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-related problems around the world. To identify the concentrations and sources of heavy metals, 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 were measured. In order to evaluate natural or anthropogenic sources of heavy metal content and their spatial distribution in agricultural fields of Central and East Parts of Black Sea Region soil geostatistic approach were combined with geographic information system (GIS). GIS technology was employed to produce spatial distribution maps of the 6 elements in the study area. The results showed that the concentration of Ni and Co exceeded its threshold level. The local pollution from Ni was attributed to the natural influences. The concentrations of the other heavy metals are relatively lower than the critical values. The mean values of the heavy metal contents arranged in the following decreasing order: Ni > Zn > Cu >Pb> Co > Cd in the study area. On the other hand, according to distribution ratio of heavy metals in total soil samples, except for Co and Ni distribution in total soil samples, all other heavy metal element exceeded concentration 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 also slightly raised, this case possibly stem from excessive P fertilization and field traffic.