River basin specific pollutants are substances that enter the river basin or parts of it in significant quantities. The quantitative assessment is done with environmental quality standards that are fixed by the European Union member states. In Luxembourg, the substances and limit values (annual average) are fixed in the grand ducal regulation of 15 January 2016 (règlement grand-ducal du 15 janvier 2016 concernant l'évaluation des masses d'eau de surface). Evaluation takes place with 2 categories (good, moderate and worse). River basin specific pollutants are used together with the general physico-chemical parameters for evaluation of the ecological status.