Mercury Volatilization from Three Floodplain Soils at the Central Elbe River, Germany

Abstract

Wetlands at the riverside of the UNESCO Biosphere Reserve “Central Elbe” are highly contaminated by heavy metals, especially mercury (Hg). The Hg-polluted Elbe floodplain soils turn out to be a source of gaseous mercury via Hg volatilization from soil into the atmosphere. A modified field sampling method was used to measure total gaseous mercury (TGM) volatilization from three different sites at the Elbe River. The modified setup had a reduced chamber size and contained an internal gas circulation system. An in-ground stainless steel cylinder minimizes Hg volatilization from adjacent soil air. Cold vapor atomic absorption spectrometry (CV-AAS) was used to determine TGM amalgamated on gold traps. Sampled TGM amounts ranged between 0.02 and 0.63 ng (absolute), whereas the calculated Hg fluxes varied from 2.0 to 63.3 ng m⁻² h⁻¹. The modified system should allow measurements of Hg volatilization at various sites with a high spatial resolution, which should enable the study of interrelations between TGM emission and several key factors influencing Hg emission from floodplain soils at the Elbe River and other riverine ecosystems in the near future.

Keywords:

• Hg fluxes
• River Elbe
• total gaseous mercury (TGM)
• wetland soils

Acknowledgements

This study is supported by a research grant of the European Fund for Regional Development (EFRE), of the Ministry of Agriculture and Environment, and advice of the Department of Environmental Protection (LAU) of the Federal German state Saxony-Anhalt (FKZ: 76213/01/05). We would like to thank Analytik Jena AG for supplying the device used to establish the connection of the gold traps with CV-AAS. We are also grateful to Mr. H. Dittrich for his technical assistance and Mr. J. Steffen for analyzing total gaseous mercury.