Abstract
The aims of this study were to analyze the spatial distributions of, contamination statuses of, and factors contributing to, heavy metals in cropland areas of different cities; thus, 55 agricultural soils were collected from 12 cities of Shandong Province, China. Concentrations of copper (Cu), lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni) and zinc (Zn) were determined. Results showed that average contents of Cu, Pb, Cd, Cr, Ni and Zn were 24.13, 31.77, 0.16, 130.63, 22.13, and 71.19 mg·kg−1, respectively, and Pb and Cd had similar spatial distributions in those cities. Specifically, contents of Cr in cities of Weifang, Weihai, Yantai and Zibo were significantly higher than it in other cities; Weihai and Zibo also had significantly high contents of Zn. Moreover, concentrations of Cr in brown soils and cinnamon soils were significantly higher than that in fluvo-aquic soils, while other metals showed no significant differences among the soil types. Furthermore, Cu, Pb and Zn showed significant concentration decreases with respect to those measured in 2007. The correlation analysis and factor analysis indicated that the contamination of Pb and Cd was mainly caused by economic activities. In addition, the significantly correlated Cu/Ni/Zn and Pb/Cd indicated the inputs from different human activities, while Cr was prone to multiple sources. This study demonstrated that more attention should be given to the contamination by Cr, Pb and Cd, and that the management of human economic activities is vitally imperative for safety of surrounding cropland soils.
Highlights
IntroductionIndustrial production and other producing activities usually discharge plenty of pollutants, which would pollute the surrounding cropland [3]
Soil is a fundamental component of ecosystems and is involved in various human activities, among which, food production is an important function for the survival of mankind [1,2].industrial production and other producing activities usually discharge plenty of pollutants, which would pollute the surrounding cropland [3]
71.19 mg·kg−1, respectively, suggesting that most cropland soils were suffering from the contamination of Cr, Pb and Cd
Summary
Industrial production and other producing activities usually discharge plenty of pollutants, which would pollute the surrounding cropland [3]. Owing to the rapid industrial and agricultural development, the accumulation of pollutants in agricultural soils in China has become increasingly serious [4,5]. Since the Chinese reform and opening up, economic development in the countryside has greatly increased by governmental effective measures, such as transferring industries from urban areas to the countryside, improving planting technology, increasing employment, etc. Large quantities of wastewater and pollutants are discharged into surrounding soils and wetlands due to the lack of pollution management and controls in China [7,8]. Industrial sewage, domestic wastewater and agrochemicals contain a great deal of heavy metals, which have the
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