Fishes are excellent dietary sources of vitamins, fatty acids, Minerals and relatively cheap proteins that are essential for healthy living, (Bahnasaway et al;2009).
Metals entering the aquatic ecosystem can be stored in fish and other aquatics chain organism through the process of Bioaccumulation and Biological magnification via the food chain and can become potentiating toxic when accumulation reaches a substantially high level (Huang, 2005). Fish which occupy a top level in the aquatic food chain are notorious for itsability to bio-concentrate heavy metals in its organ, according to Raja, (2009).
Marine pollution is however a critical environmental issue of concern across the globe when growing human population increases, the intensities of anthropogenic threat it exerts on the environment increases as a result of industrialization and agricultural activities (Raja, et al; 2009). Metals such as Mercury, cadmium and lead have no biological function in the human system and are potentially toxic even at trace concentrations. There is a growing concern that metals accumulated in fish tissues may represents a health risk, especially for high consuming population. Therefore this study was undertaken to compare the level of hazardous heavy metal, (Lead, Cadmium and Mercury) accumulated in the organs of edible fish obtained from Iko River In Eastern Obolo L.G.A.
BACKGROUND OF THE STUDY
Hundreds of living creatures are found in the aquatics environment which can majorly benefit humans. However due to continuous risk in the development of industries many of these water creatures are killed, because of contamination.
Fish a living resident of the marine environment is a common table food which is usually consumed by humans for protein nourishment as compared to other meats such as beef and pork, it is easily more digestible and inexpensive. Fish unlike other aquatics animals contain essential amino acids, fatty acids, protein, carbohydrate, vitamins and mineral (Senet al; 2011). Studying fishes for heavy metal contamination would benefit majority of individual living in a country surrounded by body of water, and Eastern Obolo would be an example for this.
Sireli et al, in 2006 stated that heavy metals such as Lead (Pb)and Cadmium (Cd) are the most common toxicant that can be found in the marine environment.
These made the environmental protection agency to set the allowable standard of Lead in foods to be 0.5ppm, while the food and Agriculture organization (FAO) and the World Health Organization (WHO) provide guidelines for the acceptable oral limit of (Cd) in foods was 0.5ppm(Sireli et al., 2006), while the W.H.O, 2008 maximum limit for Lead(Pb) in food was 0.01ppm.
This study will serve as instrument of change by enlightening the public to be aware of the possible harmful effects they may acquire in consumption of fishes to their health, also it will help the Government Agencies and Policy makers in the creation of laws and guidelines that will control the increase of heavy metals waste coming from different industries in the Country.
1.2 OBJECTIVES OF THE STUDY
The aim of this study was to examine the current levels of Lead (Pb), Cadmium (Cd) and Mercury (Hg)in marine fish organs gotten from Iko River, Eastern Obolo L.G.A
The Objectives of the study are:
(1) To quantitatively measure the levels of Lead, Cadmium and Mercury in three fish samples.
(2) To compare the levels of Lead, Cadmium and Mercury obtained to acceptable limit of heavy metals in food, by World Health Organization (W.H.O) and other agencies.
(3) To study the capacity of various fish organ like Gills, Flesh and liver in bio accumulating the heavy metals.
(4) To provide baseline data and information on the different types of fishes around Iko River at Eastern Obolo L.G.A.
(5) To assess the quality of fish for human consumption.
1.3 STATEMENT OF THE PROBLEM
Assessment of Lead, Cadmium and Mercury in marine fish organ was a question on declarative statement that ponders on the existence of the problem to be investigated, there are still lots of problem emerging which was presumed to hinder the operation of assessment of Lead, Cadmium and Mercury levels in marine fish organs.
What are the means of operation?, the materials and methods used, also was it toxic to human? And what is the recommended limit by World Health Organization?
Toxicological and environmental studies have prompted interest in the determination of toxic element in food. While Mercury, Cadmium and Lead can be tolerated at extremely low levels, at certain concentration there are exceptionally toxic to humans.
Cadmium accumulate in the human body and may induced kidney disfunction, skeletal damage and reproductive deficiencies. Also, it cannot be excluded that it acts as a human carcinogen.
Methyl mercury may induced alteration in the normal development of the brain of infant and at higher levels may induced neurological changes in adult. Mercury contaminates mostly fish and fishery products. To protect public health, maximum levels of mercury are lead down by Commission Decision 93/351/EEC.
Lead absorption may constitute a serious risk to public health; it may also induced reduced cognitive development and intellectual performance in children and increase blood pressure and cardiovascular disease in adult. Over the past decades the levels in food have decreased significantly owing to the awareness of lead as a health problem and source related efforts to reduce the emission of lead. The EC concluded in its opinion of 19 June 1992, that whereas the main level of lead in food stuff does not seem to be a cause for alarm, long term action should follow with the objectives of further lowering the mean levels of lead in food stuff. Therefore, the maximum levels should be as low as reasonably achievable.
1.5 THE SCOPE OF THE STUDY
The scope involves the study carried at Iko River Eastern Obolo L.G.A to determine;
The levels of Lead(Pb), Cadmium(Cd) and Mercury in three species of fishes.
Assess the capacity of gills, flesh and liver in bio accumulating the trace metals in the three species of fishes which are:
Micropogonians undulates (atlantic croaker)
Ethmalosafimbriata (bonga shads)
Oreochromisniloticus (tilapia fish)
Statistical analysis to test whether there was significant differences between the levels of Lead, Cadmium and Mercury observed in the different organs.