Risk Assessment and Source Analysis of Heavy Metal Pollution in Cultivated Soil in Qingzhen, Guizhou Province

Taking cultivated soil in Qingzhen City As the research object, 794 soil surface samples (0～20 cm) were collected from the study area, and the contents of 5 heavy metals (Cd, Hg, AS, Pb and Cr) in the samples were determined. The potential ecological risk index method and human health risk model were applied. The potential ecological risk and health risk of heavy metals in cultivated soil were evaluated, and the source of heavy metals was analyzed by positive definite matrix factorization (PMF). The results showed that the average contents of Cd, Hg, As, Pb and Cr were 0.84, 2.56, 1.36, 1.11 and 1.04 times of the background value of Guizhou Province, respectively. The potential ecological risk index of Hg was the highest, reaching 102.56, which was evaluated as strong potential ecological risk. The comprehensive potential risk in the study area was mainly slight potential risk. In the study area, the non-carcinogenic risk was mainly contributed by As and Pb, the carcinogenic risk was mainly contributed by Cr, and oral ingestion was the main exposure route. The health risk value of children was higher than that of adults.The main sources of the five heavy metals in the study area were: 34.19% from natural sources in the western region, 38.12% from mixed sources of industrial activities and atmospheric subsidence in the eastern region, and 41.21% from mixed sources of industrial activities and traffic emissions in the southern region.Hg element is the main polluting element in the study area and should be paid more attention to. Human health risks are within the safe range, and health risks are small, but monitoring should be strengthened to prevent potential risks; The mixed source of industrial traffic is the most important factor affecting the accumulation of heavy metals in cultivated soil in the study area.