Multi-species okadaic acid contamination and human poisoning during a massive bloom of Dinophysis acuminata complex in southern Brazil

• Published in: Harmful algae Vol. 89; p. 101662
• Main Authors: Mafra, L.L., Nolli, P.K.W., Mota, L.E., Domit, C., Soeth, M., Luz, L.F.G., Sobrinho, B.F., Leal, J.G., Di Domenico, M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2019
• Subjects: Animals; Brazil; Dinoflagellida; DSP; Environmental Monitoring; Harmful algae; Humans; Lipophilic toxins; Marine Toxins; New toxin vectors; Okadaic Acid; Seafood intoxication; Toxin in food webs; Brazil; Harmful algae; DSP; New toxin vectors; Lipophilic toxins; Toxin in food webs; Seafood intoxication
• ISSN: 1568-9883; 1878-1470
• DOI: 10.1016/j.hal.2019.101662

•These are the greatest cell abundances ever recorded for toxigenic Dinophysis spp.•Oysters accumulated exceptionally high levels of okadaic acid.•Contaminated bivalves were linked to episodes of diarrhetic shellfish poisoning.•Gastropods, crustaceans, echinoderms, fishes, penguins and dolphins were also affected.•Toxin concentrations in marine consumers were inversely related to their trophic levels. On June 2016, a major bloom of Dinophysis acuminata complex was noticed over the coast of Paraná State (PR), southern Brazil, an area unprotected by any official monitoring program. Here we report the results of an extensive sampling effort that ultimately led PR authorities to issue the first State shellfish-harvesting ban due to multi-species okadaic acid (OA) contamination. During its peak, the bloom covered an area of 201 km2 (∼2.0–3.5 × 54.0 km), attaining unprecedentedly high cell densities along the shallow (<15 m) continental shelf (mean 2.2 × 105, maximum 2.1 × 106 cells L−1) and adjacent sandy beaches (mean 2.8 × 105, maximum 5.2 × 106 cells L−1). Only OA was detected in suspension (max. 188 ng L−1). Toxin levels measured in bivalves were several times greater than the regulatory limit of 160 ng g−1, reaching up to 3600 ng g−1 in Crassostrea gasar, by far the highest OA concentrations ever reported in oysters worldwide, 7700 ng g−1 in brown mussels, Perna perna, and lower levels in clams, Anomalocardia brasiliana, and mangrove mussels, Mytella spp. Nine cases of human intoxication were officially reported and five people were hospitalized with typical symptoms of Diarrhetic Shellfish Poisoning linked to the consumption of contaminated bivalves. All bivalves quickly converted most of the OA into its esterified form, DTX-3, and eliminated the toxins only a few weeks following the bloom, with C. gasar being the slowest-detoxifying species. Lower OA levels were accumulated in zooplankton, gastropods and several novel toxin vectors, including benthic organisms such as sand dollars Mellita quinquiesperforata and the ghost-shrimp Callichirus major, which may act as a good indicator of the presence of toxins in sandy beaches, and pelagic fish species that can serve as potential alternative sources of OA to humans (Chaetodipterus faber and Mugil liza). Monitoring toxin contamination in seafood other than bivalves is thus recommended to ensure comprehensive human health protection during massive Dinophysis blooms. Additionally, since OA was also present at low concentrations in the liver of Guiana dolphins Sotalia guianensis and penguins Spheniscus magellanicus, exposure to biotoxins should be considered in conservation actions involving threatened and near-threatened marine organisms in this region.