Volatile halogenated organic compounds in European estuaries

Sources, sinks, and distribution patterns of volatile halogenated organic compounds (VHOC) in estuaries were investigated during 5 cruises within the BIOGEST programme. Due to their chemical and physical properties (e.g. toxicity, persistence, mobility) these compounds are of considerable environmental concern. A wide range of compounds has been identified and quantified generally ranging from 0.1 ng l(-1) to 350 ng l(-1). In some samples extraordinarily high values up to 4700 ng l(-1) were observed indicating contribution from anthropogenic sources. Generally, concentrations of halogenated compounds of anthropogenic origin dominated those of prevalent natural origin. Data of selected VHOC are presented in relation to salinity, particular organic carbon, and total suspended matter. Furthermore the observed concentrations are compared with established water quality regulations. Distribution patterns of VHOC along the estuary indicated common sources for specific halogenated compounds. Decreasing concentrations of most VHOC along the estuary confirm that degassing to the atmosphere and dilution with sea water are the dominating processes controlling the fate of these compounds in estuaries.