Assessment of elemental distribution and trace element contamination in surficial wetland sediments, Southern Tibetan Plateau.

An investigation was performed to measure concentrations of major and trace elements in surficial wetland sediments in the southern Tibetan Plateau in order to assess the sediment quality. Results showed that most of elements have concentrations comparable to those of the Tibetan surface soil (TSS) except for As, Ca, Cs, Sr, and Cu. Correlation analysis indicated that most elements were highly associated with major crustal elements, suggestive of their common natural origin. Sediment quality assessment revealed that the wetlands are unpolluted with most of trace elements except for Cs and As, which are likely associated with organic matters and biological activities. Despite that the wetland sediments are minimally influenced by either local or long-transported anthropogenic pollutants, and no notable trace element pollutants were detected, As was found in elevated concentrations which far exceed the level above which harmful effects on wildlife and humans are likely to be observed.