[1] M Ajigul, E Mamattursun, M Anwar et al. The spatial distribution, contamination and ecological risk assessment of heavy metals of farmland soils in Karashahar-Baghrash oasis, Northwest China. Human and Ecological Risk Assessment, 23, 1300-1314(2017).

[2] M Cai L, C Xu Z, Z Ren M et al. Source identification of eight hazardous heavy metals in agricultural soils of Huizhou, Guangdong Province, China. Ecotoxicology and Environmental Safety, 78, 2-8(2012).

[3] . HJ/T 166-2004, Technical specification for soil environmental monitoring.(2004).

[4] Y Chen H, G Teng Y, J Lu S et al. Contamination features and health risk of soil heavy metals in China. Science of the Total Environment, 512, 143-153(2015).

[5] C Chen N, X Zhang X, J Zheng Y. Heavy metal concentrations in rice from Guangzhou and associated health risks. Journal of Resources and Ecology, 9, 85-91(2018).

[6] N Duan Q, C Lee J, S Liu Y et al. Distribution of heavy metal pollution in surface soil samples in China: A graphical review. Bulletin of Environmental Contamination and Toxicology, 97, 303-309(2016).

[7] J Guo, L Yue T, T Li X et al. Heavy metal levels in kiwifruit orchard soils and trees and its potential health risk assessment in Shaanxi, China. Environmental Science and Pollution Research, 23, 14560-14566(2016).

[8] L Håkanson. An ecological risk index for aquatic pollution control: A sedimentological approach. Water Research, 14, 975-1001(1980).

[9] X Han Y, L Ni Z, L Li S et al. Distribution, relationship, and risk assessment of toxic heavy metals in walnuts and growth soil. Environmental Science and Pollution Research, 25, 17434-17443(2018).

[10] J Hu, B Lin, M Yuan et al. Trace metal pollution and ecological risk assessment in agricultural soil in Dexing Pb/Zn mining area, China. Environmental Geochemistry and Health, 41, 967-980(2019).

[11] A Hu Y, P Liu X, M Bai J. Assessing heavy metal pollution in the surface soils of a region that had undergone three decades of intense industrialization and urbanization. Environmental Science and Pollution Research, 20, 6150-6159(2013).

[12] R Leake J, A Adam B, E Rigby J. Health benefits of “grow your own” food in urban areas: Implications for contaminated land risk assessment and risk management. Environmental Health, 8, 1-6(2009).

[13] L Lei, B Ma Y, Z Zhang S et al. An inventory of trace element inputs to agricultural soils in China. Journal of Environmental Management, 90, 2524-2530(2009).

[14] E Mamattursun, M Anwar, M Ajigul et al. A human health risk assessment of heavy metals in agricultural soils of Yanqi Basin, Silk Road Economic Belt, China. Human and Ecological Risk Assessment, 24, 1352-1366(2018).

[15] . NY/T 395-2000, Procedural Regulations Regarding the Environment Quality Monitoring of Soil.(2000).

[16] . 2014. National Soil Pollution Survey of China..

[17] G Müller. Index of geo-accumulation in sediments of the Rhine River. Geojournal, 2, 108-118(1969).

[18] B Pan L, J Ma, Y Hu et al. Assessments of levels, potential ecological risk, and human health risk of heavy metals in the soils from a typical county in Shanxi Province, China. Environmental Science and Pollution Research, 23, 19330-19340(2016).

[19] S Rapant, J Kordik. An environmental risk assessment map of the Slovak Republic: Application of data from geochemical atlases. Environmental Geology, 44, 400-407(2003).

[20] C Reimann, P Caritat. Intrinsic flaws of element enrichment factors (EFs) in environmental geochemistry. Environmental Science and Technology, 34, 5084-5091(2000).

[21] M Shi X, H Wang J. Comparison of different methods for assessing heavy metal contamination in street dust of Xianyang City, NW China. Environmental Earth Sciences, 68, 2409-2415(2013).

[22] A Sinex S, R Helz G. Regional geochemistry of trace elements in Checapeake Bay sediments. Environmental Geology, 3, 315-323(1981).

[23] L Su Q, L Zhou S, M Yi H et al. A comparative study of different assessment methods of regional heavy metal pollution. Acta Scientiae Circumstantiae, 36, 1309-1316(2016).

[24] A Sutherland R. Bed sediment-associated trace metals in an urban stream, Oahu, Hawaii. Environmental Geology, 39, 611-627(2000).

[25] L Tomlinson D, G Wilson J, R Harris C et al. Problems in the assessment of heavy metal levels in estuaries and the formation of a pollution index. Helgoland Marine Surveys, 33, 566-575(1980).

[26] M Teresiah M, O Anita A, M Victorine A et al. Occurrences and toxicological risk assessment of eight heavy metals in agricultural soils from Kenya, Eastern Africa. Environmental Science and Pollution Research, 23, 18533-18541(2016).

[27] F Wang, Z Huang Y, L Wang X et al. Ecological risk assessment of heavy metals in surrounding soils of tungsten ores: Comparison of different evaluation methods. Environmental Chemistry, 34, 225-233(2015).

[28] J Wang L, D Tao W, S Richard C et al. Speciation, sources, and risk assessment of heavy metals in suburban vegetable garden soil in Xianyang City, Northwest China. Frontiers of Earth Science, 12, 397-407(2017).

[29] X Wu W, M Li K, G Wang et al. Evaluation of heavy metal pollution in river sediment: A comparative case study in Tanjiang River. Environmental Science and Technology, 35, 143-149(2012).

[30] J Xie X, C Kang J, J Li W. Analysis on heavy metal concentrations in agricultural soils of Baoshan, Shanghai. Environmental Science, 31, 768-774(2010).

[31] Y Xie Z, J Zhang Y, Q Chen D et al. Research on assessment methods for soil heavy metal pollution: A case study of Guangzhou. Journal of Agro-Environment Science, 35, 1329-1337(2016).

[32] Y Zhang Z, A Jilili, Q Jiang F et al. Environment risk and chemical forms of heavy metals in farmland of Ebinur Basin. Scientia Geographica Sinica, 35, 1198-1206(2015).

[33] Z Zheng G. Theory and practice of research on heavy metal pollution in agricultural soil.(2007).

[34] S Zhou C, Z Zou S, J Li L et al. Comparison of evaluation methods for soil heavy metals contamination. Earth and Environment, 43, 709-713(2015).