Relationships between Pressures, Chemical Status, and Biological Quality Elements. Analysis of the Current Knowledge Gaps for the Implementation of the Water Framework Directive

Abstract

The general objective of the REBECCA project1 is to provide relevant scientific support for the implementation of the Water Framework Directive (WFD). The two specific aims of the project are, firstly, to establish links between ecological status of surface waters and physico-chemical quality elements and pressures from different sources, and, secondly, to develop and validate tools that member states can use in the process of classification, in the design of their monitoring programs, and in the design of measures in accordance with the requirements of the WFD. Historically, there has been great success in maintaining and improving the quality of surface waters by developing an understanding of the links between anthropogenic pressures (e.g. water abstraction, agriculture, and effluent discharges) and the chemical status of waters, although there remain many challenges in reliably designing and implementing the necessary programs of measures. Our present understanding of the link between chemical properties and ecological state, while good in some instances, is generally not adequate to support management intervention against ecological objectives. In this report we review and identify information gaps in our knowledge on relations between pressures, chemical and ecological status for the major pressures types and biological quality elements. We also give an overview of the chemical parameters that are used to determine the ecological status of water body types and of the biological indicators currently applied and/or potentially applicable as classification parameters for inland and coastal waters. This gap-analysis is needed to 1) identify the key areas of further work within the REBECCA project and 2) to identify the areas where further experimental or monitoring work would be needed (beyond the scope of REBECCA), due to lack of data or quantitative understanding of the functional relationships between chemical status and biological quality indicators. This report should help in focusing the on-going WFD intercalibration process in 2005-6. In particular it should provide insights on which biological and pressure parameters should be selected and which data there would be available to illustrate the degradation of the biological quality with respect of pressure gradients.