Presence of less monitored bioactive cyanotoxins (anabaenopeptins, saxitoxins, and BMAA isomers) in surface waters

The proliferation of harmful cyanobacterial algal blooms is of concern due to the associated release of toxins affecting ecosystems and human health. Among a range of cyanobacterial toxins, the hepatotoxic microcystins are the most documented and have been associated with numerous poisoning episodes. Other bioactive cyanopeptides, such as anabaenopeptins or cyanopeptolins, are rarely monitored in surface water and drinking water. Nonproteinogenic neurotoxic cyanotoxins such as saxitoxins (and analogues) and β-methylamino-l-alanine (BMAA) (and isomers) can also be produced, but there are many analytical challenges in their measurement. Here, we set out to document the occurrence of saxitoxin, neosaxitoxin, and their decarbamoyl analogues, BMAA and isomers (AEG, BAMA, DAB), and anabaenopeptins -A and -B in bloom-impacted surface waters. A large set of lake samples were collected from North America and Western Europe countries and submitted to three specific high-resolution mass spectrometry methods, with limits of detection in the range of 0.7-20 ng/L. The initiative provides much-needed data on the occurrence of infrequently monitored cyanotoxins beyond microcystins.