Behavior of some trace chemical constituents in estuarine waters

Abstract

The major variations in physicochemical conditions within estuaries give rise to the possibility of non-conservative (chemically interactive) behavior of some of the dissolved substances during the mixing of river and sea waters, with consequent modification of the flux of riverborne dissolved material to the open ocean. Approaches to the study of the behavior of trace constituents in estuarine systems have relied primarily upon environmental surveys of variations with salinity in the concentrations of individual constituents in the dissolved fractions. Better understanding of the processes involved in the interactions of dissolved and particulate material is obtainable from environmental studies in which a group of constituents, the behavior of which may be inter-related, is examined, with relevant measurements on particulate fractions. Complete descriptions of chemical speciation in these systems cannot be obtained for the trace constituents by present methods. Analytical resolution of dissolved and particulate material into further operationally defined fractions, and the simulation of processes in model solutions, including modified natural waters, can give valuable information, however, on the mechanisms of interactive processes. These approaches are illustrated by recent findings on trace constituents in the Beaulieu Estuary, with particular reference to the behavior of iron and selenium. © IUPAC