Objective This study aims to investigate the migration and accumulation characteristics of heavy metals in soil−crop systems and their enrichment patterns in the black soil region of Lishu County, Jilin Province, as well as to assess the health risks posed by soil heavy metals.

Methods A total of 30 mature rice grain samples, 30 corn grain samples, and 60 corresponding root−zone soil samples were systematically collected. Concentrations of heavy metals (Cu, Zn, Cr, Cd, Pb, As, Hg) as well as soil organic matter (SOM) content and pH value were measured. The enrichment characteristics and influencing factors of heavy metals in soils and crops, along with soil heavy metal health risks, were analyzed using the index of geoaccumulation (Igeo), bioconcentration factor (BCF), correlation analysis, and health risk assessment models.

Results Soils in Lishu County are acidic to neutral with relatively high SOM content. The average concentrations of Cd, Hg, and Cr slightly exceeded the local soil background values, while all seven heavy metals were below the risk screening values. Among crops, Zn had the highest concentration, and Cd and Hg had the lowest, with minor differences in other heavy metal concentrations between rice and corn. Both rice and corn grains showed strong absorption and enrichment capacities for Zn and Cu, but weak capacities for Cd, Cr, Hg, As, and Pb. Correlation analysis revealed that Cu in rice grains was significantly positively correlated with Cu, Zn, and Cd in root−zone soils; Zn in rice grains was positively correlated with Zn, As, and Cd in soils; and Pb in rice grains was positively correlated with Cd in soils. For corn, Zn in grains was significantly positively correlated with Cu, Zn, and Pb in root−zone soils. As and Cr were the main contributors to non−carcinogenic risks, while Cr and As dominated carcinogenic risks. Oral ingestion was identified as the primary exposure pathway for health risks.

Conclusions The ecological risks of crops in the study area are safe and controllable. Soil pH and SOM are key factors influencing heavy metal concentrations in crops. Soil heavy metals do not pose non−carcinogenic risks to humans, and the carcinogenic risks are within an acceptable range. Overall, soil heavy metal pollution in the region is safe and controllable.