Available online at International Journal of Research in Pure and Applied Chemistry

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1 Available online at International Journal of Research in Pure and Applied Chemistry Universal Research Publications. All rights reserved ISSN Original Article DETERMINATION OF HEAVY METALS IN SOIL, WATER, SEDIMENT, FISH AND CRAY FISH OF JABI LAKE IN THE FEDERAL CAPITAL TERRITORY, FCT, ABUJA - NIGERIA *UMAR, M. A. and EBONG, M. C. DEPARTMENT OF CHEMISTRY, UNIVERSITY OF ABUJA, ABUJA, FCT, NIGERIA *For correspondence, contact Umar, M. A. on or mfonmfon4ever@yahoo.com Received 01 May 2013; accepted 29 May 2013 Abstract Water, Sediment, Soil, Crayfish and Fish from the Jabi Lake were analysed for copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni) and lead (Pb). Crayfish and Fish samples were bought from the Fishermen while still alive. Water samples were collected from different points in the lake while sediment was collected at the point of municipal runoff entry. Soil (control) sample was collected at a point 15m from the lake at a depth of 5m. Standard procedures were employed in sample preparation and the heavy metals concentrations were determined using flame atomic absorption spectrophotometry (AAS). The result showed that the pollution of sediment in Jabi lake is related to the pollution in water because they follow the same pattern of decreasing concentrations of heavy metals: Zn > Cu > Cd > Ni > Pb. The pattern of decreasing concentrations for Fish and Crayfish were Cu > Zn > Cd > Ni > Pb. Average concentrations of Zn in water (4.72 ±0.63) and Cd (0.28 ±0.32) were found to be higher than International permitted range, while others (Cu, Ni and Pb) were within the range. Cu, which showed bioaccumulation in Fish and Crayfish samples to the magnitude of and with concentrations of ±0.94 and ±1.38 respectively, was higher than International accepted range. Concentrations of other metals (Zn, Ni, Cd and Pb) however fell within accepted range. Concentration values for soil(control) for all metals under study fell within accepted range, thus exonerating the surrounding soils of Jabi Lake as being the possible source of heavy metal contamination in the lake. The study showed that the most important source of heavy metals pollution in the lake was the sewage disposal point and erosional runoffs from the flower farms. Jabi Lake was polluted with Zn and Cd. Crayfish and Fish samples were polluted with Cu. However, the lake is not heavily burdened with Ni and Pb, but they should be controlled to avoid excessive concentrations Universal Research Publications. All rights reserved Key Words: Heavy Metals, Jabi Lake, Water, Cray Fish, Fish, Sediment, Soil, Bioaccumulation INTRODUCTION chain. Sediments may concentrate large amounts of metals The fate of heavy metals introduced by human activities, from water, making Crayfish and Fish which are bottom chemical and geochemical processes into the aquatic dwelling to pick up these metals from the sediment which ecosystem have recently become the subject of widespread might be toxic for human consumption (Papagiannis et al., concern; since beyond the tolerable limits they become 2004). The effects of heavy metals on the health of Abuja toxic (Gbaruko and Friday, 2007; WHO, 1971; Koller, et residents are of great interest today, especially for the al., 2004; Umar, et al., 2010). Pollution of water bodies realities of their dependence on aquatic food products from could occur due to run-offs flowing through agricultural Jabi Lake in Abuja Municipal. areas where fertilizers and pesticides may have been There are a few studies about heavy metals in Jabi Lake applied and catchment settlements where there may have (Umar and Abdullahi, 2010). In fact, data on heavy metals been indiscriminate waste disposals (Suhendan et al., in the samples undertaken in this research from Jabi Lake 2010). Water, sediments and the biota are generally metal became very important due to the research findings of reservoirs in aquatic environment and may assume several Speciation of Heavy Metals in Jabi Dam sediments by orders of magnitude greater than the amount found in water Umar and Abdullahi (2010) that a significant percentage (Smical, 2008). of the total metal was associated with the non-residual It is known that heavy metals are the most important form fractions, indicating that they could be potentially bioavailable. of pollution and they may accumulate in the tissues of Cray It was therefore thought necessary to investigate fish and Fish which are often at the top of aquatic food the concentrations of Cu, Zn, Cd, Ni, and Pb in soil, 5

2 Sediment, Fish and Cray fish found in Jabi Lake, since determination of harmful and toxic substances including heavy metals in water, sediment and biota, gives direct information on the significance of pollution in the aquatic environment. The aim of this study was to estimate the extent of pollution of Jabi Lake and the potential risk to the residents. JABI LAKE Jabi Lake, which is a man-made reservoir of water from the foot of Katampe rocks, is located within Kado and Jabi districts of the Federal capital Territory (FCT). Due to increases in urbanization around the lake area, the initial intention of meeting the water need of FCT residence for which the lake was created was dropped as the lower Usman Dam was constructed in Bwari for the purpose of servicing the water needs of the Federal Capital Territory (FCT Water Board, 2005). Increases in urbanization and socio-economic activities within and around Jabi Lake poses threat to its pollution with heavy metals. The Lake may have experienced several episodes of heavy metal pollution emanating from flower farming and block molding industries around the lake as well as discharge of erosion run offs into the lake which may undoubtedly carry municipal wastes. The presence of heavy metals in the water and sediments would lead to bioaccumulation in the aquatic life. These bioaccumulations may have a profound effect on the citizenry which depend on these aquatic lives such as fishes and Cray fish as the main source of food. Consequently, the potential long term impact on public health and ecosystem cannot be ignored. point of municipal runoff (SDP); point two (2) was middle SAMPLING AND SAMPLE SITES of the lake (ML); point three (3) was Under the Jabi Water samples were collected in triplicate from five (5) Bridge(UB); point four (4) was River Entry Point (EX) and different points in the lake. Point one (1) was the discharge point Five (5) was the location Near Water Board (NWB). 6

3 Sediment sample was collected in triplicate from the discharge point of municipal runoff only as there was difficulty of taking samples at other locations for which water was sampled due to depth. Fish and Cray fish samples were bought fresh from the local fishermen operating in the Jabi Lake and apportioned randomly in triplicate. Soil sample was collected in triplicate from a location 15m from the edge of the lake at a depth of 5m and stored in well-labeled metal free polythene bags ready for treatment and analysis. SAMPLE PREPARATION Fish, Crayfish, sediment and soil samples were spread on cardboard papers and dried under the sun for two days after manual removal of debris. They were later dried in oven at a temperature of 60 o C. The dried samples were entirely transferred to new well labeled polythene bags.each of the three replicate of fish, Crayfish, sediment and soil samples were ground to get a good representative and homogeneous mixture. The samples were respectively poured into a mortar and ground with a pestle, one after the other, into fine powder. The mortar was washed and dried after each sample pounding to avoid contamination. The ground samples were sieved using 2mm screen and quickly transferred into sample bottles ready for digestion. Water samples from the 5 different locations were collected as grab samples into pre-cleaned plastic bottles in triplicate form and treated with trioxonitrate (v) acid (HNO 3 ). They were stored in a cool box and transported to the laboratory. For digestion of the respective samples, 1g each of the three replicate of the sieved soil and sediment samples were weighed into 100ml beaker. 10ml concentrated HNO 3 and 5ml of concentrated HClO 4 were added in the ratio of 2:1 respectively. These were covered with a watch glass. The mixtures were placed on a hot plate under fume cupboard and heated to dryness with colour changing to white and allowed to cool before leaching. The residue was then dissolved in 5ml of 20% HNO 3. The dissolved mixture was made up to a volume of 20cm 3 with distilled water. Finally, the filtrates were collected in a small rubber container in preparation for the determination of the concentration of the heavy metals under study (Pb, Cd, Ni, Zn and Cu). Two grams (2g) weight of each portions of Cray fish and Fish samples were taken in triplicates for each sample and acid digested using a mixture of nitric acid and perchloric acid (1:3). These were wet oxidized as described above. Water samples were thoroughly mixed and aliquots of 50ml taken in triplicates. These were digested with a mixture of nitric acid and perchloric acid (1:3) until clear solutions were obtained. Digests were filtered and stored in plastic bottles. AAS ANALYSIS Flame atomic absorption spectrometer (AAS-buck scientific VGP 210 model) was used in the analysis. The concentrations of the metals were determined in triplicates. The accuracy and precision of the analytical procedure were determined. A series of standards were prepared for instrumental calibration by serial dilution of working solutions (100ppm) prepared from analytical grade stock solutions (1000ppm) from BDH poole, USA. A standard and blank sample was run after every seven samples to check for instrumental drift. RESULTS AND DISCUSSIONS HEAVY METAL CONTENTS IN WATER The heavy metal content in waters of Jabi Lake is presented in Table 1 and Figure 1. The results indicate that the average concentrations of heavy metals in water in decreasing order at the different sampling points is Zn Cu Cd Ni Pb, with the corresponding values (mg/l) of 4.7 ± 0.63, 0.30 ± 0.24, 0.28 ± 0.32, 0.08 ± 0.01 and 0.05 ± 0.01 respectively. However, water samples at river entry point (Ex) for Cu; under bridge (UB) for Cu, Zn, Cd and Ni; mid lake (ML) for Cd and Pb; Near Water Board (NWB) for Cu Zn; and Sewage Disposal Point (SDP) for Cd, were not detected. This does not entirely mean that the metals concern are not present, but may be below the detection limit of the instrument being used. TABLE 1: Concentration of Heavy Metals in Water Samples at the Different Sampling Points in Jabi Lake Samples Cu (mg/l) Zn (mg/l) Cd (mg/l) Ni (mg/l) Pb (mg/l) River Entry Point (Ex) ND 5.00 ± ± ± ± 0.01 Under Bridge (UB) ND ND ND ND O.17 ± 0.01 Mid Lake (ML) 0.23 ± ± 1.05 ND 0.01 ± 0.00 ND Near Water Board (NWD) ND ND 0.20± ± ± 0.01 SEWAGE Disposal point (SDP) 0.37 ± ± 1.40 ND 0.04 ± ± 0.01 AVERAGE 0.30 ± ± ± ± ± 0.01 ND Not Detected. Zn (4.7 ± 0.63)mg/l and Cd (0.28 ± 0.32) exceeds the International acceptable range of mg/l and mg/l respectively; thus giving a convincing indication that the water of Jabi Lake is contaminated with Zinc and Cadmium. 7

4 However, the concentrations of other metals (Ni, Cu and Pb) under study are within the International permitted range in the respective water samples, with Pb having the overall lowest concentrations. The pollution of the Lake by Zinc may be attributed to pollutant residual of the boating activities within the lake. The concentration of all these metals (Cu, Cd, Ni and Pb) in the water is almost similar throughout the Lake (at all the sampling points). This may indicate that they are within background concentration level in the water of the lake. HEAVY METAL CONTENTS IN SOIL, SEDIMENT, CRAYFISH AND FISH The heavy metal contents in soil, sediment, Crayfish and Fish are presented in Table 2 and Figure 2, indicating wide Figure 1: spatial Distribution of Heavy Metals in Water variations of heavy metal concentrations among the Samples respective samples. TABLE 2: Concentration of Heavy Metals in Soil, Sediment, Crayfish and Fish Samples Samples Cu (mg/kg) Zn (mg/kg) Cd (mg/kg) Ni (mg/kg) Pb (mg/kg) Soil (control) 3.96 ± ± ± ± ± 0.13 Crayfish ± ± ± ± ± 0.03 Fish ± ± ± ± ± 0.22 Sediment 4.10 ± ± ± ± ± 0.03 The result shows that the pattern of decreasing concentrations of heavy metals in soil (control) and sediment are: Zn > Cu > Cd >Ni > Pb. However, the pattern of decreasing concentrations in Crayfish and Fish samples is Cu > Zn > Cd >Ni > Pb. The concentrations of all the metals for the respective samples under study were within the International permitted range (Balfour et al, 2012), except the concentrations of Cu for Crayfish (107 ± 0.94)mg/kg and Fish (41.61 ± 1.38)mg/kg, which were higher than the International permitted range of mg/kg. This gives a convincing indication that Crayfish and Fish of Jabi lake is polluted with Cu. Figure 2: Distribution of Heavy Metals in the different samples in Jabi Lake Figure 2 shows that Pb recorded the lowest concentrations across all the samples under investigation, which could possibly be due to the embargo placed on mechanic workshops around the lake. The concentrations of Cu in Crayfish and Fish which were above the threshold alert could be a direct consequence of inflows from the flower farms (Njogu et al, 2011). Pearson correlation analysis (p <0.05) reveals that concentrations for water samples at different sampling points were correlated for all metals under study except lead between entry point and under bridge. The correlation analysis between water and sediment gave a positive correlation for cadmium (r=0.94). Other metals under study were inversely correlated between water samples and sediment (Cu: r = -1.00; Zn: r= -1.00; Ni: r= - 1.0; and Pb: r = ), which means that the concentration of heavy metals in Sediment were higher than that in water, possibly due to adsorption on particulate matter and dissolved carbon.concentrations of Cu in fish and crayfish samples gave inversely correlation (r = and r = -0.91) to sediment, indicating a bioaccumulation of copper in the biota. Only crayfish sample gave an inverse correlation (r = -0.40) for Zn with sediment. Inter-metallic relationships for water samples reveal positive correlation and significant regression relation among the metals. The positive correlation coefficients with p < 0.05 were: Cd - Zn (r = 0.2), Ni Cu (r = 0.4), Ni Zn (r = 0.5), Pb Cu (r = 0.8), Pb Zn (r = 0.4) and Pb Ni (r = 0.9). There was however inverse relationships between Zn Cu (r = -0.2), Cd Cu (r = -0.9), Ni Cd (r = -0.5) and Pb Cd (r = -0.8). Sediment samples gave positive correlations between Ni Zn (r = 0.1), Ni Cd (r = 0.9) and Pb Cu (r = 0.8) whereas the inverse relationships were between Zn Cu (r = -0.7), Cd Cu (r = -0.6), Ni Cu (r = -0.7), Pb Zn (r = -0.9), Pb Cd (r = ) and Pb Ni (r = -0.1). It was a complete inverse relationship in Fish samples between Cu Zn (r = -0.1), Cu Cd (r = -0.9), Cu Ni (r = -0.8) and Cu Pb (r = -0.9); others were positive relationships between Cd Zn (r = 0.3), Ni Cd (r = 0.7), Pb Zn (r = 0.5), Pb Cd (r = 0.9) and Pb Ni (r = 0.5) with Ni Zn giving an inverse relation (r = -0.5). Crayfish samples gave the most significant inter-metallic correlation between Zn Cu (r = 0.8), Cd Cu (r = 0.7), Cd Zn (r = 0.9), Ni Zn (r = 0.3), 8

5 Ni Cd (r = 0.4), Pb Cu (r = 0.9), Pb Zn (r = 0.6) and Pb Cd (r = 0.4); inverse relationships however were between Ni Cu (r = -0.3) and Pb Ni (r = -0.6). The positive correlations between heavy metal concentrations suggested either a common or a similar geochemical behavior origin. The inverse correlations and low positive correlations (r = 1) could mean that the contaminations are coming from different sources or have different chemical behavior in the lake bed. BIOACCUMULATION STUDIES Bioaccumulation of metals in fish and crayfish were quantified by a bioaccumulation factor (BAF), which is the ratio of particular metal concentration in the specimen to the concentration of that metal in the water column. The values of bioaccumulation factors were calculated using the following equation: BAF = Concentration (mg/kg tissue) / concentration (mg/l water) Table 3: Bioaccumulation Factor for Fish and Crayfish in relation to Water Heavy Metals Water (mg/l) Crayfish (mg/kg) Fish (mg/kg) BAF= Conc. (mg/kg tissue) Conc. (mg/l Water) Crayfish Fish Cu 0.30 ± ± ± Zn 4.72 ± ± ± Cd 0.28 ± ± ± Ni 0.08 ± ± ± Pb 0.05 ± ± ± ppm = mg/kg = mg/l = µl/l = µg/g = µg/ml Table 3 shows that the BAF values for Crayfish is 358(Cu), 3(Zn), 4(Cd), 7(Ni) and 4(Pb); that of Fish is 139(Cu), 4(Cd), 6(Ni) and 4(Pb) with Zn showing no bioaccumulation for Fish. The bioaccumulation as witnessed in the above results may be due to the fact that heavy metals dissolves more in lipids than water, that is why the Fish and crayfish samples are able to have concentrations of the metals in a higher proportion than that found in water. Bioaccumulation, especially Copper, in Fish and Crayfish samples is consistent with the findings on Jabi Dam by Umar and Abdullahi (2010), that a significant percentage of the total metal was associated with the non-residual fractions, indicating that they could be potentially bioavailable, with the bioaccumulation pattern for both Fish and Crayfish in decreasing order being Cu > Ni > Pb > Cd > Zn. These BAF values are low compared to BAF values reported in other studies (Njogu et al., 2011). In conclusion, results of this study agree with the report of Umar and Abdullahi (2010) that Jabi Lake is contaminated with Zn. The study however reveals an increase in Cd contamination in the lake waters. Crayfish and Fish samples recorded contamination with Cu as witnessed in the bioaccumulation studies. Jabi Lake is not heavily burdened with Ni and Pb, but they should be controlled to avoid excessive concentrations. REFERENCES 1. Balfour, S., Kwafi, A. and Manima, S. (2012), Methodology for Agrochemical Analysis of Soils for Establishing the Needs for Amendments, ICPA Press, Bucharest, Romania, pp FCT Water Board, (2005), Purpose and Intent of the lower Usman Dam, FCT water Board bulletin, Vol. 6. Page Gbaruko, B. C. and Friday, O. U. (2007), Bioaccumulation of Heavy Metals in some Fauna and Flora, International Journal of Environmental Science and Technology, Vol. 4(2), Koller, K., Brown, T., Spurgeon, A. and Levy, L. (2004), Recent Development in Low Level Exposure and Intellectual Impairment in Children, Environ. Health Perspect. Vol. 112(9), pp Nigeria Tourism Development corporation-ntdc, (2009),Tourism Guide to Recreational Centers in the FCT, A publication of the Federal Ministry of Culture and Tourism, Abuja, Page Njogu, P. M., Keriko, J. M., Wanjau, R. N. And Kitetu, J. J. (2011), Distribution of Heavy Metals in various lake matrices: water, Soil, Fish and Sediments: A case study of lake Naivasha Basin, Kenya, JAGST Journal, Vol. 13(1) pp Papagiannis, I., Kagaloub, I., Leonardos, J., Petridis, D. and Kalfakakou, V. (2004), Copper and Zinc in Four Freshwater Fish species from Lake Pamvotis (Greece), Environment International, Vol. 30, pp Smical, A., Hotea, V., Oros, V., Juhasz, J. and Pop, E. (2008), Studies on Transfer and Bioaccumulation of Heavy Metals from Soil into Lettuce, Environmental Engineering and Management Journal,Vol.7,No. 5, pp. 9. Suhendan, M., Ozkan, O. and Oymak, S. (2010), Trace Metal Contents in Fish Species from Ataturk Dam Lake (Euphrates, Turkey), Turkish Journal of Fisheries and Aquatic Science, Vol. 10. Pp Umar, M. A. and Abdullahi, I. (2010), Speciation Studies of Ni, Pb, Zn, Cd and Cu in Jabi Dam Sediments using Chemical Fractionating Methods, Katsina Journal of Pure and Applied Science, Vol. 2(1& 2), pp Umar, M. A., Isa, H. and Idris, H. (2010), Bioaccumulation of Heavy Metals in African Spinach (Amaranthus Hybridus) Irrigated with Water from River Kaduna, Kaduna State, Nigeria, Katsina Journal of Pure and Applied Science, Vol. 2(1& 2), pp World Health Organization (1971), WHO International Ref. Center for Waste Disposal, IRCWD News, Vol. 6, page 15. Source of support: Nil; Conflict of interest: None declared 9