Spatial Distribution of Heavy Metals Along Gt Road from Sialkot to Rawalpindi: Correlation with Road Proximity and Risk Assessments

Abstract

The rapid development and urbanization along the GT roadside has brought severe heavy metals (HMs) contamination to the soil and may lead to considerable risk to the ecosystem. In this study, the concentrations, spatial distribution along with ecological risk, and health risk assessments of HMs (Pb, Cr, Cu, and CD) in the GT roadside soil from Sialkot to Rawalpindi are evaluated, aiming to provide a theoretical understanding of managing and mitigating the HMs contamination. 200 samples are collected at varying distances from the road’s edge across 4 different zones (Sialkot, Gujrat, Jhelum, and Rawalpindi). A non-linear fitting model is applied to analyze the correlation between HMs and roadside distance. The maximum concentration of HMs is observed in Sialkot, while the minimum is noted in Jhelum. The mean concentrations of HMs follow this descending order: Pb > Cu > Cr > Cd. Roadside soil ranges from “unpolluted” to “moderately polluted” for all metals excluding Cr. Cr and Cu pose a lower ecological risk as compared to Pb and Cd. The trend of the average daily dose of HMs (ADD) in soil via the three pathways is noted in the order of ADDinh ˂ ADDderm ˂ ADDing. Among ADD of soil, ADDderm has maximum value in adults, while ADDing and ADDinh values are maximum for children. The hazard index (HI) for all inspected HMs in the soil is below 1, demonstrating no considerable health risk for either children or adults. The Pakistani government should prioritize traffic, and industrial-related environmental issues along GT road. This study is helpful to further analyze and assess the health risks associated with exposure to HMs near highways, including those in industrial areas globally.

Keywords: Heavy metals contamination, roadside soils, spatial distribution, ecological index, health assessment