Fractionation, Mobility, and Sources of Selected Heavy Metals in Topsoils from the Middle Black Sea Region of Turkey

Abstract

An investigation into spatial distribution, pollution sources, and mobility of heavy metals was conducted on 19 topsoil samples from the Samsun, Sinop, Merzifon, and Ilgaz Provinces of the Middle Black Sea Region, Turkey. Metal concentration, chemical fractionation, enrichment, and mobility factors were determined for Zn, Cu, Pb, and Cd. Concentrations varied from 29 to 328mgkg(-1) for Zn, 3.35 to 130.80mgkg(-1) for Cu, 3.45 to 217.70mgkg(-1) for Pb, and 0 to 5.8mgkg(-1) for Cd. Enrichment factors decreased in the order Cu> Zn> Pb> Cd. Significant enrichments were found for some Samsun and Sinop soils. Sequential extraction revealed that Zn is associated with Fe/Mn oxide and organic fractions, Cu with residual and organic fractions and Pb with residual fraction. The abundances of heavy metals in the mobile phases were evaluated with a mobility factor, which increased with metal concentration. Generally, the mobility of Zn poses a higher risk, but the most mobile metal varied between soils.