Persistent Organochlorine Compounds Levels in Selected Fish Species from Lake Victoria and Associated Human Health Risks

Concentrations of heavy metals (Cr, Co, Fe, Ni, Cu, Zn, As, Se, Pb and Hg) in muscle tissues of two fish species (Clarias gariepinus and Oreochromis niloticus) in an Ethiopian rift-valley lake (Hawassa) and a neighboring stream (Boicha) were determined. Target hazard quotients (THQ), hazard index (HI) and target cancer risk (TCR) were used as indices to evaluate potential human health risks from fish consumption. Average concentrations of metals decreased in the order Zn>Fe>Se>Cu>Hg>As>Ni>Cr>Co>Pb and Zn>Fe>Se>Cu>As>Hg>Cr>Ni>Pb>Co in muscle tissues of C. gariepinus and O. niloticus, respectively. Mean concentrations of Hg (0.34+0.04 mg kg-1) in muscle tissues of C. gariepinus from Lake Hawassa, and As (0.18+0.05 mg kg-1) as well as Hg (0.46+0.03 mg kg-1) in muscle tissues of C. gariepinus from Boicha stream were above the safety limits set by WHO/FAO. Likewise, mean concentrations of As (0.31+0.03 mg kg-1) and Hg (0.19+0.05 mg kg-1) in muscle tissues of O. niloticus from Lake Hawassa and Cr (0.19+0.03 mg kg-1), As (0.33 +0.04 mg kg-1), and Hg (0.34+0.09 mg kg-1) in O. niloticus from Boicha stream were also above safety limits. From the results of human health risk assessments it was concluded that Cr, Cu, Hg and As pose potential health risks due to consumption of the two fish species from both water bodies. Moreover, effects of all heavy metals put together may affect human health as indicated by the high HI. Effluents from industries are assumed to be the main sources of the heavy metals. Therefore, regular monitoring of the water bodies and policy interventions with respect to waste disposal are recommended to protect the health of the ecosystem and the public. Keywords: Fish consumption, health risk, heavy metals, Lake Hawassa

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Contamination and oxidative stress biomarkers in estuarine fish following a mine tailing disaster

PeerJ ◽

10.7717/peerj.10266 ◽

2020 ◽

Vol 8 ◽

pp. e10266 ◽

Cited By ~ 1

Author(s):

Fabrício Â. Gabriel ◽

Rachel Ann Hauser-Davis ◽

Lorena Soares ◽

Ana Carolina A. Mazzuco ◽

Rafael Christian Chavez Rocha ◽

...

Keyword(s):

Trace Metals ◽

Trace Metal ◽

Human Health ◽

Health Risks ◽

Fish Species ◽

Reduced Glutathione ◽

Estuarine Sediments ◽

Metal Concentrations ◽

Human Health Risks ◽

Muscle Tissues

Background The Rio Doce estuary, in Brazil, was impacted by the deposition of iron mine tailings, caused by the collapse of a dam in 2015. Based on published baseline datasets, the estuary has been experiencing chronic trace metal contamination effects since 2017, with potential bioaccumulation in fishes and human health risks. As metal and metalloid concentrations in aquatic ecosystems pose severe threats to the aquatic biota, we hypothesized that the trace metals in estuarine sediments nearly two years after the disaster would lead to bioaccumulation in demersal fishes and result in the biosynthesis of metal-responsive proteins. Methods We measured As, Cd, Cr, Cu, Fe, Mn, Pb, Se and Zn concentrations in sediment samples in August 2017 and compared to published baseline levels. Also, trace metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Se and Zn) and protein (metallothionein and reduced glutathione) concentrations were quantified in the liver and muscle tissues of five fish species (Cathorops spixii, Genidens genidens, Eugerres brasilianus, Diapterus rhombeus and Mugil sp.) from the estuary, commonly used as food sources by local populations. Results Our results revealed high trace metal concentrations in estuarine sediments, when compared to published baseline values for the same estuary. The demersal fish species C. spixii and G. genidens had the highest concentrations of As, Cr, Mn, Hg, and Se in both, hepatic and muscle, tissues. Trace metal bioaccumulation in fish was correlated with the biosynthesis of metallothionein and reduced glutathione in both, liver and muscle, tissues, suggesting active physiological responses to contamination sources. The trace metal concentrations determined in fish tissues were also present in the estuarine sediments at the time of this study. Some elements had concentrations above the maximum permissible limits for human consumption in fish muscles (e.g., As, Cr, Mn, Se and Zn), suggesting potential human health risks that require further studies. Our study supports the high biogeochemical mobility of toxic elements between sediments and the bottom-dwelling biota in estuarine ecosystems.

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