黑龙江省绿豆主产区土壤重金属污染特征及生态风险评估

为了解黑龙江省绿豆主产区土壤重金属污染状况，选择黑龙江省泰来县、杜蒙县、龙江县和大庆四个主要绿豆种植区，对0~20 cm处土壤进行取样分析，测定土壤样本的pH值、有机质和重金属含量，以国家《土壤环境质量/农用地土壤污染风险管控标准(试行)》（GB 15618-2018）为背景值，采用内梅罗综合污染指数法和潜在生态风险指数法对研究地区土壤中七种重金属铜、锌、镉、铅、铬、砷、镍进行风险评价。结果表明：0~20 cm土壤中，土壤pH平均值为8.04，有机质含量平均值为2.21%，土壤呈弱碱性；研究区土壤重金属铜、锌、镉、铅、铬、砷、镍含量范围分别为4.40~25.88 mg/kg、27.16~66.97 mg/kg、0.06~0.19 mg/kg、11.36~19.19 mg/kg、11.63~69.95 mg/kg、10.46~58.92 mg/kg、7.03~33.63 mg/kg，其中砷含量超过国家标准规定的风险筛选值；综合污染指数值范围为0.98~1.24，属于轻度污染水平；综合潜在生态风险指数范围为20.03~23.95，小于80，潜在生态危害轻微。黑龙江省绿豆主产区土壤重金属污染程度总体处于轻度污染水平。

Pollution Characteristics and Ecological Risks of Soil Heavy Metals in Major Mung Bean Producing Areas in Heilongjiang Province of China

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.