A state-backed and European Union-approved plan to reunify Lake Volvi – Greece’s second-largest – with the heavily polluted Lake Koroneia, could provoke serious environmental problems, experts at Thessaloniki’s Aristotle University warned yesterday. Lake Koroneia is Greece’s dirtiest body of water, believed to contain the highest rate of cyanobacteria (blue-green algae) in the world. Lake Volvi, also located in the Thessaloniki prefecture, is relatively clean. Rejoining the two lakes – which used to run into each other 30 years ago – would harm them both, experts maintain. «We propose the biological monitoring of the two lakes separately so we can find out how to save Koroneia without disturbing the ecological balance of Volvi,» said the university’s biology professor Maria Moustaka. But authorities in charge of plans to create a channel between the two lakes say there is no risk. «This has been approved by experts, ministries and the EU,» said Savvas Anastassiadis, the regional official overseeing the project.