Abstract:Four major mung bean growing areas, Tailai County, Dumeng County, Longjiang County, and Daqing County, in Heilongjiang Province were studied to investigate the soil heavy metal pollution in the major mung bean producing areas in the province. Soil samples were obtained at 0~20 cm below the ground surface to determine the pH values, organic matter contents, and heavy metal contents. Risk assessments for seven heavy metals, namely, copper, zinc, cadmium, lead, chromium, arsenic, and nickel, in soil were carried out using the Nemero comprehensive pollution index and the potential ecological risk index. In the calculations of these indices, the background values were adopted from the national soil environmental quality/agricultural land soil pollution risk control standard (trial) (GB 15618-2018). The results indicated slight soil heavy metal pollution levels in the major mung bean producing areas in Heilongjiang. For the soil at 0~20 cm, the average pH value is 8.04, indicating that the soil is slightly alkaline. The average organic matter content is 2.21%, and the contents of copper, zinc, cadmium, lead, chromium, arsenic, and nickel are 4.40~25.88, 27.16~66.97, 0.06~0.19, 11.36~19.19, 11.63~69.95, 10.46~58.92, and 7.03~33.63 mg/kg. In particular, the arsenic content exceeds the screening value stipulated by the national standard. The comprehensive pollution index values range from 0.98 to 1.24, suggesting a slight pollution level. The comprehensive potential ecological risk index values range from 20.03 to 23.95. They are much lower than 80, indicating that the potential ecological harm is slight.
