Multivariate and geostatistical analyses of the sources and spatial distribution of heavy metals in agricultural soil in Gongzhuling, Northeast China

The content, source, and spatial distribution of heavy metals in soils are necessary to establish quality standard on a regional level, to assess the potential threat of metals to food safety and human health and to target policies of environment friendly and significant economic benefits. The surface horizons of 166 agricultural soils in Gongzhuling, a representative agricultural area in the black soil region, Northeast China, were sampled, and the total contents of Cu, Ni, Zn, Pb, Cr, and Cd were analyzed. Multivariate statistics and geostatistical analysis were combined in characterizing spatial distribution of heavy metals and determining their sources in this study. The mean values of the heavy metal concentrations were 19.61 +/- 6.23, 27.16 +/- 11.85, 57.82 +/- 14.28, 28.34 +/- 8.91, 53.04 +/- 19.27, and 0.106 +/- 0.048 mg kg(-1) for Cu, Ni, Zn, Pb, Cr, and Cd, respectively, slightly higher than their background values of Siping topsoil, but lower than the guideline values of Chinese Environmental Quality Standard for soils with the exception of individual samples of Ni and Cd. Multivariate and geostatistical analyses suggested that Pb and Cd were related to anthropogenic activities, such as the atmospheric deposition of industrial soot, dust and aerosols and coal burning exhausts, the application of fertilizers, livestock manures and agrochemicals, and the disposal of anthropogenic wastes, whereas Cr and Zn were mainly due to the parent materials, and Cu and Ni displayed a mixed origin of both lithogenic and anthropogenic origin. The analyses of content and sources of heavy metals in agricultural soils are basis for undertaking appropriate action to protect soil quality.