This paper is the result of environmental geological survey engineering.

Objective This study explored the distribution characteristics, pollution levels, and health risks of heavy metals in typical farming areas in northern Henan Province, China, and analyzed the sources of heavy metals in heavily polluted areas.

Methods A total of 161 surface soil samples were systematically collected, and the concentrations of heavy metals such as Cu, Pb, Zn, Cr, Cd, As, Ni, and Hg were determined. The Nemero Comprehensive Pollution Index and Geological Accumulation Index were used to assess the degree of heavy metal pollution. The potential ecological risk index method was used to assess the risk. The health risk assessment model was used to assess the health risks of adults and children in the study area. Using the PMF model to trace the sources of eight heavy metals in key area soil.

Results Except for As, the mean values of 7 heavy metal elements all exceeded the soil background values in Henan Province,, and 80.75% of the stations exceeding risk screening values for Cd. The pollution assessment showed that the study area was generally in a mildly polluted range, with Cd contributing significantly more than the other seven heavy metals, followed by Hg and Pb. The potential ecological risk assessment showed that the study area was at a high ecological risk level, with Cd and Hg as the main contributors to ecological risks, accounting for 71.69% and 21.89% respectively. The health risk assessment showed that some stations had certain health risks for adults and children, including carcinogenic risks for children and non-carcinogenic risks for adults. The risk levels were shown to be higher for children than for adults, with As, Cr, and Pb being the main contributors to health risks. Through correlation analysis and PMF modeling, it was found that there were three sources of heavy metals in key areas: As mainly came from natural sources such as rock weathering; Cd mainly came from industrial wastewater discharge sources; and the other six heavy metals mainly came from transportation sources and coal combustion sources. The contribution rates of the three sources are 8.27%, 2.34%, and 89.39%.

Conclusion The heavy metal pollution areas in cultivated soil in the study area were mainly concentrated in Fengquan District and Muye District, with Cd as the main contributor. As, Cr, and Pb were the main contributors to health risks.