Impact of anthropogenic inputs on Pb content of moss Sanionia uncinata (Hedw.) Loeske in King George Island, West Antarctica revealed by Pb isotopes

The accumulation of heavy metals in plant communities has been investigated in the maritime Antarctica but their sources are not clearly identified yet. Here we measured Pb isotope ratios in the mosses Sanionia uncinata (Hedw.) Loeske, soils and bedrocks on King George Island, South Shetland Islands, West Antarctica in order to elucidate the sources of Pb in the moss samples. The enrichment factor of Pb indicated that the moss samples near the research station and oil tank are highly enriched in Pb which is attributed to either leaded gasoline and/or Patagonian aeolian dust. However, Pb isotope ratios clearly indicated that leaded gasoline is the main source of Pb in the moss within 1 km from the station and that chemical weathering of soil and bedrock controls Pb content in the moss far from the station (over 1 km from the station). This study clearly demonstrated that Pb in plant communities, especially moss Sanionia uncinata (Hedw.) Loeske, on King George Island is mainly originated from a mixture of leaded gasoline and chemical weathering with a little effect of Patagonian aeolian dust.