Prevalence of okadaic acid in benthic organisms associated Prorocentrum lima complex in a sub-tropical estuary

ABSTRACT

Lipophilic toxins were investigated in different benthic compartments of Paranaguá Bay, southern Brazil. Relatively low concentrations of okadaic acid (OA) were frequently reported in macrophyte extracts (maximum 0.64 ng g⁻¹), mainly in sheltered estuarine areas, correlated with the cell abundance of toxigenic benthic dinoflagellates, Prorocentrum lima. Non-conjugated OA was also detected in benthic marine animals, mostly during summer-autumn 2016. Higher OA concentrations were found in the viscera of Genidens genidens fish (24.3 ± 3.7 ng g⁻¹) and in soft tissues of Mytella guyanensis bivalves (21.3 ± 2.13 ng g⁻¹), whereas lower levels were less frequently reported in many other benthic feeders, including cephalopods, gastropods, crustaceans and fishes. Although OA concentrations were below the levels associated with acute human intoxication, possible chronic effects to benthic animals and their consumers cannot be disregarded due to the frequent presence of this biotoxin in various fishery resources. Human health risks are substantially enhanced for small-scale fishing communities and other socioeconomically vulnerable populations.

Graphical Abstract

KEYWORDS:

• Diarrhoetic toxins
• harmful algae
• seafood safety
• toxin bioaccumulation
• microphytobenthos
• estuarine fauna

Acknowledgments

The authors are most grateful to CAPES and CNPq (Brazil) for the Ph.D. scholarship awarded to A.R.M.G. (2014–2018) through the co-funded PEC-PG Programme, to the International Atomic Energy Agency for funding the study via Research Contract 18827 (‘Bentox Project’) and to the following researchers and students from Universidade Federal do Paraná who assisted with specific analytical procedures: André P. Cattani for identifying the fish species; Ligia F. G. da Luz for assisting with graphic design and Dayane de França Morais, André Lucas dos Santos Oro and Felipe Martins Ricardo for their help with sample processing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

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Additional information

Funding

This work was supported by the CAPES [PEC-PG programme], CNPQ [PEC-PG Programme] and International Atomic Energy Agency (IAEA) [RC #18827].