First occurrence of Cylindrospermopsin in the Azores (Lake São Brás, S. Miguel Island)

Abstract

Anthropogenic impacts have been reported as one of the main causes of eutrophication in freshwater systems and nutrient availability, mainly from discharges, are key to cyanobacteria development and harmful cyanobacteria blooms (cyanoHABs) upsurge. As these scenarios are common in the Azores, a cyanobacteria monitoring program was implemented in the lakes of the archipelago, which comprises cyanobacteria identification and cyanotoxin (only microcystin) analysis in over 15 lakes. However other cyanotoxins should be searched as is the case of cylindrospermopsin (CYN). This cyanotoxin has been reported more recently in a wider range of countries, because of global warming. Using ESI–LC–MS/MS (electrospray ionization–liquid chromatography–mass spectrometry), the presence of CYN was investigated in samples from four eutrophic lakes. Cylindrospermopsin was detected in one sample from Lake Sao Bras, which represents a threat to environmental and public health. This is the first CYN identification in the Azores reinforcing the necessity for lake monitoring. We propose the use of a polyphasic approach to fully understand CYN presence in the Azorean lakes, investigating the producing taxa, the environmental factors that promote cyanobacteria growth, and CYN toxicity effects.