Heavy Metal Distribution in Soil Profiles in Riyadh (Saudi Arabia)

Abstract

The distribution of Pb, Zn, Cu, Cr and Ni in Riyadh soil profiles
was detennined. Their levels were investigated in relation to organic
matter content, soil pH and samples location. Samples were collected
from urban, suburban, rural, highway and industrial area.
Surface soils of highway and urban areas were found to be highly
polluted with Pb and with a lesser extent Zn. High correlation was
found between Pb, Zn, Cu and Cr indicating automobiles as a
common source. No evidence of Ni contamination of soils was
obtained. Soil profile results showed that Pb, Zn and Cu were largely
concentrated in the upper surface soils, which is attributed to the
low rainfall in the study area. It was foulld that approximately 74.7%
of the lead, '56.6% of the zinc and 40.3% of the copper are concentrated
in the top 5 cm confirming an airborne origin.