Assessment of Heavy Metals in Lake Uluabat, Turkey
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African Journal of Biotechnology Vol. 6 (19), pp. 2236-2244, 4 October 2007 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2007 Academic Journals Full Length Research Paper Assessment of heavy metals in Lake Uluabat, Turkey Aye Elmaci, Arzu Teksoy, Fatma Olcay Topaç, Nihan Özengin, Sudan Kurtolu and Hüseyin Sava Bakaya Uluda University, Faculty of Engineering and Architecture, Department of Environmental Engineering, Görükle, Bursa, 16059, Turkey. Accepted 27 July, 2007 The accumulation of heavy metals (Cu, Ni, Zn, Cd, Pb, Cr, B, As) was measured in water, plankton and sediment samples taken from different areas of Lake Uluabat during January 2003 to February 2004. The sequential extraction used in this study is useful to assess the potential mobility of heavy metals in the sediment indirectly. In this study, Cu, Pb, Cr, Cd, Ni and Zn concentrations were detected at higher levels at Lake Uluabat for selected stations, especially in plankton samples. The magnitude of heavy metal concentrations in water and plankton samples was determined as B>Zn>As>Cd>Pb>Ni>Cr and Zn>Ni>Cu>Cr>Cd>Pb, respectively. The mobile heavy metals in sediment samples were sequenced as Pb>Cu>Cr>Ni>Cd>Zn, whereas the magnitude of easily mobilizable metal concentration was determined as Pb>Ni>Cr>Cu>Cd>Zn. Concentration of Cu and Cr in mobile fraction is detected higher than in easily mobilizable fraction. Concentration of Pb, Cd, Zn and Ni in mobile fraction is detected in lower levels than in easily mobilizable fraction. Key words: Fraction of heavy metals, Lake Uluabat, plankton, sediment, water. INTRODUCTION Fresh water lakes support many life forms, providing potential to release the sediment-bound metals and other recreation and game fishing to the communities, as well pollutants to overlying waters, and in turn adversely as being a good source of water for drinking and water affects aquatic organisms (Wang et al., 2004). production by municipal water works. The contamination Many important wetlands in Turkey have been polluted of soils, sediments, water resources and biota by heavy by different type of heavy metals and other contaminants metals is of major concern especially in many industria- like Lake Uluabat. Lake Uluabat, which is located in lized countries because of their toxicity, persistence and Marmara region, Bursa (TURKEY) (40º10' N, 28º35' E) is bioaccumulative nature (Ikem et al., 2003). Toxic metals one of the most productive lakes with respect to aquatic can alter many physiological processes and biochemical ecosystems. It has a mean surface area of 133.1 km2 in parameters, either in blood or in tissues including struc- 1984, 120.5 km2 in 1993 and 116.8 km2 in 1998. Lake tural deformations in aquatic animals (Cengiz and Ünlü, Uluabat is one of the most important wetlands not only in 2002; Barlas et al., 2005). Being non-biodegradable, they Turkey but also in the Middle East and Europe. It is one can be concentrated along the food chain, producing their of the most nationally and internationally important area. toxic effects at points often far away from the source of The Lake is staging site for globally threatened and pollution (Fernandez et al., 2000). legally protected species such as Pygmy cormorant, The build-up of metals in sediments has significant Phalacrocorax pygmeus, the Dalmatian Pelecanus cris- environmental implications for local communities, as well pus and the Otter Lutra lutra. During the first full survey of as for lake quality (Demirak et al., 2006). Sediment con- breeding birds at Lake Uluabat in 1998 by the Royal titutes the most important sink of metals and other Society for the Protection of Birds (RSBP), Lake Uluabat pollutants; it can act as a non-point source and has the was found to be the most important site in Turkey for Pygmy cormorant and Whiskered Tern Chlidonia hybrid- dus. Lake Uluabat is also the second most important site for the globally threatened Ferrugionus Duck Aythya *Corresponding author. E-mail: [email protected]. Fax: +90 nyroca. Accordingly, Lake Uluabat is an incredibly 224 44291 48. Tel: +90 224 2942107. important site. Besides, Lake Ulubat has the largest white Elmaci et al. 2237 Figure 1. A map of Lake Uluabat (Aksoy and Özsoy, 2002). water lily beds in Turkey (Anonymous, 2000). Due to its Halilbey. The animal wastes runs to the Lake at the shores in the importance, Lake Uluabat was designated by the Ministry biggest island of the Lake, Halilbey. Furthermore, the entrance of of Environment as a RAMSAR site in 1998 and conse- the Mustafakemalpa a stream is close to the second station. The third station was in the southwestern of Island Mutlu, which is quently it was chosen as a partner of International Living th located nearby the village of Eskikaraa aç. Domestic wastewater Lakes Network in the 4 International Conference at drains to the lake from this place. The fourth station was between EXPO 2000 (Aksoy and Özsoy, 2002). Island Mutlu and village of Eskikaraaaç. The new highway passes The objective of this study was to examine the close to the villages. And finally the fifth station was near the village concentration of selected heavy metals in water, sedi- of Akçalar. Domestic and industrial wastewaters especially, that arise from a tinning factory are discharged to the lake from Akçalar. ment and plankton samples at different stations in Lake Water and plankton samples were collected from the water Uluabat, during February 2003 – January 2004. In addi- surface in 1 liter pre-cleaned polyethylene bottles. Water samples tion it was aimed to evaluate the distribution of mobile were filtered through Whatman membrane filters (cellulose nitrate). and easily mobilizable metal fractions in sediments of 150 ml of water samples were acidified with HNO3 and kept for Lake Uluabat. analyses. Plankton samples were taken with the aid of plankton sampler (Hydrobios Kiel plankton net). Filtered plankton samples (Whatman glass microfiber filter (GF/C) were acidified with HCl and MATERIALS AND METHODS kept for analyses. Sediment samples were collected using pre- cleaned stainless steel sediment sampler and immediately placed A map of Lake Uluabat showing sampling locations is presented in in plastic bags. Samples were transported to the laboratory as soon Figure 1. Sampling of the Lake’s water for analytical purposes was as possible and air-dried in the laboratory at room temperature performed monthly from February 2003 to January 2004 from 5 (21˚C ± 2). Air-dried sediment samples were homogenized and different stations. The first station was near the outflow of Lake sieved (0.2 mm). Sediment samples were stored in acid washed Uluabat. The second station was in the southern of the Island polyethylene bottles. Sequential extractions have been applied 2238 Afr. J. Biotechnol. using extractants with progressively increasing extraction capacity. level in October. In F2 highest cadmium level was found In order to extract mobile fraction (F1) and easily mobilizable in July and lowest level in April. fraction (F2) of heavy metals ammonium nitrate and acetate ammo- Mean Ni concentrations in water samples were high in nium buffer solutions were used (Zeien and Brümmer, 1989). All -1 -1 glassware used for the analyses were carefully cleaned with nitric July and August (0.0343 mg l , 0.0331 mg l , acid followed by rinsing with distilled water before use. All reagents respectively), in addition to this, low in October (0.0119 -1 used were of analytical reagent grade (Merck, Germany). Deionized mg l ). Also, in plankton samples mean Ni concentrations water was used throughout the study. All analyses were done in were significantly higher in April (30.794 mg g-1). How- duplicate. ever, Ni concentrations were low in August (1.380 mg g-1) Cu, Pb, Cr, Cd, Ni, Zn concentrations in all samples were analysed by atomic adsorption spectrophotometer with air- in plankton samples. In sediment samples highest nickel acetylene flame method (UNICAM 929 AA Spectrometer). In level in F1 was found in September and lowest level in addition boron and arsenic analyses were performed by using kits December. In F2 highest nickel level was found in (Merck) in water samples. Some physical parameters such as pH October and lowest level in June. and temperature (Metrohm type pH meter), EC(25°C) (Jenway 4310 Mean Zn concentrations in water samples were high in type conductometer) and dissolved oxygen (DO) (Winkler method) March (0.2102 mg l-1) and low in November (0.0564 mg l- were also measured during the study period. Measurements and 1). Also, in plankton samples, mean Zn concentrations analyses were per-formed according to standard methods (APHA, -1 1998). were significantly higher in April (84.284 mg g ). How- -1 ever, Ni concentrations were low in August (2.513 mg g ) in plankton samples. In sediment samples highest zinc RESULTS level in F1 was found in September and lowest level in February. In F2, highest zinc level was found in May and Heavy metals appeared in all of the samples analyzed. lowest level in August (Tables 1 – 6). The evaluated data in water, sediment and plankton Seasonal variation of physical properties of water samples are shown in Tables 1 – 4. Higher copper con- samples for the average of 5 stations are given in Table centrations were detected in water and plankton samples, 5. The temperature of water ranged between 9.28 - in March and April. In June, the Cu residue level was 25.68°C and the pH ranged between 8.63 - 8.78. found low in water samples. In plankton samples lowest Conductivity values ranged between 501 – 721 S cm-1. Cu level was found in August. In sediment samples, Also dissolved oxygen values changed from 8.01 to highest Cu level in F1 was found in September and 11.28 mg l-1 (Table 5).