The purpose of this Decree is to protect waters against pollution caused by nitrates from agricultural sources and to reduce the level of already existing pollution caused by nitrates. This Decree applies to those engaged in agriculture and to those activities affecting surface and underground waters. Article 4 provides for the designation of nitrate vulnerable zones and they must be reviewed once in four years. Article 5 contains a list of principal nitrate vulnerable zones. Agricultural activities in nitrate vulnerable zones may be exercised in conformity with the provisions of the action program and the compulsory rules of the Good Agricultural Practices referred to by the action program. The action program is to be enacted in separate ministerial decree. General rules of nitrate pollution prevention are contained in Article 7. Information of farmers is foreseen by Article 8. Articles 10 and 11 cover inspection and control of implementation and observation of the provisions of this Decree by the competent animal production and soil conservation authorities. A penalty may be levied in certain cases for offenders. Article 12 foresees a national monitoring system.