Occurrence of microcystins, anabaenopeptins and other cyanotoxins in fish from a freshwater wildlife reserve impacted by harmful cyanobacterial blooms

Harmful algal blooms of cyanobacteria (CyanoHABs) can lead to the release of potent toxins that can seriously affect ecosystem integrity. Some freshwater watersheds are particularly at risk considering the threats to already imperiled wildlife. The consumption of tainted drinking water and contaminated food also raises concerns for human health. In the present study, a pilot survey was conducted in the riverine ecosystem of the Pike River Ecological Reserve (QC, Canada) near Missisquoi Bay, Lake Champlain. We examined the occurrence of multi-class cyanotoxins including 12 microcystins, anatoxins, cylindrospermopsin (CYN), anabaenopeptins (AP-A, AP-B), and cyanopeptolin-A in surface waters and wild-caught fish during the summer 2018. Out of the 18 targeted cyanotoxins, 14 were detected in bloom-impacted surface water samples; toxins peaked during early-mid September with the highest concentrations for MC-LR (3.8 mu g L-1) and MC-RR (2.9 mu g L-1). Among the 71 field-collected fish from 10 species, 30% had positive detections to at least one cyanotoxin. In positive samples, concentration ranges in fish muscle were as follows for summed microcystins (Sigma MCs: 0.16-9.2 mu g kg(-1)), CYN (46-75 mu g kg(-1)), AP-A (1.1-5.4 mu g kg(-1)), and AP-B (0.12-5.0 mu g kg(-1)). To the best of our knowledge, this is one the first reports of anabaenopeptins occurrence in wildlife. The maximum Sigma MCs in fish was 1.15-fold higher than the World Health Organization (WHO) daily intake recommendation for adults and nearly equated the derived value for young children. The concentration of CYN was also about 3-fold higher than the limit derived from the human health guideline values.

Automated summary

Harmful algal blooms of cyanobacteria can release potent toxins that seriously affect ecosystem integrity and human health. A pilot survey near the Pike River Ecological Reserve in Canada revealed the presence of multiple cyanotoxins in surface waters and wild-caught fish, highlighting potential risks to wildlife and human consumption.