Histopathological changes in the livers and kidneys of fish in Sariyar Reservoir, Turkey

Environmental Toxicology and Pharmacology 23 (2007) 242–249

Histopathological changes in the livers and kidneys of fish in Sariyar Reservoir, Turkey Zafer Ayas a,∗ , Guler Ekmekci a , Murat Ozmen b , Sedat V. Yerli a a

Hacetepe University, Science Faculty, Department of Biology, 06800 Beytepe, Ankara, Turkey b Inonu University, Arts & Science Faculty, Department of Biology, 44280 Malatya, Turkey

Received 2 June 2006; received in revised form 19 October 2006; accepted 7 November 2006 Available online 15 November 2006

Abstract In this study, a total of 180 fish specimens (wels: Silurus glanis-60; common carp: Cyprinus carpio-60; bleak: Alburnus escherichii-60) of ages between one and two were caught at three different stations in Sariyar Reservoir. The histological changes in the livers and kidneys of three different species of fish were detected microscopically and evaluated with quantitative analyses. Also, organochlorine pesticide residues (OCP) have also been determined in the water and sediment samples and in the adipose tissues of fish caught in these stations. Results show that the reservoir was polluted by different kinds of OCP compounds and these chemicals have accumulated in the fish tissues. As a result of these analyses, histopathological changes were observed in the livers and kidneys of fish specimens, such as mononuclear cell infiltration, congestion and nuclear picnosis. Also intra-cytoplasmic cholestasis in their livers and tubular degenerations in the kidneys were observed. The incidences of the histopathological changes in wels and carps were found to be higher than bleak. Furthermore, histopathological changes in fish samples caught from Usakbuku were much more than the samples caught from other stations (Sariyar and Nallihan Bird Paradise Stations). In this study the possible reasons of histopathological changes were evaluated with respect to different fish species and localities and also the findings were evaluated in relation to OCP contamination. © 2006 Elsevier B.V. All rights reserved. Keywords: Histopathology; Fish; Organochlorine pesticides; Contamination; Sariyar Reservoir; Turkey

1. Introduction If it is desired to improve the quality of aquatic ecosystems, it is necessary to know how the rivers and lakes are impaired and what factors caused the environmental deterioration. Pollution of water sources due to chemicals plays a primary role for destroying ecosystems but chemical analyses alone may not suffice to describe the adverse effects of the complex mixtures of chemicals present at contaminated sites. The potential utility of biomarkers for monitoring both environmental quality and the health of organisms inhabiting in the polluted ecosystems has received increasing attention during the last years (Lopes et al., 2001; de la Torre et al., 2005; Mdegela et al., 2006; Minier et al., 2006). Organochlorine pesticides (OCP) were the first synthetic organic pesticides that were used in agriculture. DDT and BHC

∗

Corresponding author. E-mail address: [email protected] (Z. Ayas).

1382-6689/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.etap.2006.11.003

(now HCH) are probably the best known of these types of pesticides. The production and intensive agricultural and industrial use of persistent organochlorinated pollutants (POPs), such as OCP, have caused the widespread contamination of the environment (de Boer et al., 2000). Being lipophilic, POPs are characterized by a high bioaccumulation potential in food chains and therefore may pose a serious threat to higher trophic levels of aquatic communities (Ayas et al., 1997; Fisk et al., 2001; Boon et al., 2002; Falandysz et al., 2002; Erdogrul et al., 2004). Humans are exposed by mistake to POPs through numerous sources, of which the consumption of contaminated fish is one of the most important pathways (F¨urst, 1993; Mackay and Fraser, 2000). Most countries have restricted or banned the use of OCP. In Turkey, OCP have been used since 1945 and large quantities of these chemicals were used during 1960–1970s. Since 1983, the usage of OCP has been severely restricted or banned (C¸ok et al., 1997; Kolankaya, 2006). Fish is a suitable indicator for the environmental pollution monitoring because they concentrate pollutants in their tissues

Z. Ayas et al. / Environmental Toxicology and Pharmacology 23 (2007) 242–249

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Fig. 1. Study area and sampling stations of the reservoir (coordinates; 40◦ 2 24 N–31◦ 36 36 E).

directly from water, and also through their diet, thus enabling the assessment of transfer of pollutants through the tropic web (Fisk et al., 2001; Boon et al., 2002). Due to being exposed to pollutants, major structural damages may occur in their target organs, histological structure may change and physiological stress may occur. This stress causes some changes in the metabological functions. The changes in the functions are initiated with the changes in the tissue and cellular level. Although qualitative data are used in most cases to study the pathologies the environmental pollutants cause, quantitative data shows better the reactions of the organisms to pollutants (Jagoe, 1996). This study was carried out examining the pollution situation in the Sariyar Dam Lake (hereinafter it will be called as “reservoir”). The reservoir is located in Central Anatolia (Fig. 1) and has a surface area of 8400 ha. The reservoir is surrounded mainly by bare land, small villages and limited agricultural areas. Sariyar Dam was built on Sakarya River, which receives various kinds of effluents, such as domestic and industrial effluents of the settlements and industries located upstream of the dam, as well as irrigation and surface runoff. This work is important due to the fact that it is the first comprehensive study in this reservoir for determining the pollution levels using quantitative histopathological data. Therefore, we believe that the results of the study also provide a base for further similar studies at future for monitoring the reservoir. The reservoir has a significant potential of fishery but unfortunately environmental pollutants such as OCP residues, heavy metals, PAHs, etc. are being discharged into Sakarya River directly or through its tributaries for many years. Especially OCP residues were detected in very high quantities in water, sediments and fish adipose tissues (Barlas, 1999a; Ekmekc¸i et al., 2000). Histopathological changes are selected to biomonitoring health conditions of three economically important fish species, wels (Silurus glanis), common carp (Cyprinus carpio) and bleak (Alburnus escherichii). Besides its economic importance, bleak is also an endemic species (Ekmekc¸i et al., 2000).

2. Materials and methods 2.1. Fish species and sampling stations Three fish species (wels: Silurus glanis; common carp: Cyprinus carpio; bleak: Alburnus escherichii) having different feeding habits were selected for biomonitoring purpose. The carnivorous wels, omnivorous common carp and bleak are the most important fish species for fishery in the reservoir. The reservoir is located about 180 km to the northwest of Ankara (Fig. 1). Fish specimens were caught from three localities in the lake: Usakbuku, Sariyar and Nallihan Bird Paradise (hereinafter it will be called as “NBP”). These stations were selected according to their limnologic and hydrologic characteristics.

2.2. Histological samples For the histological studies, 20 fish sample of each fish species were caught alive by using monofilament gill nets. Fish samples were numbered and weighed and their lengths were measured on site. Those that have the same weight, length and age (2 and 2+) were preferred for the histological examinations, as much as possible. This preference aims to minimize the variations due to age and weight differences of the samples. For light microscopic examinations, the livers and kidneys of fish were immediately removed and fixed in Bouin’s solution, processed with ethanol series than, washed xylene and were embedded in paraffin. Paraffin sections of tissues were cut into 5 ␮m thickness and stained with Hematoxylin and Eosin (Gurr, 1972) for light microscopy examination. Histopathological changes observed in each tissue of the fish were determined and classified according to the species and stations. For the statistical analyses, the occurrence percentages of the lesions were calculated according to the species and stations.

2.3. Residual analysis Water, sediment and lipid content of fish (bleak, carp and wels) samples were collected from three stations (Usakbuku, Sariyar, and NBP) in the reservoir. Water samples were taken into glass bottles from 0.1 m below the water surface and stored at +4 ◦ C. The upper 10 cm of the bottom layer sediment was sampled with Ekman sampler and stored in sterile 250 mL glass bottles. Water samples were filtered through 0.45 ␮m millipore filters and both water and sediment samples were prepared for gas chromatography analysis (Sodergren and Wartiovaara, 1988). Fish samples were taken from fish of the same size and age as much as possible. The length (mm) and weight (g) of fish samples from the three stations were measured and then they were frozen until the laboratory analysis.

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Table 1 Levels of organochlorine pesticides and their residues determined in water (mg/L), sediments and fish (mg/kg) sampled from three different stations in Sariyar Reservoir Sample

Na

Sampling stations Usakbuku Residue

␣-BHC Water Sediment Bleak (Alburnus escherichii) Carp (Cyprinus carpio) Wels (Silurus glanis)

4 4 5 5 5

0.061 0.151 0.115 0.378 1.884*

␤-BHC Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.029 0.61 0.042 0.69* 0.439*

Lindane Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.056 0.708 0 0.512 0.632

Aldrin Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.024 0.308 0 0 0.063

Dieldrin Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0 0 0 0.084 0.183*

Heptachlore Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0 0.085 0 0 0.059

Heptachlor epoxide Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.044 0.502 0 0.162 1.169

o,p -DDT Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.04 0.256 0.037 0.095 2.033

p,p -DDT Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.014 0.399 0.061 0.421 0.771

Sariyar BAFb

Residue

1.8 6.2 30.9*

0.05 0.398 0.109 0.435 0.625*

1.4 23.8* 15.1*

0.022 0 0.027 0.12 0.532*

0 9.1 11.2*

0 0 0 0 0.122

0 0 2.6

0 0 0 0 0

0 0 0

0 0.153 0 0 0.055

0 0 0

0 0 0 0 0

0 3.7 26.6*

0 0 0 0 0

0 2.3 50.8*

0 0 0 0 0

4.3 30.1* 55.1*

0.011 0 0.061 0.107 0.172

NBP BAFb

Residue

BAFb

2.1 8.7 12.5*

0.027 0.161 0 0.053 1.804

1.2 5.4 24.1*

0 0.559 0.025 0.098 0.129

0 0 0

0 0 0

0 0.458 0 0.032 0

0 0 0

0 0 0

0 0 0 0 0

0 0 0

0 0 0

0 0 0 0 0.116

0 0 0

0 0 0

0 0.012 0 0 0

0 0 0

0 0 0

0 0.606 0 0.062 0.323

0 0 0

0 0 0

0.051 0.469 0 0.074 0.748*

0 1.4 14.6*

0.069 0.42 0.056 0.093 0.687

0 1.3 9.9*

5.5 9.7 15.6*

0 1.9 66.8*

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Table 1 (Continued ) Sample

Na

Sampling stations Usakbuku Residue

o,p -DDD Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.034 0.243 0 0.134 2.422

p,p -DDD Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.028 0.113 0 0.179 1.68

p,p -DDE Water Sediment Bleak (A. escherichii) Carp (C. carpio) Wels (S. glanis)

4 4 5 5 5

0.026 0.364 0.137 0.307 1.724

* a b

Sariyar BAFb

0 3.9 71.2*

0 6.3 60*

5.2 11.8 66.3*

Residue 0.037 0.272 0.033 0.047 0.152 0 0.19 0 0 0,12 0 0 0.118 0.098 0.105

NBP BAFb

Residue

0 1.2 4.1

0.067 0.379 0 0.047 1.303

0 0 0

0.046 0.226 0 0 0.784

0 0 0

0.044 0.522 0.107 0.148 0.83

BAFb

0 0 19.4*

0 0 17*

2.4 3.3 18.8*

Statistically significant. Number of samples for each stations. Calculated as the ratio of mean concentration in the fish to that in the water belong to Usakbuku, Sariyar and NBP.

Fish adipose tissues (30 g fresh tissues) were homogenized and extracted according to the procedure of FAO (1984) and extracts were prepared for OC analysis according to the procedure described by Solly and Shanks (1969). Identification and quantification of OC compounds were accomplished using standard mixture solutions of o,p -DDT, p,p -DDE, p,p -DDD, o,p -DDD, p,p -DDT, heptachlor, heptachlor epoxide, aldrin, dieldrin, lindane, ␣-BHC, and ␤-BHC. Gas chromatography (GC) analysis was carried out using Chrompack-SFC Instrument 138 A with Nickel Electron Capture Detector, automatic sampler, digital processor and 4% SSE-30/60% QF-capillary column. The column temperature was maintained at 270 ◦ C and the flow rate of carrier gas nitrogen was set to 40 mL/min. Each sample was analyzed in duplicate injections of 0.2 ␮L. The detection limit was 0.001 mg/L. The bioaccumulation factor (BAF) is a number that describes the bioaccumulation as the ratio of the concentration of a chemical inside an organism (CF ) to the concentration in the surrounding environment (CWT ). The BAF values for each fish species are calculated as the ratio of OCP residue concentration in the fish (CF ) to that in the water (CWT ) as “BAF = CF /CWT ” (Mackay and Fraser, 2000).

2.4. Statistical analysis All statistical analyses are made with Minitab 13.20, Statistical software. In order to find out the differences among the histopathological changes (in which way), the One-way ANOVA test is used. To establish the differences among the fish species and sampling stations of these lesions statistically, the Post-Hoc Test is used. The results of the statistical analyses are evaluated and commented according to the fish species and sampling stations (p < 0.05) (Minitab, 2005). Due to relatively large dispersion of the values, the concentrations of pollutants in water, sediment and fish are summarized using median values. The distribution of OCP residues is not normal (Shapiro–Wilks test, p > 0.05) and therefore non-parametric statistics are employed. The levels of contaminants between species are compared using non-parametric Kruskal–Wallis Test. Comparison of profiles and concentrations between species were performed by using Wilcoxon non-parametric test. Finally, all correlations were carried out using non-parametric Spearman Rank correlation. The level of significance was set at α = 0.05 throughout this study. (Minitab 13.20, Statistical Software, 2005).

3. Results 3.1. Residues in water sediments and fish Table 1 illustrates the levels of organochlorine pesticide residues in water and sediment, and lipid contents of fish in the sampling stations. Organochlorine residues were detected at low levels in water samples (ranged from 0.011 mg/L for p,p -DDT in Sariyar to 0.069 mg/L for p,p -DDT in NBP). Organochlorines in sediments are much higher than in the water of the reservoir with respect to both varieties and levels. The levels of some residues in the sediments are even higher than in the fish. The highest level of organochlorines in sediments, among three stations was determined in Usakbuku (11 different types of organochlorines with maximum levels of Lindan; 0.708 mg/kg). The results showed that organochlorine accumulations in fish lipid content is significantly higher than both in water and sediments (p < 0.05). DDTs were the prevalent contaminants found in the investigated fish from the reservoir. Among the species studied, maximum bioaccumulation was found in wels and the level of accumulation increased in the fish samples caught at Usakbuku, mainly DDT metabolites. Twelve (all) types of organochlorine residues were detected in the wels from NBP, Usakbuku and Sariyar. The highest organochlorine levels were determined in the samples of wels from Usakbuku (2.422 mg/kg for o,p-DDD). It was determined that the levels of organochlorine residues in wels are significantly higher than in bleaks and carps (p < 0.05). The bioaccumulation factors indicated that DDTs, heptachlor epoxide, BHCs and lindan accumulation was highest in wels,

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Fig. 2. Most characteristic histopathologic changes. (a) Mononuclear cell infiltration (black arrow) and (b) congestion (white arrows) in the wels’ liver (H&E, 180×); (c) tubular degenerations (*) and congestion (white arrow) in the kidneys. H&E, 300×.

lowest in bleaks, carps being at the middle. Furthermore, p,p -DDE have the highest bioaccumulation levels in wels. Particularly, bioaccumulation rates of DDTs are high in wels. In addition, heptachlor epoxide and ␣- and ␤-BHC also have considerable bioaccumulation rates in the fish species. 3.2. Histopathological findings The results of the histological examinations showed that, histopathological changes such as mononuclear cell infiltration (MCI), congestion (CON), nuclear picnosis (NP) and intracytoplasmic cholestasis (ICC); tubular degenerations (TD) are present in the livers and kidneys of the wels, carps, and bleaks caught in the sampling stations. Most characteristic changes are shown in Fig. 2. The incidences of the histopathological changes observed according to the fish species and stations are illustrated in Table 2. When considering the findings generally, the wels caught in the Usakbuku station have the highest rate of histopathological changes.

The liver is the tissue that the highest rate of histopathological changes is observed in all three fish species. Considering the sampling stations, the percentages of the histopathological changes observed are in the order of Usakbuku > Sariyar > NBP. The MCI, NP and ICCH percentages in the livers of the fish caught in Usakbuku are much higher compared to those of the fish caught in NBP and the difference among them is statistically significant. Similarly, the CONG found in the livers of the fish caught in Sariyar and NBP are considerably different. The TD percentages observed in the kidneys were in the order of Usakbuku > Sariyar > NBP. This difference between the stations is found to be statistically important. When generally considering the species handled, the occurrence percentages of the histopathological changes are in the order of wels > carp > bleak. The occurrence percentages of the MCI in the livers of the wels are much higher than the occurrence percentages of the CONG in the carps and bleaks. Also the difference between wels and bleak is determined to be statistically important. It was found that, NP in the livers is

Table 2 The incidences of the liver and kidneys lesions in wels, carp and bleak from three different stations of the reservoir Species

Stations

N

Histopathological changes Mononuclear cell infiltration

Congestion

Nuclear pignosis

Intracytolasmic cholestasis

Tubular dejeneration

liver

kidneys

liver

kidneys

liver

kidneys

liver

kidneys

Wels (S. glanis)

Usakbuku Sariyar NBP

20 20 20

7 (35)* 6 (30)* 0 (0)

4 (20)* 3 (15) 0 (0)

4 (20)* 5 (25)* 0 (0)

2 (10) 3 (15) 0 (0)

8 (40)* 5 (25) 0 (0)

6 (30) 6 (30) 1 (5)

6 (30)* 2 (10) 0 (0)

7 (35)* 2 (10) 0 (0)

Carp (C. carpio)

Usakbuku Sariyar NBP

20 20 20

4 (20)* 2 (10) 1 (5)

5 (25)* 2 (10) 1 (5)

3 (15) 4 (20) 0 (0)

4 (20)* 2 (10) 1 (5)

1 (5) 0 (0) 1 (5)

3 (15)* 1 (5) 0 (0)

4 (20) 2 (10) 0 (0)

3 (15)* 1 (5) 0 (0)

Bleak (A. escherichii)

Usakbuku Sariyar NBP

20 20 20

1 (5) 0 (0) 0 (0)

1 (5) 0 (0) 1 (5)

1 (5) 0 (0) 0 (0)

1 (5) 0 (0) 0 (0)

1 (5) 0 (0) 1 (5)

1 (5) 1 (5) 1 (5)

1 (5) 0 (0) 0 (0)

1 (5) 0 (0) 0 (0)

N: number of the fish (percentages of the lesion incidences); NBP: Nallihan Bird Paradise. * Statistically significant.

Z. Ayas et al. / Environmental Toxicology and Pharmacology 23 (2007) 242–249

observed in a much higher rate in wels fish and the differences among the species (except for the difference between the carp and bleak fish) are statistically important. This situation is also same for NP observations in the kidneys. The ICC observed in the livers and the TD observed in the kidneys also have higher occurrence percentages in the wels compared to the other two species and the difference between the wels and bleaks are statistically important. The occurrence percentages of the histopathological changes in the livers are more widespread than those in the kidneys, and MCI, CON, and NP are more frequent than ICC and TD. The histopathological changes in the livers of the wels are much more than it is in the other two fish species. The difference between the percentages of the MCI and CON observed in wels and bleaks are statistically important.

4. Discussion The objective of this work is to investigate the results of pollution in the reservoir by studying the histopathological changes for three different fish species having different feeding habits. The reservoir is one of the most important water sources for fishery in Central Anatolia in Turkey. Its importance is also attributed to the ecological characteristics since the reservoir has nestling areas for some birds such as herons, Egyptian vultures, golden eagles, ruddy shelducks and many other species (Perktas and Ayas, 2005). But, the reservoir is also extensively polluted by different kinds of pollutants such as agricultural chemicals, industrial and urban discharges (Ekmekc¸i et al., 2000). Barlas (1999a) and Kolankaya (2006) reported that illegal use of OC pesticides is an ongoing process in the agricultural areas in Sakarya Basin and other different localities in Turkey. In line with these findings, our results also indicate that the presence of OCP compounds in the surface water systems flowing into the reservoir lake might be the most important factor for the pollution of the lake (Ekmekc¸i et al., 2000). Residue analysis data show that 12 different organochlorine pesticide and their degradation products contaminate water, sediments and fish in the reservoir. Ten different pesticide residues were detected in water samples in selected stations (ranging from 0.011 mg/L o,p -DDT in Usakbuku Station to 0.238 mg/L o,p DDD in Sariyar station). The highest amount of OCP residues in sediments, among all stations, was determined in Usakbuku (lindane, 0.708 mg/kg) and also 12 different types of OCP residues were determined in all stations. Twelve different OCP compounds were determined in adipose tissues of wels and the highest concentration was 2.422 mg/kg for o,p’DDD at Usakbuku station. The bioaccumulation factors indicated that DDTs, heptachlor epoxide, BHC and lindan accumulated in high levels in the fish tissues in the order of wels > carps > bleaks. The highest bioaccumulation rates are 71.2 for o,p -DDD, 66.8 for ␣-BHC and 60 for o,p -DDD in wels which may indicate the illegal use of OCP in the area. The usage of the pesticides indicated above started to decline after 1978, when their usage was restricted. However, they are still being used illegally in some parts of Turkey (Kolankaya, 2006).

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It was also determined that the lake and its water sources and sediments are contaminated by different kinds of heavy metals such as Pb, Cd, Cu and Ni. The results show that these metals are widespread throughout the studied area. Metal levels of all of the water samples are found to be below the detection limits. Pb, Cd, Cu and Ni contaminations were determined in sediments and fish samples. These metals have accumulated and biologically magnified in fish tissues. Metal concentration levels in sediment samples were even higher than the levels observed in the fish species. The highest amounts of metal concentrations in sediment samples among all stations were determined in Usakbuku (Pb: 0.49 mg/kg), Sakarya River (Cu: 1.12 mg/kg) and Sariyar (Ni: 0.77 mg/kg). Heavy metal accumulation on the liver and fatty tissues of fish samples showed that accumulation of these metals in liver tissue were higher than in adipose tissues (Ekmekc¸i et al., 2000). The histological results show that the fish in the reservoir can be negatively affected at tissue level by the cause of OCP contamination. The histopathological changes observed in the tissues are the reactions in a histological level to the pollutants. Similar findings on the effect of pollutants were found in previous studies (Hinton, 1993; Teh et al., 1997; Barlas, 1999b). The histopathological changes observed in all three fish species caught from the reservoir show considerable similarity with the changes observed by previous study in the carp fish sampled from Sakarya River which is flowing to this reservoir. Barlas (1999b) has also explained the reason of the histopathological changes by high rate of OCP contamination in the Sakarya River. This fact also explains the high frequency of histopathological changes we have observed in the samples from Usakbuku station. Also, these histopathological changes were previously determined as the bio-monitors of the OCP compounds for the fish exposed to these contaminants in the laboratory conditions or in the contaminated areas (Sindermann, 1978; Hayes et al., 1990; Hinton et al., 1992; Ayas et al., 1997; Mora et al., 2001; Simpson et al., 2002; Wester et al., 2002). These previous histological findings are similar to what we have found in this work and is confirming our histological results. Ozmen et al. (2006) have found that microsomal EROD (ethoxyresorufin o-deethylase), GST (glutathion S-transferase), and CAT (carboxylesterase) enzyme activities increases in the fish due to OCP contamination in Karakaya Dam (East of Turkey). These enzymes were indicated as very useful biomarkers for environmental pollution. Using enzymatic parameters as biomarkers together with histological parameters is a very realistic approach and may be applied in Sariyar for future studies. It is observed that the histopathological changes are different for the three fish species studied. This can be explained by the fact that OCP accumulation is higher in the piscivorus organisms such as wels because of their feeding habits. In addition, OCP contaminants have a high affinity for the undissolved organic matter in the benthic zone and the organisms living in the benthos are more exposed to these contaminants (Larsson et al., 1992; Svobodov`a et al., 1995) The levels of OCP accumulation determined in carps are higher than in bleaks, but lower than in wels. This is due to

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the omnivorous feeding habits (generally with invertebrates, though they prefer plants) of carps and their habitat (benthos zone). As mentioned earlier, both wels and carps prefer to live in the benthos. Bleaks feed on small invertebrates and live in the epipelagic zone (Ekmekc¸i et al., 2000). It was determined that OCP accumulation in bleak samples taken from the reservoir is lower than the wels and carp. This is because of the fact that bleaks are not exposed to the contaminants in the benthos zone. The findings in this study indicate that chronically sub-lethal pollution may lead to changes in some histological indicators of wels and carps in this reservoir. Results showed that some OC compounds are still illegally used in the basin. The present data point to the necessity of a comparative monitoring of biochemical markers and pathological changes in the tissues, in order to use these histological parameters as indicators of organ dysfunction. Some of the biomarkers selected for this study are being used world wide in several pollution monitoring programs and thus they could be readily incorporated into future biomonitoring studies. On the other hand, there is a strong necessity for investigating the aquatic ecosystems in other parts of Turkey for monitoring and its effects on fish populations due to environmental pollution. Acknowledgements This study is a part of a comprehensive project that is supported by The Scientific and Technical Research Council of Turkey (TUBITAK). Authors wish to thank Agriculture, Forestry and Food Technologies Research Grant Committee of TUBITAK for their financial support of the project (Project no: TUBITAK, TARP-1846). References Ayas, Z., Barlas, N.E., Kolankaya, D., 1997. Determination of organochlorine pesticide residues in various environments and organisms in G¨oksu Delta, Turkey. Aquat. Toxicol. 39, 171–181. Barlas, N.E., 1999a. Determination of organochlorine pesticide residues in aquatic systems and organisms in upper Sakarya Basin, Turkey. Bull. Environ. Contam. Toxicol. A 62, 278–285. Barlas, N., 1999b. Histopathological examination of gill, liver and kidney tissues of carp (Cyprinus carpio L., 1758) fish in the upper Sakarya River Basin. Truck. J. Vet. Anim. Sci. B 23, 277–284. Boon, J.P., Lewis, W.E., Choy, M.R., Allchin, C.R., Law, R.J., de Boer, J., 2002. Levels of polybrominated diphenyl ether (PBDE) flame retardants in animals representing different trophic levels of the North Sea food web. Environ. Sci. Technol. 36, 4025–4032. ¨ ¨ C ¸ ok, I., Bilgili, A., Ozdemir, M., Ozbek, H., Bilgili, N., Burgaz, S., 1997. Organochlorine pesticide residues in human breast milk from agricultural regions of Turkey, 1995–1996. Bull. Environ. Contam. Toxicol. 59, 577– 582. de Boer, J., de Boer, K., Boon, J.P., 2000. Polybrominated biphenyls and diphenylethers. In: Paasivirta, J. (Ed.), The Handbook Of Environmental Chemistry. Part K, vol. 3. Springer-Verlag, Berlin, pp. 61–95. de la Torre, F.R., Ferrari, L., Salibi´an, A., 2005. Biomarkers of a native fish species (Cnesterodon decemmaculatus) application to the water toxicity assessment of a peri-urban polluted river of Argentina. Chemosphere 59, 577–583. ¨ Ekmekc¸i, F.G., Yerli, S.V., Ayas¸, Z., Ozmen, M., 2000. Report: the effects of pollution on fish in Sarıyar Dam Lake and its Tributaries. Project No: 1846;

Agriculture, Forestry and Food Technologies Research Grant Committee, T¨ubitak, The Scientific and Research Council of Turkey, Ankara. Erdogrul, O., Covaci, A., Schepens, P., 2004. Levels and distribution of organohalogenated contaminants in 5 fish species from Sır Dam Lake, Kahramanmaras¸,Turkey. Organohalogen Compd. 66, 1678–1683. Food and Agriculture Organization of The United Nations (FAO), 1984. Manuals of Methods in Aquatic Environment Research. Part 9. Analysis of Metals and Organochlorines in Fish. FAO Fisheries Technical Paper, 41 pp. Falandysz, J., Wyrzykowska, B., Strandberg, L., Puzyn, T., Strandberg, B., Rappe, C., 2002. Multivariate analysis of the bioaccumulation of polychlorinated biphenyls (PCBs) in the marine pelagic food web from the southern part of the Baltic Sea, Poland. J. Environ. Monit. 4, 929–941. Fisk, A.T., Hobson, K.A., Norstrom, R.J., 2001. Influence of chemical and biological factors on trophic transfer of persistent organic pollutants in the Northwater Polynya marine food web. Environ. Sci. Technol. 35, 732–738. F¨urst, P., 1993. Contribution of different pathways to human exposure to PCDDs/PCDFs. Organohalog Compd. 13, 1–8. Gurr, E., 1972. Biological Staining Methods. Kent Printers, Tonbridge, 143 pp. Hinton, D.E., Baumann, P.C., Gardner, G.R., Hawkins, W.E., Hendricks, J.D., Murchelano, R.A., Okihiro, M.S., 1992. Histopathological biomarkers. In: Huggett, R.J., Kimerle, R.A., Mehrle Jr., P.M., Bergman, H.L. (Eds.), Biomarkers: Biochemical, Physiological, and Histological Markers of Anthropogenic Stress. Lewis Publishers, Inc., Boca Raton, FL, pp. 155–209. Hinton, D.E., 1993. Toxicological histopathology of fishes: a systemic approach and overview. In: Couch, J.A., Fournie, J.W. (Eds.), Pathobiology of Marine and Estuarine Organisms. CRC Press, Boca Raton, FL, pp. 177–215. Hayes, M.A., Smith, I.R., Rushmore, T.H., Crane, T.L., Thorn, C., Kocal, T.E., Ferguson, H.W., 1990. Pathogenesis of skin and liver neoplasms in white suckers from industrially polluted areas in Lake Ontario. Sci. Total Environ. 94, 105–123. Jagoe, C.H., 1996. Responses at the tissue level: quatitative methods in histopathology applied to ecotoxicology. In: Newman, M.C., Jagoe, C.H. (Eds.), Ecotoxicology, A Hierarchial Treatment. Lewis Publishers, CRC Press, New York. Kolankaya, D., 2006. Organochlorine pesticide residues and their toxic effects on the environment and organisms in Turkey. Int. J. Anal. Chem. 86 (1–2), 147–160. Larsson, P.L., Collvin, L., Okla, L., Meyer, G., 1992. Lake productivity and water chemistry as governors of the uptake of persistent pollutants in fish. Environ. Sci. Technol. 26, 346–352. Lopes, P.A., Pinheiro, T., Santos, M.C., Mathias, M.L., Collares-Pereira, M.J., Viegas-Crespo, A.M., 2001. Response of antioxidant enzyme in freshwater fish populations (Leuciscus alburnoides complex) to inorganic pollutants exposure. Sci. Total Environ. 280, 153–163. Mackay, D., Fraser, A., 2000. Bioaccumulation of persistent chemicals: mechanisms and models. Environ. Pollut. 110, 375–391. Mdegela, R., Myburgh, J., Correia, D., Braathen, M., Ejobi, F., Botha, C., Sandvik, M., Skaare, J.U., 2006. Evaluation of the gill filament-based EROD assay in African sharptooth catfish (Clarias gariepinus) as a monitoring tool for waterborne PAH-type contaminants. Ecotoxicology 15, 51–59. Minier, C., Abarnou, A., Jaouen-Madoulet, A., Le Guellec, A.M., 2006. A pollution-monitoring pilot study involving contaminant and biomarker measurements in the Seine Estuary, France, using zebra mussels (Dreissena polymorpha). Environ. Toxicol. Chem. 25, 112–119. Mora, M.A., Papoulias, D., Nava, I., Buckler, D.R.A., 2001. Comparative assessment of contaminants in fish from four resecas of the Texas, USATamaulipas, Mexico border region. Environ. Int. 27, 15–20. Ozmen, M., G¨ung¨ord¨u, A., Kucukbay, F.Z., Guler, E.R., 2006. Monitoring the effects of water pollution on Cyprinus carpio in Karakaya Dam Lake, Turkey. Ecotoxicology 15, 157–169. Perktas, U., Ayas, Z., 2005. Birds of Nallihan Bird Paradise (Central Anatolia Turkey). Turk. J. Zool. 29, 45–59. Simpson, M.G., Walker, P., Helm, A., Leah, R., 2002. Histopathological observations on liver kidney and gonad of plaice (Pleuronectes platessa) taken from The Mersey estuary. Mar. Environ. Res. 54, 543–546. Sindermann, C.J., 1978. Pollution associated diseases and abnormalities of fish and shelfish: a review. Fish Bull. 76, 717–749.

Z. Ayas et al. / Environmental Toxicology and Pharmacology 23 (2007) 242–249 Sodergren, A., Wartiovaara, J., 1988. Methods for determination of organochlorine compound in water, sediment and biological samples. Water Sci. Technol. 20, 13–24. Solly, S.R.B., Shanks, V., 1969. Organochlorine insecticides in rainbow trout from three north island lakes. N. Z. J. Mar. Freshwater Res. 3, 585–590. Svobodov`a, Z., Piacka, V., Vykusov`a, B., M`achov`a, J., Hejtm`anek, M., Hrbkov`a, M., 1995. Residues of pollutants in Siluriformes from various localities of the Czech Republic. Acta Vet. BRNO 64, 195–208.

249

Teh, S.J., Adams, S.M., Hinton, D.E., 1997. Histopathologic biomarkers in feral freshwater fish populations exposed to different types of contaminant stress. Aquat. Toxicol. 37, 51–70. Wester, P.W., Ven, L.T., Vethaak, M., Grinwis, G.C.M., Vos, J.G., 2002. Aquatic toxicology; opportunities for enhancement through histopathology. Environ. Toxicol. Pharmacol. 11, 289–295.