Lead concentrations and isotope ratios from two speleothems from the Han-sur-Lesse cave in southern Belgium were measured in order to study the ability of speleothems to act as archives of atmospheric pollution. To address this aim we analyzed trace elemental Al and Pb compositions by LA-ICP-MS and ICP-MS as well as Pb isotopes by MC-ICP-MS. The results help to identify three intervals characterized by particularly high enrichment of Pb: from 1880 to 1905. AD, from 1945 to 1965. AD, and from 1975 to 1990. AD. The speleothem record shows similar changes as the known historical atmospheric pollution level in Belgium. Lead isotope ratios discriminate between Pb sources and confirm that coal and gasoline combustion, combined with regional metallurgical activities, were the predominant Pb pollution sources in the stalagmites during the last 250. years. This study opens possibilities to determine anthropogenic versus natural metal sources in well-dated speleothem archives.
Bibliographical noteFunding Information:
We thank all the persons who contribute to this work and especially Jacque Navez, Laurence Monin from (LA-ICP-MS analyses), Nadine Mattielli and Ivan Petrov at ULB (MC-ICP-MS analyses), and Dr Chris Ottley at Durham (ICP-MS analyses). This study was funded by the Walloon Region ( Visa 08/13701 ) and the FNRS . M. Allan received funding through a PhD grant from the government of Syria and Erasmus Mundus EPIC . Thanks to the personal of Han-sur-Lesse caves and especially to Mme. Malou, Guy Evrard and the guide Etienne Lannoye for their help during sampling. The manuscript has been improved by the constructive comments of the reviewers and by the editor, Dr. L Reisberg.
- Atmospheric pollution
- Pb isotopes
- Trace metals
- Western Europe