Accumulation of toxic metals in fish raised from sewage-fed aquaculture and estimated health risks associated with their consumption

Abstract

We determined the health risks associated with the consumption of toxic metals in fish raised from a sewage-fed aquaculture. Concentrations of toxic metals in fish, water and sediments in the waste stabilization ponds were determined using atomic absorption spectrophotometer. All the fish samples had some amount of toxic metals in them. The maximum concentrations of lead, cadmium, copper, chromium and mercury in the water samples were 28.7, 18.2, 246.0, 310.0 and 150.0 μg/kg, respectively, which were all below the US-EPA limits. The maximum concentrations of Pb, Cu, Cr and Hg in all sediment samples are 27.4, 323.0, 240.0 and 150.0 μg/kg, respectively. The maximum concentrations of Pb, Cd, Cu, Cr and Hg in the fish samples were 48.6, 18.9, 434.0, 300.0 and 320 μg/kg, respectively, which were below the EU maximum residual limit. The estimated daily intake calculated ranged from 1.0 × 10−6 to 6.0 × 10−5 mg/kg/day. Mercury showed the highest health risk, while Pb had the lowest. None of the risk indexes was up to 1, indicating that human beings who consume fish from the ponds are not be exposed to health risks as far as toxic metals are concerned.