Some heavy metals distribution in wetland soils under different land use types along a typical plateau lake, China

Topsoil (0–20 cm) samples were collected from three sampling plots under different land use types (uncultivated wetland, cultivated wetland and cultivated wetland after abandonment) along the eastern region of the Yilong Lake in October, 2005. Total concentrations of As, Cd, Cu, Pb and Zn were determined using the inductively coupled plasma atomic absorption spectrometry in order to assess and compare contamination levels of the three sampling plots. Results showed that the average concentrations of these heavy metals were generally higher in wetland soils and abandoned tilled soils than those in conventionally tilled soils. Compared with wetland soils, contamination indices were lower for As and Cd in conventionally tilled soils, as well as lower for As in abandoned tilled soils, while no significant differences were observed for other heavy metals. The integrated contamination indices showed low contamination levels for cultivated soils, and high contamination levels for wetland soils and abandoned tilled soils.