title: Heavy metal pollution and ecological risk assessment of the paddy soils near a zinc-lead mining area in Hunan.
abstract: Soil pollution by Cd, Hg, As, Pb, Cr, Cu, and Zn was characterized in the area of the mining and smelting of metal ores at Guiyang, northeast of Hunan Province. A total of 150 topsoil (0-20 cm) samples were collected in May 2012 with a nominal density of one sample per 4 km(2). High concentrations of heavy metals especially, Cd, Zn, and Pb were found in many of the samples taken from surrounding paddy soil, indicating a certain extent of spreading of heavy metal pollution. Sequential extraction technique and risk assessment code (RAC) were used to study the mobility of chemical forms of heavy metals in the soils and their ecological risk. The results reveal that Cd represents a high ecological risk due to its highest percentage of the exchangeable and carbonate fractions. The metals of Zn and Cu pose a medium risk, and the rest of the metals represent a low environmental risk. The range of the potential ecological risk of soil calculated by risk index (RI) was 123.5~2791.2 and revealed a considerable-high ecological risk in study area especially in the neighboring and surrounding the mining activities area. Additionally, cluster analyses suggested that metals such as Pb, As, Hg, Zn, and Cd could be from the same sources probably related to the acidic drainage and wind transport of dust. Cluster analysis also clearly distinguishes the samples with similar characteristics according to their spatial distribution. The results could be used during the ecological risk screening stage, in conjunction with total concentrations and metal fractionation values to better estimate ecological risk.
authors.affiliation: China National Environmental Monitoring Centre, Beijing, 100012, China.
authors.forename: Sijin
authors.initials: S
authors.lastname: Lu
authors.affiliation: China National Environmental Monitoring Centre, Beijing, 100012, China. yywang126@sina.com.
authors.forename: Yeyao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
authors.forename: Yanguo
authors.initials: Y
authors.lastname: Teng
authors.affiliation: College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Yu
mesh_terms: D002104:Cadmium / Q000032:analysis; D005591:Chemical Fractionation; D002681:China; D016000:Cluster Analysis; D004463:Ecology; D004784:Environmental Monitoring / Q000379:methods*; D007854:Lead / Q000032:analysis; D008628:Mercury / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis*; D008906:Mining; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D015032:Zinc / Q000032:analysis
chemical_list: D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D008628:Mercury; D015032:Zinc
keywords: Potential ecological risk; Soil heavy metals; Zinc-lead mining area