Biogenic Volatilization of Trace Elements from European Estuaries

This paper describes the importance of volatile chemical forms of selected trace elements in the environment with emphasis on the estuarine aquatic environment. The occurrence, distribution and fluxes of gaseous species of trace elements such as Mercury (Hg), Selenium (Se), Tin (Sn) and Iodine (I), was investigated in three European macro-tidal estuaries in relation with the main biogeochemical parameters. Water and air samples were collected according to ultra-clean methods, in the Gironde, the Rhine and the Scheldt estuaries. On a seasonal basis, this approach allowed us to evaluate the potential pathways of these gaseous species in estuarine waters and to derive their seasonal fluxes to the atmosphere. We were then able to provide an estimation of the global contribution of European estuarine emission of these trace elements and to compare it with anthropogenic sources.