Assessment of heavy metal contamination in soil and wheat (Triticum Aestivum L.) plant around the Corlu–Cerkezkoy highway in Thrace region

Pollution caused by traffic activities is increasingly becoming a great threat to human health in the
region of Thrace in north-west of Turkey. Thirty six soil and plant samples were collected from the
vicinity of Çorlu–Çerkezköy Highway. The samples were taken at distances of, 1, 25, 50, 100, 250
and 500 m from the highway. The each plant sample was divided into two subsamples. One
subsamples of each plant was washed with with distilled water, while other part was not washed
and were analyzed without any washing. All samples were analyzed for their heavy metal
concentrations (Pb, Zn, Cd, Cu, Ni, Mn, Cr and Fe). The results showed that the soils in the study
area were polluted by Pb. The lead concentration in the soil showed values from 19±0.2 mg kg -1
to 351±0.3 mg kg-1 and found to be higher than the allowable maximum limits in soils. The
manganese levels of soils were slightly high and varied from 182±0.1 mg kg-1 to 806±0.1 mg kg-1. In
this study, metal concentrations of unwashed plant samples were higher than those of the washed
ones. This study indicated that the heavy metal contents decreased with increasing distances from
the highway in unwashed plants.