Pollution Analysis and Health Implications of Heavy Metals under Different Urban Soil Types in a Semi-Arid Environment

Abstract

A fundamental requirement for the effective prevention and management of soil contamination involves the determination of heavy metal contamination levels and the assessment of associated health risks for human populations. In this study, an analysis was conducted to evaluate the pollution levels and health risks associated with heavy metals in urban soils, specifically focusing on four distinct soil types, namely Calcisols, Cambisols, Fluvisols, and Regosols. The mean values of five heavy metals (Zn, Cu, Cd, Pb, and Ni), some soil pollution indices, and human health risk indices were determined. Pollution indices including the integrated Newerow pollution index (PIN), single pollution index (PI), and pollution load index (PLI) showed a moderate pollution class in most soil samples. The non-carcinogen risk index of elements (HI) in each exposure pathway and the total of the exposure pathways (THI) was <1 for three different population groups (children, adult females, and adult males) and in all soils. This shows the lack of non-cancerous risk for local residents in the study site. The variations in HI and THI for the three population groups and three different exposure pathways was in the order of adult males > adult females > children and ingestion > dermal contact > inhalation. The carcinogenicity risk (CR) of Cd, Pb, and Ni through exposure by ingestion was >1 × 10−4 for children in all soils, meaning that soil ingestion is hazardous to children in the study region. For all three population groups and all soil types, Pb was most effective in HI and THI, whereas Cd had the highest carcinogenicity potential.