Analysis of Heavy Metal Concentration in Liver of Cow in Idah Local Government Area, Kogi State, Nigeria Edimeh, Peter Okpanachi1*, Onuwa2, O. Peter, Mustapha, Hauwa1 and Omale, Peter3 1. Chemistry Unit, Department of Medical Laboratory Sciences, College of Health Sciences and Technology, P.M.B 1047, Idah Kogi State, Nigeria. 2. Department of Chemistry, University of Agriculture, Makurdi, Benue State 3. Department of Chemistry, Nigerian Defence Academy, Kaduna State, Nigeria. Correspodent's e-mail: deaconedimeh@yahoo.com , Phone: 07030153295 ABSTRACT Idah local government is at the south eastern part of Kogi State. This local government is bounded by Ibaji Local Government Area to the North-East. The people of this area are predominantly farmers and this community has an abattoir situated in their long-aged market which is the major market that provides beef for consumption in these areas. Some heavy metals were analysed from the livers of cows for five months consecutively using Atomic Absorption Spectrophotometry (AAS) according to (AOAC, 1990) standard method, so as to find out their safety level for human consumption. The mean concentration (mk/kg) of the metals were determined as follows; As (0.03 ± 0.01), Cd (0.04 ± 0.03), Pb (0.04 ± 0.01), Ni (0.04 ± 0.01) and Cr (0.17 ± 0.10), respectively. The results indicated that arsenic was lower than the limit of 2ppm, lead and cadmium were less than 1 ppm and 0.5 ppm limits set by (FAO/WHO), respectively while Cr was higher than the limit of 0.10 μg/g. Most of the metals were less than permissible limits except Cr, however a continuous research is envisaged. Keywords: Heavy metals, contamination, livers, safety, spectrophotometry 1. Introduction Animal husbandry and agriculture are major contributors in terms of gross domestic product, employment and foreign exchange earnings. In developing countries, people spend almost 50 % of their income on food: among lower income households this figure may rise above 70 % (Malik, 1993). Thus, when food quality is jeopardized, consumers may not get their money’s worth and may suffer in terms of economics and health hazards. The widespread indiscriminate use of pesticides, metals, drugs, inorganic fertilizers and untreated effluents from industries pollute the environment and end up as residues in food, water and air. The impact of these chemicals on animal and agricultural produce has resulted in chronic and acute intoxications and their residues are further transferred into meat, dairy and poultry products (Shull and Cheeke, 1983). Many possibilities abound that food products get contaminated with various metals from the production point, carriage process until it reaches the consumer (Malik, 1993). Metals for which there is no nutritional values may react with biological systems to cause adverse effects, even excessive doses of nutritionally essential metals can also cause adverse effects, particularly the heavy metals. Heavy metals from man-made pollution continue to be released into aquatic and terrestrial ecosystems. Heavy metal contamination has been a perennial threat due to their chronic and acute toxicity, bioaccumulation and biomagnifications in the food chain (Demirezen and Uruc, 2006). One of the ways on how heavy metals get in and interfere with human health is through consumption of food, they are either from raw materials or from contamination which occurs during processing. Meat and its products are important sources of wide range of essential trace metals for humans, these reflect the kind of food that are usually consumed by many people, but which may bring a number of toxic metals or substances residues. Although, the amounts are small enough in the flesh, but are often consumed in certain parts of the cattle, for instance, the liver and kidneys, often show concentration of toxic substances to be high enough (Khalafalla et al., 2011). Kidney and liver are tissues and organs that have tendency to bioaccumulate toxic metals like As, Cd, Hg, Pb and some essential elements like Cu, Zn, Fe, Cr and Ni. The residues measured in these animal organs may also indicate the human diet. Kidney and liver are cost effective and are component of some traditional Nigerian diets, therefore, toxic residues can affect those with low incomes who may not have access to regular medical care. Animals vary in their arsenic accumulation depending on the type of food consumed by them (John and Jeanne, 1994). Acute arsenic exposure can give rise to symptoms with rapid onset of headache, nausea and severe gastrointestinal irritation (Allan et al., 1995). The toxic effects of lead, like those of mercury, have been principally established in studies on people exposed to lead in the course of their work. Short-term exposure to high levels of lead can cause brain damage, paralysis (lead palsy), anaemia and gastrointestinal symptoms. Longer-term exposure can cause damage to the kidneys, reproductive and immune systems in addition to effects on the nervous system. The most serious effect of low-level lead exposure is on intellectual development in young children and like mercury, lead crosses the placental barrier and accumulates in the foetus. Infants and young children are more susceptible to the toxic effects of lead than adults, and they also absorb lead more readily. Short-term, low-level exposures of young children to lead are even considered to have an effect on neuro behavioural development. Consumption of food containing lead is the major source of exposure for the general population. The most common harmful effect of nickel in humans is an allergic skin reaction in those who are sensitive to nickel. Cadmium is one of the most toxic heavy metals which affect human health. Cadmium is primarily toxic to the kidney, especially to proximal tubular cells. Bone demineralization is affected by cadmium toxicity directly by bone damage and indirectly as results of renal dysfunction. Industrial workers exposed to airborne cadmium have higher risk in developing lung impairment and lung cancer (Bernard, 2008). 2.0 Materials and Methods 2.1 Materials All reagents used were of analytical grades. Glass ware were washed with detergents, rinse with tap water then dilute HNO3 and finally rinsed with distilled water. Laboratory materials include AAS (Thermo Scientific Ice 3000 series), Crucibles, Beakers, Volumetric Flask, Filter paper, Digital weighing balance, Oven. Reagents include Distilled H2O, HNO3 . 2.1 Background of the Sampling Area Idah local government is at the south east of Kogi State. The local government is bounded by Ibaji Local Government Area to the North-East while to the south is a part of Edo State by the River Niger. On the northern part lies Igalamela-Odolu Local Government. The River Niger is within Idah metropolis; it is in the eastern part of Idah town. It has latitude 70 07N and Longitude of 60 42E and serves as natural boundary between Idah in Kogi State and Agenebode in Edo State. Though the 1991 provisional census figure placed the population of Idah Local Government at 214,785, based on realistic projection and other reliable data, the population of the area is over 473,526. The people of Idah Local Government are predominantly farmers. Before 1920, the abattoir of Idah was situated at the Ega Market. The abattoir in the market was said to be as old as Ega Market itself. In 1965, Zango was created. One at Oji-olofe in Ega and the other in Angwa. Oji-olofe is about half a kilometer distance from the back of Ega Market. It is a natural elevated land between Ega Market and the River Niger. The sales of cows are done here during the dry season. Though the abattoir at Ega was removed in view of health hazard, cows were still slaughtered at Ega and some undersigned areas and the meat brought to the market for sale. For health concern, a slaughter-slab was created in 2008, by Idah Local Government Council at Angwa by the bank of Inachalo River, entering Idah from the Inachalo Odolu Road. During the rainy season, flood runs through side of the slaughter slab and flows into the Inachalo River which pollutes Inachalo waters on daily bases. 2.2 Collection of Samples and Storage Cow livers taken from the slaughter slab at Inachalo sample site were coded as sample 'A' while cow livers taken from the Abattoir in Ega Market were also coded as sample 'B'. Both samples were taken monthly for five consecutive times within a period of five months.

Figure 1: Map of Idah showing the sampling stations 2.3 Digestion of Samples and Instrumentation Mineral contents in the air-dried samples were digested according to the method described by Association of Official Analytical Chemists (AOAC, 1990), 10g of the sample was weighed and digested with nitric acid. The sample was heated to achieve complete digestion. When the colour of the sample become clear, it was taken from the heating mantle and allowed to cool to room temperature in fume cupboard. The digested solution was diluted with deionized water and filtered, the volume was then made up to mark in 100 mL volumetric flask with deionized water. Thermo Scientific, Ice 3000 series flame atomic absorption spectrophotometry was used to analyse the metal contents. Water sample was aspirated into the equipment and the absorbance of the sample was read directly on the AAS. Working standard solutions of Cadmium (Cd), Lead (Pb), Arsenic (As), Chromium (Cr) and Nickel (Ni) were prepared from stock standard solution (1000 ppm), in 2M HNO3 and absorbance was recorded for standard solution of each element. The calibration curves were obtained for concentration versus absorbance for respective elements. A blank reading was also taken and necessary corrections was made during the calculation of concentration of various elements. 4.0 Results and Discussion The mean concentration (mg/kg) of arsenic obtained for the five months period from slaughter slab at Inachalo (sample A) and abattoir at Ega market (sample B) are presented in Table 1. April has the highest mean concentration (0.03 mg/kg), closely followed by the month of May with a concentration of 0.02 mg/kg. arsenic was not detected for the months of march, June and July respectively. Table 2 shows the concentration of cadmium metal in cow livers for the whole duration of work in obtained from both sample sites. Table 1: Concentration (mg/kg) of arsenic across the months Metal As Metal Concentration (mg/kg) sample A B mean SD March _ _ _ _ April 0.03 0.02 0.03 0.01 May 0.02 0.02 0.02 0 June _ _ _ _ July _ _ _ _ Table 2: Concentration (mg/kg) of cadmium across the months Metal Cd Metal Concentration (mg/kg) Sample A B Mean ± SD March 0.023 0.01 0.02±0.010 April 0.01 _ 0.01±0 May _ 0.01 0.01±0 June 0.01 0.02 0.02±0.01 July 0.031 0.09 0.06±0.04 Table 3: Concentration (mg/kg) of lead across the months Metal Pb Metal Concentration (mg/kg) Sample A B Mean ± SD March 0.03 0.014 0.02 ± 0.0.01 April _ _ _ May _ _ _ June 0.02 0.03 0.02 ± 0.01 July 0.04 0.04 0.04 ± 0.004 Table 4: Concentration (mg/kg) of nickel across the months Metal Ni Metal Concentration (mg/kg) Samples A B Mean ± SD March 0.03 0.03 0.03 ± 0 April 0.02 0.02 0.02 ± 0 May 0.01 0.01 0.01 ± 0 June 0.04 0.02 0.03 ± 0.01 July _ 0.01 0.01± 0 Table 5: Concentration (mg/kg) of chromium across the months Metal Cr Metal Concentration (mg/kg) Sample A B Mean ± SD March _ 0.001 0.001 ± 0 April 0.22 0.17 0.195 ± 0.04 May 0.21 0.19 0.200 ± 0.01 June _ 0.001 0.001 ± 0 July 0.004 0.012 0.008 ± 0.01

Figure 1: Mean Concentration (mg/kg) of all the heavy metals in cow livers Metals Total (mg/kg) Mean (mg/kg) SD (mg/kg) As 0.09 0.031 0.005 Cd 0.2 0.043 0.026 Pb 0.159 0.041 0.011 Ni 0.19 0.036 0.011 Cr 0.808 0.172 0.104 Conclusion The mean concentration (mg/kg) of all the sampled metals (As, Cd, Pb, Ni and Cr) indicates that the concentrations of these metals in cow livers were less than the permissible limit of 1ppm, and so within international statutory safe limits. The cows are therefore safe for consumption as at this period. It is recommended that more area coverage and persistent monitoring be carried out. REFERENCES: Allan, G., Roberts, A.C., O’Reilly, D.S.J., Steward, M.J. and James, S. (1995). Clinical Biochemistry, 2nd edition, Harcourt Brace and Company Ltd., pp: 114-115. Demirezen, D. and Uruc, K. (2006). Journal of Meat Science. 74, pp 255-260. John, H.H. and Jeane, I.R. (1994). Food Additives contaminants and natural toxins. In: Maurice E.S., James A.O., Moshe, S.L., and Febiger, (Eds), Mordern Nutrition in Health and Disease. 8th Edn., part 11, pp: 1597-1598. Khalafalla, F.A, Ali, F.H, Schwagele, F. and Abd-El-Wahab, M.A. (2011). Heavy Metal Residues in Beef Carcasses in Beni-SuefAbbatoir, Egypt. Veterinaria Italiana 47 (3): 351-361. Malik, R.K. (1993). Integrating consumers and industry food control. Food, nutrition and agriculture. 819 pp. 1-10. Shull, L.R. and Cheeke, P.R. (1983). Effects of synthetic and natural toxicants on livestock. Journal of Animal Sciences and Supplement, 2:330-354. Hussain, T.R., Manal Ebraheem, K.M. and Moker, M.H. (2012). Assessment Of Heavy Metals (Cd, Pb and Zn) Contents In Livers of Chicken available in the Local Markets of Basrah City, Iraq; Bas.J.Vet.Res., 11(1), 43-51.