Many of the lakes and rivers in northern Greece are showing signs of degenerating water quality and need immediate attention if they are to be saved, according to a study by scientists at Thessaloniki’s Aristotle University. As far as rivers are concerned, the Axios is the most worrying, experts say. The river, which flows into Greece from the Former Yugoslav Republic of Macedonia (FYROM), «cleans itself» on its way southward but is polluted once again near Polykastro, in Kilkis, experts said. The River Nestos is also fueling concern as it is reportedly being polluted by the runoff from landfills in Bulgaria despite a bilateral agreement with the neighboring country regarding the river’s management. As for lakes, Koroneia, near Thessaloniki, is in the worst shape by far. Experts say long-delayed measures need to be taken to clean up these bodies of water. «Effective waste water management is the key to guaranteeing the health of our rivers,» Professor Maria Lazaridou told Kathimerini. The destruction of riverside foliage, which is an effective pollution filter, is also a problem, she said. Experts stressed that the attitude of the Greek authorities needs to change if any progress is to be made. «We must hurry if we are to reach the level of other (European Union) member states, rather than trying constantly to secure an extension for the implementation of directives,» the report said. There are also financial concerns. Greece has been fined several times for failing to meet EU water quality standards and faces another penalty unless it improves its management of lakes and rivers.