Metals Content of Roadside Soils in Riyadh (Saudi Arabia), with Particular Reference to Traffic Density

Abstract

The metals content (Pb, Zn, Cu, Cr, Ni and Li) of roadside
surface and subsurface soils was determined along the major roads
and highways in Riyadh city. Their levels were investigated in
relation to traffic loads. Results showed that enhanced levels of Pb,
Zn, and Cu correlated well with traffic density. Cr correlated well
with Pb indicating the same source. No evidence of Ni contamination
of roadside soils was obtained. Concentrations of Pb, Zn and
Cu in soil showed enrichment in the upper surface soils, which is
attributed to the low rainfall in the study area An important source
of lead is the combustion of leaded gasoline used for transportation
in Saudi Arabia.