Evaluation of flesh and serum concentrations of Al, Zn, Mn and Sb in African cat fish (Clarias gariepinus) reared in plastic ponds in Benin City, Nigeria

Fishing in both natural and artificial habitats is a major occupation in Nigeria. Fishing in plastic ponds is one of such artificial habitats. This study seeks to determine and compare the bioaccumulation of selected toxic and essential trace metals-Aluminum, Antimony, Manganese and Zinc in body, serum and water habitat of Clarias gariepinus obtained from five different plastic fish ponds in Benin metropolis, using fishes from Ikpoba River as control. Catfish were obtained from five different farms and the controls were from Ikpoba River. The concentrations of Aluminum, Antimony, Manganese and Zinc were determined using inductively coupled plasma mass spectrophotometer. Results revealed that pond A Mn concentration (75.7 ± 1.2 mg/g),was lowest, and followed by pond B (96.8 ± 1.5). The level of Zn in body of pond A, B, C, D were all high (p<0.001). High level of Antimony was observed in pond A, B, C and D ranging from (0.019 ± 0.001 to 0.020 ± 0.0005mg/g). Zinc level was high in pond A, C, D, E ranging from (118.8±3.4 to 124.8±1.0 mg/g. Sb is slightly high in pond B, C, D with a range of (0.018±0.001 to 0.021±0.001) but was low in pond A (0.002±0.000) when compared with control (0.003±0.000). The above results were all statistically significant at (p<0.001).This study demonstrated an increase in the body and serum levels of toxic metals in Clarias gariepinus across the various ponds and the control river. The concentrations of aluminum, antimony, manganese and zinc in the body and serum of Clarias gariepinus were above the WHO recommended limit for fish and fish products. Hence, it is concluded that these metals have been bio-accumulated in the tissues and organs of these fish and may therefore pose an immediate threat on the health of consumers of fish and fish products from these various plastic ponds within Benin metropolis.Keywords: Toxic, Trace, Metals, Cat-fish, Plastic pond