Distributional Characteristics and Source Identification of Cadmium in Soils of the Pearl River Delta, China

The results of the Multi-Purpose Geochemical Survey in the Pearl River Delta (PRD) show that the pollution is serious. In this study, the influence of geological genesis, soil-forming process, and human activities on soil quality in PRD is analyzed, and the influence factors, genesis and spatial distributional characteristics of cadmium (Cd) in different soil depths are studied by inverse distance weighted (IDW) and hot spot analysis. The results show that the spatial distribution of Cd is significantly different in PRD and high-value is mainly concentrated in the central cities of Guangzhou-Foshan-Jiangmen-Zhongshan-Zhuhai. Moreover, hot spots with higher Cd content in deep are mainly along Beijiang, Dongjiang, and Pearl River Estuary (PRE). Overall, our findings suggest that the high background value areas formed by marine-land and fluvial sediments as well as intensive human activities that make PRD become an area under the dual restriction of geological genesis and human activities, pollution control cannot be ignored.