Concentration of toxic metals and potential risk assessment in edible fishes from Congo River in urbanized area of Kinshasa, DR Congo

Abstract

The objective of this research is to determine the concentration and potential health risks of toxic metals in six most consumed freshwater fish species (Auchenoglanis occidentalis, Bagrus ubangensis, Citharinus gibbosus, Distichondus fasciolatus, Marcusenius moorii, and Schilbe mystus). A total of 126 samples of these fish species were collected from seven sites of Congo River in the vicinity of Kinshasa City, Democratic Republic of the Congo. Toxic metals (Cr, Co, Ni, Zn, Se, Ag, Cd, Sn, Sb, and Pb) levels in fish muscle tissues were determined using Inductively Coupled Plasma Mass Spectrometry whereas Hg analysis was carried out using atomic absorption spectrophotometry. The maximum metal concentration (mg kg⁻¹ wet weight) of Zn (59.72), Sb (5.98), and Pb (4.96) was detected in muscle tissues of M. moorii, C. gibbosus, and D. fasciolatus, respectively. Pb, Zn, and Hg values in many fish samples exceeded the permissible levels set by Food and Agriculture Organization and World Health Organization for human consumption. Given the concentrations of Pb in all fish species and Zn in M. moorii, human health implications are likely to occur on continuous consumption. Addition, the evaluation of potential health risks for fish consumers indicates that there may or not be adverse effects.

Keywords:

• Toxic metals
• pollution
• edible fish
• Hg toxicity
• human health risks
• Congo River

Acknowledgments

This research presents the collaboration between University of Geneva (Department F. A. Forel), University of Kinshasa and Pedagogic National University of Congo (The Democratic Republic of the Congo).

Compliance with ethical standards

We confirm that the field studies did not involve endangered and protected species. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Conflict of interest

The authors declare no conflict of interest.

Additional information

Funding

We are grateful to financial support from the Swiss National Science Foundation (grant no. 31003A_173281/1).