## 4 Conclusions  
The assessment of soil heavy metal pollution status and sources in the study area was conducted using various indices, correlation analysis, and the PMF receptor model. The average concentrations of heavy metals in the soil of the study area, expressed in mg\(\cdot\)kg\({}^{-1}\), are as follows: Mn (543.81) \(>\) V (110.18) \(>\) Cr (71.72) \(>\) Zn (69.99) \(>\) Cu (35.98) \(>\) Ni (32.94) \(>\) Pb (28.88) \(>\) Co (14.95) \(>\) As (9.98) \(>\) Cd (0.13) \(>\) Hg (0.09). Among these, the mean values of Cd, Cr, Cu, Ni, Mn, and V exceed the local soil background values by 1.19 times, 1.41 times, 1.61 times, 1.23 times, 1.38 times, and 1.12 times, respectively. Spatially, although the mean values of Pb and Zn do not exceed the local soil background values, their overall concentration distribution in the study area is relatively high. For As, Hg, and Se, the spatial distribution exhibits an overall low concentration; however, one or two locations have significantly elevated concentrations. The \(I_{geo}\) values indicate that, excluding Cr, Cu, and Mn, more than 75% of the sampling sites can be considered unpolluted by heavy metals. \(RI\) values indicate that the ecological risk in the study area shows significant spatial variability, with low risk in the eastern and western regions and moderate risk in the central and northwestern regions. The \(HI\) and \(TLCR\) values suggest that, on the whole, the carcinogenic risk in the study area is moderate. However, the central-southern and central-western regions exhibit significantly elevated carcinogenic risks, consistent with the distribution of \(RI\) values. Considering the changes in land use types in the study area, it can be inferred that agricultural production has a minimal impact on soil heavy metal pollution. The correlations between Cd-Mn, Cu-Zn, Cd-Cu, Cu-V, Cr-Ni, Cd-V, Mn-Co, Cr-Cu, Cu-Co, Cd-Co, Zn-Co, Mn-V, and Cd-Zn suggest that these metals are likely from the same pollution source. According to the simulation results of EPA PMF 5.0, factors 1, 2, 3, and 4 are likely natural sources, coal combustion and atmospheric pollution sources, industrial pollution sources from non-ferrous metal smelting and the paper industry, and traffic emission pollution sources, respectively. The relative contribution rates of factors 1, 2, 3, and 4 are 17.62%, 18.50%, 28.35%, and 35.56%, respectively. The accumulation of heavy metals in the study area's soil is influenced by four sources, reflecting the negative impact of human activities and industrial development on the soil environment, consistent with [PERSON] et al. 's findings on Jiangsu Province's heavy metal distribution and sources [53]. This study is based on data from the national soil pollution census, which might not accurately represent current conditions or temporal variations in heavy metal concentrations. The analysis relating heavy metal pollution to human activities may oversimplify complex environmental interactions. Our primary focus was on assessing the pollution status and sources of heavy metals in the soil in the study area. During our human health risk assessment, elements like Fe were not included, potentially leading to an incomplete evaluation of the non-carcinogenic and carcinogenic risks associated with the distribution of heavy metals in the soil. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app142210559/s1](https://www.mdpi.com/article/10.3390/app142210559/s1)]([https://www.mdpi.com/article/10.3390/app142210559/s1](https://www.mdpi.com/article/10.3390/app142210559/s1)). Table S1. Exposure factors used for the health risk assessment [38; 39; 40; 41]. Table S2. Reference doses (RFD, mg/kg/day) and cancer slope factors (SF, kg/day/mg) of heavy metals [38; 40; 41]. Conceptualization, D.Q., L.H. and H.C.; methodology, D.Q., L.H. and H.C.; software, D.Q. ; validation, D.Q., L.H. and H.C.; formal analysis, D.Q. ; data curation, J.S., L.H. and H.C.; writing--original draft preparation, D.Q. ; writing--review and editing, L.H.