Determination of Heavy Metal Levels in Some Commonly Consumed Frozen Fish in Ibadan, Southwest, Nigeria

Abstract

There is a growing concern on the safety of frozen fish imported from various parts of the world where the levels of contamination of water bodies may not be well ascertained and regulatory measures not strictly adhered to. Concentrations of four heavy metals (Lead (Pb), Cadmium (Cd), Copper (Cu) and Mercury (Hg)) in the muscle, gill and liver were investigated for three most consumed frozen fish species (Umbrina canosai, Clupea harengu and Scomber scombrus) within Ibadan, metropolis. Samples were digested as described by FAO/SIDA. The concentrations of metals were quantified using a Varian AA240 Fast Sequential Flame Atomic Absorption Spectrophotometer (AAS). Heavy metals like Cd, Cu and Hg were significantly higher (p<0.05) in the liver of the three species than in the muscle and gills. There was no significant difference in the Pb concentration for the three organs in S. scombrus, whereas, Pb was significantly higher in the liver of U. canosai (9.73 mg kgG 1) and C. harengus (4.40 mg kgG 1) than in the muscle (6.92 and 2.11 mg kgG 1 , respectively) and gill (8.73 and 2.52 mg kgG 1 , respectively). Copper concentration was marginally higher in S. scombrus (5.06 mg kgG 1) with the least value recorded in U. canosai (3.28 mg kgG 1). However, no significant variation (p>0.05) was observed in the muscle Cd, Cu and Hg levels for the three species. Comparatively, S. scombrus has the highest concentration of heavy metals. This study revealed that the heavy metals investigated in the major organs and flesh was all above the limits recommended by World Health Organization.

Levels of Heavy Metals in Pseudotolithus Elongatus From Badagry Market, Nigeria

“…However, the Pb level in this study was higher than those reported by Jenyo-Oni and Oladele (2016) in Oreochromis niloticus. On the contrary, Pb content in the present study was lower than those recorded in Scomber scombrus by Abubakar et al, (2014) and Kareem et al, (2016). The presence of heavy metals in the fish samples is an indication that the fish is exposed to pollution whose sources could be either point or non-point sources.…”

Heavy Metal Concentrations in Chrysichthys nigrodigitatus (Lacepede, 1803) and Eichhornia crassipes (Mart) from Ologe Lagoon and its Tributaries in Lagos, Nigeria

“…The Zn, Pb and Cd values in fish in this study are above those found in Oreochromis niloticus [11] and in Pseudotolithus elongatus [32]. On the contrary, Pb and Cd contents recorded in C. nigrodigitatus in the present study is lower than the valus recorded in Scomber scombrus [34,35]. The results of this study is comparable to earlier reports on fish samples from Anambra River [36], Calabar River [37] and Izmir bay in Turkey [38].…”

Occurrence and Impact of Heavy Metals on Some Water, Land, Flora and Fauna Resources across Southwestern Nigeria

“…Olusola and Festus [79] during their study of coastal waters of Ondo state, noted that distribution of heavy metals in different fish parts were organ specific, Heavy Metals -Their Environmental Impacts and Mitigation as higher concentrations of metals were recorded in the gills and eyes compared to other organs. In contrast, [80] recorded highest concentration of Pd, Cd, Cu and Hg in liver than other parts of frozen fishes sold in storage facilities in Ibadan, Oyo State. Some of the concentrations recorded in these parts were considered to be above maximum acceptable limit by [81].…”