The According to the Convention for the Protection of the Rhine against Chemical Pollution, 1976 the Rhine states are obliged to take appropriate measures to: (1) eliminate pollution of the surface waters of the Rhine basin by dangerous substances in the families and groups of substances appearing in Annex I; and (2) reduce the pollution of the Rhine by dangerous substances in the families and groups of substances appearing in Annex II. Under the Convention, emission standards and limit values are established for: (1) the maximum permissible concentration of polluting substances in discharges; and (2) the maximum permissible quantity of a polluting substance in discharges during one or more specific periods. The limit values applicable to Annex I substances are laid down mainly on the basis of toxicity, persistence and bioaccumulation (taking into account the best available technical means).
The Parties are required to establish a national inventory of discharges into the surface waters of the Rhine basin containing the substances listed in Annex I, which are subject to emission standards (that may not exceed the limit values proposed by the International Commission for the Protection of the Rhine against Pollution). In the case of existing discharges, the authorization must fix a time limit within which the conditions laid down in the authorization must be met. The Commission shall propose to the Parties these time limits. The Parties have to take all legislative and administrative measures to ensure that the storage and deposit of Annex I and II substances is so carried out as to entail no danger of pollution to the Rhine. If necessary, the Commission may propose to the Parties appropriate measures for protecting groundwater in order to prevent pollution of the Rhine by Annex I and II substances. The discharge of any Annex II substance likely to affect the quality of Rhine water must be regulated by the national authorities with a view to strict limitation. The governments must strive to establish national programmes for the reduction of the pollution of the Rhine by Annex II substances. The national programmes must lay down deadlines for their implementation.
The Parties agreed the black list of substances with considerable delay. The five countries and the EU also agreed the Rhine Action Programme that aims to reduce the concentrations of hazardous chemical substances and nutrients in the Rhine. The Programme's specific aims are to reduce emissions of a large number of substances by between 50 and 70 per cent between 1958 and 1995 and to restore the Rhine to its natural state so that some fish species can return to its waters. Although the programme regulates some substances, it leaves out many others. Its approach is more pragmatic than the Convention. A reduction of 50 percent for most substances was achieved by 1995; for some substances a greater reduction will be possible. The Ministers Conference on the protection of the Rhine against pollution that was held on 30 November 1989 in Brussels, extended the scope of the Rhine Action Plan to include the protection of the North Sea.
The Parties notify the Commission the contents of their inventories of discharges, which have to be updated at intervals not exceeding three years. Each government is also required to establish monitoring stations along the Rhine in order to determine concentrations of the substances and they should inform the Commission of the monitoring results at least once a year.