**4. Conclusions**

Eleven trace elements in soil from Huangpi district were studied. All trace elements except As, Sb, Hg and Cd were detected in all samples at both soil depths. The obtained mean concentration of Cr, Ni, Cu, As, Cd, Pb were above the soil background value of Wuhan and Hubei Province. The mean concentration values of Cd and Co exceed FAO/ISRIC (2004), WHO/FAO (2001) and USEPA (1983) recommended values of trace elements in soil. The mean concentration of Ni was above the permissible limit of FAO/ISRIC (2004), WHO/FAO (2001), but less than the permissible limit of USEPA (1983). Pearson's correlation result indicated that there was a significant positive correlation among trace elements, whereas, weak and negative correlations between trace elements and soil properties (pH and TOC). PCA, HCA and EF of the soil indicated that anthropogenic factors are the major sources of trace elements in Huangpi soil. The result of contamination factor (*Cif*) for trace elements were in decreasing order of Co > Cd > Ni > Pb > Cu > Cr > As > Hg > Fe > Sb > Zn. The obtained *Cd* values indicated that there is high degree of soil contamination. The result of ecological risk factor (*Eif*) of elements were in the decreasing order of Co > Cd > Hg > Ni > Pb > As > Cu > Sb > Cr > Zn > Fe. Potential ecological risk index (*RI*) result for the studied soil (*RI* > 600) indicated that there is a high ecological risk of elements in the study area. Enrichment factor (EF) showed that there is extremely high enrichment from Cd and Co, moderate from Ni, Cu, Hg and Pb, and low from Cr, Fe, As, Sb and Zn. The geo accumulation index (*Igeo*) results point out that the study area is highly contaminated with Cd and Co. From the obtained result it's concluded that Huangpi soil is contaminated with trace elements. Therefore, more attention should be given and remediation action should be set to minimize the concentration and ecological impacts of trace elements in the study area. Further research should be conducted on human health impact of trace element in Huangpi soil.

**Author Contributions:** Author Contributions: Sampling, Q.X.; and X.J.; Statistical Analysis, T.G.; Writing—Original Draft Preparation, A.W.T.; Writing-Review and Editing, J.W.

**Funding:** This research was funded by the Sino-Africa Joint Research Center, Chinese Academy of Sciences, gran<sup>t</sup> number [Y623321K01].

**Acknowledgments:** The authors would like to thank all members of Pollution Ecology Laboratory for their support during laboratory analysis. In addition, the authors are grateful to all friends that helped to edit final manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.
