Evaluation of cadmium, chromium, copper, lead and zinc concentrations in the fish head/viscera of Oreochromis niloticus and Synodontis schall of River Galma, Zaria, Nigeria
Nnaji, JC; Uzairu, A; Harrison, GFS; Balarabe, ML
River Galma was demarcated into Upstream and downstream areas. Oreochromis niloticus and Synodontis schall were caught with cast net from twenty sampling points. Weight, standard and total lengths of the fish samples were measured. The samples were dissected to separate the fish head/viscera from other parts. They were digested with concentrated acid solution and the digests analysed with flame Atomic Absorption Spectrometer (AAS). Mean metal contents in the fish head/viscera of O. niloticus in the upstream area were: Cd, 0.020±0.0105; Cr, 0.149±0.063; Cu, 0.90±0.225; Pb, 0.618±0.250; Zn, 8.3±1.44 and values for S. schall were: Cd, 0.036±0.0286; Cr, 0.435±0.335; Cu, 1.85±0.79; Pb, 0.412±0.276 and Zn, 15.74±2.03. In the downstream area, mean metal contents in the fish head/viscera of O. niloticus were; Cd, 0.085±0.0803; Cr, 0.085±0.0803; Cu, 1.36±0.52; Pb, 0.83±0.461 and Zn, 17.72±5.29 while those of S. schall were: Cd, 0.353±0.285; Cr, 0.281±0.125; Cu, 1.54±0.78; Pb, 0.83±0.248 and Zn, 21±5.27. Comparison of these values with FAO limits in fish tissue shows that it is unsafe to consume the fish head/viscera of both fish species from River Galma.
cadmium; chromium; copper; food contamination; food safety; head; lead; zinc; Nigeria; Oreochromis niloticus; West Africa; Africa South of Sahara; Africa; Developing Countries; ACP Countries; Commonwealth of Nations; Anglophone Africa; Oreochromis; Cichlidae; Perciformes; Osteichthyes; fishes; vertebrates; Chordata; animals; aquatic organisms; aquatic animals; eukaryotes; food contaminants; Synodontis; Synodontis schall; Aquaculture (Animals) (MM120); Aquatic Produce (QQ060); Food Contamination, Residues and Toxicology (QQ200); Human Toxicology and Poisoning (VV810) (New March 2000)
