Heavy Metals in Fish: Bioaccumulation and Health (Published)
Heavy metals occur during natural processes and are also obtained during anthropogenic activities. Heavy metals include chromium, cadmium, arsenic, lead, zinc, nickel, mercury, selenium and copper hence their presence in the aquatic habitat are highly toxic to fishes and shell fishes. Heavy metals are found in the aquatic environment as a result from contamination by heavy metals from industrial, agricultural waste and by-products and domestic waste and by products. The increasing level of heavy metals in fish is alarming and has spurred scientists to make researches on the dangers caused by the heavy metals resulting to heavy metal accumulation and bioaccumulation of life cells. The aim of this study was to assess the possible sources of heavy metal in the aquatic environment, impact of heavy metals in the aquatic environment, its bioaccumulation in fish and human health impact. Several reports tell of the detrimental effect of heavy metals in fish (some of which include; poisonous effect in the blood such as anemia, eosinophilia, lymphocytosis, renal lesions, convulsions and ataxia, detachment of gills, fusion of secondary gill filaments, acute inflammation in the liver, amongst several others) and in man (some of which include, skin diseases, Irritation of the gastrointestinal mucosa, nephritis, lung cancer, liver and kidney damage, necrosis, neurological and behavioral disorders and death amongst others). In conclusion, the toxic effects of heavy metals in fish and the effect of bioaccumulation and bio-magnification have been reviewed in this paper. It is therefore recommended that the treatment of all forms of wastewaters, agricultural waste, sewage, industrial effluents be carried out before their discharge in to the environment. Also, the enforcement of all laws, legislations regarding the protection of aquatic life and environment should be enforced and sanctions meted out against defaulters.
Keywords: Bioaccumulation, Death, Growth, Health, Heavy Metals, Pollution