This paper is the result of environmental geological survey engineering.

Objective The study of soil heavy metal environmental quality is of great significance for maintaining ecological balance, ensuring agricultural productivity, and safeguarding human health.

Methods In this study, 553 surface soil samples (0–0.20 m) and 154 deep soil samples (1.50–2.00 m) were collected from the urban area of Jining City and Weishan County. The concentrations of eight heavy metals in the samples were determined using plasma mass spectrometry, X-ray spectrometry, and other analytical methods. The spatial distribution characteristics and potential ecological risks of heavy metals in the soils of Jining urban area and Weishan County were evaluated and analyzed.

Results As and Cd are significantly enriched in the surface soils of Changgou Town, Rencheng District, Jining City, while Hg is significantly enriched in the urban surface soils of Rencheng District. However, the concentrations of these elements do not exceed the risk screening values of agricultural land, suggesting that human activities have influenced their distribution, with limited impact on deep soil layers. The single-factor pollution index revealed that the surface soils of As reached warning levels (P=2.91), Cd reached both warning and pollution levels (P=2.16 and 6.71), and Hg reached warning levels (P=2.72). The remaining heavy metals were within safe limits. While individual pollution points were observed in deep soil layers, the overall condition remained clean and safe. The Nemerow Comprehensive Pollution Index indicated that the overall heavy metal environment in the surface soil layer is favorable. Areas classified as clean, safe, alert, and contaminated accounted for 76.9%, 22.9%, 0.098%, and 0.066%, respectively. The alert and contaminated zones were mainly located in Changgou Town, Rencheng District, Jining City, which has attributed to As and Cd. Arsenic accumulation was likely linked to ore transportation, coal mining waste discharge, and wastewater leakage during mining activities, whereas Cd was primarily associated with fertilizer and pesticide application in farmland. Deep soil layers remained clean and safe. Potential ecological risk assessment showed that heavy metals in both surface and deep soil layers posed minor ecological hazards. Areas with strong to very strong ecological hazards in surface soils were concentrated in Changgou Town and the urban area of Rencheng District, Jining City, while strong ecological hazards in deep soils were mainly observed in urban Weishan County, consistent with the distribution of coal mines.

Conclusions Changgou Town should enhance monitoring of As leaching from coal mining and Cd enrichment resulting from fertilization and pesticide use in surface soils. Rencheng District should focus on Hg enrichment in surface soils caused by mining and industrial emissions. Yanzhou District and urban areas of Weishan County should monitor heavy metals leaching from surface soils due to mining activities, with high concern given to heavy metal accumulation in deep soil layers of urban Weishan County.