Polychlorinated biphenyls in fish from Black Sea, Bulgaria

Polychlorinated biphenyls in fish from Black Sea, Bulgaria

Food Control 72 (2017) 205e210 Contents lists available at ScienceDirect Food Control journal homepage: www.elsevier.com/locate/foodcont Polychlori...

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Food Control 72 (2017) 205e210

Contents lists available at ScienceDirect

Food Control journal homepage: www.elsevier.com/locate/foodcont

Polychlorinated biphenyls in fish from Black Sea, Bulgaria Mona Stancheva, Stanislava Georgieva*, Lubomir Makedonski Department of Chemistry, Medical University e Varna, Marin Drinov 55, 9002 Varna, Bulgaria

a r t i c l e i n f o

a b s t r a c t

Article history: Received 27 April 2015 Received in revised form 28 April 2016 Accepted 4 May 2016 Available online 7 May 2016

Polychlorinated biphenyls (PCBs) were measured in muscle tissue of six marine fish species: sprat (Sprattus sprattus sulinus), grey mullet (Mugil cephalus), bluefish (Pomatomus saltatrix), turbot (Psetta maxima), red mullet (Mullus barbatus) and garfish (Belone belone). Samples were collected from different parts of Bulgarian Black Sea coast. The PCBs were analyzed in order to evaluate the status of pollution in Bulgarian Black Sea coastal area and to assess the dietary intake through fish consumption. The PCBs (including Indicator and dioxin-like PCBs) were determined by capillary gas chromatography system with mass spectrometry detection. Total PCBs were found in all fish species at concentrations ranging between 134.2 ng/g lipid weight (lw) in bluefish and 571.9 ng/g lw in turbot. The sum of the six Indicator PCBs ranged from 100.3 to 453.8 ng/g lw (in bluefish and turbot, respectively). Dioxin e like PCBs were used in order to estimate the toxicity potential (TEQs) of PCB exposure. TEQs of the 6 “dioxinelike” PCB congeners were calculated from 0.04 pg TEQ/g wet weight (ww) (turbot) to 0.14 pg TEQ/g ww (bluefish) and did not exceed the limit of 3 pg TEQ/g ww, according to European Commission. The experimental results for PCBs in fish species from different sampling sites showed no significant differences between the North, Varna and South coast sampling area. The levels of PCBs in marine fish from Bulgarian Black Sea were found lower than those reported from the other regions. Estimated dietary intake of polychlorinated biphenyls through the analysed marine species does not seem to pose a health risk. © 2016 Elsevier Ltd. All rights reserved.

Keywords: PCBs TEQs Fish Dietary intake Black Sea Bulgaria

1. Introduction Polychlorinated biphenyls (PCBs) are lipophilic contaminants, very persistent, widely distributed in the environment and can be accumulate in aquatic organisms. PCBs are transported by air all over the world, because they are driven by temperature and their volatility (Gouin et al. 2005). Although these contaminants are present in the water at low levels, they could be bioconcentrate in aquatic organisms and bioaccumulate to the higher levels in the food chain, especially in predatory fish. The contamination of PCBs is a significant health problem because they can cause several adverse effects to human health and wildlife survival (Falandysz et al. 2004; Fisk, Hobson, & Norstrom, 2001). In biological systems, several of these chemicals are potentially carcinogenic and may cause alterations in endocrine, reproductive and nervous systems (Langer et al. 2003). For these reasons, most countries have restricted the use of PCBs since 1970s. Some of PCBs are classified as dioxin-like PCBs (dl-PCB), they show a similar

* Corresponding author. E-mail address: [email protected] (S. Georgieva). http://dx.doi.org/10.1016/j.foodcont.2016.05.012 0956-7135/© 2016 Elsevier Ltd. All rights reserved.

toxicity as polychlorinated dibenzodioxins and polychlorinated furans. The dl-PCBs are used in order to estimate the toxicity potential of PCB exposure as toxic equivalency (TEQ). TEQ is defined by the sum of the concentration of each dl-PCB congener in a mixture multiplied by its toxic equivalency factors (TEF), developed by the World Health Organization (WHO-TEF) (Van den Berg et al. 2006). The risk assessment of PCBs in fish for human diet is important and necessary (Binelli & Provini, 2003; Smith & Gangolli, 2002). In most cases, dietary intake is the major source of the total human exposure to PCBs (European Commission, 2000; Smith & Gangolli, 2002). It has been reported that meat, dairy products and fish, makes up more than 90% of the intake of PCBs for the general population (Schecter, Cramer, Boggess, Stanley, & Olson, 1997; , & Llobet, 2007; Zhang et al. 2012.) Bocio, Domingo, Falco The objectives of this study were to determine the levels of PCB congeners in six fish species from different sites in the Black Sea along the coast of Bulgaria and to estimate the intake of PCBs through dietary consumption of fish.

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turbot) contained approximately between 5 and 10 individuals. Number of samples (n) is presented in Table 1. The length and weight of each specimen were measured and they were rinsed with distilled water to remove sand and impurities.

2. Materials and methods 2.1. Sampling and sample preparation Samples were caught by local professional fishermen by net from 2007 to 2011. The sampling strategy allows covering the entire Bulgarian Black Sea coast and includes three important fishing regions: North (near cape Kaliakra, Krapec and Balchik), Varna Bay and South (Bourgas, Nessebar). The map of the study area is presented on Fig. 1. The sampling campaigns took place during SeptembereNovember in every year. The samples were transferred immediately to the laboratory in foam boxes filled with ice and were stored in a freezer (20  C) until analysis. The fish species were selected according to their characteristic feeding behaviour and importance to human consumption in Bulgaria: sprat (Sprattus sprattus sulinus), grey mullet (Mugil cephalus), bluefish (Pomatomus saltatrix), turbot (Psetta maxima), red mullet (Mullus barbatus) and garfish (Belone belone). Each sample was prepared from edible tissue of several individuals. The fish tissues were homogenized using a blender; pools of about 300 g were made for every sample. The samples of small species (sprat, red mullet) were comprised 15e20 individuals and samples of bigger species (bluefish, grey mullet, garfish and

2.2. Analytical methods Twenty grams of homogenized fish tissue were mixed with 100 g of anhydrous sodium sulfate and was extracted with hexane/ dichloromethane (3/1, v/v) in Soxhlet Extractor. Each sample was spiked with internal standards PCB 30 and PCB 204. The solvent was carefully evaporated and the lipid content was determined gravimetrically of an aliquot of the extract (1/5th). The extract was cleaned-up on a glass column (10  250 mm) packed with 2 g neutral silica, 4 g acid silica and 2 g neutral silica (Merck KGaA, Darmstadt, Germany). PCBs and DDTs were eluted with 80 ml nhexane followed by 50 ml n-hexan/dichloromethane (80:20) (Sigma-Aldrich Chemie, Taufkirchen, Germany). The eluates were concentrated to near dryness and reconstituted in 0.5 ml in hexane. One micro liter of purified extract was injected into GC/MS. Gas chromatographic analysis of PCBs were carried out by GC FOCUS (Thermo Electron Corporation, Austin, Texas, USA) using POLARIS Q Ion Trap mass spectrometer and equipped with an AI

Fig. 1. Black sea map and sampling area.

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Table 1 Concentrations of Indicator PCBs (ng/g lipid weight, mean values and standard deviation) determined in fish collected from the Black Sea. Species

Area

n

Lipids, %

Sprat

North Varna South North Varna South North Varna South North Varna South North Varna South North Varna South

8 6 8 7 6 6 6 5 6 3 3 4 7 5 6 4 6 7

3.7 5.4 6.2 9.6 6.4 9.2 20.7 19.5 17.9 1.6 1.5 1.7 14.3 17.0 17.5 8.8 9.6 7.2

Grey mullet

Bluefish

Turbot

Red mullet

Garfish

± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

0.3 0.4 0.4 0.6 0.4 0.5 1.7 1.4 1.6 0.2 0.2 0.3 1.4 1.5 1.7 0.9 1.2 0.8

PCB 28

PCB 52

PCB 101

PCB 138

17.8 ± 5.8 13.9 ± 3.9 26.7 ± 7.3 19.6 ± 5.8 19.9 ± 6.2 16.9 ± 5.1 9.5 ± 2.6 4.4 ± 1.3 6.6 ± 1.7 <0.2 <0.2 43.8 ± 13.2 16.2 ± 4.8 <0.2 19.9 ± 6.3 27.2 ± 8.5 8.7 ± 2.9 19.5 ± 6.1

17.5 ± 6.2 16.8 ± 5.6 19.1 ± 6.6 19.8 ± 7.1 15.9 ± 5.8 10.7 ± 3.2 6.5 ± 1.5 4.5 ± 1.3 10.6 ± 2.9 23.9 ± 7.1 <0.2 <0.2 <0.2 <0.2 9.4 ± 2.9 25.1 ± 7.5 8.0 ± 2.1 17.6 ± 6.3

19.8 ± 6.0 18.0 ± 5.2 25.2 ± 7.7 24.9 ± 7.1 16.5 ± 4.8 9.2 ± 2.8 11.0 ± 3.1 14.9 ± 4.8 11.1 ± 3.1 55.3 ± 16.2 55.9 ± 14.7 24.6 ± 7.9 <0.2 <0.2 <0.2 30.2 ± 9.2 8.5 ± 2.5 21.1 ± 6.5

58.7 36.0 70.1 61.8 33.6 21.1 24.8 28.9 28.3 176.4 155.3 60.0 25.3 45.9 43.0 74.0 35.4 77.2

± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

PCB 153 18.9 13.5 23.8 21.2 12.1 6.9 6.9 7.8 8.8 61 52 22.6 8.1 14.8 13.9 24.8 12.2 26.3

61.8 48.5 74.4 67.0 48.0 20.7 39.4 32.7 28.1 174.8 265.4 67.4 46.2 54.0 87.7 80.1 53.2 76.4

± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

PCB 180 19.5 16.9 24.6 31.2 15.7 6.7 12.1 10.2 8.3 57 80 30 15.1 17.2 26 23.5 16.3 26.7

52.4 24.1 41.1 37.3 26.9 19.8 14.2 13.6 11.8 98.2 112.2 48.5 28.0 43.8 37.0 31.5 25.5 37.5

± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

16.3 6.5 13.5 13.8 7.1 5.3 4.9 3.8 3.6 29.6 35 15.1 8.6 13.5 12.9 10.8 8.0 11.8

n e number of samples.

3000 autosampler. Experimental MS parameters are the following: the Ion source and Transfer line temperatures were 220  C and 250  C, respectively. The splitless Injector temperature was 250  C. The PCBs experimental temperature program was 90  C for 1 min,    then programmed 30 C/min to 180  C, 2 C/min to 270  C, 30s C/ min to 290  C with a final hold for 3.0 min. Splitless injections of 1 ml were performed using a TR-5MS capillary column (Bellefonte, PA, USA) coated with cross-linked 5% phenyl methyl siloxane with a length of 30 m, 0.25 mm ID and a film thickness of 0.25 mm. Helium was applied as carrier gas at a flow of 1 ml/min. The selectivity of the ITeMS (Ion Trap masspectrometry) method was based on the appropriate selection of parent ions for the detection of each analyte by mass spectrometry extracted ion mode. Pure reference standard solutions (PCB Mix 20 e Dr. Ehrenstorfer Laboratory, Augsburg, Germany), were used for instrument calibration, recovery determination and quantification of compounds. Measured compounds were: 15 PCB congeners: IUPAC No 28, 31, 52, 77, 101, 105, 118, 126, 128, 138, 153, 156, 169, 170, 180. The isomers PCB 28 and 31 were co-eluted by these GC column 5MS. The results were presented like sum of their concentrations. The sum of all 15 measured congener concentrations is referred below as SPCBs. The concentrations of the individual “dioxin-like” PCBs (dl-PCB, UPAC No 77, 105, 118, 156, 126, 169) in a sample are multiplied by their respective TEF and subsequently summed to give total concentration of dioxin-like compounds expressed in TEQs (Van den Berg et al. 2006). Each sample was analyzed three times and was taken an average of the results obtained. The limits of quantification (LOQ) varied for individual PCBs from 0.2 to 0.5 ng/g lw.

2.3. Quality control The quality control was performed by regular analyses of procedural blanks and certified reference material BB350 (PCBs in Fish oil) e Institute for Reference Materials and Measurements, European Commission. Recovery of PCBs from certified reference material varied in the range 85e109% for individual congeners. Procedural blanks and a spiked sample with standards were analyzed between each 5 samples to monitor possible laboratory contamination. Blanks did not contain traces of contaminants.

2.4. Statistical analysis The statistical analysis of the data was based on the comparison of average values by a t-test and a significance level of p < 0.05 was used. All statistical tests were performed using SPSS 16 software. 2.5. Dietary intake estimation On the basis of the measured concentrations in the shellfish samples, the daily dietary intake of PCBs and OCPs was calculated using the following equation:

EDI ¼ C  Intake =BW where EDI is the estimated daily intake (ng/kg body wt./day), C is the average of measured PCBs (ng/g wet wt.), intake is the daily food consumption of fish (13.2 g/day for Bulgarian standard adult (NSI, National Statistical Institute, 2010) and BW is the average body weight (70 kg for adult men). 3. Results and discussion 3.1. PCBs levels The PCBs load of each fish was estimated on the basis of the six Indicator congeners (PCBs: IUPAC 28, 52, 101, 138, 153 and 180) recommended by the European Union for assessing the pollution by PCBs (EU, 1999). The lipid content and mean concentrations of Indicator PCB congeners in investigated fish species from the Black Sea coast of Bulgaria are shown in Table 1. The lipid percentage ranged from 1.5% in turbot to 20.7% in bluefish. The lipids in fish tissue are influenced by several factors, such as sex, age, species, nourishment and spawning status (Voorspoels, Covaci, Maervoet, De Meester, & Schepens, 2004). The PCB pattern found in fish showed a predominance of PCB 153, 138, 180 and 118 may be related to their high lipophilicity, stability and persistence in the aquatic ecosystem. PCB 153 was the dominant congener in all investigated species and was found from 20.7 ng/g lw in grey mullet to 265.4 ng/g wl in turbot. The predominance of hexachlorinated PCBs in marine fish species, especially PCB 153 and PCB 138, has been reported by several authors for different coastal areas in the Mediterranean Sea (Naso, Perrone, Ferrante, Bilancione, & Lucidano, 2005; Stefanelli et al. 2004), in

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the Adriatic Sea (Bayarri, Baldassarri, Iacovella, Ferrara, & di Domenico, 2001; Perugini et al. 2004) and in Marmara Sea (Coelhan, Stroheimer, & Barlas, 2006). Fig. 2 show average distribution pattern of individual I-PCB. The sum of the six indicator congeners (Sum I-PCBs) ranged from 96.5 ng/g lw (bluefish, South) to 588.6 ng/g lw (turbot, Varna) e Fig. 3. Total I-PCBs concentrations were almost the double in grey mullet coming from North compared to the ones found in samples coming from South (p < 0.05). The experimental results for grey mullet and turbot showed that North and Varna sampling area were generally more polluted with PCBs than South, possibly due to historical discharges from the Danube River into the Black Sea (Zhulidov et al., 2003). With regard to the I-PCBs, no significant differences were found in bluefish, sprat, red mullet and garfish coming from different sampling area (p > 0.05). Fish species studied do not present any trend in the geographical variations and cannot be used to assess the sources of pollution. Statistically significant differences in the concentrations of contaminants were observed between the three catchment areas only for grey mullet and turbot. The northern area appears more contaminated by PCBs than South. The percent distribution of total determined I-PCB among the geographical areas is 38%, 33% and 29% for North, Varna and South, respectively. The mean levels of I-PCBs (average of the three fishing regions) ranged between 100.3 ng/g lw (bluefish) and 453.8 ng/g lw (turbot), calculated as the sum of 6 Indicator PCB congeners. The differences in concentrations of PCBs may be attributable to various factors such as the nature of the habitat, feeding preferences and lipid contents. The statistical test indicated that the levels of PCBs found in turbot were significantly higher than those detected in bluefish (p < 0.05). The higher levels of PCBs in turbot compared to other fish species may be due to its feeding behavior e turbot is a predator species that feed mainly on other bottom-living fish. Actually, in marine organisms, habitat and geographical origin are also important aspects that explain accumulations and pollutants elimination (Bodiguel et al., 2009). Bluefish and horse mackerel migrate from the Marmara Sea into the Black Sea in summer. This behavior makes interpreting contaminant levels in migratory fish difficult regarding different geographical environments. Consequently, these two species could not be expected to offer a reliable picture of the level of pollution at the site where they are caught. The European Union has recommended a maximum level of 75 ng/g wet weight, calculated as the sum of the six I-PCBs in muscle meat of fish (European Commission, 2011). The sum of IPCB congeners was expressed also on a wet weight basis (ng/g ww) in order to compare our results with European maximum level e Fig. 4. Our results for Sum of I-PCBs in all fish species did not exceed this limit. Concentrations of dioxin-like PCBs are presented on wet weight basis (Table 2), because they are used to calculate the toxic equivalents (TEQ). From the ‘‘dioxin-like’’ congeners analysed, PCB118

Fig. 2. Distribution pattern of individual I-PCB in marine fish species from Black Sea coast of Bulgaria.

Fig. 3. Total contents of I-PCBs in fish species from three sampling areas in the Black Sea coast.

Fig. 4. The sum of the six I-PCBs (ng/g ww, mean values) in fish species from the Black Sea.

was the most abundant one. The toxic dl-PCBs showed the lowest levels, especially the non-ortho congeners (PCBs 77, 126, and 169) with concentrations below LOD for most of the samples. In agreement with our data, PCB118 congeners are the prevalent ones usually reported in marine samples (Bayarri et al., 2001; Storelli & Marcotrigiano, 2006). In order to compare the results obtained to permissible limits set forth in the EU Council Regulation, the TEQ values were calculated for each sample and mean values for three catchment areas are shown in Fig. 5. TEQ values were calculated by multiplying the individual congener levels measured in each sample with its toxic equivalency factors (TEF), established by the World Health Organization (WHO-TEF) (Van den Berg et al. 2006). As it is shown, the lowest total TEQ values, expressed as pg TEQ/ g ww, are found in turbot samples (mean 0.04 pg TEQ/g ww) and the highest results were observed for bluefish and garfish samples (mean 0.14 pg TEQ/g ww). The comparison of our results for TEQ values in fish with those in the literature showed lower levels than the TEQs in sardine from Spanish Atlantic southwest coast (0.75 pg TEQ/g ww) (Bordajandi, Martin, Abad, Rivera, & Gonzalez, 2006) and lower than those in salmon from the Baltic Sea (12.6 pg TEQ/g ww) (Isosaari et al. 2006). The Total WHO-TEQ values measured in fish from southern Baltic Sea varied from 3.4 pg/g fresh weight to 15.2 pg/g fresh  ska, & Grabic, weight (Szlinder-Richert, Barska, Usydus, Ruczyn 2009). The European Union has set a limit of 3.0 pg TEQ/g wet weight in muscle meat of fish for the sum of dioxin-like PCBs (European Commission, 2011). In our study TEQs of the 6 dl-PCBs for all investigated fish species did not exceed this limit.

M. Stancheva et al. / Food Control 72 (2017) 205e210

209

Table 2 Concentrations of dl-PCBs (ng/g ww, mean values and standard deviation) determined in fish collected from the Black Sea. Species

Area

PCB 77

PCB 105

Sprat

North Varna South North Varna South North Varna South North Varna South North Varna South North Varna South

nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd

0.64 1.03 3.71 1.48 0.77 0.77 1.27 1.11 1.73 0.64 nd nd nd nd 1.47 2.69 0.83 1.45

Grey mullet

Bluefish

Turbot

Red mullet

Garfish

± ± ± ± ± ± ± ± ± ±

0.16 0.31 0.92 0.37 0.19 0.21 0.36 0.32 0.46 0.18

± ± ± ±

0.35 0.67 0.22 0.32

PCB 118 0.83 1.52 1.95 2.25 1.13 0.99 3.36 3.95 2.57 1.21 1.42 0.63 1.79 3.62 3.45 4.14 2.53 1.98

± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

0.23 0.38 0.56 0.65 0.28 0.26 0.84 0.99 0.77 0.36 0.35 0.16 0.45 0.89 0.78 1.04 0.61 0.59

PCB 126

PCB 156

PCB 169

Sum dl-PCB

nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd

nd nd 0.10 ± 0.03 0.26 ± 0.08 nd nd nd nd 0.22 ± 0.06 nd nd nd nd nd nd nd nd nd

nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd

1.47 2.55 5.76 3.99 1.90 1.76 4.63 5.06 4.52 1.85 1.42 0.63 1.79 3.62 4.92 6.83 3.36 3.43

± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±

0.37 0.63 1.42 0.97 0.46 0.43 1.14 1.22 1.13 0.41 0.35 0.16 0.45 0.89 1.23 1.71 0.84 0.86

nd e not detectable.

Fig. 5. Mean values TEQs in fish species from three sites in the Black Sea coast.

3.2. Comparison with PCBs levels from other regions The concentrations of PCBs detected in the edible parts of marine fish from the Bulgarian Black Sea were compared with those found in similar species from other marine ecosystems. Total PCBs (as sum of all PCB congeners measured) were found in fish species at concentrations ranging between 134.2 ng/g lipid weight (lw) in bluefish and 571.9 ng/g lw in turbot. The PCB levels found in this study are generally lower than those reported from the other regions. The levels of indicator PCBs found in present study were lower than the results of fish species from Gulf of Naples, the Mediterranean Sea (1921.9e39406.5 ng/g lw), reported by Naso et al. 2005. Our results were found lower than PCBs concentrations in Atlantic mackerel (1096 ng/g lw) collected in the Central Adriatic Sea (Perugini et al. 2004). The low levels of PCBs observed in fish tissues correspond with the fact that no industrial production of PCBs took place in Bulgaria. 3.3. Estimated daily intake (EDI) of PCBs Seafood accounts for a small portion of human diet, but it has been proven to be one of the major routes of human exposure to organic contaminants (Smith & Gangolli, 2002). The consumption of contaminated fat-food can be a potential risk for the consumer. To comprehensively evaluate risk exposure, the mean EDIs for these harmful chemicals in each fish species were calculated. The estimated daily intake of the PCBs in the six fish species are shown in Table 3. We calculated the estimated daily intake on the

basis of a fish consumption rate of 13.2 g/day (NSI, 2010) for adults with body weight of 70 kg, on the mean exposure level. The EDIs of the I-PCBs calculated in marine fish species were compared to the minimum risk level (MRL) for oral intake of these compounds (ATSDR, 2010). The EDI of PCBs in fish from Black Sea was calculated between 1.39 and 4.73 ng/kg day and did not exceeded the MRL of 20 ng/kg day (Table 3). WHO has set a tolerable daily intake (TDI) for the sum of PCDD/ F-TEQ and dl-PCB-TEQ of 1e4 pg TEQ kg/body weight (WHO 2000), which is comparable with a tolerable weekly intake of 14 pg TEQ kg-1 body weight as fixed by the European Union Scientific Committee on Food (ECSCF, 2001). In this study, estimated daily intake of dl-PCBs from Bulgarian food-consumption data was from 0.015 to 0.027 pg TEQs kg/body weight/day (for sprat and bluefish, respectively). Both of these values were lower than the TDI of 1e4 pg TEQs kg/body weight/day recommended by WHO (2000). These estimations were also lower than those reported in Spain e mean dietary intake of dl-PCBs from fish and seafood was estimated at 15.18 pg WHO-TEQ/day in 2010 (Perello, Gomez-Catalan, Castell, Llobet, & Domingo, 2012). We can conclude that the dietary intake of polychlorinated biphenyls through the analysed marine species for the adult Bulgarian consumer does not seem to pose a health risk.

4. Conclusions This study provides data on levels of organochlorine contamination in marine fish species from the Bulgarian Black Sea coast. The mean levels of I-PCBs (average of the three fishing regions) ranged between 100.3 ng/g lw (bluefish) and 453.8 ng/g lw (turbot). The data of our study did not reveal clear local point sources for the contaminants that bioaccumulate in fish along the Bulgarian coast of the Black Sea. Our results for sum of I-PCBs in all fish species did not exceed the maximum level of 75 ng/g ww. WHO-TEQs were found in the range from 0.04 pg TEQ/g ww for turbot to 0.14 pg TEQ/g ww for bluefish and garfish and did not exceed the limit of 3.0 pg WHO-TEQ/g ww for sum of dioxin-like PCBs. The contamination of the fish species investigated with PCBs appears to be relatively low compared to other European studies. The lower observed levels of PCB in fish tissues than from fish tissues of other aquatic ecosystems were potentially due to the absence of PCB manufacturing in Bulgaria. The estimated intake levels of PCBs in this study were several orders lower than their

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Table 3 Estimated daily intakes (EDI) of PCBs through fish by human (average body weight 70 kg).. Fish species

MRL/TDI (Reference)

EDI

Indicator PCBs, ng/kg bw/day dl-PCBs, pg WHO-TEQ 2005/kg bw/day

Sprat

Grey mullet

Bluefish

Turbot

Red mullet

Garfish

1.96 0.015

2.45 0.015

3.58 0.027

1.39 0.008

4.73 0.017

3.43 0.025

30 ng/kg day (MRL ATSDR, 2010) 1-4 pg TEQ/kg bw (TDI WHO 2000)

MRL e minimum risk level, TDI e tolerable daily intake.

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