Vorkamp, K. & Sanderson, H. 2016. EQS variation study: European Environmental Quality Standards (EQS) Variability Study. Analysis of the variability between national EQS values across Europe for selected Water Framework Directive River Basin-Specific Pollutants. Aarhus University, DCE – Danish Centre for Environment and Energy, 96 pp. Scientific Report from DCE – Danish Centre for Environment and Energy No. 198. http://dce2.au.dk/pub/SR198.pdf
Under the Water Framework Directive of the European Union (EU), member states are to establish national environmental quality standards (EQSs) for River Basin Specific Pollutants. A technical guidance document (TGD) exists, which was published in 2011. Despite of this, previous studies have shown a significant variation between national EQS values. The aim of the present study was to investigate possible reasons for the variability observed for some EQS values derived by individual member states.Based on questionnaires targeting 19 selected substances with relatively large EQS variations, the member states provided details on how the national EQSs for these substances had been derived . The analysis showed that the year of the different national EQSs (e.g. older than the TGD) likely caused some variation. While other EU guidance and directives had been used frequently, the TGD had only been used for few of the selected substances. Furthermore, the protection endpoint and hence assessment factor used also contributed to the variation.