Environmental outlook 2008 for Wallonia - Eutrophication of watercourses
The link address is: http://etat.environnement.wallonie.be/index.php?mact=tbe,mf7538,default,1&mf7538what=fiches&mf7538alias=eutrophication-of-watercourses&mf7538returnid=35&page=35