Detection of free and bound microcystins in tilapia fish from Egyptian fishpond farms and its related public health risk assessment
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Microcystins (MCs), the most common cyanobacterial toxins in freshwaters, can accumulate in aquatic animals in free and bound forms. MCs therefore pose a risk to human health upon consumption of contaminated fish tissues, as they cause severe liver damage and death with potential carcinogenic effects. While there have been extensive studies on free MC contents in fish tissues, the detection of bound MCs in fish is largely unexplored. In the present study, both free and bound MCs were monthly monitored in tilapia fish from three tropical fishponds in Egypt for one year. Fishpond waters contained high concentrations of MCs (18–44 µg/l). Free MCs were estimated in tilapia fish organs at levels up to 11.8 ng/g in intestines, 8.3 ng/g in livers and 0.38 ng/g in edible tissues. Concentrations of bound MCs in edible tissues as determined by Lemieux oxidation technique (15,000–19,000 ng/g fresh weight, FW) were several-folds higher than free MCs. The estimated daily intake (EDI) for free MCs (0.0006–0.002 μg/kg/day MCs) in edible tissues was lower than the WHO limit (0.04 µg/kg/day), while EDI of bound MCs exceeded this limit by a factor of 77–2396. Therefore, both free and bound MCs in fish tissues should be considered when fish are monitored for human consumption.
KeywordsAccumulation Bound microcystins Cyanobacteria Fish Human health
The authors appreciate and acknowledge the Deanship of Scientific Research at King Khalid University for providing ELISA kits and MC standards and funding this study through the collaborative Research Groups Program under Grant # R.G.P. 2-14-40
Compliance with ethical standards
Conflict of interest
The authors declare that there is no conflict of interest.
- APHA (1995) Standard methods for the examination of water and wastewater, 14th edn. American Public Health Association, Washington, DCGoogle Scholar
- Komárek J, Anagnostidis K (2005) Cyanoprokaryota. 2. Teil: Oscillatoriales. Süßwasserflora von Mitteleuropa; Band 19/2. Elsevier, Műnchen, p 759Google Scholar
- Pawlik-Skowrońska B, Toporowska M, Rechulicz J (2012) Simultaneous accumulation of anatoxin-a and microcystins in three fish species indigenous to lakes affected by cyanobacterial blooms. Oceanol Hydrobiol Stud 41:53–65Google Scholar
- WHO (1998) Guidelines for drinking water quality. Addendum to volume 1. Recommendations, 2nd edn. World Health Organization, GenevaGoogle Scholar