Determination of Geogenic and Anthropogenic Share of Heavy Metals in Soils of Pars Special Economic Energy Zone in Southern Iran

Objective of this study is fractionation of geogenic and anthropogenic share and also determination of contamination level of trace heavy metals in surface soil of Pars Special Economic Energy Zone in southern Iran. Soil sampling in 14 points for two depths of 0-10 and 40-50 cm across a 395.4 km2 located in Asalouyeh county Pars Special Economic Energy Zone along coastal strip of Bushehr Province in southern Iran was conducted in 2020. Geogenic and anthropogenic share of heavy metals of Cd, Se, As, Co, Pb, Cr, Ni, Cu, Zn in surface soil were determined using concentration differences of them between the two depths of 0-10 and 40-50 cm compared to the three reference elements of Fe, Nb and U. The results showed that the highest anthropogenic content of the measured heavy metals was found in the middle of the study area just beside the refineries and petrochemical installations. Dominant wind blow direction of west to east resulted in a shift of accumulation of anthropogenic share of elements in surface soil with an eastward tendency but a decreasing of content with increasing distance from refinery and petrochemical installation was seen. As a whole anthropogenic share of the studied heavy metals in the surface soils of the region was less than their geogenic share. Contamination level of these elements based on Integrated Pollution Index was non to mild pollution in 11 points (less than 1), mild pollution in 2 points (1.06 and 1.22) and mild to strong pollution in 1 point (2.38).