3.2 Soil metallomes
ICP-MS determined the contents of 18 metal elements in soil samples. At the site I (Fig. 2a ), compared with the control, short-term oil pollution increased the contents of Ca, Co, Cu, Fe, Mn, Ni, Pb, and Zn (p <0.05), and significantly reduced the contents of As, GA, Kr, SC, Ti and V. With the extension of pollution duration, soil Ca, Cu, Mn, Pb and Zn accumulated significantly. At site II (Fig.2b ), compared with the control, short-term oil pollution increased the contents of Ca, Co, Cu, Mg, Mn, Ni, and Zn (p <0.05), and significantly reduced the contents of As, Cr, Fe, GA, SC, Ti and V. With the extension of pollution years, soil Ca, Co, Cu, Kr, Mn, Pb and Zn accumulated significantly.
PCoA analysis and Spearman correlation analysis were based on soil physicochemical properties and metal datasets (Fig. 3 ). The results showed that soil samples from different sites and groups were significantly separated. Correlation analysis showed a strong positive correlation between the contents of Cu, Zn, Mn, Co, TS, and Pb (p <0.05), and there was a significant positive correlation between the contents of V, Cr, TP, Mg, and Ca. In addition, soil pH showed the most correlation with other indicators, followed by TPH.