Samples from a total of 134 lakes, practically all freshwater lakes in Åland, SW Finland, were screened for microcystins, hepatotoxic peptides of cyanobacteria, using high performance liquid chromatography (HPLC), time-resolved fluoroimmunoassay (TR-FIA), and protein phosphatase inhibition (PPIA) during two summers. Microcystins were recorded in 4 of 54 lakes in 1999 and 14 of 134 lakes in 2000, especially in eutrophic lakes but also in some dystrophic lakes and one oligotrophic. There was a satisfactory agreement between results obtained with different methods. The most likely microcystin-producers involved, as judged by microscopical examination, were Planktothrix agardhii, Microcystis aeruginosa, and Anabaena lemmermannii. One drinking-water reservoir and several lakes used for irrigation were microcystin-positive. Microcystins were also detected in late autumn samples from some eutrophic lakes.
|Status||Publicerad - 15 sep 2003|