Pollution characteristics and health risk assessment of potentially toxic elements of street dust in the ancient civilization city of Baghdad, Iraq

Abstract

The levels of potentially toxic elements (PTEs) Mn, Zn, Cr, Co, Ni, Cu, Pb, As, Sb and Cd in street dust from Baghdad city were determined. The sources of PTEs in street dust were analyzed using multivariate statistical analysis that combined with the spatial distributions of PTEs. The mean concentration of the PTEs in the present study follows a trend of Mn > Zn > Cr > Co > Ni > Cu > Pb > As > Sb > Cd. The overall contamination of PTEs in street dust was characterized as moderate to strongly contaminated due to As, Cd and Pb. The ecological risk associated with As was very high, while the ecological risks associated with and Ni, Sb, Co, Zn, Cr, and Mn were low. The overall ecological risk of PTEs was defined as moderate, driven by As. The carcinogenic risks of PTEs to inhabitants fell within safety limits while there is a non-carcinogenic risk for children. A comprehensive analysis of PTEs sources revealed that Zn, Cu, and Pb were principally associated with traffic emissions, which accounted for about 17.8% of these PTEs' contents. Mn, Ni, Cr, Co, Cd, and Sb were mainly related with industrial source, which contributed to about 54.7% of these PTEs' concentrations. Arsenic is primarily derived from coal combustion, which was not resolved from PCA in this study. However, the spatials distribution map and statistical analysis imply that coal combustion is another source influencing the levels of PTEs in the study area. This study demonstrates that industrial and traffic emissions are the main anthropogenic sources of PTEs contamination in the street dust in the Baghdad city.