Copper Concentration in Soil of Xijiang River Basin of Guangxi and Risk Assessment
2018, 33 (4):
In order to understand copper concentration and distribution in soil of Xijiang River Basin of Guangxi and evaluate the ecological risk, this paper collected 1 381 dryland soil samples, 729 paddy soil samples, 129 mining soil samples and 293 background soil samples during 2012-2015, and measured the content of copper in soils. According to statistical analysis, the influence of copper accumulation in different types of soil was explored, the spatial distribution of copper content was interpolated through geostatistical analysis and the risk was assessed. The results showed that the geometric mean of copper concentrations was 27.60 mg/kg. The copper concentrations in dryland, paddy, mining and background soil ranged from 0.3 to 317.91, 3 to 495.81, 7.5 to 2 287.66 and 0.68 to 284.27 mg/kg, and the geometric means were 27.75, 25.19, 79.38 and 21.21 mg/kg, respectively. The copper concentration in mining soil was significantly higher than in other soils. Compared to baseline value, the corresponding exceeding rate of mining, dryland and paddy soil were 33.25%, 3.76% and 0.68%, respectively. The spatial pattern of copper content in Xijiang River Basin showed medium autocorrelation with strong structural variability. Clean soil occupied 61% in Xijiang River Basin, while 36% of soil belongs to light pollution soil which mainly distributed in Nandan, Du’an, Wuxuan and Guiping counties where lead-zinc ores are concentrated. Generally speaking, copper content in soil of Xijiang River Basin had some accumulation but the pollution was not serious and it was assessed to be safe. Besides, the risk should be prevented in the areas of Nandan, Du’an, Wuxuan and Guiping counties.
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