Effect of metal and polycyclic aromatic hydrocarbon contamination on soil organic carbon storage in semiarid areas

Abstract

AbstractMetal and polycyclic aromatic hydrocarbon (PAH) contamination severely influences the carbon storage potential of the biosphere. This study was conducted to investigate the changes in soil organic carbon (SOC) under metal and PAH contamination in the industrial area of Shiraz, Iran, over a period of 5 years. Canonical correspondence analysis and linear correlation analysis were performed to identify the relationship between metals, PAHs, vegetation and SOC. The results showed that both metals and PAHs significantly reduced SOC (p < 0.001). Metals played a more important role in SOC changes than PAHs by changing the vegetation characteristics. Increasing concentrations of ∑PAH (R2 = 0.33), phenanthrene (R2 = 0.36) and naphthalene (R2 = 0.42) were directly related to decreasing SOC. Additionally, the metals copper (Cu), lead (Pb), strontium (Sr), vanadium (V), chromium (Cr) and zinc (Zn) with the highest enrichment factor (EF; i.e. Pb = 5.42) had a negative correlation with SOC (R2 = 0.77). In general, metal contamination was more visible than PAH contamination and severely reduced the SOC. Overall, the management and filtration of polluting sources can prevent vegetation decline from reducing the SOC.