Various human production activities have caused tremendous damage to the soil ecological environment of cultivated land. Regional ecological risk assessments and the safe use of cultivated land have received widespread attention. The ecological risk assessment of heavy metals based on soil geochemical zoning has not been reported in the past. Using 14,389 topsoil samples, considering comprehensive geological background information, Yishui County in northern China was divided into three soil geochemical areas and 14 soil geochemical sub-regions by means of principal component factor superposition. The results of environmental quality and risk assessments of eight heavy metals based on soil geochemical zoning show that the single pollution index was greater than 1.0 and the Nemerow pollution index was greater than 0.7 for Ni in a sub-region, indicating that Ni pollution had reached the early warning limit, which demonstrates that Ni has a certain enrichment trend. Meanwhile, the geoaccumulation index of Ni and Cr was greater than zero in some sub-regions, indicating a slight pollution level. In addition, the potential ecological risk factor of the measured heavy metals was greater than 40 in 9 sub-regions, indicating a moderate ecological hazard, and the risk index was greater than 150 in a sub-region, revealing moderate ecological intensity, in which Hg and Cd were leading contributors to potential ecological hazards with a contribution rate between 58% and 76%. This method is suitable for the evaluation of soil environmental quality and safety for medium and large scales, and can provide a scientific basis for further zoning and grading prevention and control of soil pollution in cultivated land.

This study investigates the accumulation, influencing factors, sources, and health risks of eight potential toxic elements (PTEs) in soils from the central–southern Shandong Peninsula, a region characterized by a high geological background and intensive human activities. Concentrations of Cr, Cd, Cu, Ni, Pb, Zn, As, and Hg were analyzed in 19,484 topsoil samples. The results showed that Cr, Cu, and Ni levels exceeded national background values, primarily linked to basalt distribution. Utilizing positive matrix factorization (PMF), spatial analysis, and comparative assessment, four primary sources were identified: natural sources (36.79%), combined traffic and agricultural activities (34.20%), coal combustion (17.32%), and industrial emissions (11.69%). A health risk assessment indicated that while non-carcinogenic risk was within the acceptable limits for the general population, it exceeded the threshold for children in 2.53% of cases, with As from coal combustion being the predominant contributor. These findings provide a critical theoretical basis for implementing targeted, source-oriented control strategies to mitigate PTE pollution in areas where high geological background and anthropogenic activities intersect.