Considering the uncertainty caused by the random error of the sample measurement, the heterogeneity of spatial and temporal distribution of pollutants, and the traditional method of selecting a single parameter for evaluation, based on fuzzy theory, Hakanson potential ecological risk index (considering heavy metal enrichment, ecotoxicity and bioavailability) and United States Environmental Protection Agency health risk assessment system, the fuzzy ecological risk and health risk assessment methods for of heavy metals in soil were established. In the soil of the Jinling Reservoir area, Cd, which has high bioavailability, had the highest average contribution rate to RI, and thus was, regarded as a priority metal for ecological risk. Sites JL9 and JL11 were the priority areas. The heavy metals did not pose a clear hazard to human health, but children had a higher health risk. Pb and As were regarded as the priority metals for health risk. Fuzzy evaluation provided the risk interval and membership degree, contained more parameter information, quantified and reduced the uncertainty of parameters, provided more comprehensive results, and compensated for the deficiency of deterministic evaluation. As the main source of heavy metals, the intensity of agricultural activities in the study area must be controlled to avoid excessive input and accumulation of heavy metals, which may damage the ecological environment and endanger human health.

Wetlands are recognized as one of the most important natural environments for humans. At the same time, heavy metal pollution has an important impact on wetlands. China's Raoyanghe Wetland is one of the most important natural wild species gene banks in China. Eight heavy metal elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in surface layer and deep layer soils were analyzed using statistical-, pollution index-, and Nemerow index-based methods, the Hakanson potential ecological risk index method, and principal component and cluster analyses. The results showed that the maximum concentrations of heavy metals exceeded the background values in the core area and buffer zone of the wetland, but the heavy metal content of the soils was generally low and did not exceed 30%. With the exception of Hg, heavy metal concentrations showed strong spatial differentiation. The differences between the surface layer and deep layer soils of the core area were smaller than in the buffer zone. With the exception of Cd, a clear vertical zonation in the buffer zone soils was observed, showing greater evidence of external influences in this zone than the core. With the exception of partial surface soils, which indicated a safe level of pollution in the core area, all other soils were classified as having a ‘mild’ level of pollution. Thus, the wetland is moderately polluted, with both the core area and the buffer zone presenting a low level of potential ecological risk. According to the results of the present study, heavy metal contaminants in the wetland soils were found to be derived mainly from the natural sources.