Analysis and Pollution Evaluation of Heavy Metal Content in Arsenic Rock, Sand and Compound Soil in Yulin Area, Shaanxi Province

Abstract

By using the Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) for measuring heavy metal Cr, Ni, Cu, As, Cd, Hg, and Pb contents in sand mixed soils in the project area of arsenic rock and sand mixed-use soil in Yulin Area, Shaanxi Province, Single-factor pollution index method and Nemerow comprehensive pollution index method were used to evaluate the degree of soil contamination. The results showed that the average content of Cd in compound soil and arsenic rock were 0.27 times and 1.03 times higher than the national natural background value of soil environmental quality. The average content of other heavy metals in compound soil arsenic rock and sand was within the national natural background value of soil environmental quality. Compared with the arsenic rock, the contents of Cr, Ni, Cu, Zn, As, Cd, and Pb in the compound soil except Hg were decreased by 0.13 times, 0.41 times, 0.42 times, 0.49 times, 0.50 times, 0.38 times and 0.14 times respectively. Heavy metals were all less than 1 in individual pollution indexes of compound soil, arsenic rock, and sand. After 3 years of planting, the content of heavy metals such as Mn, Ni, Cd, Cr, Cu, Zn, As, and Pb in the compound soil was lower than the secondary standard of the soil environmental quality standard. The comprehensive pollution index of heavy metals was 0.109, belonging to the alert level, is still clean, are in line with the standard clean. The research shows that the mass ratio of heavy metals in the arsenic rock-sand compound soil conforms to the soil environmental quality standards for farmland and can ensure the quality of the soil environment and the safety of agricultural products.