2. Materials and Methods

Transcription

1 Resources and Environment 2013, 3(3): DOI: /j.re Levels of Bioaccumulation of Some Heavy Metals in Fish (Tilapia zilli) and Their Concentration in Water and Sediment of Owubu Creek, Niger Delta, Nigeria Upadhi Friday *, Wokoma O. A. F, Edoghotu Jonah Azibodi Department of Biology, Faculty of Pure and Applied Sciences, Ignatius Ajuru University of Education, Rumuolumin, P.M.B 5047, Port Harcourt, Rivers State, Nigeria Abstract Bioaccumulation of some heavy metals were determined in water, sediment and fish samples from owubu creek using atomic absorption spectrometer. The result indicated that the order of bioaccumulation of heavy metals in water were 2.85, 0.35, 0.03 and 0.02 for Cu>Pb>Fe>Mg, with Cu having the highest bioaccumulation. In sediment the order of bioaccumulation was Fe>Cu>Pb >Cd with their values of 674, 8.31, 6.22 and 0.01 respectively, with Fe having the highest value. The order of bioaccumulation of metals in fish tissue and digestive systems were Fe>Cu>Pb and Fe>Cu>Pb with their values of 72.17, 4.29, 0.01 and 46.12, 2,55, 0.13 respectively, there was high bioaccumulation of heavy metal in tissue system than in digestive system. The bioaccumulation factor in fish tissue were 26.81, 0.10, and 0.01 for Cu, Fe, and Pb, while the bioaccumulation factor in the digestive system were 15.93, 0.06 and 0.02 for Cu, Fe and Pb. The bioaccumulation factor in tissue was higher than in digestive system, this suggest that the fish samples could be used to monitor Cu, Fe, Pb pollution levels in owubu creek. Keywords Bioaccumulation, Heavy Metals, Fish, Bioconcentration, Sediment, Water 1. Introduction The accumulation of some heavy metals in freshwater ecosystem has been a major concern. Heavy metals generally enter the aquatic environment through natural (atmospheric deposition, erosion of geological matrix) or anthropogenic activities (caused by industrial effluents, domestic sewage, mining and agricultural waste[1]. Fish being one of the main aquatic organisms in the food chain often accumulate large amounts of certain metal above the levels in aquatic environment[2]. Heavy metals are commonly found in natural waters and some are essentials to living organisms, yet they may become highly toxic when present in high concentration[3]. The natural aquatic systems may equally be contaminated with heavy metals released from domestic, industrial and other man- made sources[4,5]. As these metals equally gain access into the ecosystem through anthropogenic source yet distributed in the water body, suspended solids and sediments during the course of their mob ility [6]. The rate of bioaccumulation of heavy metals in aquatic organisms depend on the organisms ability * Corresponding author: murphyentre@yahoo.com (Upadhi Friday) Published online at Copyright 2013 Scientific & Academic Publishing. All Rights Reserved to digest the metals and concentration of the metals in water[7], the concentration of the heavy metals in the surrounding sediment, as well as feeding habit of the organism. Aquatic animals (including fish) bioaccumulate trace metals in considerable amounts exposed. Fishes have been recognized as good accumulator of organic and inorganic pollutants[8]. Since heavy metals cannot be degraded, they are deposited, in water, assimilate therefore are available for fish to incorporate[9]. Fish, particularly of the Tilapia family is the most abundant, cheep and accessible source of protein in the study area, as such its contamination can easily affect humans which is the ultimate consumers. The study is therefore designed to determine the levels of bio accumulation of heavy metals (Cu, Fe, Pb, Hg, and Cd in tissue and digestive system of Tillapia Zilli and its concentration in water and sediment of Owubu Creek in Niger Delta, Nigeria so as to protect human life. 2. Materials and Methods 2.1. Sampling Site Owubu creek system is a fresh water body, located in a swamp in Ukpeliede Community in Ahoada West Local Government Area of Rivers State, Niger, Delta Nigeria. The creek lies between the latitude I to I E and

2 60 Upadhi Friday et al.: Levels of Bioaccumulation of Some Heavy Metals in Fish (Tilapia zilli) and Their Concentration in Water and Sediment of Owubu Creek, Niger Delta, Nigeria longitude 5 0 to 52 I N, the creek is lin ked to Orashie River. Owubu creek received effluents such as agricultural run-off, fro m farm lands, adjourning and oil spill fro m Nigeria Agip Oil Company oil wells and flow stations located within the bank of the creek. Owubu Creek is very important to the local dwellers because of its economic value, as it is used for recreational activities and fishing which is the major occupation of the native Sample Collection A total of 12 samples were collected in three stations monthly from the creek system during the sampling period (between March and July 2012). The samples collected are surface water, sediment and fish. Water samples were treated with nitric acid while fish samples were preserved in cold box before transferring to the laboratory for further analysis Procedure Water samples were digested according to the methods described in[10], while sediments were digested after drying according to[11] method. Different fish organs were digested after drying according to prescribed methods in[12]. The levels of Cb, Fe, Hg, Pb and Cu in fish were determined by Shimadzu atomic absorption spectrophotometer using different cathode lamps with air acetylene flame method. Before acid digestion, fish samples were dissected and different organs(tissue and digestive systems) separately and frozen according[13]. The cathode lamps had wave length ranged from 190 to 900[13] Bio-Accumul ati on Factor (BAF) Bio-Accumulation Factor (BAF) is expressed as the ratio of the contaminant in an organism to the concentration in the ambient environment at a steady state, where the organism can take in the contaminant through ingestion with its food as well as through content[14, 15]. 3. Results The data were analyzed separately for each station using descriptive statistics (mean, range and standard deviation) Water Samples The mean concentration of heavy metal in water samples were 2.85± 0.40, 0.35±0.14, 0.03±0.21 and 0.02±0.02 ppb respectively (Table 1and Figure 1). Average mean concentration of Cu was the highest and that of Mg was the lowest in water. Cd was not detected in water sample. The order of heavy metal accumulation in water sample was Cu>Pb>Fe>Mg>Cd. Ta ble 1. Mean heavy metals (ppb) in water of Owubu creek compared to international permissible limits Paramet er Cadmium Iron Mercury Lead Copper Mean St.Dv WHO(1985) Sediment Samples Mean concentrations in sediment sample were 674±12.31, 8.31±0.31, 6.22±0.16, and 0.01±0.01 ppb respectively (Table 2 and Figure 2). Fe has the highest Value in sediment, while Cd have the lowest value in the sediment sample, Mg was not detected in sediment. The order of heavy metal concentrations in sediment was Fe>Cu>Pb >Cd CU Pb Fe Mg Fi gure 1. Mean heavy metal concent rat ion in wat er of owubu creek

3 Resources and Environment 2013, 3(3): Fe Cu Pb Cd 3.3. Fish Samples Fi gure 2. Mean heavy metal concentration in sediment of owubu creek Table 2. Mean heavy metals (ppb) concentrations in sediment of Owubu creek Paramet er Cadmium Iron Mercury Lead Copper Mean St. Dv Tissue system Fe Cu Pb Fi gure 3. Mean heavy metal concentration in fish of owubu creek

4 62 Upadhi Friday et al.: Levels of Bioaccumulation of Some Heavy Metals in Fish (Tilapia zilli) and Their Concentration in Water and Sediment of Owubu Creek, Niger Delta, Nigeria Table 3. Mean heavy metals (ppb) concentrations in different tissues of Tilapia zilli Paramet er Cadmium Iron Mercury Lead Copper Tissues System Mean St. Dv Digestive System Mean St.Dv Table 4. Bioaccumulation Factor of heavy metals in fish of owubu creek Heavy metals Sediment Tissue System BAF Sediment Digestive System BAF Cadmium 0.01 ND 0.01 ND Iron Mercury ND ND ND ND Lead Copper The mean concentration of heavy metals in tissue and digestive systems of fish are represented in Table 3 and Figure 3. The mean concentration of Fe in tissue and digestive systems were 72.17±10.69 and 46.12±4.42 ppb respectively. The result however revealed that tissue system accumulated the highest concentration while the d igestive system accumulated the lowest concentration. Mean concentrations of Cu in both systems were 4.29±1.22 and 2.55±1.38 ppb, this shows that Cu concentration was highest in tissue than in the digestive system. Mean concentration of Pb was 0.12±0.13 and 0.13±0.11 ppb respectively, this result indicate that Pb accumulated highest in the digestive system and lowest in the tissue system. Cd and Mg were not detected in tissue and digestive systems. The data revealed that tissue accumulated the highest concentration of heavy metals in this study than the digestive system. The order of heavy metal concentrations in tissue was Fe> Cu>Pb, while the order of heavy metal concentration in digestive system was Fe>Cu>Pb Accumulation Factor (BAF) The bioaccumulation factor in tissue and digestive systems of the fish sample is shown in Table 4. The result showed that Cu, Fe and Pb have bioaccumulation factor of 26.81, 0.10 and 0.01 ppb respectively in tissue, where as the bioaccumulation factor in Cu, Fe and Pb for the digestive system were 15.93, 0.06 and 0.02 ppb respectively. This result however indicates that bioaccumulation factor was highest in the tissue system than in the digestive system. 4. Discussion Occurrence of metal contaminants especially the heavy metals in excess of natural loads has become a problem of increasing concern. The situation has arisen as a result of the rapid population growth, increase urbanization and expansion of industrial activities, exploration and exploitation of natural resources, extension of irrigation and other agricultural practices as well as lack of environmental regulations[3, 13]. The levels of heavy metals recorded in water in this study were generally low when compared with the limit of chronic values suggested[16]. The accumulation of heavy metals in water recorded in this study is lower than values previously obtained[13]. Low concentration in water corroborated with this report[17]. Low concentration of pollutants in study was due to adsorption of pollutant compounds by particulate matter, and sediment particles from the water column. Thus, the creek sediment contains very significant amounts of heavy metals when compared with their concentration in water. Sediments therefore act as the most important reservoir or sink for metals and other pollutants in the aquatic environment[18]. The concentration of Fe and Pb obtained in this study is however higher when compared with concentrations in non oil exploration locations of Sombrero River (I9). Concentrations of Cu, Mg and Cd are lower than values obtained in Wadi Hanifah, Saudi Arabia[13]. Heavy metal contamination in sediment can affect water quality and bioaccumulation of metals in aquatic organisms. This may resulte in potential long term implication on human health and ecosystems[20]. The results of the present study showed that tissue accumulate highest concentrations of Fe and Cu than Pb. The values of Fe and Cu obtained from tissues in this study are higher above the values obtained in freshwater fro m Ko llida m River, Tanilnadu, India[2]. Concentrations of heavy metals in digestive system is lower than values obtained in tissue, however the concentrations of Cu and Pb is higher in digestive system than in tissue. Difference in bioaccumulation level in different organs can primarily be attributed to differences in physiological role in organ, other factors such as regulatory ability, behavior and feeding habit may equally play significant role in bioaccumulation differences in the organs[9, 14]. The chemical nature of metal ionic strength and P H tends to be a master variable in accumulation process. Low accumulation and concentration in the digestive system recorded in this study does not conform to the findings of[7].

5 Resources and Environment 2013, 3(3): Bioaccumulation factor in tissue were 26.81, 0.10 and 0.01 for Cu, Fe and Pb respectively. Bioaccumulation factor of Fe in T. zilli of this study is relatively higher to that of T. fuscastu and C. gasa of So mbreiro River[21]. Bioaccumulation factor in digestive system were 15.93, 0.06 and 0.02 for Cu, Fe and Pb respectively and is lower than BAF obtained in digestive system of fish obtained in River Benue[7]. This observation also reveals the status of heavy metal bioaccumulation of heavy metals in tissue and digestive systems of fish of Owubu creek. The high level of bioaccumulation factor of Cu and Fe shows that they are good bio- indicator to monitor heavy metal pollution in the creek. However, it is quite evident in this study that there is heavy metal bioaccumulated in water, sediment and fish of Owubu creek. 5. Conclusions The result of this study give valuable information on the bioaccumulation of heavy metals in the various matrixes considered in this study, bioaccumulation of heavy metal was highest in sediment samples when compared with water samples. The studies also revealed that fish tissue have the tendency of accumulating iron, copper and minimum of lead. While digestive system has tendency to accumulate ma ximu m of lead and a minimum accumulation of iron and copper. Copper, iron and lead has bioaccumulation factors in tissue and digestive systems. This is an indication that fish in owubu creek has the ability to accumulate the meta ls of this study. However the concentration of heavy metal in water samples recorded in this study is below maximu m levels of recommended by regulatory agencies(who). Central Nigeria. Pak. J. Anal. Environ. Chem Vol. 12, No. 1&2, [8] R.P, King and G. E and Jonathan, Aquatic Environmental Perturbations and monitoring, African experience, USA [9] P. M, Linnik and I.B, Zubenko, Role of bottom sediments in the secondary pollution of aquatic environments by heavy metals compounds. Lakes and Reservoirs Res. Manage. 5(1): [10] APHA, Standard Methods for the Examination of Water and Waste Water. American Public Health Association, 18 th ed., Academic Press. Washinton D.C pp [11] L. Kouadia, J.H.Trefry, Saline trace metal contamination in the Ivory Coast West Africa. Air, Water Soil Pollut. 32: [12] AOAC, Official Methods of Analysis of AOAC international. 16 th ed., Vol. (Cunnif, P.Ed.), AOAC Int. Arlington, Virginia, USA [13] A.S. Abdel-Baki, M. A, Dkhil, and S. Al-Quraishy, Bioaccumulation of some heavy metals in tilapia fish relevant to their concentration in water and sediment of Wadi Hanifer, Saudi Arabia. African Journaln of Biotechnology. 2011, Vol. 10(13). pp [14] (USEPA), U.S. Environmental Protection Agency, Methods for Measuring the Toxicity and Bioaccumulation of sediment Associated Contaminants with Freshwater Invertebrates. 2 nd Edn., EPA boo/r , Office of Research and Development Washington, DC. 2000b. [15] F.Upadhi and O. A. F. Wokoma, Examination of Some Pesticides Residues in Surface Water, Sediment and Fish Tissue of Elechi Creek, Niger Delta, Nigeria. Research Journal of Environmental and Earth Sciencse 4(11): [16] WHO, Guidelines for Drinking Water Quality(Recommenda tions). WHO. Geneva REFERENCES [1] D. W Connell and G.J Miller. Chemistry and Ecotoxicology of Pollution. John Wiley and Sons. New York. 373 pp.1984 [2] G. Ambedkar and M. Muniyan. Archives Appl. Sci. Res., 3(3): [3] U.J. Ibok, E. D. Udosen and O.M. Udoidiong. Nig. J. Tech. Res., (1) [4] D.Velez and R. Montoro. Arsenic speciation in manufactured seafood products: a review. J.Food. Product, 61 (9) [5] H.B. Conache, B.D. Page and J.J. Ryan. Industrial Chemical Contamination of foods (review). Food Addit: Contam. 10 (1), [6] A,A. Olaijiri and F.E. Imeokparia. Bull. Chem. Soc. Ethiop [7] S. E, Ishaq, Rufus Shak Ato and P.A. Annune, Bioaccumulation of Heavy Metals in Fish (Tilapia Zilli and Clarias Gariepinus) Organs from River Benue, North- [17] O. Osibanjo, C.Binecy, D. Culuman, N. Kaba, I. L. Mbome, H. Naev, P.B.O, Ochomba and M.A.H. Sadd, Chlorinated Hydrocarbon substance review of pollution in the African aquatic environment, Pp [18] A. Gupta, D.K. Rai, R.S. Pandey and B. Sharma, Analysis of some heavy metals in the riverine water, sediment and fishes from river Ganders at Allahabad. Environ. Monit. Assess. 157: [19] T.J.K. Ideriah, O.A. Briggs, and H. O. Stanley, Bioaccumulation of heavy metals in periwinkle from lower Sombreiro River, Nigeria. Journals of Environmental Society (JNES), volume 5,(3). [20] C. Fernandes, A. Fontainhas, F. Peixoto, M. A. Salgado, Bioaccumulation of heavy metals in liza saliens from the Esomriz-Paramos coastal lagoon. Portugal. Ecotox. Environ. Saf. 66: [21] S. Jent, J.S. Heing and C.M. Ttate, Concentration distribution and composition of selected trace metals in bed sediment and fish tissue in the South Platte River Basin, USA, National Water- Quality Assessment( NAWQA) program report.1998.

6 64 Upadhi Friday et al.: Levels of Bioaccumulation of Some Heavy Metals in Fish (Tilapia zilli) and Their Concentration in Water and Sediment of Owubu Creek, Niger Delta, Nigeria [22] I. C. Howard, U.U.Gabriel, B.C. Onyekwere, Bioconcentration patterns of some trace metals in Tympanotonus Fuscatus (Var. Radula) and Crassostrea Gasar from the tidal flats of the Sombriero River, Niger Delta, J.NES vol.7.no 3.