Potential health risks of trace metals in muscle tissue of tilapia and catfish from Mozambican markets

Due to the toxicity of trace metals and the propensity of fishes to bioaccumulate metals in their tissues, we investigated the concentrations of arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), mercury (Hg), and zinc (Zn) in the muscles of tilapia (Oreochromis mossambicus) and catfish (Chrysichthys nigrodidatatus) collected from open markets in Mozambique. Fe and Hg were the most and least bioaccumulated metals in the fishes, respectively. One-way ANOVA showed significant differences between sites for the analytes. Furthermore, we estimated the possible health risks (estimated daily intake (EDI), target hazard quotient (THQ), and maximum allowable consumption rate (CRlim)) associated with fish consumption. The concentrations of As, Cd, and Pb exceeded the recommended maximum permissible limits (MPL) in fish samples, ranging between 5.65 – 12.7, 1.05 – 12.9, and 1.88 – 6.45 mgkg-1, respectively, whereas values lower than MPL viz. 5.25 – 18.9, ND – 0.033, and 30.8 – 52.3 mgkg-1 were observed for Cu, Hg, and Zn, respectively. Similarly, the EDI (mgkg-1day-1) were below the provisional tolerable daily intake (PTDI) with decreasing order: Fe >Zn >Cu >As >Cd >Pb>Hg. However, the THQ (mg kg-1) was slightly > 1 for As and Cd in some samples. Moreover, the CRlim (kg day-1) showed a decreasing order of Hg >Fe >Zn >Pb> Cu >Cd >As. Generally, consumers are susceptible to health hazards associated with As and Cd. Hence, regular toxicological monitoring of the fishes from the study area is imperative.