Analyse des cyanotoxines dans différents organismes aquatiques et habitats de la réserve écologique de la Rivière-aux-Brochets
The diversity and widespread distribution of cyanobacteria in aquatic ecosystems lead to harmful effects in water through the production of a variety of cyanobacterial toxins, which pose a great danger to fauna and human health. Different emerging analytical techniques have been developed to detect and quantify cyanobacterial toxins in the environment. In this thesis we examined the presence of multi-class cyanotoxins, including 12 microcystins, anatoxins, cylindrospermopsin (CYN), anabaenopeptins (AP-A, AP-B) and cyanopeptolin-A in surface water and wild fish. Sampling was conducted during the 2018 summer season in the fluvial ecosystem of the Pike River ecological reserve (QC, Canada) near Missisquoi Bay, Lake Champlain. This study was carried out using an analytical method combining ultra-high-performance liquid chromatography and ionization by electrospray (UHPLC-ESI) with the use of a triple quadrupole mass spectrometer. Of the 18 cyanotoxins targeted, 14 were detected in surface water samples impacted by the bloom; toxins peaked in early mid-September with the highest concentrations of MC-LR (3.8 μg L-1) and MC-RR (2.9 μg L-1). Among the 71 fish sampled in the field from 10 species, 38% had positive detections of at least one cyanotoxin. In positive samples, the concentration ranges in fish muscle were as follows: the sum of microcystins ΣMC (0.16-9.2 μg kg-1), CYN (46-75 μg kg-1), AP -A (1.1-5.4 μg kg-1) and AP-B (0.01 to 5.0 μg kg-1). Overall, 17% of the fish samples were positive for AP-A or AP-B; to our knowledge, this is the first report of accumulation of anabaenopeptins in wildlife. The maximum sum ΣMC of microcystin concentrations in fish was 1.15 times higher than the recommendation of the World Health Organization (WHO) Daily Intake (8 μg kg-1 tissue-1) for adults and was almost equivalent to the derived value for young children 9.3 μg kg-1. The concentration of CYN was also approximately 3 times higher than the limit derived from the recommended human health values.
Anabaenopeptins Quantification UHPLC-ESI-MS Cyanobacterial toxins Distribution Microcystins Cylindrospermopsin Fish