Spatial distribution, sources and risk assessment of potentially toxic elements contamination in surface soils of Yellow River Delta, China

The contamination status and ecological risk of soil potentially toxic elements (PTEs) in Yellow River Delta (YRD) are still poorly understood. Thirty surface soil samples were collected in YRD, determined for contents of PTEs, and assessed using four kinds of proxies. Results indicated that PTEs contents basically met the Environmental Quality Standard for Soils, and spatial heterogeneity of PTEs was not distinctive except for a few sampling sites. Results of geo-accumulation index (Igeo) and enrichment factor (EF) indicated significant enrichment of As and Sb in YRD. The multivariate analysis results distinguished the possible sources of these PTEs and demonstrated that sources of Ag, As, Cd, Cu, Pb, Sb and Zn could be influenced by anthropogenic activities (industrial and agri-cultural sources). Moreover, Ni, Cr and As had relatively high contributions to sum of toxicity units (sigma TUs). This study provides basic information for understanding soil PTEs contamination status of YRD.