This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and

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2 Marine Pollution Bulletin 73 (2013) Contents lists available at SciVerse ScienceDirect Marine Pollution Bulletin journal homepage: Baseline Investigation of heavy metal pollutants at various depths in the Gulf of Izmit Halim Aytekin Ergül a, Tolga Varol b, Ümit Ay b, a Department of Biology, Kocaeli University, Kocaeli, Turkey b Department of Chemistry, Kocaeli University, Kocaeli, Turkey article info abstract Keywords: Heavy metal Deep seawater Atomic absorption spectrophotometer Gulf of Izmit In this study, we report results concerning the accumulation of heavy metals in seawater from Izmit Bay. The bay was divided into the three parts: the eastern, the central and the western basins. The goal of this study was to determine levels of heavy metals at various depths in the bay between April 2008 and May Liquid liquid extractions were performed on seawater samples. An atomic absorption spectrophotometer was used to measure levels of six metals: lead, cadmium, chromium, iron, manganese and zinc. We applied our results to evaluate the status of pollution in the Gulf of Izmit. Significant seasonal differences in metal concentrations and higher concentrations of many metals in water near the shore are evidence for uncontrolled release of pollutants in the water. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Seawater pollution is a serious concern for many nations because it is an integral part of environmental pollution worldwide (Multia et al., 2012). Heavy metals and similar pollutants from various sources in the atmosphere and on lands accumulate in the seas where they upset the balance of nature, alter the biological environment and, consequently, enter the food chain and affect human health (Yu et al., 2012). These pollutants include organic compounds, industrial wastes, petroleum derivatives, synthetic agricultural fertilizers, detergents, radioactive materials, pesticides, inorganic salts and other chemical substances. Pollution, in turn, may be divided into three categories: physical, biological and chemical. Chemical pollution occurs when chemical substances and industrial waste are released, intentionally or unintentionally, into nature. Paints, detergents, pesticides and petroleum products are examples of chemical pollution. Heavy metal pollution is dominant form of chemical pollution. Heavy metals from, for example, industrial wastes, pesticides and mining operations persist in the environment and are transferred through the food chain (Wu et al., 2012). In the sea, the most significant pollutants are chemical substances that stay in the environment for prolonged periods of time and have toxic effects. Heavy metals are the leading form of chemical pollution in seawater. In fact, very low concentrations of heavy metals are natural components of fresh water and seawater. However, due to human activities, metal ion levels have increased in many natural water systems. Mining, Corresponding author. Tel.: ; fax: address: umurege@kocaeli.edu.tr (Ü. Ay). petroleum and gas exploration in oceans, industrial manufacturing (e.g., textiles, paints, leather, fertilizers and medicine), household waste, agricultural runoff and acid rains all increase metal concentrations in natural water (Petrooshina, 2003). Limited amounts of heavy metals positively affect biological characteristics of organisms. However, higher amounts of metals negatively the affect biological activity of organisms and upset the balance of organisms in the food chain (Peakall and Burger, 2003). Thus, seawater pollution should be prevented and controlled. Pollution control depends on monitoring pollutants in seawater and determining their sources. For example, Taymaz et al. (1984) analyzed levels of mercury, cadmium and lead in samples of sediment, seawater and fish from Izmit Bay. These researchers study showed that Hg and Cd levels were high near plants producing chlor-alkali chemicals. The results were similar for sediment samples from shore areas and fish. Pekey et al. (2004) collected water samples from 10 locations in Dil Stream during two different seasons and determined the amounts of certain elements. Water quality was designated according to metal content. That study showed that Cd, Cr, Cu, Pb and Zn values exceeded the highest reference concentration values. Guhathakurta and Kaviraj (2000) examined the Cd, Pb, Zn and Fe concentrations in samples of water, sediment, shrimp and mullet from India s Sunderban fresh water lake. Okonkwo et al. (2005) performed a study on three rivers in South Africa and compared heavy metal levels in water samples taken during the winter and the summer. Metal concentrations were higher in the winter than in the summer, most likely because rainwater is added to rivers in the winter. The Pb concentration was higher than the other metals in each of these three rivers during both seasons. In this study, seasonal variations in heavy metal pollution were monitored in X/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.

3 390 H.A. Ergül et al. / Marine Pollution Bulletin 73 (2013) Fig. 1. Sampling station locations in Izmit Bay. Table 1 Depths for sample collection. Basin I. Depth II. Depth III. Depth IV. Depth V. Depth East Surface 10 m 20 m Central Surface 10 m 20 m 50 m 80 m West Surface 10 m 20 m 50 m water samples taken from different depths at designated stations where industrial activity and biological life co-exist in Izmit Bay. Six metals are the focus of this study: iron, manganese, zinc, copper, cadmium and lead. These metals were selected due to their toxic effects on living organisms and their presence at measurable levels in sea water samples. Sampling stations were located at three different areas in Izmit Bay, the east, the west and the central basins (Fig. 1). Seawater samples were collected at designated depths that depended on total basin depth. Water was obtained at depths given in Table 1 using a Nansen bottle. Samples were collected with the assistance of a Control L Boat with an onboard manual crane from the Kocaeli Metropolitan Municipality (see Table 1). Sample collection began in spring 2008 and continued without interruption until spring We periodically performed sampling in each season at the designated depths in three basins of the Izmit Bay. The Nansen bottle was submerged in the sea at the designated depth and a sample was taken using the manual crane. Water samples were stored in high-density polyethylene bottles. The night before these bottles were used, they were prepared by washing with dilute nitric acid and rinsing with pure water three times. Water samples were placed in portable iceboxes Fig. 2. Seasonal variations in heavy metal concentrations in Izmit Bay during 2008.

4 H.A. Ergül et al. / Marine Pollution Bulletin 73 (2013) Fig. 3. Seasonal variations in heavy metal concentrations in Izmit Bay during to prevent spoiling and brought to the laboratory shortly after they were collected. Seawater samples were filtered through coarse filter paper, acidified with HNO 3 and adjusted to between ph 1.5 and 2.0. The samples were stored at +4 C. For the metal analysis, at least three 100 ml aliquots from each sample were tested in parallel. Samples were adjusted to ph 7 8 and transferred into 250 ml separatory funnels. A ligand solution, 10 ml (C 2 H 5 ) 2 NCSSNa3H 2 O (sodium diethyldithiocarbamate trihydrate), and 10 ml methyl isobutyl ketone were added to each separatory funnel. Separation funnels were shaken for 5 min and were left until phases separated. The lower (aqueous) phases were transferred into a 250 ml separation funnels. Then 5 ml of methyl

5 392 H.A. Ergül et al. / Marine Pollution Bulletin 73 (2013) isobutyl ketone was added to these lower phases, the funnels were shaken for 5 min and left to separate. After separation of phases, the upper (organic) phase was extracted and the lower phases were discarded. Then, the upper phases were combined and then 4 ml deionized water and 1 ml concentrated HNO 3 were added to these upper phases. The funnels were shaken for 5 min again and left for 30 min for separation of phases. After separation of phases, the upper phases were discarded and the lower phases were stored in darkness to be conditioned for analysis with the atomic absorption spectrophotometer (AAS). Elemental concentrations (lg/l) in water samples from various depths in three basins in Izmit Bay are shown (Figs. 2 4). Data from the east, the west and the central basins show that dissolved element concentrations were higher in winter 2010 than the other seasons. These concentration variations are thought to be related to factory wastes and weather conditions. The highest elemental concentration in surface water was 419 lg/l of Zn in the central basin during winter The results obtained for the surface water in the west basin were inconsistent. The highest concentration of Zn was 82.0 lg/l in the west basin during summer Because difficult weather conditions prevented us from performing field works in the west basin in winter 2010, no data were obtained. For Fe in the west basin, the highest concentration was in spring 2010, which differed from Zn. In general, Zn and Fe concentrations were high. The most important reason for inconsistent surface water results was uncontrolled pollution from factory and vessel wastes and other sources. At greater depths in the basins, Zn was maximized in winter 2010 at a depth of 10 m. In winter 2010, the Zn concentration was 418 lg/l in the east basin at 10 m and 703 lg/l in the central basin. When we compared data from a depth of 20 m in the east basin, Zn had the highest concentration. The concentration of dissolved Fe, which was 447 lg/l at 20 m in the central basin during autumn 2009, fell to 17.9 lg/l in winter When we compared results for the central and west basins at 20 m, Fe had the highest concentrations in both basins. The maximum concentrations of Fe were observed in autumn 2009 in the central basin and in spring 2010 in the west basin. At a depth of 80 m in the central basin, Fe, Mn and Zn reached their highest values in autumn 2009 and winter Metal concentrations in the central basin rose higher than other depths. These concentration increases are related to higher pressures are greater depths and cold conditions due to climatic change. When we considered Cu in the east basin with regard to depth and climate variations, the highest value of 18.1 lg/l was observed in summer 2009 at a depth of 20 m. When we evaluated the depth and climate variations for each trace element, we observed that values of Zn and Fe exceeded acute levels from time to time. The highest levels of Cu, Fe, Zn and Mn in the east basin were observed in summer 2009 and winter At the same time, the highest concentration of Mn in the east basin surface water was 2832 lg/l during autumn This deviation is thought to be related to intense pollution sources, because the analysis is performed on surface water. Lead and Cd concentrations are acceptable in the east basin. Iron, Zn and Mn metals increased far above tolerable levels in the central basin during autumn 2009 and spring Concentrations of Pb, Cu and Cd were low. The west basin had high levels of Mn, Zn and Fe, while Pb, Cu and Cd concentrations were within tolerable limits. When the east, the west and the central basins of Izmit Bay were tested for Cd, this element reached its highest value, 6.50 lg/l, in winter Lead reached its highest values in winter 2009 and spring 2009 and increased in winter Manganase reached its highest value in autumn 2009 and increased in winter 2009, following a period when it was relatively constant. High Fig. 4. Seasonal variations in heavy metal concentrations in Izmit Bay during 2010.

6 H.A. Ergül et al. / Marine Pollution Bulletin 73 (2013) values of Zn were measured between winter 2010 and spring 2010 in most basins. Peak values of Fe were observed between autumn 2009 and spring Copper was the same in summer 2009 and autumn 2009 and was usually under the tolerable limits. Although Cu and, particularly, Cd were present at high concentrations in the east basin in certain seasons, their overall seasonal average concentrations were generally higher at stations near the west basin. However, concentrations of Fe, Mn, Zn and Pb were generally high at stations near the east basin. Metal concentrations variations due to, for instance, temperature and dissolved oxygen concentrations, affect metal dissolution. This study showed that Cu concentrations, in particular, tended to decrease with depth during summer and increase with depth during winters. In general, Fe and Mn concentrations were low at surfaces and higher in deeper water. Hydroxides of Fe and Mn have notably low solubility and this may explain their lower concentrations in surface waters. Variations in Zn, Pb and Cd concentrations through the water column are thought to arise from mixtures, geological structures in the regions and proximity to industries. In certain cases, Cu and Zn concentrations were above tolerable limits. Elevated levels of Cu and Zn are thought to originate from uncontrolled release of factory waste in waters. Significant seasonal differences in metal concentrations and higher concentrations of many metals in water near the shore are evidence for uncontrolled release of pollutants in the water. In this study, seasonal variations in pollution in Izmit Bay were analyzed for 2 years. Water samples taken from different locations and depths in Izmit Bay were analyzed for heavy metal content. Data showed that Izmit Bay is being affected by sources of pollution located near its east, west and central basins. The close proximity of the region to industrial operations caused some inconsistent results. Because measured metal concentrations in some areas are always over tolerable limits, permanent sources of pollution are present in these areas. The pollution of sea water, which is the habitat of many living species, harms biological life and threatens habitats of sea organisms. Because Pb and Cd levels do not vary, there may be few or no sources of Pb and Cd pollution in the area. However, other metals demonstrated seasonal variations that are thought to originate from discharge of untreated water and seasonal effects related to shipping activities. It appears that there is uncontrolled or illegal discharge into Izmit Bay by many industrial enterprises in the area. Prevention of uncontrolled or irregular discharges that threaten the ecosystem, principled port activities and long-term studies control pollution in Izmit Bay and the surrounding area. Acknowledgements We express our thanks to Kocaeli University Research Fund, Linde Gas Company for their support and TÜB _ ITAK (Project No. 107Y261). References Guhathakurta, H., Kaviraj, A., Heavy metal concentration in water, sediment, shrimp (Penaeus monodon) and Mullet (Liza parsia) in some brackish water ponds of Sunderban, India. Mar. Pollut. Bull. 40, Multia, T.M., Virani, M.Z., Moturi, W.N., Muyela, B., Mavura, W.J., Lalah, J.O., Copper, lead and cadmium concentrations in surface water, sediment and fish, C. Carpio, samples from Lake Naivasha: effect of recent anthropogenic activities. Environ. Earth Sci. 67, Okonkwo, J.O., Mothiba, M., Awofolu, O.R., Busari, O., Levels and speciation of heavy metals in some rivers in South Africa. Bull. Environ. Contam. Toxicol. 75, Peakall, D., Burger, J., Methodologies for assessing exposure to metals: speciation, bioavailability of metals, and ecological host factors. Ecotoxicol. Environ. Saf. 56, Pekey, H., Karakasß, D., Ayberk, S., Tolun, L., Bakoğlu, M., Ecological risk assessment using trace elements from surface sediments of Izmit Bay (Northeastern Marmara Sea) Turkey. Mar. Pollut. Bull. 48, Petrooshina, M., Landscape mapping of the Russian Black Sea cost. Mar. Pollut. Bull. 47, Taymaz, K., Yigit, V., Özbal, H., Ceritoglu, A., Müftügil, N., Heavy metal concentrations in water, sediment and fish from Izmit bay, Turkey. Int. J. Environ. Anal. Chem. 16, Wu, J.L., Zeng, H.A., Yu, H., Ma, L., Xu, L.S., Qin, B.Q., Water and sediment quality in lakes along the middle and lower reaches of the Yangtze River, China. Water Resour. Manage. 12, Yu, T., Zhang, Y., Hu, X.N., Meng, W., Distribution and bioaccumulation of heavy metals in aquatic organisms of different trophic levels and potential health risk assessment from Taihu lake, China. Ecotoxicol. Environ. Saf. 81,