Heavy metals in agricultural soils from a typical township in Guangdong Province, China: Occurrences and spatial distribution

摘要

To investigate contamination level, origins and spatial distribution characteristics of heavy metals (Cu, Pb, Zn, Hg, Ni, Cd, As, and Cr) in agricultural soils of Gaogang Town, a typical industrial transfer-undertaking region of the Pearl River Delta (PRD), China, a total of 162 surface soil samples were collected in August 2016 and determined using inductively coupled plasma mass spectrometry, inductively coupled plasma optical emission spectrometry and atomic fluorescence spectrometry. Moreover, heavy metals contents were systematically analyzed by pollution index, enrichment factor, multivariate statistical approaches and geostatistical analysis. The results showed that the mean concentrations of Cd, Pb, Zn, Ni, Cu and Hg were higher than the soil background values of Guangdong Province, and the relatively high values of pollution index and enrichment factor indicated that these elements (Cd, Pb, Zn and Hg) had cumulative trends in soil. All results of multivariate statistical approaches and geostatistical analysis showed that pollution were heavily distributed in areas of industries, river and dense road network. The eight heavy metals in agricultural soils of Gaogang Town came from three different sources. Arsenic, Cr, Cu and Ni arose mainly from parent materials. Agricultural practices and traffic activities were the main sources of Cd, Pb and Zn. Mercury mainly came from industrial practices.