Spatial distribution and risk assessment of heavy metals in contaminated paddy fields – A case study in Xiangtan City, southern China

• Published in: Ecotoxicology and environmental safety Vol. 171; pp. 281 - 289
• Main Authors: Deng, Yan, Jiang, Luhua, Xu, Liangfeng, Hao, Xiaodong, Zhang, Siyuan, Xu, Menglong, Zhu, Ping, Fu, Shaodong, Liang, Yili, Yin, Huaqun, Liu, Xueduan, Bai, Lianyang, Jiang, Huidan, Liu, Hongwei
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 30-04-2019
• Subjects: Cancer risk; Chemical fractions; Environmental risk assessment; Heavy metals; Paddy soils; Spatial distribution; Environmental risk assessment; Spatial distribution; Chemical fractions; Heavy metals; Paddy soils; Cancer risk
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2018.12.060

An extensive investigation on spatial distribution and environmental risk assessment based on total content and fractions of heavy metals, as well as the cancer risk of Cd from seven adjacent contaminated paddy fields at Xiangtan City, southern China, was conducted in this study. A total of 63 soil samples were analyzed for soil physical properties and concentrations of eight heavy metals (Cd, Cr, Co, Cu, Mn, Ni, Pb, Zn). The results showed that concentrations of metals except for Cr, Mn and Ni exceeded the background values to varying degrees, and particularly, content of Cd was as 57.4–612 times higher than background values. Principal components analysis and correlation analysis revealed three groups: industry activities for Cd and Zn; natural sources mainly for Cu, Pb, Ni and Cr, with some slight anthropogenic activities for Cu and Pb accumulation; and manganese ore associated with cobalt for Co and Mn. Combined with different indices, Cd and Zn were the major contributors to the ecological risk, and cancer risk of Cd indicated an unacceptable degree in this area. Altogether, results from this study will facilitate a better understanding of metals distribution characteristics and provide a scientific basis for further comprehensive management for these paddy fields. Combination of functional microbial agent and plants promises to be a feasible and effective remediation method for cadmium pollution in the study area.
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•Soil quality and residents’ health were seriously threatened by accumulation of Cd.•A noticeable environmental heterogeneity of heavy metals occurred at a small scale.•Human activities and soil properties might explain for high coefficient of variation.•Focus on both total content and fractions of metals to assess the environment risk.