Occurrence of cyanobacterial toxins in freshwaters of the Alpine region

Different genera of freshwater cyanobacteria have the ability of producing toxic metabolites (cyanotoxins). Massive proliferation of these organisms can lead to harmful concentration of toxins in the water. An increase in frequency, magnitude and duration of harmful blooms has been documented globally in the last decades. It is therefore important to gather information about the occurrence of these contaminants in order to understand their geographical spread. The distribution of cyanotoxins in freshwater bodies of the alpine region was investigated in the frame of the “EcoAlps-Water '' project, funded by the European Interreg Alpine Space Program. The sampling was conducted in lakes and rivers of Austria, Italy, Slovenia and Switzerland using uniform protocols. Both pelagic and benthic samples were sampled. Toxins’ analysis was conducted in a reference laboratory (at the Fondazione Edmund Mach) using LC-MS/MS methodologies, able to distinguish the different classes of toxic compounds: hepatotoxic microcystins, neurotoxic anatoxins and saxitoxins, cytotoxic cylindrospermopsins. The investigation revealed the presence of cyanotoxins in the majority of investigated lakes, with microcystins being the most represented. Moreover, anatoxins were found in a few water bodies. In conclusion, cyanotoxins represent an additional risk that lakes of the Alpine Space region are facing. Constant attention to this issue must therefore be paid because global climatic changes and other local anthropogenic pressures can synergistically increase the risk of high cyanotoxins levels.