Kalkan H; Sisman T; Kiliç D

Research Article

Austin J Environ Toxicol. 2015;1(1): 1004.

Assessment of Heavy Metal Bioaccumulation in Some Tissues of Leuciscus Cephalus from Karasu River, Erzurum-Turkey

Kalkan H¹, Sisman T¹* and Kiliç D¹

¹Department of biology, University of Maribor, Slovenia

²Agricultural Institute of Slovenia, Slovenia

*Corresponding author: Sisman T, Department of Biology, Science Faculty, Atatürk University, 25240 Erzurum, Turkey

Received: September 29, 2014; Accepted: February 16, 2015; Published: February 18, 2015

Abstract

Karasu River, the only river in the Erzurum plain, is the source of Euphrates River (Eastern Anatolia of Turkey). It is considered that artificial fertilizers, pesticides, municipal sewage, industrial and factory wastes are polluted the Karasu River. The pollution in the river also threatens the Euphrates basin. Fish live in direct contact with their immediate external environment. Therefore, fish are frequently used to determinate the aquatic pollution. In this study, we aim to determine concentrations of metals such as Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Hg and Pb on liver, muscle and gill tissues of Leuciscus cephalus (chub) which was obtained from the selected two points (Dumlu and Askale) on Karasu River. The heavy metals were measured by ICP-MS (Inductively Coupled Plasma-Mass Spectrometer). The concentrations of heavy metals in tissue of fish from the Askale site were significantly higher than those from the Dumlu site. High levels of metals were found in the gills in fish from Askale site. These results show that the concentrations are below the limits for fish proposed by Turkish Food Codex, FAO/WHO and EC, and safe within the limits for human consumption in the edible parts of fish species in the region.

Keywords: Heavy metals; Karasu River; Pollution; Leuciscus cephalus; Health risk

Introduction

There are countless pollutants in the surface waters and sediment that are compromising the survival of the organisms, altering their physiologies or giving rise to carcinogenesis. Consequences caused by these pollutants may remain recessive for several generations or may exhibit major effects in the population. Pollution in the aquatic environment causes multiple damages in the organisms, at the level of population and ecosystem, as in organ function, reproductive performances and biological diversity [1]. In aquatic environments, particularly industrial and domestic wastes discharged without being treated, are the source of heavy metals [2]. The increasing of heavy metal contamination in aquatic systems and decreasing sediment quality may cause toxicity in freshwater ecosystems [3]. The toxicity of metals depends on the metal type and concentration, the period of exposure and other factors. Also, metals join in the food chain and are responsible for adverse effects and death in the aquatic organisms [4]. In addition to this contamination causing an adverse effect on aquatic biota, the metallic contaminants can be ingested by humans through consumption of the seafood products [5].

In some areas of the world, aquatic organisms, especially fish, are the most important sources of protein in the human diet. Fish are widely being used for evaluating the quality of the aquatic environment and as bioindicators of environmental pollution [6,7]. Fish have also been used extensively to study the physiological behavior of heavy metals in body organs [8]. The concentration of metals is a function of species, and metals accumulate more in some fish tissues than in others [9]. Different tissues of fish species have different bioaccumulation capacities [10]. The sampling location and season, as well as diet preferences and fish size may influence the level of bioaccumulation in the same fish species [11]. Liver and gills, as metabolically active organs, are target organs for metal accumulation [12], while the accumulation in muscle tissue is lower [13]. The concentrations of metals in the organs of fish are governed primarily by the level of pollution in the water and food and so are indicative of the level of pollution in the environment [14]. Furthermore, ecological needs, gender, size and seasonal changes can affect metal accumulation in different tissues of fish [15,16].

The Karasu River, which is the only river in Erzurum plain, is the source of the famous river Euphrates. The river is also an important tributary of the Tigris River and has been polluted substantially with sewage water and effluent wastes of slaughterhouses, fat, sugar and cement factories. Hence, mass fish deaths have been occurred twice in the past 10 years [17]. The pollution in the Karasu River also threatens the Euphrates basin. Leuciscus cephalus (chub) is fish species belonging to the Cyprinidae family. Although the fish can be found in the upper zones of the Tigris and Euphrates rivers, they live mainly in the upper regions of Karasu River [18]. In this study, chub is used as a bioindicator for monitoring the aquatic environment because the fish is abundant at Karasu River.

Over the last decades, there has been interest in determining metal contents in fresh water environment, and attention was drawn to the measurement of pollution in public food supply especially fish. Several reliable analytical methods were available for monitoring metal levels in fresh water and marine food samples, but Inductively Coupled Plasma Mass Spectrometer (ICP-MS), being the most sophisticated and reliable technique was widely used for determination and quantification of trace metals in food samples [19]. The present study was undertaken to determine the concentrations of selected metals (Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Hg and Pb) in the surface water and liver, muscle, and gill tissues of Leuciscus cephalus (chub) from the selected two sites (Dumlu and Askale) on Karasu River.

Materials and Methods

The Karasu River is located in the Eastern Anatolia region of Turkey (Erzurum) and drains an area of approximately 1642 km2 and joins the Euphrates River. At the upper section of the river, various industrial activities, like textile dyeing, cement and sugar factories release their waste into the river. Due to the extended domestic and industrial activities, various pollutants reach the river at different points and potentially change the water quality. Two sampling sites were selected in the Karasu River, with different levels of chemical impact (Figure 1). Firstly, an impacted site was Askale site located approximately 80 km further downstream which is a heavily contaminated tributary collecting industrial effluent. Dumlu site relatively uncontaminated location was used as control, another tributary of the Karasu River. All located inside the city provinces of Erzurum. Askale site at near the Askale district shows strong anthropogenic influence, receiving domestic, agricultural and industrial effluents. The site is 58-km outside the Erzurum city.

The coordinates of sampling Dumlu site are 40o 01' 52K, 41° 18' 49D and that of sampling Askale site are 38o 22' 33K, 36o 58' 26D (Figure 1).

Figure 1: Map of Erzurum city and the basin of the Karasu River showing the two sampling sites.

    
    
    Figure 1:  Map of Erzurum city and the basin of the Karasu River showing the two sampling sites.

From May to August 2012, a total number of 56 fish species (28 fish from each site) were collected. The fish were carried live to the laboratory in tanks filled with water obtained from the sites where the fish were caught. The wet weight and total body length of the fish were measured (61,68 ± 12,2 - 58,15 ± 5,8 g; 19,25 ± 3,0 - 17,75± 1,2 cm). Liver muscle and gill samples were quickly removed, rinsed with distilled water, and stored at -18oC prior to analysis. We confirm that all procedures were performed in compliance with the relevant laws and institutional guidelines, ant that the appropriate institutional committees have approved them.

Water samples were collected from a depth of 0.5 m below the surface into clean 1-l polyethylene bottles by means of a Nansen Sampler. The water temperature, electrical conductivity, dissolved oxygen, and pH were measured in situ. Then, 1 ml of 0.5% HNO₃ was added to acidify the water samples. The samples preservation and analyses were made following the American Public Health Association and the American Water Works Association standard methods [20].

Frozen liver, muscle and gill samples were dried using freeze dryer and homogenized. A temperature-controlled microwave heating device was used for digestion of the dried fish tissues. Sample preparation was carried out according to the procedure described by Uluozlu [21]. Approximately 0.5 g of homogenized samples were taken and placed in a Teflon digestion vessel with 3 mL of ultrapure HNO3 and 1 mL of Hydrogen Peroxide (H₂O₂). Sealed containers were placed in a microwave oven and heated according to the digestion program. After digestion, sample solutions were cooled to room temperature then transferred quantitatively into acid cleaned 25 mL standard volumetric flasks and made up to 25 mL with double distilled deionized water and prepared under the same conditions as the calibration standards in 6% (v/v) HNO3. Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Hg and Pb in fresh water fish were analyzed using ICP-MS (PerkinElmer Élan 9000 USA). Heavy metals in the fish samples were successively extracted as the acid soluble fraction, reducible fraction and oxidizable fraction. The residual fraction was determined by the mass balance between the total and the nonresidual fractions. For Quality Assurance/Quality Control (QA/QC) purposes, digestion of procedure blanks, duplicates of 10% sample load. For better operating conditions the ICP-MS was adjusted to nebulizer gas flow 0.91 L/min, radio frequency 1200W, lens voltage 1.6V, cool gas 13.0 L/min, and auxiliary gas 0.70 L/min [22]. All data were tested using normality and equal variance tests. Parametric and nonparametric tests were performed to determine whether there were any significant differences in metal concentrations between the sampling sites. Statistical significance was set to a level of 5% (p<0.05). Statistical analyses were performed using the SPSS 15.0 software. Additionally, concentrations of metals in fish samples were evaluated and compared with permitted limits set by Turkish Food codex (TFC), Food and Agricultural Organization (FAO), and European Commission (EC) [23, 24, 25]. All data were expressed in microgram per gram dry weight.

Results and Discussion

The water quality of the sampling sites was evaluated by comparing the results of some metal concentrations. Regarding total metal concentrations, higher values were recorded in the Askale site than in the Dumlu site water course for all the elements analyzed (Table 1). Zn, Al, Co, Pb, and As concentrations surpassed the benchmark values for surface waters provided by SWECO databases [26]. Water samples from the Karasu River showed different concentrations and accumulation levels of metallic contaminants. The concentration of Al was highest and Hg lowest in water samples. In all cases, these concentrations were higher than those recommended for drinking and irrigation purposes. As seen in Table 1, the metal concentrations in water were higher than those recommended by SWECO for surface waters [26]. Metal concentrations in the muscle, liver and gills of Leuciscus cephalus are presented tables 2-3, which include mean concentrations with associated standard deviations results from other studies and guidelines, and background levels. Each individual metal displays a wide variation in concentration, as reflected by the large standard deviation values. Due to variations within each element, mean concentration might be significantly affected via the extremely high or low values. In Table 2, mean element concentrations for Leuciscus cephalus tissue samples are presented. The Kruskal-Wallis test (a nonparametric test) revealed significant differences between sites with regard to element levels in liver for Mn, Fe, Ni, Cu, Cd, and Pb (p<0.05), in muscle for Cr, Fe, As, Cd, and Pb (p<0.05), and gills for Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Hg and Pb (p<0.05). For the liver, this test showed that Askale site fish had significantly higher levels of Mn, Fe, Ni, Cu, Cd, and Pb, compared to Dumlu site fish. For muscle, this test showed that Askale site chub had statistically different levels of Cr, Fe, As, Cd, and Pb, compared to Dumlu site. Askale site fish had a statistically higher level of all tested elements in gills than Dumlu site fish. The element analyses showed that fish from Askale site had statistically high levels of all tested elements. There was metal accumulation in the gills compared to muscle and liver tissues. We also found that Zn had the highest metal concentration in gills of Askale site fish (35.9±0.18 μg/g).

Table 1: Means and standard deviation of some metals in water from the sites (μg/L).




  
    Metals 
    Dumlu site 
    Askale site 
  
  
    Al
    192.10±22.22
    287.8±51.22
  
  
    Cr
    0.84±0.04
    0.85±0.04
  
  
    Mn
    18.9±1.5
    24.42±1.22
  
  
    Fe
    1.65±0.86
    1.75±0.17
  
  
    Ni
    37.33±10.23
    88.78±15.01
  
  
    Cu
    0.9±0.05
    0.82±0.04
  
  
    Zn
    0.59±0.06
    0.68±0.01
  
  
    As
    2.90±0.22
    3.28±0.62
  
  
    Cd
    0.03±0.01
    0.04±0.01
  
  
    Hg
    0.02±0.01
    0.04±0.01
  
  
    Pb
    0.25±0.01
    0.56±0.02



Table 1:  Means and standard deviation of some metals in water from the sites (μg/L).

Statistically, significance analysis was performed between Dumlu and Askale site (Table 2). In general, the concentration differences two sites in tissues of fish were small. The subtle differences of concentration in gill, liver and muscle were reflected in the relatively small difference in the pollution ratios of two sites. In addition, the results show that the metal accumulation in tissues of Leuciscus cephalus indicates resembling variation between two sites, therefore, we conclude that there is no heavy metal adding source in Dumlu site.

Table 2: Concentration of metals (in microgram per gram) in tissues of Leuciscus cephalus from Karasu River.




  
    Metals (�g/g)
    Tissues
    Dumlu site
    Askale site
  
  
    Al
    Liver
    6.73±0.07^{A, a}
    6.26±0.063^{B, a}
  
  
     
    Muscle
    0.74±0.19^{B, a}
    0.73±0.025^{C, a}
  
  
     
    Gill
    0.03±0.01^{C, b}
    14.83±0.47^{A, a}
  
  
    Cr
    Liver
    0.06±0.01^{A, a}
    0.05±0.01^{A, a}
  
  
     
    Muscle
    0.01±0.00^{B, b}
    0.04±0.01^{A, a}
  
  
     
    Gill
    0.02±0.00^{B, b}
    0.07±0.01^{A, a}
  
  
    Mn
    Liver
    0.25±0.01^{B, b}
    0.4±0.01^{B, a}
  
  
     
    Muscle
    0.38±0.01^{B, a}
    0.3±0.01^{B, a}
  
  
     
    Gill
    1.32±0.02^{A, b}
    11.33±0.14^{A, a}
  
  
    Fe
    Liver
    19.47±0.31^{A, b}
    21.15±0.12^{B, a}
  
  
     
    Muscle
    3.08±0.05^{B, b}
    4.03±0.04^{C, a}
  
  
     
    Gill
    8.02±0.1^{B, b}
    31.68±0.26^{A, a}
  
  
    Ni
    Liver
    0.03±0.01^{A, b}
    0.06±0.01^{B, a}
  
  
     
    Muscle
    0.05±0.01^{A, a}
    0.04±0.01^{B, a}
  
  
     
    Gill
    0.06±0.02^{A, b}
    0.44±0.04^{A, a}
  
  
    Cu
    Liver
    1.3±0.03^{A, b}
    2.76±0.08^{A, c}
  
  
     
    Muscle
    0.12±0.01^{B,    a}
    0.14±0.03^{B, a}
  
  
     
    Gill
    0.11±0.01^{B,    b}
    0.52±0.03^{B, a}
  
  
    Zn
    Liver
    4.54±0.1^{B,    a}
    3.43±0.03^{B,    a}
  
  
     
    Muscle
    3.30±0.06^{B,    a}
    2.45±0.09^{B, a}
  
  
     
    Gill
    11.47±0.3^{A,    b}
    35.9±0.18^{A, a}
  
  
    As
    Liver
    0.03±0.01^{A,    a}
    0.03±0.01^{B, a}
  
  
     
    Muscle
    0
    0.03±0.00^B
  
  
     
    Gill
    0.01±0.00^{A,    b}
    0.23±0.04^{A, a}
  
  
    Cd
    Liver
    0
    0.002±0.00^A
  
  
     
    Muscle
    0
    0.002±0.00^A
  
  
     
    Gill
    0
    0.003±0.00^A
  
  
    Hg
    Liver
    0.03±0.00^{B,    a}
    0.04±0.00^{B, a}
  
  
     
    Muscle
    0.03±0.00^{B,    a}
    0.02±0.00^{B, a}
  
  
     
    Gill
    0.3±0.01^{A,    b}
    0.68±0.01^{A, a}
  
  
    Pb
    Liver
    0
    0.001±0.00^C
  
  
     
    Muscle
    0
    0.01±0.00^B
  
  
     
    Gill
    0
    0.5±0.02^A
  
  
    Al: aluminum; Cr: chromium; Mn: manganese; Fe: iron; Ni: nickel; Cu:    copper; Zn: zinc; As: arsenic; Cd: cadmium; Hg: mercury; Pb: lead. 
  
  
    *Vertically letters �A, B and C" show differences among tissues for    the same site fish (p<0.05). Horizontally, letters �a and b" show    differences among sites for the same tissues (p<0.05).



Table 2:  Concentration of metals (in microgram per gram) in tissues of Leuciscus cephalus from Karasu River.

In Table 3, maximum metal concentrations for Leuciscus cephalus two tissue samples and Maximum Acceptable Concentrations (MAC) in some guidelines are presented. The levels of Fe, Ni, Cr, Mn, As, Cu, Hg, Zn, Cd, and Pb did not exceed the MAC prescribed by the National Regulation of Turkey (Turkish Food Codex, 2002) in any of the muscle and liver samples. Furthermore, the levels of Ni, Cr, Mn, Cu, Zn, Cd and Pb did not exceed the MAC prescribed by TFC, FAO/WHO and by the EC. (Table 3). Fish have high protein content, low saturated fat and also contain omega fatty acids. However, fish accumulate contaminants from aquatic environment and therefore, they have been extensively used in pollution monitoring systems of the aquatic environment [27]. Previous studies have shown that target organs such as gonad, gill and muscle have a tendency to accumulate heavy metals at higher rates in many species of fish from different geographical areas [7,16]. Metals accumulate in the tissues of fish and thus metals determined in the tissues of fish can reflect the past exposure [28]. Levels of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Hg and Pb in liver, gills and muscle of Leuciscus cephalus caught in the Karasu River are presented in the current study. Accumulation trend of metals in Leuciscus cephalus is mostly in gills.

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Citation: Kalkan H, Sisman T and Kiliç D. Assessment of Heavy Metal Bioaccumulation in Some Tissues of Leuciscus Cephalus from Karasu River, Erzurum-Turkey. Austin J Environ Toxicol. 2015;1(1): 1004. ISSN:2472-372X

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Assessment of Heavy Metal Bioaccumulation in Some Tissues of Leuciscus Cephalus from Karasu River, Erzurum-Turkey

Abstract

Introduction

Materials and Methods

Results and Discussion

0.12±0.01^{B, a}

0.11±0.01^{B, b}

4.54±0.1^{B, a}

3.43±0.03^{B, a}

3.30±0.06^{B, a}

11.47±0.3^{A, b}

0.03±0.01^{A, a}

0

0.03±0.00^B

0.01±0.00^{A, b}

0

0

0

0.03±0.00^{B, a}

0.03±0.00^{B, a}

0.3±0.01^{A, b}

0

0

0

Conclusion

Acknowledgement

References

	Fe	Ni	Cr	Mn	As	Cu	Hg	Zn	Cd	Pb
This study
Liver	21.15	0.06	0.05	0.4	0.03	2.76	0.04	3.43	0.002	0.001
Muscle	4.03	0.04	0.04	0.3	0.03	0.14	0.02	2.45	0.002	0.01
Turkish Guidelines^a	50	-	-	20	1.0	20	0.5	50	0.1	0.1
Tolerance level in fish^b	-	0.4	0.15	2.5	-	30	-	30	0.5	0.5
European Commision^c	-	-	-	-	-	-	-	-	0.05	0.3
^aTurkish Food Codex (2002)
^bFAO/WHO (1989)
^cEC (2006)
(-) means that no values were presented in the standards.

Assessment of Heavy Metal Bioaccumulation in Some Tissues of Leuciscus Cephalus from Karasu River, Erzurum-Turkey

Abstract

Introduction

Materials and Methods

Results and Discussion

0.12±0.01B, a

0.11±0.01B, b

4.54±0.1B, a

3.43±0.03B, a

3.30±0.06B, a

11.47±0.3A, b

0.03±0.01A, a

0

0.03±0.00B

0.01±0.00A, b

0

0

0

0.03±0.00B, a

0.03±0.00B, a

0.3±0.01A, b

0

0

0

Conclusion

Acknowledgement

References

0.12±0.01^{B, a}

0.11±0.01^{B, b}

4.54±0.1^{B, a}

3.43±0.03^{B, a}

3.30±0.06^{B, a}

11.47±0.3^{A, b}

0.03±0.01^{A, a}

0.03±0.00^B

0.01±0.00^{A, b}

0.03±0.00^{B, a}

0.03±0.00^{B, a}

0.3±0.01^{A, b}