Characteristics and origins of heavy metals in sediments from Ximen Co Lake during summer monsoon season, a deep lake on the eastern Tibetan Plateau

• The dominant contaminated elements in sediment core from a deep lake were detected.
• The high EF values showed the source of anthropogenic pollutants.
• The increase of element As from 4.5 cm layer represents increase of As in aerosols.
• The continuous deterioration of atmospheric environment from the 1940s was reflected.

The concentration and enrichment factor (EF) values of heavy metals in sediments collected from Ximen Co Lake, a deep lake on the eastern Tibetan Plateau, displayed obvious changes on profile in August of 2009. The dominating contaminating elements were Be, Ag, Cd, Pb and As. The high concentration and EF values showed that the anthropogenic pollutants in atmospheric aerosol from the West, Central Asia and South Asia could be carried to the Tibetan Plateau under the influence of southwest monsoon. The obvious increase of concentration of As from 4.5 cm layer of sediment core represented the increase of As in aerosols, and reflected the continuous development of manufacturing and living and the dramatic deterioration of atmospheric environment of the West, Central Asia and South Asia regions since the 1940s.