Modeling Lead Input and Output in Soils Using Lead Isotopic Geochemistry

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• 作者：R. M. Semlali ; J.-B. Dessogne ; F. Monna ; J. Bolte ; S. Azimi ; N. Navarro ; L. Denaix ; ^O ; M. Loubet ; C. Chateau ; and F. van Oort
• 刊名：Environmental Science & Technology
• 出版年：2004
• 出版时间：March 1, 2004
• 年：2004
• 卷：38
• 期：5
• 页码：1513 - 1521
• 全文大小：172K
• 年卷期：v.38,no.5(March 1, 2004)
• ISSN：1520-5851

文摘

The aim of this study is to model downward migration oflead from the plow layer of an experimental site locatedin Versailles (about 15 km southwest of Paris, France). Since1928, samples have been collected annually from thetopsoil of three control plots maintained in bare fallow.Thirty samples from 10 different years were analyzed fortheir lead and scandium contents and lead isotopiccompositions. The fluxes are simple because of the well-controlled experimental conditions in Versailles: onlyone output flux, described as a first-order differentialfunction of the anthropogenic lead pool, was taken intoaccount; the inputs were exclusively ascribed to atmosphericdeposition. The combination of concentration and isotopicdata allows the rate of migration from the plowedtopsoil to the underlying horizon and, to a lesser extent,the atmospheric fluxes to be assessed. Both results are ingood agreement with the sparse data available. Indeed,the post-depositional migration of lead appears negligibleat the human time scale: less than 0.1% of the potentiallymobile lead pool migrates downward, out of the first 25 cmof the soil, each year. Assuming future lead inputs equalto 0, at least 700 yr would be required to halve theamount of accumulated lead pollution. Such a low migrationrate is compatible with the persistence of a majoranthropogenic lead pool deposited before 1928. Knowledgeof pollution history seems therefore to be of primaryimportance.