Abstract
To understand the effect of intense human activities in suburbs on environmental quality, we obtained 758 measurements of the heavy metals in certain farmland soils of the Beijing suburbs. Multivariate statistical analysis and geostatistical analysis were used to conduct a basic analysis of the heavy metal concentrations, the distribution characteristics and the sources of pollution of the farmland soils in these suburbs. The results showed the presence of eight heavy metals in the agricultural soils at levels exceeding the background values for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn. In particular, all the measured Cr concentrations exceeded the background value, while As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were present at 1.13, 1.68, 1.95, 1.43, 1.63, 0.79, 0.92 and 1.36 times their background values, respectively. The results of correlation, factor and spatial structure analyses showed that Cd, Cu, Pb and Zn were strongly homologous, whereas Cr and Hg showed a degree of heterogeneity. The analysis further indicated that in addition to natural factors, Cd, Cu, Pb and Zn in the soil were mainly associated with distribution from road traffic and land use status. Different agricultural production measures in the various areas were also important factors that affected the spatial distribution of the soil Cr concentration. The major sources of Hg pollution were landfills for industrial waste and urban domestic garbage, while the spatial distribution of As was more likely to be a result of composite pollution. The regional distribution of the heavy metals indicated that except for Cr and Hg, the high heavy metal levels occurred in districts and counties with higher organic matter concentrations, such as the northwestern and southeastern suburbs of Beijing. There was no significant Ni pollution in the agricultural soils of the Beijing suburbs.
Highlights
The suburbs of cities are urban-rural ecotones with unique geographical locations and various activities, a situation that induces industrial development in the region and makes the region an important vegetable and grain production area
Because the assumptions of the kriging interpolation model were ignored in these applications, that is, because the ordinary kriging model was used for calculation and interpolation without examining the distribution characteristics of the data, there were certain limitations in the results that may affect the accuracy of the analyses
We studied the farmland soils of several suburbs (Changping, Tongzhou, Shunyi, Daxing and Haidian) that are close to the urban area of Beijing through the survey and analysis of eight heavy metals, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the farmland soils of these regions
Summary
The suburbs of cities are urban-rural ecotones with unique geographical locations and various activities, a situation that induces industrial development in the region and makes the region an important vegetable and grain production area. Because the assumptions of the kriging interpolation model were ignored in these applications, that is, because the ordinary kriging model was used for calculation and interpolation without examining the distribution characteristics of the data, there were certain limitations in the results that may affect the accuracy of the analyses For these reasons, we studied the farmland soils of several suburbs (Changping, Tongzhou, Shunyi, Daxing and Haidian) that are close to the urban area of Beijing through the survey and analysis of eight heavy metals, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the farmland soils of these regions. After a statistical description and analysis of the spatial distribution and data tendencies, an optimal interpolation model and parameters were selected for each heavy metal for further estimation and in-depth investigation of the spatial structure characteristics to analyze the pollution sources of the heavy metals and scales in the agricultural soils of the Beijing suburbs. Note that the background values of Cu, Cr, As, Cd and Pb are from the “Systematic study on background values of soil heavy metals in Beijing” and that of Hg is from the “Environmental Background Values Data Handbook” [26,27].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
