Geochemical transfer of thallium and accompany metals in the Pearl River: Implications from sediment profiles, South China

Since the pollution of thallium (Tl) broke out successively in the Pearl River branches (such as North River, the He River), the issue of Tl contamination has gained public concerns. In an attempt to explore the... [ view full abstract ]

Since the pollution of thallium (Tl) broke out successively in the Pearl River branches (such as North River, the He River), the issue of Tl contamination has gained public concerns. In an attempt to explore the characteristic of Tl contamination and its geochemical transfer in the Pearl river, sediment profiles were taken both from anoutlet of a Pb-Zn smeltery (representing a major Tl pollution point-source) and its near basin. The inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze the concentration and the spatial distribution of Tl and accompany heavy metals (Pb, Zn, Cd, Cu, etc.). The Geoaccumulation Index (Igeo) and the Hakanson Potential Ecological Index were applied to evaluate the pollution degree of Tl and other metals in the sediment. The results indicate that serious Tl contamination and high potential ecological risks present in both the sediment profiles from the smeltery outlet and the North river entrance , and nonlinearly concentrates as the depth increases. The correlation analysis and principal component analysis (PCA) indicates that the main source of Tl pollution may be the waste discharge of the near smeltery.