[Characteristics of Soil Pollution and Source Analysis of Typical Pollutants in the Petrochemical Site]

Taking the soil of a petrochemical site in Chongqing as the research object, the pollution sources of heavy metals and volatile organic pollutants in the study area were quantitatively analyzed using principal component analysis and a positive definite matrix decomposition model. The research results showed that:① the average values of Cd, Cu, Pb, Hg, and Mn in the soil of the petrochemical site and its surrounding areas were higher than the soil background values in Chongqing, and the content of Co in 6% of sampling points was higher than the risk screening value of the first type of land use for construction land(GB 36600-2018). The pollution level of Hg, Mn, chloroform, ethylbenzene, m/p-xylene, and o-xylene in the soil of the site was more serious than that of the soil around the site. The industrial production activities of the site will cause significant pollution to the soil of the site. ② Eight heavy metals in the soil could be classified into four sources:62.50% Cd, 54.53% Ni, 54.12% Cu, 51.26% Co, 49.34% Pb, and 31.80% Hg were from the mixed sources of industrial emissions and agricultural activities. A total of 47.61% Mn was from the mixed source of natural and raw material production activities; 62.79% Hg, 21.57% As, 19.43% Mn, and 18.42% Cd were from the emission of coal-fired industrial activities; and 78.01% As, 46% Pb, 39.94% Cu, 38.15% Ni, 36.49% Co, 26.12% Mn, and 14.29% Cd were from the original material soil. ③ Seven volatile organic compounds in the soil of the site were mainly classified into three types of sources:86.49% dichloromethane and 90.14% tetrachloroethylene were from human activities in petrochemical sites; 98.88% m/p-xylene, 96.28% o-xylene, 84.62% ethylbenzene, and 76.46% toluene were from petrochemical site pollutant leakage sources; and 80.24% chloroform was from the natural sources.