Distribution of three non-essential trace metals (Cadmium, Mercury and Lead) in the organs of fish from Aiba Reservoir, Iwo, Nigeria

Abstract

The distribution of non-essential trace elements in some vital organs of 11 fish species from Aiba Reservoir, Iwo, Nigeria was assessed between November 2010 and June 2011. The fish species belong to seven families; family Mormyridae, family Cyprinidae, family Hepsetidae and family Channidae each with one species; family Bagridae and family Clariidae each with two species; and family Cichlidae with three species. All families, except Clariidae and Channidae, are common in the daily catch from the reservoir. Atomic absorption spectrophotometry was used to determine the levels of cadmium, mercury and lead in fish organs. The concentration of toxic trace metals in fish ranged from 0.001 to 0.100 ppm (Cd), 0.000–0.067 ppm (Hg) and 0.001–0.125 ppm (Pb) dry weight. This study shows similarity (p > 0.05) in the distribution of Cd, Hg and Pb among fish species; and a non-uniform distribution of toxic trace metals within fish organs with Kidney > Liver > Gill ≥ Intestine ≥ Muscle. Canonical variate analysis shows clear discrimination of Clarias macromystax and Channa obscura for gill trace metal levels of Cd, Hg and Pb while Labeo senegalensis and Oreochromis niloticus were discriminated for liver trace metal values of Cd and Pb only when compared to other fish species studied. The discrimination of some fish species based on trace metals in the gills and liver suggests different regulatory strategies for trace metal accumulation. Variation due to comparison among different fish species from the same water body suggests that accumulation may be species dependent. Differential accumulation of toxic trace metals in fish organs makes them good bioindicators of freshwater contamination.

Bioaccumulation of heavy metals in fish species from the Meiliang Bay, Taihu Lake, China

“…Similar results have been reported seasonal distribution of heavy metals in Cyprinus carpio and Acanthobrama marmid species [ [77] , [78] , [79] , [53] , [49] ]. Chromium is an essential heavy metal because metal amount of trivalent Cr (III) plays an essential role of Cu and Cr may have toxic effects for humans.…”

Exposure of the endangered Milky stork population to cadmium and lead via food and water intake in Kuala Gula Bird Sanctuary, Perak, Malaysia

“…1 ). Variation among the different species from the same water body suggests that the accumulation may be species dependent [17] , possibly due to the differences of feeding habits and bioaccumulation factor [18] . However, Cd levels in Site 3, 4 and 5 were generally higher that Site 1 and this could be due to the increasing anthropogenic activity in these areas.…”

Accumulation and histological transformation in the gills, liver, muscles, and skin in <i>Oreochromis</i> <i>niloticus</i> induced by mercury

“…The concentration levels of metals in fish tissue are also affected by the position of the fish in the food chain, its size and age (16) and the duration of exposure (17). According to previous studies (6,10,18), the affinity of metals with specific organs seems to vary. For example, it seems that the liver, kidney, and gills are the main organs for the accumulation of metals in fish exposed to toxicants.…”