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
Human Activities and Heavy Metal Concentrations in Aba River, Abia State, Nigeria (Published)
Water samples were collected from seven different locations along the Aba River close to various human, industrial, commercial and domestic activities. The heavy metals were analyzed using the Atomic Absorption Spectrometer (AAS). The result revealed that the concentration of some heavy metals like Iron, Copper, Manganese and Chromium are above the WHO and FMEnv Standard limits for surface water. These high values could be attributed to indiscriminate disposal of wastes into the river. The various parameters of the water samples from the control site (Okpu-Umuobu) were significantly different from those of locations close to the major industrial/commercial activities. This confirms the impact of human activities on the quality of the Aba River. The impacts of dredging and sand mining in and along the river bank were obvious. These activities have an adverse effect on the environment and ecology, speeding up flow and potentially increasing the risk of flooding downstream. This also has the potential to damage ecology by directly affecting its physical habitat, disrupting riverine processes and reduced connectivity with the floodplain. It is therefore recommended that effluent treatment plants be installed to treat waste generated before they are discharged into the stream as well as regular monitoring of the River should be encouraged by the regulatory bodies.
Keywords: Aba River, Anthropogenic Activities, Dredging, Effluents, Heavy Metals, Pollution