Species Distribution and Source Analysis of Heavy Metals in Surrounding Soil Around Typical Petroleum Sites

In order to understand the speciation characteristics and sources of heavy metals in the surface soil around a petroleum site in Jingmen City, the total amount and occurrence form of nine heavy metals including Cr, As, Cd, Sb, Hg, Pb, Ni, Cu, and Pb in the soil of the study area were determined, and the ecological risk and bioavailability of heavy metals in the soil were evaluated. The sources of heavy metals were analyzed using multivariate analysis. The results showed that Cd was mainly in acid-soluble and reducible forms in the soil, with an average content of 0.19 mg.kg -1, accounting for 79.86% of the total of the four forms; Cr, Cu, Zn, As, Sb, and Pb were mainly in the residual form. Hg was mainly in the residue state and oxidizable state and had good stability in the soil. Cr was in a risk-free state, and the risk assessment results of Sb, Pb, Ni, and Cu indicated low risk. The risk indexes of Cd, Hg, Zn, and As all reached the medium risk level, especially Cd, which was close to the high risk standard, thus requiring particular attention. The correlation and principal component analysis of the total amount of heavy metals in the soil and their existing forms showed that the main sources of heavy metals such as As, Cr, Ni, Sb, Hg, and Pb were greatly affected by natural input, and the heavy metal Cd was more obviously affected by exogenous factors caused by human activities in industrial production. © 2022 Science Press. All rights reserved.