Spatial distribution of heavy metals density in cultivated soils of Central and East Parts of Black Sea Region in Turkey

Abstract

Heavy metal contamination has caused serious environmental and health-relatedproblems around the world. To identify the concentrations and sources of heavymetals, 3400 surface soil samples (0-20 cm depth) were collected from the study area.Subsequently, the concentrations of Cd, Co, Cu, Ni, Pb and Zn in the samples weremeasured. In order to evaluate natural or anthropogenic sources of heavy metalcontent and their spatial distribution in agricultural fields of Central and East Parts ofBlack Sea Region soil geostatistic approach were combined with geographicinformation system (GIS). GIS technology was employed to produce spatial distributionmaps of the 6 elements in the study area. The results showed that the concentration ofNi and Co exceeded its threshold level. The local pollution from Ni was attributed to thenatural influences. The concentrations of the other heavy metals are relatively lowerthan the critical values. The mean values of the heavy metal contents arranged in thefollowing decreasing order: Ni > Zn > Cu >Pb> Co > Cd in the study area. On the otherhand, according to distribution ratio of heavy metals in total soil samples, except for Coand Ni distribution in total soil samples, all other heavy metal element exceededconcentration in samples were determined about less than 10% total soil samples.However, in some regions of the study area, the Cd, Cu and Zn contents were alsoslightly raised, this case possibly stem from excessive P fertilization and field traffic.