh

Kalimur Rahman,Fahim Ahammad,Md Akramul Alam,Saurav Barua

doi:10.14419/ijag.v8i1.30789

Abstract

The Shitalakya River, located near Dhaka City of Bangladesh, supplies water to the city dwellers and hence it is essential to determine pollu-tion condition, ecological risk and sources of heavy metals in the river sediments. Sediment works as the sink and source of heavy metals in the riverine ecosystem. The samples collected from the ten sites of the Shitalakhya River were investigated in the study. Average concentra-tion of different heavy metals in the sediments are Cu>Zn>Ni>Pb>Cr>Cd. Geo-accumulation index reveals moderately pollute Cu concen-tration, unpolluted to moderately pollute Ni concentration and unpolluted for the rest of the heavy metals. The order of geo-accumulation index are Cu>Ni>Pb>Cd>Zn>Cr. Overall, the heavy metals render low potential ecological risk and the order of potential ecological risk index are Cd>Cu>Ni>Pb>Cr>Zn. Though the concentration of Cd is low in sediment, it poses higher ecological risk. Positive matrix factor-ization (PMF) identifies two sources of pollution, S1 and S2. Where, S1 consists with Cu, Ni, Pb, Zn; which come from industrial wastewater. S2 consists with Cr, Cd, Pb, Zn; which originate from natural sources. The outcomes of the study provide as a reference to plan, control and manage heavy metal pollution and protect the water source of the Shitalakhya River.Â Â Â Â

Highlights

Heavy metals accumulate in sediment of river and they act as the reservoirs to contain heavy metal for a long time
Heavy metal pollution in sediment pose ecological risk due to their severe toxicity to mix with food chain and biota
Ni concentration in sediment were high at S-9 (Kachpur Bridge), S-4 (Adamjee EPZ) sites and USEPA and Toxic rating value (TRV) recommended values

Summary

Introduction

Heavy metals accumulate in sediment of river and they act as the reservoirs to contain heavy metal for a long time. Sediments of river bed act as a sink to accumulate, receive, absorb pollutants, release pollutants into water due to disturbance and consider as an important indicator of water pollution. Heavy metals, such as, Pb, Cd, Cr, Cu, Ni and Zn can accumulate in fine grained sediment and subsequently, carried to the river downstream (Banerjee et al 2016). The Shitalakhya River supplies water to the City Corporation of Dhaka This river flowing through the Dhaka, Narayanganj and Gazipur districts and receives huge amount of waste discharges from the industries located along the river bank. The findings of the study reveal the geo-chemical characteristics of heavy metals and provide a guideline to control and remedy environmental pollution for the similar types of rivers

Methods

Results

Conclusion