This paper is the result of environmental geological survey engineering.

Objective This study explored the spatial distribution and concentrations of heavy metals in the surface soils of Xiji County, Guyuan City, Ningxia Autonomous Region, to assess the ecological characteristics and health risks associated with heavy metals in this region.

Methods The study used the Nemerow comprehensive pollution index, the potential ecological risk index, the geo-accumulation index, and health risk-assessment models to comprehensively evaluate the ecological and health risks associated with heavy metals in the soil.

Results The concentrations of all heavy metals, apart from Cr, in the surface soils generally exceeded the background values of soil elements. This was especially noticeable for Cu and Zn, both of which exhibited significant enrichment. Soil levels of Hg was high and exhibited uneven distributions and significant spatial differences. Among the eight heavy metals analyzed, the potential ecological risk indices for Hg was 46, indicating a moderate level of risk. The overall potential ecological risk index was 110.44; this was below 150, thereby indicating a low level of ecological risk. The geo-accumulation indices were below 0 for all elements, suggesting a lack of significant pollution and heavy-metal accumulation in the soil. The results of the health risk assessment indicated that the carcinogenic risk index for As exceeded 10⁻⁶, indicative of carcinogenic risk, although remaining within an acceptable range. The overall carcinogenic risk indices were 1.13×10⁻⁵ for adults and 1.75×10⁻⁵ for children, both of which are acceptable and suggest an absence of carcinogenic risk from soil heavy metals to human health.

Conclusions Although the overall soil quality in Xiji County was found to be good, the observed trend of heavy-metal accumulation warrants continuous long-term monitoring and attention.