Heavy metal synergistic pollution risk assessment in the soil-crop system of the nanyang basin

The enrichment law of heavy metals and pollution assessment in the soil-crop system have become the focus of research on environmental pollution issues. Evaluating the co-pollution risk of heavy metals in the soil-crop system of the Nanyang Basin is of great significance for food safety and the governance of regional heavy metal environmental pollution. This study collected 5778 surface soil samples, 185 wheat samples, 75 corn samples, 114 peanut samples, and 374 corresponding root soil samples from each crop in the Nanyang Basin. The concentrations of arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb) were measured. The pollution index and potential ecological risk assessment methods were utilized to assess the pollution of heavy metals in the soil. The bioconcentration factor (BCF) method was employed to analyze the metal transfer dynamics. The synergistic risk of heavy metals in the soil-crop system was assessed utilizing the soil-crop comprehensive quality index (IICQ). The results revealed that most of the study areas had low levels of soil pollution, with unpolluted and lightly polluted areas predominating. The crops of wheat, corn and peanuts in the study area are generally at a safe level, with the crop pollution index less than 1, while the crop pollution index at some other points is greater than 1. Wheat, peanuts, and corn showed strong bioaccumulation capacity for Cd, with peanuts exhibiting the highest accumulation ability. The largest proportion of sampling points was categorized under unpolluted soil and crops, with peanuts being the most affected crop.