Assessment of Heavy Metal Contamination in Roadside Soil along Dhaka-Mymensingh Highway, Bangladesh

Abstract

This study aims at evaluating the contamination level of heavy metals in roadside soils along Dhaka Mymensingh highway. Composite surficial soil samples were collected from 8 sites along the highway. The samples have been analyzed for the six potentially toxic heavy metals (HM) namely Cr, Cd, Ni, Pb, Zn and Cu through X-ray Fluorescence (XRF). Zn exhibits the highest average concentration, followed by Cu, Pb, Cr, Ni, and Cd. The degree of contamination levels of these heavy metals were assessed using two widely used geochemical indices such as contamination factors (CF) and Pollution Load Index (PLI). The CF values vary in the order Cr (56.58)> Cd (25.25)> Ni (20.78)> Pb (6.18)> Zn (5.51) >Cu (4.36) reflecting Cr as the prominent contaminant. On the other hand the value of PLI of the sampling points varies in the order S6> S7> S3> S4> S2> S5> S8> S1 revealing the sampling site S6 as the heavily contaminated portion of the study area. Pearson correlation reveals that the anthropogenic sources are the chief contributors of the HM pollution. Chemical industries, steel workshop, open dumping sites and roadside markets have been emerged as the major contributing sources. The findings from the study will contribute to sustainable environmental management in the study area.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 14(2), 2025, P 103-116