Concentration of Mercury in Fish from Nungwe Bay of Lake Victoria: Public Health Implication

Abstract

In the present study we investigated accumulation of mercury (Hg) in fish collected from Nungwe bay in Lake Victoria, an area known to be at risk for Hg contamination from Mugusu small-scale gold mine. Fish samples were acid-digested, and levels of Hg determined by atomic absorption spectrophotometer under the cold vapour technique. Total Hg concentration varied with fish species and sizes. While Hg levels in sardine (Rastrineobola argentea), furu (Haplochromines spp), and lung-fish (Protopterus aethiopicus) samples were below the limit of detection, mean total Hg levels for Nile perch (Lates niloticus), Tilapia (Oreochromis niloticus) and Catfish (Clarias gariepinus) were 0.41 ± 0.041, 0.24  ± 0.014, and 0.53 ± 0.17 µg/g respectively. There was a significant positive correlation between total Hg concentration and fish length for Nile perch (r= 0.5608 and P<0.05). Based on our results it is suggested that, eating tilapia and average sized Nile perch from Nungwe bay is safe, but caution should be excised for eating catfish and large Nile perch.