- Email: [email protected]
Polybrominated diphenyl ethers and their methoxylated analogs in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) from Bizerte Lagoon, Tunisia
Marine Environmental Research 72 (2011) 258e264
Contents lists available at SciVerse ScienceDirect
Marine Environmental Research journal homepage: www.elsevier.com/locate/marenvrev
Polybrominated diphenyl ethers and their methoxylated analogs in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) from Bizerte Lagoon, Tunisia Walid Ben Ameur a, Sihem Ben Hassine a, Ethel Eljarrat b, *, Yassine El Megdiche a, Souad Trabelsi a, Bèchir Hammami a, Damià Barceló b, Mohamed Ridha Driss a a b
Laboratory of Environmental Analytical Chemistry (05/UR/12-03), University of Carthage, Faculty of Sciences, Bizerte, 7021 Zarzouna, Tunisia Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 July 2011 Received in revised form 12 September 2011 Accepted 15 September 2011
Concentrations of ten polybrominated diphenyl ethers (PBDEs) and eight methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) collected from the Bizerte Lagoon and the Mediterranean Sea were investigated. To the best of our knowledge, this is the first report of these compounds in marine fishes from Tunisia. The PBDE mean concentrations in fish from Bizerte Lagoon were 45.3 and 96.2 ng g1 lw respectively in mullet and sea bass, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea were 7.80 and 27.9 ng g1 lw respectively. MeO-PBDE concentrations in mullet and sea bass from Bizerte Lagoon ranged from 6.46 to 286 ng g1 lw and from 49.4 to 798 ng g1 lw respectively, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea ranged from 190 to 401 ng g1 lw and from 353 to 578 ng g1 lw respectively. The total PBDEs and total MeO-PBDEs concentration in fish from Bizerte Lagoon were similar or slightly lower than those reported for other species from other locations around the world. Ó 2011 Elsevier Ltd. All rights reserved.
Keywords: PBDEs MeO-PBDEs Mullet Sea bass Bizerte Lagoon
1. Introduction Polybrominated diphenyl ethers (PBDEs) are brominated organic compounds used as additive flame retardants in plastics, paints, textiles, and building materials. PBDEs have a structure in which 1e10 bromines are substituted on two benzene rings connected by an ether bond. According to the numbers of bromines and their substitution positions, theoretically there are 209 congeners. Among these man-made chemicals, approximately 30 are normally found in environmental samples. There are three major commercial mixtures of these compounds: the Penta-, Octaand Deca-mixtures. Penta-BDE, marketed under the trade names Bromkal-70 and DE-71, contains predominately the congeners BDE-47, 99, 100, 153, and 154. It is used mainly in polyurethane foams and textiles (Department of Health and Human Services, 2004). The Octa-mixture, which is principally composed of BDE183 and 153, is used in styrenes, polycarbonates and thermosets (Department of Health and Human Services, 2004). Deca-mixtures are used in most types of synthetic materials including textiles and * Corresponding author. CSIC e Institute of Environmental Assessment and Water Research, Department of Environmental Chemistry, Barcelona, Spain. Tel.: þ34 93 400 6100; fax: þ34 93 204 5904. E-mail address: [email protected] (E. Eljarrat). 0141-1136/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.marenvres.2011.09.009
electronics (Birnbaum and Staskal, 2004). The annual worldwide production of the three technical PBDE products in 2001 was 67,000 metric tons (de Wit, 2002). Contamination by PBDEs is of environmental concern due to their persistence, potential for endocrine disruption and bioaccumulation, and long-range transport. As a result, they have been widely found in air, soil, water, sediment, freshwater fish and marine organisms, and in human tissues from around the world. In in vivo and in vitro studies using experimental mammals and human cell lines, it has been reported that PBDEs cause adverse effects, such as clinical, morphological, immunological, and behavioral changes, disturbance of thyroid hormone homeostasis, and enzyme induction (Darnerud, 2003; Gill et al., 2004; Legler and Brouwer, 2003). Several structural PBDE analogs, such as the methoxylated PBDEs (MeO-PBDEs), have recently been evidenced in fish and marine mammals and measured at high concentrations in marine organisms, including top-predators (Weijs et al., 2009). There are no known anthropogenic sources of these compounds. MeO-PBDEs are known to occur as natural products from marine environments (Gribble, 2000) and metabolites (Feng et al., 2010) of anthropogenic polybrominated diphenyl ethers (PBDEs). The possibility of MeOPBDEs formation via methylation of either PBDEs or their hydroxylated homologs has also been reported (Teuten et al., 2005). It has
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
been shown that MeO-PBDEs can also be demethoxylated to OHPBDEs in vitro, at a faster rate than that of PBDE transformation to OH-PBDEs (Wan et al., 2010). MeO-PBDEs are naturally-produced in the marine environment by sponges or algae (Vetter et al., 2002; Malmvärn et al., 2005). There is at present exceedingly little information about the biological effects and thus the toxicological potential of environmentally relevant MeO-PBDEs in laboratory animals and wildlife. A previous study showed the cytotoxic effect of 6-MeO-BDE-47 in human hepatoma cell line HepG2 (An et al., 2010). Biological activity has been investigated for 20 -MeO-BDE-68, where antibacterial and anti-inflammatory activity was observed in bacteria (Kuniyoshi et al., 1985). The aims of this study were to measure PBDE and MeO-PBDE concentration in muscle samples of two fish specie (Mugil cephalus and Dicentrarchus labrax) from the Bizerte Lagoon and the Mediterranean Sea and to identify the potential sources of these two kinds of brominated organic pollutants. Both species have high economic importance and gastronomic value and have demonstrated to be suitable for aquatic ecosystems biomonitoring. 2. Materials and methods 2.1. Sample collection Populated cities and/or industrial zones in northern Tunisia have been mostly developed along Mediterranean coastal lagoons, e.g. Tunis and Bizerte. Bizerte Lagoon located in northern Tunisia, is
259
one such lagoon near the industrial and urban zones. It extends for about 150 km2, between latitude 37 08 and 3714N and longitude 9 48 and 9 56E and is connected to the Mediterranean Sea and Lake Ichkeul by straight channels. Fifteen fish samples from the Bizerte Lagoon (BL) and five fish samples from the Mediterranean Sea (MS) 8 km northwards from the lagoon (reference site) for each specie were sampled using a net, in November 2009 (Fig. 1). The low analyzed number of fish collected from the MS is due to difficulty of their fishing in this area. The fish were immediately sacrificed, weighed, measured, dissected and kept frozen (20 C) until required for chemical analyses. The biota species collected in the present study included Mullet (M. cephalus), and sea Bass (D. labrax). Table 1 shows the information on the fish samples used in the present study. 2.2. Chemicals The solvents used in this study (n-hexane, acetone and dichloromethane) were pesticide quality and were obtained from Fluka (Buchs, Switzerland). Sulfuric acid was obtained from Biotechnica. Florisil (60e100 mesh) was obtained from Fluka, activated at 650 C for 8 h and re-heated at 130 C for 5 h before use. Anhydrous sodium sulfate suitable for use in pesticide analysis was purchased from Fluka, heated at 300 C and stored in a 130 C oven. Individual standard solutions of PBDEs (BDE-28, BDE-47, BDE66, BDE-85, BDE-99, BDE-119, BDE-138, BDE-153, BDE-154, and BDE-183) at 50 mg mL1 in isooctane were purchased from Supelco (CIL, USA). The MeO-PBDE analytical mixture standard solution was
Fig. 1. Map showing sampling areas.
260
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
Table 1 Details of samples from the Bizerte Lagoon (BL) and the Mediterranean Sea (MS). Common name
Mullet Sea bass
Scientific name
Mugil cephalus Dicentrarchus labrax
Number of samples
Weight g (SD)
Length cm (SD)
Lipid % (SD)
BL
MS
BL
MS
BL
MS
BL
MS
15 15
5 5
265.8 (83.4) 265.3 (52.6)
185 (15.0) 290 (10.0)
30.5 (3.5) 29.4 (1.3)
26.7 (1.7) 30.7 (1.0)
6.30(5.4) 4.60 (3.1)
5.70 (1.6) 6.10 (4.4)
SD: standard deviation.
purchased from Wellington Laboratories (Guelph, ON, Canada) containing 6-MeO-BDE-47, 20 -MeO-BDE-68, 5-MeO-BDE-47, 4MeO-BDE-49, 5-MeO-BDE-100, 4-MeO-BDE-103, 5-MeO-BDE-99, and 4-MeO-BDE-101 at 5 mg mL1 in nonane. These standard solutions were further diluted by n-hexane to obtain mixed fortifying and GC calibration standard solutions for all compounds. 2.3. Sample preparation PBDEs and MeO-PBDEs were analyzed following the method described by Guo et al. (2008) with slight modifications. Samples of freeze dried muscle tissues (10 g) was Soxhlet extracted with nhexane:acetone (4:1; v/v) for 16 h at a rate of five cycles per hour. The extract was concentrated with a rotary evaporator. An aliquot of 1 mL was used for gravimetric determination of the extractable lipid content. The remaining lipids, after adding BDE-77 as internal standard were removed by treatment with concentrated sulfuric acid (4 10 mL). Further, cleanup was done on a column (40 cm 0.5 cm ID) packed with 5 g of activated Florisil and topped with 1 g of anhydrous sodium sulfate. The extract was eluted with 50 mL of dichloromethane and n-hexane (1:9; v/v). The eluate was finally concentrated to incipient dryness and re-dissolved with 50 mL of hexane prior to the analysis by gas chromatography coupled with electron capture negative ionization mass spectrometry (GCeECNI-MS).
methodology, recoveries ranged from 46 to 72% for PBDEs and from 53 to 90% for MeO-PBDEs. All samples were recovery corrected. The limit of detection (LOD) calculated as three times the signal-tonoise ratio, ranged from 57 to 695 pg g1 lipid weight (lw) for PBDEs and from 35 to 645 pg g1 lw for MeO-PBDEs. Relative standard deviations of the method (n ¼ 3) were in the range of 1e13%. Moreover, procedural blanks were carried out and no analytes of interest were detected. Multi-level calibration curves in the linear response interval of the detector were created for the quantification and good correlation (r2 > 0.999) was achieved. 2.6. Statistical analysis Statistical treatment of the obtained results was performed with SPSS software (SPSS 10.0 for Windows, SPSS Inc.). Our data were not normally distributed. In the first step we tried to log-transform the data, but even then most of them were still not normally distributed. Therefore we further used non-parametric tests for these data. For general comparisons, we used k-independent sample and if difference was significant (p < 0.05), subsequent multiple comparisons between fish groups and sites were tested using ManneWhitney U-test. Spearman rank correlation was used to examine the strength of associations between parameters. Statistical significance was accepted at p < 0.05. 3. Results
2.4. Instrumental analysis 3.1. Polybrominated diphenyl ethers GCeECNI-MS analyses were performed on a gas chromatograph Agilent 6890 connected to a mass spectrometer Agilent 5973 a, Madrid, Spain). An HP-5ms Network (Agilent Technologies Espan (30 m 0.25 mm i.d., 0.25 mm film thickness) containing 5% phenyl methyl siloxane (model HP 19091S-433) capillary column was used for the determination of the PBDEs and MeO-PBDEs. The temperature program was from 110 C (held for 1 min) to 180 C (held for 1 min) at 8 C/min, then from 180 C to 240 C (held for 5 min) at 2 C/min, and then from 240 C to 265 C (held for 6 min) at 2 C/ min, using the splitless injection mode during 1 min, and injection volume of 2 mL. The operating conditions were as follows: ion source temperature ¼ 250 C, ammonia as chemical ionization moderating gas at an ion source pressure of 1.9 104 torr. Experiments were carried out monitoring the two most abundant isotope peaks from the mass spectra corresponding to m/z ¼ 79 and 81 ([Br]) (Eljarrat et al., 2002). 2.5. Quality assurance and quality control Confirmation criteria for the detection and quantification of PBDEs and MeO-PBDEs should include the following: (1) the retention time should match that of the standard compound within 1 s, (2) the signal-to-noise ratio (S/N) should be 3, and (3) the deviation of the two monitored ions intensities ratio should be within 15% of that of the standard compound. Quantification of the target compounds was carried out by internal standard procedure with the BDE-77 as internal standard. Using the described
Of the 10 PBDE congeners measured, seven compounds (BDE28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) were frequently detected in the fish samples. Therefore, only data for these seven PBDE congeners are reported herein. The concentrations of PBDEs expressed in nanograms per gram lipid weight (ng g1 lw) in the muscle of the analyzed species are presented in Table 2. PBDEs were detected in all samples, indicating ubiquitous contamination by these compounds in aquatic biota from the BL. P At both sampling areas, the PBDE concentrations in sea bass are higher than those of mullet, with values ranging from 37.3 to 218 ng g1 lw for sea bass, and 8.01e98.8 ng g1 lw for mullet in BL, and from 20.8 to 36.6 ng g1 lw for sea bass, and 5.52e10.4 ng g1 lw for mullet in the MS. However no statistically significant differences in concentration existed between mullet and sea bass (p ¼ 0.28). On the other hand and comparing the two P sampling sites, PBDEs in the two studied species were higher in BL than in the MS. However, although the concentrations were found to be different between the two areas, no statistically significant differences in concentration were observed between sites (p ¼ 1.000 mullet; p ¼ 0.99 sea bass). The compounds analyzed in the current work were constituents of the PBDE Penta-mixture (BDE-28, BDE-47, BDE-66, BDE-99, BDE100, BDE-138, BDE-153 and BDE-154) and Octa-mixture (BDE-153, BDE-154 and BDE-183). The PBDE profiles measured in BL fish and in MS fish are presented in Fig. 2. As is shown, very similar patterns were obtained for mullet and sea bass samples in both studied sites.
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
261
Table 2 PBDE and MeO-PBDE concentrations (ng g1 lw) in fishes from Bizerte Lagoon (BL) and the Mediterranean Sea (MS). Compound
Mugil cephalus
Dicentrarchus labrax
BL
MS
BL
MS
Mean
Range
Mean
Range
Mean
Range
Mean
Range
BDE-28 BDE-47 BDE-99 BDE-100 BDE-153 BDE-154 BDE-183 P PBDEs
3.01 26.8 0.48 0.31 3.47 3.41 7.86 45.3
(3.20) (20.9) (1.05) (1.07) (3.45) (4.81) (8.14) (31.12)
nde8.80 4.66e68.8 nde3.07 nde3.70 nde10.2 nde14.1 nde21.6 8.01e98.8
0.57 (0.51) 4.83 (1.44) 0.12 (0.20) 0.17 (0.29) 0.44 (0.47) 0.38 (0.93) 1.25 (0.41) 7.80(2.44)
nde1.00 3.74e6.46 nde0.35 nde0.50 nde0.93 nde0.90 0.95e1.27 5.52e10.4
9.40 49.4 2.59 1.74 9.57 11.4 12.1 96.2
(16.0) (26.1) (4.61) (8.71) (8.71) (18.4) (4.41) (48.1)
nde39.3 20.3e98.7 nde14.0 nde15.5 nde26.8 nde63.9 1.63e16.1 37.3e218
2.92 14.6 0.44 0.92 1.28 1.79 5.90 27.9
(2.79) (4.48) (0.77) (1.59) (0.91) (0.81) (3.20) (8.03)
nde5.57 9.45e17.8 nde1.33 nde2.75 0.42e2.23 1.30e2.73 2.26e8.26 20.8e36.6
6-MeO-BDE-47 20 -MeO-BDE-68 5-MeO-BDE-47 SMeO-PBDEs
72.5 28.2 4.56 105
(97.3) (40.1) (4.33) (114)
nde220 nde96.3 nde32.1 6.46e286
211 82.1 23.7 317
130e253 60.3e109 nde71.1 190e401
223 34.3 43.1 300
(152) (47.7) (77.4) (218)
45.9e530 nde115 nde267 49.4e798
242 189 51.4 482
(54.1) (252) (44.8) (117)
180e281 100e252 nde81.7 353e578
(70.9) (109) (41.0) (112)
nd ¼ not detected, and assumed as 0 for the calculation of total PBDE and total MeO-PBDE values. Values in parentheses represent the standard deviation.
In all the samples, BDE-47 was the predominant among the seven P detected congeners. For instance, its contribution to PBDEs ranged from 24.2% to 82.7% in mullet and from 25.3% to 92.6% in sea bass from BL. 3.2. Methoxylated polybrominated diphenyl ethers Only three out of the 8 targeted MeO-PBDE congeners were found at measurable levels in the studied fish samples (Table 2). The MeO-PBDEs detected in fish samples were 20 -MeO-BDE-68, 6MeO-BDE-47 and 5-MeO-BDE-47. Concentrations of MeO-PBDEs in mullet and sea bass from BL ranged from 6.46 to 286 ng g1 lw and from 49.4 to 798 ng g1 lw respectively, while the concentrations of these compounds in mullet and sea bass from MS ranged from 190 to 401 ng g1 lw and from 353 to 578 ng g1 lw respectively. The P MeO-PBDEs were shown to be significantly higher for sea bass compared with mullet for both studied areas (p ¼ 0.03 BL; p ¼ 0.001 MS). Moreover, concentrations of MeO-PBDEs in the two species were significantly higher in the MS than in BL (p ¼ 0.02). 20 -MeO-BDE-68, 6-MeO-BDE-47 and 5-MeO-BDE-47 accounted P for 68.9%, 26.8% and 4.33% of the MeO-PBDE concentration in P mullet from BL and 74.4%, 11.3% and 14.4% of the MeO-PBDE concentration in sea bass from BL respectively. MeO-PBDE profiles were similar in the two investigated groups for the two studied areas, with 20 -MeO-BDE-68, 6-MeO-BDE-47 and 5-MeO-BDE-47 P contributing with almost 90.7% and 91.0% of the MeO-PBDEs in fish from BL and MS respectively. 5-MeO-BDE-47 contribution to P the MeO-PBDEs in fish from BL and MS was 9.30% and 9.00% respectively.
Fig. 2. PBDE congener profiles in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) from the Bizerte Lagoon (BL) and the Mediterranean Sea (MS).
In our study there was no significant correlation between the levels of BDE-47 and 6-MeO-BDE-47 in mullet (rs ¼ 0.23, p ¼ 0.48), and in sea bass (rs ¼ 0.37, p ¼ 0.22) from BL. The levels of 6-MeOBDE-47 were highly correlated with the levels of 20 -MeO-BDE-68 in mullet and sea bass from BL (rs ¼ 0.93, p ¼ 0.03) and (rs ¼ 0.99, p ¼ 0.01). 3.3. Correlation of characteristics
P
PBDEs and
P
MeO-PBDEs with fish
Levels of PBDEs in mullet and sea bass from BL were not correlated with weight (rs ¼ 0.38, p ¼ 0.21 and rs ¼ 0.5, p ¼ 0.89 respectively) or length (rs ¼ 1.55, p ¼ 0.63 and rs ¼ 0.32, p ¼ 0.31 respectively) or with lipid percentage (rs ¼ 0.41, p ¼ 0.18 and rs ¼ 0.38, p ¼ 0.22 respectively). Moreover, levels of MeO-PBDEs in biota from BL were not correlated with weight (rs ¼ 0.89, p ¼ 0.79 and rs ¼ 0.50, p ¼ 0.45 respectively) or length (rs ¼ 0.35, p ¼ 0.91 and rs ¼ 1.55, p ¼ 0.78 respectively) or with lipid percentage (rs ¼ 0.47, p ¼ 0. 85 and rs ¼ 0.50, p ¼ 0.76 respectively). 4. Discussion 4.1. Polybrominated diphenyl ethers The interspecies differences in PBDE levels are possibly related to their feeding habits, their trophic position in the food chain and to the difference in the metabolic capacity of both species (Johnson and Olson, 2001; Wan et al., 2010). The low concentrations of PBDEs in mullet may be attributed to its feeding habits being omnivorous and consuming mostly phytoplankton, and to its low trophic position in the food chain (Nyunja et al., 2009). In contrast, the sea bass is a top predator (carnivorous fish) and has a high trophic position in the food chain (Pasquaud et al., 2008). The lack of inter-site variability in PBDE levels may partly be due to large variations in concentrations between individual fish specimens. This high variability in concentrations of persistent chemicals has been reported in a similar study (Gevao et al., 2010), even when samples were collected within a small geographical region, as was the case in this study. Also, it is may be due to the low number of samples and the relatively high standard deviation of weight values. The relatively high PBDE levels in BL may be caused by the industrial development and population growth. The most obvious sources are effluents from factories producing textile and plastic products and from local wastewater discharges.
262
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
The similarity of PBDE abundances across the two fish species indicates that the seven congeners are accumulated in the fish to the same extent. The dominance of BDE-47 in the present study was consistent with the general pattern found in fish samples collected from Anoia and Cardener River, Spain (Labandeira et al., 2007). In this study, the aquatic biota from the BL seemed to accumulate higher proportion of tri-BDEs (BDE-28) than penta-BDEs (BDE100, BDE-99). This result was in line with results in the Yangtze River Delta (Xian et al., 2008) and Pearl River Delta (Guo et al., 2008). The congener pattern observed in this study was similar to those described in previous studies conducted for fish samples (Xian et al., 2008; Gao et al., 2009). These profiles do not reflect the composition of Penta-mixture or Octa-mixture formulations, but this might be explained, for example, by the differences in the uptake and clearance efficiency of particular congeners. Table 3 shows a global view of the PBDE levels in fish samples P from other studies located in different geographical areas. PBDE concentrations and concentrations of an individual congener (BDE47, commonly the most abundant congener in biological samples) are shown. Concentrations observed in BL samples were comparable to those obtained in fish from Georgia coast, USA (Sajwan et al., 2008), from Gironde Estuary, France (Tapie et al., 2011) and from Sydney Harbor, Australia (Losada et al., 2009). However, concentrations in the present study were relatively lower to those from Anoia and Cardener River, Spain (Labandeira et al., 2007) and from Tokyo Bay, Japan (Mizukawa et al., 2009), while these concentrations were much lower to those found in fishes from Hardley Lake, USA (Dodder et al., 2002) and from Virginia watersheds, USA (Hale et al., 2001). The concentrations observed in BL were relatively higher to those from Northwestern Arabian Gulf (Gevao et al., 2010) and much higher to those from Eastern China coastline (Xia et al., 2011) and from Storfjorden, Svalbard Islands, Norway (Wolkers et al., 2004). Mean BDE-47 concentration in fish from BL was lower than that found in fish collected from Northwestern Arabian Gulf (Gevao et al., 2010), Eastern China coastline (Xia et al., 2011) and from Storfjorden, eastern Svalbard (Wolkers et al., 2004). Moreover this concentration was lower to that found in fish sampled from Yakima River, USA (Johnson and Olson, 2001) and from Hardley Lake, USA (Dodder et al., 2002). However this mean concentration was similar to that found in fish caught from
Georgia coast, USA (Sajwan et al., 2008) and from Sydney Harbour, Australia (Losada et al., 2009). 4.2. Methoxylated polybrominated diphenyl ethers The MeO-PBDEs found in fish muscle from this study have been also detected in previous studies (Pena-Abaurrea et al., 2009; Su et al., 2010). As in the case of PBDEs, the interspecies differences in MeOPBDE levels are possibly related to their feeding habits, their trophic position in the food chain and to the difference in the metabolic capacity of both species (Johnson and Olson, 2001; Wan et al., 2010). The existence of a difference in MeO-PBDE levels between the two investigated locations is in accordance with a result obtained in a work conducted in Brazil that showed that concentration levels of MeO-PBDEs are higher in samples collected from oceanic waters than those collected from coastal waters (Dorneles et al., 2010). The MeO-PBDE profiles in fish from the investigated areas agree with published literature for marine species (Pena-Abaurrea et al., 2009). The lower level of 5-MeO-BDE-47 in fish simple compared to that of 6-MeO-BDE-47 and 20 -MeO-BDE-68 is in accordance with results obtained by Pena-Abaurrea et al. (2009) and by Wan et al. (2010). P The MeO-PBDEs concentrations in the two fish species are P higher than the PBDEs in both areas. These results are similar to those reported by Strid et al. (2010) and by Su et al. (2010) and may indicate the natural origin of the MeO-PBDEs. According to Malmvärn et al. (2005), the fact that MeO-BDEs are present at much higher concentrations than the PBDEs in both the alga and mussel samples may also provide further evidence supporting a natural origin for these compounds. Our result showed a difference in MeO-PBDE concentrations for both species between the BL and the MS. Because there is no anthropogenic source of these MeO-PBDEs, the difference in the concentrations may possibly be due to the difference in the distribution of marine sponge, algae, and other aquatic organisms that are known to synthesize these compounds. The absence of significant correlation between the levels of BDE47 and 6-MeO-BDE-47 in the two fish species suggests that 6-MeOBDE-47 is not only a possible metabolic product of BDE-47 in fish but could also come from other marine sources. This fact is also supported by Vetter et al. (2001) who did not detect significant amounts
Table 3 Global PBDE levels in fish muscles (ng g1 lw). Location
Species
Georgia coast, USA
Anchovy, Flounder, Rock sea bass, Silver Perch, Spot and Spade fish Eel Flounder, tailor, yellowfin bream, luderick, fanbelly leatherjacket and sea mullet Carp Japanese sea bass Ureogenic goby Carp Carp Carp Mullet, tonguesole and yellowfin seabream Yellow croaker and silver pomfret Polar cod Carp Mullet and sea bass
Gironde Estuary, France Sydney Harbour, Australia
Anoia and Cardener River, Spain Tokyo Bay, Japan Yakima River, USA Hardley Lake, USA Virginia watersheds, USA Northwestern Arabian Gulf Eastern China coastline Storfjorden, eastern Svalbard Yangtze River, China Bizerte Lagoon, Tunisia nr ¼ not reported.
P
PBDE Mean (min-max)
BDE-47 Mean (min-max)
Number of measured PBDE congeners
References
77.5 (9.9e337)
27.4 (10e241)
6
Sajwan et al. (2008)
(24e237) (24e115)
(97e121) (13.2e78.2)
12 9
Tapie et al. (2011) Losada et al. (2009)
160 (29e744) 130 (nde177) 960 1600 (760e2500) 7200 (5e47900) 19.5 (2,80e190)
105 (20e565) 66.5 910 400e1200 74 12.5 (1,8e130)
40 21 nr nr nr 4
Labandeira et al. (2007) Mizukawa et al. (2009) Johnson and Olson (2001) Dodder et al. (2002) Hale et al. (2001) Gevao et al. (2010)
3.04 (1.11e5.28) 3.55 (2.53e4.98) 140 (17e1100) 70.8 (8.01e218)
1.79 (0.47e4.29) 2.09 (1.33e3.28) 8.3e160 38.1 (4.66e98.7)
9 6 nr 10
Xia et al. (2011) Wolkers et al. (2004) Xian et al. (2008) This study
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
of parent compounds (PBDEs) in marine mammals from northeastern Australia despite the high levels found of 60 -MeO-BDE-47. Since the levels of 6-MeO-BDE-47 were highly correlated with the levels of 20 -MeO-BDE-68, it is highly plausible that these compounds have both accumulated from similar sources. The literature on MeO-PBDEs in fish from different locations is rather scarce and only a few reports of these compounds in other aquatic organisms are available. The mean MeO-PBDEs concentration found in our study, 203 ng g1 lw, is similar to that found in wild bluefin tuna (Thunnus thynnus) from the Mediterranean Sea, 150 ng g1 lw (Pena-Abaurrea et al., 2009) and it was higher than that found in anchovy (coila sp.) from the Yangtze River Delta, 9.10 ng g1 lw (Su et al., 2010) and to that found in marine species from the Sydney Harbor, 26.7 ng g1 lw (Losada et al., 2009). However, and compared with those obtained in Brazilian waters, the mean MeO-PBDEs concentrations in the present study were lower than those found in dolphin (Pseudorca crassidens), mean 148 700 ng g1 lw (Dorneles et al., 2010). 4.3. Correlation of characteristics
P
PBDEs and
P MeO-PBDEs with fish
The PBDE levels in BL fish were not significantly correlated either with fish size, or with fish weight and or with lipid percentage. These results were similar to those found by Mariottini et al. (2008); Borghesi et al. (2009); by Gao et al. (2009) and by Strid et al. (2010). The absence of significant correlation between MeOPBDE concentrations and lipid percentage, between MeO-PBDE concentration and fish length was in accordance with the results obtained by Valters et al. (2005) and by Strid et al. (2010). This suggests that these characteristics were not large determinants of contaminant burdens. 5. Conclusions PBDEs and MeO-PBDEs were detected in mullet and sea bass from the Bizerte Lagoon. This is the first report of these compounds in P P marine fishes of Tunisia. PBDEs and MeO-PBDEs in sea bass were higher than those in mullet in both investigated areas, a pattern which may be related to the different feeding habits and trophic position in the food chain of the two species. Similar profiles of anthropogenic and naturally-produced organobrominated compounds were observed in the two studied species from the both areas. The PBDE and MeO-PBDE concentrations in biota from the Bizerte Lagoon were similar to or slightly lower than those reported for other species from other locations around the world. The results of this study as well as those of other studies suggest that PBDEs in both fish species are primarily of synthetic origin and released by human activities around Bizerte Lagoon, while MeO-PBDEs in the two studied species are primarily from nature as natural products from the sea instead of metabolism of PBDEs in these fishes. Acknowledgments The authors are grateful to R. Chaler, D. Fangul and M. Comesaña for their assistance with the gas chromatographyemass spectrometry (GCeMS) analyses. We thank also the anonymous referees for their helpful comments, which will improve the paper. References An, J., Li, S., Zhong, Y., Wang, Y., Zhen, K., Zhang, X., Wang, Y., Wu, M., Yu, Z., Sheng, G., Fu, J., Huang, Y., 2010. The cytotoxic effects of synthetic 6-
263
hydroxylated and 6-methoxylated polybrominated diphenyl ether 47 (BDE47). Environ. Toxicol. doi:10.1002/tox.20582. Birnbaum, L., Staskal, D., 2004. Brominated flame retardants: cause for concern? Environ. Health Persp 112, 9e17. Borghesi, N., Corsolini, S., Leonards, P., Brandsma, S., de Boer, J., Focardi, S., 2009. Polybrominated diphenyl ether contamination levels in fish from the Antarctic and the Mediterranean Sea. Chemosphere 77, 693e698. Darnerud, P.O., 2003. Toxic effects of brominated flame retardants in man and wildlife. Environ. Int. 29, 841e853. de Wit, C., 2002. An overview of brominated flame retardants in the environment. Chemosphere 46, 583e624. Department of Health and Human Services (US), Public Health Service, Agency for Toxic and disease registry, September 2004. Toxicological Profile for Polybrominated Biphenyls and Polybrominated Diphenyl Ethers. Dodder, N.G., Strandberg, B., Hites, R.A., 2002. Concentrations and spatial variations of polybrominated diphenyl ethers and several organochlorine compounds in fishes from the northeastern United States. Environ. Sci. Technol. 36, 146e151. Dorneles, P.R., Lailson-Brito, J., Dirtu, A.C., Weijs, L., Azevedo, A.F., Torres, J.P., Malm, O., Neels, H., Blust, R., Das, K., Covaci, A., 2010. Anthropogenic and naturally-produced organobrominated compounds in marine mammals from Brazil. Environ. Int. 36, 60e67. Eljarrat, E., Lacorte, S., Barceló, D., 2002. Optimization of congener-specific analysis of 40 polybrominated diphenyl ethers by gas chromatography/mass spectrometry. J. Mass Spectrom 37, 76e84. Feng, C., Xu, Y., He, Y., Luo, Q., Zha, J., Wang, Z., 2010. Debrominated and methoxylated polybrominated diphenyl ether metabolites in rainbow trout (Oncorhynchus mykiss) after exposure to decabromodiphenyl ether. J. Environ. Sci. (Beijing, China) 22, 1425e1434. Gao, Z., Xu, J., Xian, Q., Feng, J., Chen, X., Yu, H., 2009. Polybrominated diphenyl ethers (PBDEs) in aquatic biota from the lower reach of the Yangtze River, East China. Chemosphere 75, 1273e1279. Gevao, B., Jaward, F.M., Al-Bahloul, M., Uddin, S., Beg, M.U., Zafar, J., 2010. Polybrominated diphenyl ethers in three commercially important fish from the Northwestern Arabian Gulf: occurrence, concentration, and profiles. Arch. Environ. Contam. Toxicol. 60, 636e642. Gill, U., Chu, I., Ryan, J.J., Feeley, M., 2004. Polybrominated diphenyl ethers: human tissue levels and toxicology. Rev. Environ. Contam. T. 183, 55e97. Gribble, G.W., 2000. The natural production of organobromine compounds. Environ. Sci. Pollut. Res. Int. 7, 37e49. Guo, L., Qiu, Y., Zhang, G., Zheng, G.J., Lam, P.K., Li, X., 2008. Levels and bioaccumulation of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in fishes from the Pearl River estuary and Daya Bay, South China. Environ. Pollut. 152, 604e611. Hale, R.C., La Guardia, M.J., Harvey, E.P., Mainor, T.M., Duff, W.H., Gaylor, M.O., 2001. Polybrominated diphenyl ether flame retardants in Virginia freshwater fishes (USA). Environ. Sci. Technol. 35, 4585e4591. Johnson, A., Olson, N., 2001. Analysis and occurrence of polybrominated diphenyl ethers in Washington state freshwater fish. Arch. Environ. Contam. Toxicol. 41, 339e344. Kuniyoshi, M., Yamada, K., Higa, T., 1985. A biologically active diphenyl ether from the green algae Cladophora fascicularis. Experientia 41, 523e524. Labandeira, A., Eljarrat, E., Barceló, D., 2007. Congener distribution of polybrominated diphenyl ethers in feral carp (Cyprinus carpio) from the Llobregat River, Spain. Environ. Pollut. 146, 188e195. Legler, J., Brouwer, A., 2003. Are brominated flame retardants endocrine disruptors? Environ. Int. 29, 879e885. Losada, S., Roach, A., Roosens, L., Santos, F.J., Galceran, M.T., Vetter, W., Neels, H., Covaci, A., 2009. Biomagnification of anthropogenic and naturally-produced organobrominated compounds in a marine food web from Sydney Harbour, Australia. Environ. Int. 35, 1142e1149. Malmvärn, A., Marsh, G., Kautsky, L., Athanasiadou, M., Bergman, A., Asplund, L., 2005. Hydroxylated and methoxylated brominated diphenyl ethers in the red algae Ceramium tenuicorne and blue mussels from the Baltic Sea. Environ. Sci. Technol. 39, 2990e2997. Mariottini, M., Corsi, I., Della Torre, C., Caruso, T., Bianchini, A., Nesi, I., Focardi, S., 2008. Biomonitoring of polybrominated diphenyl ether (PBDE) pollution: a field study. Comp. Biochem. Physiol. C. Toxicol. Pharmacol. 148, 80e86. Mizukawa, K., Takada, H., Takeuchi, I., Ikemoto, T., Omori, K., Tsuchiya, K., 2009. Bioconcentration and biomagnification of polybrominated diphenyl ethers (PBDEs) through lower-trophic-level coastal marine food web. Mar. Pollut. Bull. 58, 1217e1224. Nyunja, J., Ntiba, M., Onyari, J., Mavuti, K., Soetaert, K., Bouillon, S., 2009. Carbon sources supporting a diverse fish community in a tropical coastal ecosystem (Gazi Bay, Kenya). Estuar. Coast. Shelf Sci. 83, 333e341. Pasquaud, S., Elie, P., Jeantet, C., Billy, I., Martinez, P., Girardin, M., 2008. A preliminary investigation of the fish food web in the Gironde estuary, France, using dietary and stable isotope analyses. Estuar. Coast. Shelf Sci. 78, 267e279. Pena-Abaurrea, M., Weijs, L., Ramos, L., Borghesi, N., Corsolini, S., Neels, H., Blust, R., Covaci, A., 2009. Anthropogenic and naturally-produced organobrominated compounds in bluefin tuna from the Mediterranean Sea. Chemosphere 76, 1477e1482. Sajwan, K.S., Kumar, K.S., Nune, S., Fowler, A., Richardson, J.P., Loganathan, B.G., 2008. Persistent organochlorine pesticides, polychlorinated biphenyls,
264
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
polybrominated diphenyl ethers in fish from coastal waters off Savannah, GA, USA. Toxicol. Environ. Chem. 90, 81e96. Strid, A., Athanassiadis, I., Athanasiadou, M., Svavarsson, J., Päpke, O., Bergman, A., 2010. Neutral and phenolic brominated organic compounds of natural and anthropogenic origin in northeast Atlantic Greenland shark (Somniosus microcephalus). Environ. Toxicol. Chem. 29, 2653e2659. Su, G.Y., Gao, Z.S., Yu, Y., Ge, J.C., Wei, S., Feng, J.F., Liu, F.Y., Giesy, J.P., Lam, M.H., Yu, H.X., 2010. Polybrominated diphenyl ethers and their methoxylated metabolites in anchovy (Coilia sp.) from the Yangtze River Delta, China. Environ. Sci. Pollut. Res. Int. 17, 634e642. Tapie, N., Menach, K.L., Pasquaud, S., Elie, P., Devier, M.H., Budzinski, H., 2011. PBDE and PCB contamination of eels from the Gironde estuary: from glass eels to silver eels. Chemosphere 83, 175e185. Teuten, E.L., Xu, L., Reddy, C.M., 2005. Two abundant bioaccumulated halogenated compounds are natural products. Science 307, 917e920. Valters, K., Li, H., Alaee, M., D’Sa, I., Marsh, G., Bergman, A., Letcher, R.J., 2005. Polybrominated diphenyl ethers and hydroxylated and methoxylated brominated and chlorinated analogues in the plasma of fish from the Detroit river. Environ. Sci. Technol. 39, 5612e5619. Vetter, W., Hiebl, J., Oldham, N.J., 2001. Determination and mass spectrometric investigation of a new mixed halogenated persistent component in fish and seal. Environ. Sci. Technol. 35, 4157e4162.
Vetter, W., Stoll, E., Garson, M.J., Fahey, S.J., Gaus, C., Müller, J.F., 2002. Sponge halogenated natural products found at parts-per-million levels in marine mammals. Environ. Toxicol. Chem. 21, 2014e2019. Wan, Y., Liu, F., Wiseman, S., Zhang, X., Chang, H., Hecker, M., Jones, P.D., Lam, M.H.W., Giesy, J.P., 2010. Interconversion of hydroxylated and methoxylated polybrominated diphenyl ethers in Japanese Medaka. Environ. Sci. Technol. 44, 8729e8735. Weijs, L., Losada, S., Das, K., Roosens, L., Reijnders, P.J., Santos, J.F., Neels, H., Blust, R., Covaci, A., 2009. Biomagnification of naturally-occurring methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in a fish-marine mammal food chain from the North Sea. Environ. Int. 35, 893e899. Wolkers, H., Van Bavel, B., Derocher, A.E., Wiig, O., Kovacs, K.M., Lydersen, C., Lindström, G., 2004. Congener-specific accumulation and food chain transfer of polybrominated diphenyl ethers in two Arctic food chains. Environ. Sci. Technol. 38, 1667e1674. Xia, C., Lam, J.C., Wu, X., Sun, L., Xie, Z., Lam, P.K., 2011. Levels and distribution of polybrominated diphenyl ethers (PBDEs) in marine fishes from Chinese coastal waters. Chemosphere 82, 18e24. Xian, Q., Ramu, K., Isobe, T., Sudaryanto, A., Liu, X., Gao, Z., Takahashi, S., Yu, H., Tanabe, S., 2008. Levels and body distribution of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in freshwater fishes from the Yangtze River, China. Chemosphere 71, 268e276.
Contents lists available at SciVerse ScienceDirect
Marine Environmental Research journal homepage: www.elsevier.com/locate/marenvrev
Polybrominated diphenyl ethers and their methoxylated analogs in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) from Bizerte Lagoon, Tunisia Walid Ben Ameur a, Sihem Ben Hassine a, Ethel Eljarrat b, *, Yassine El Megdiche a, Souad Trabelsi a, Bèchir Hammami a, Damià Barceló b, Mohamed Ridha Driss a a b
Laboratory of Environmental Analytical Chemistry (05/UR/12-03), University of Carthage, Faculty of Sciences, Bizerte, 7021 Zarzouna, Tunisia Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 July 2011 Received in revised form 12 September 2011 Accepted 15 September 2011
Concentrations of ten polybrominated diphenyl ethers (PBDEs) and eight methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) collected from the Bizerte Lagoon and the Mediterranean Sea were investigated. To the best of our knowledge, this is the first report of these compounds in marine fishes from Tunisia. The PBDE mean concentrations in fish from Bizerte Lagoon were 45.3 and 96.2 ng g1 lw respectively in mullet and sea bass, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea were 7.80 and 27.9 ng g1 lw respectively. MeO-PBDE concentrations in mullet and sea bass from Bizerte Lagoon ranged from 6.46 to 286 ng g1 lw and from 49.4 to 798 ng g1 lw respectively, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea ranged from 190 to 401 ng g1 lw and from 353 to 578 ng g1 lw respectively. The total PBDEs and total MeO-PBDEs concentration in fish from Bizerte Lagoon were similar or slightly lower than those reported for other species from other locations around the world. Ó 2011 Elsevier Ltd. All rights reserved.
Keywords: PBDEs MeO-PBDEs Mullet Sea bass Bizerte Lagoon
1. Introduction Polybrominated diphenyl ethers (PBDEs) are brominated organic compounds used as additive flame retardants in plastics, paints, textiles, and building materials. PBDEs have a structure in which 1e10 bromines are substituted on two benzene rings connected by an ether bond. According to the numbers of bromines and their substitution positions, theoretically there are 209 congeners. Among these man-made chemicals, approximately 30 are normally found in environmental samples. There are three major commercial mixtures of these compounds: the Penta-, Octaand Deca-mixtures. Penta-BDE, marketed under the trade names Bromkal-70 and DE-71, contains predominately the congeners BDE-47, 99, 100, 153, and 154. It is used mainly in polyurethane foams and textiles (Department of Health and Human Services, 2004). The Octa-mixture, which is principally composed of BDE183 and 153, is used in styrenes, polycarbonates and thermosets (Department of Health and Human Services, 2004). Deca-mixtures are used in most types of synthetic materials including textiles and * Corresponding author. CSIC e Institute of Environmental Assessment and Water Research, Department of Environmental Chemistry, Barcelona, Spain. Tel.: þ34 93 400 6100; fax: þ34 93 204 5904. E-mail address: [email protected] (E. Eljarrat). 0141-1136/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.marenvres.2011.09.009
electronics (Birnbaum and Staskal, 2004). The annual worldwide production of the three technical PBDE products in 2001 was 67,000 metric tons (de Wit, 2002). Contamination by PBDEs is of environmental concern due to their persistence, potential for endocrine disruption and bioaccumulation, and long-range transport. As a result, they have been widely found in air, soil, water, sediment, freshwater fish and marine organisms, and in human tissues from around the world. In in vivo and in vitro studies using experimental mammals and human cell lines, it has been reported that PBDEs cause adverse effects, such as clinical, morphological, immunological, and behavioral changes, disturbance of thyroid hormone homeostasis, and enzyme induction (Darnerud, 2003; Gill et al., 2004; Legler and Brouwer, 2003). Several structural PBDE analogs, such as the methoxylated PBDEs (MeO-PBDEs), have recently been evidenced in fish and marine mammals and measured at high concentrations in marine organisms, including top-predators (Weijs et al., 2009). There are no known anthropogenic sources of these compounds. MeO-PBDEs are known to occur as natural products from marine environments (Gribble, 2000) and metabolites (Feng et al., 2010) of anthropogenic polybrominated diphenyl ethers (PBDEs). The possibility of MeOPBDEs formation via methylation of either PBDEs or their hydroxylated homologs has also been reported (Teuten et al., 2005). It has
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
been shown that MeO-PBDEs can also be demethoxylated to OHPBDEs in vitro, at a faster rate than that of PBDE transformation to OH-PBDEs (Wan et al., 2010). MeO-PBDEs are naturally-produced in the marine environment by sponges or algae (Vetter et al., 2002; Malmvärn et al., 2005). There is at present exceedingly little information about the biological effects and thus the toxicological potential of environmentally relevant MeO-PBDEs in laboratory animals and wildlife. A previous study showed the cytotoxic effect of 6-MeO-BDE-47 in human hepatoma cell line HepG2 (An et al., 2010). Biological activity has been investigated for 20 -MeO-BDE-68, where antibacterial and anti-inflammatory activity was observed in bacteria (Kuniyoshi et al., 1985). The aims of this study were to measure PBDE and MeO-PBDE concentration in muscle samples of two fish specie (Mugil cephalus and Dicentrarchus labrax) from the Bizerte Lagoon and the Mediterranean Sea and to identify the potential sources of these two kinds of brominated organic pollutants. Both species have high economic importance and gastronomic value and have demonstrated to be suitable for aquatic ecosystems biomonitoring. 2. Materials and methods 2.1. Sample collection Populated cities and/or industrial zones in northern Tunisia have been mostly developed along Mediterranean coastal lagoons, e.g. Tunis and Bizerte. Bizerte Lagoon located in northern Tunisia, is
259
one such lagoon near the industrial and urban zones. It extends for about 150 km2, between latitude 37 08 and 3714N and longitude 9 48 and 9 56E and is connected to the Mediterranean Sea and Lake Ichkeul by straight channels. Fifteen fish samples from the Bizerte Lagoon (BL) and five fish samples from the Mediterranean Sea (MS) 8 km northwards from the lagoon (reference site) for each specie were sampled using a net, in November 2009 (Fig. 1). The low analyzed number of fish collected from the MS is due to difficulty of their fishing in this area. The fish were immediately sacrificed, weighed, measured, dissected and kept frozen (20 C) until required for chemical analyses. The biota species collected in the present study included Mullet (M. cephalus), and sea Bass (D. labrax). Table 1 shows the information on the fish samples used in the present study. 2.2. Chemicals The solvents used in this study (n-hexane, acetone and dichloromethane) were pesticide quality and were obtained from Fluka (Buchs, Switzerland). Sulfuric acid was obtained from Biotechnica. Florisil (60e100 mesh) was obtained from Fluka, activated at 650 C for 8 h and re-heated at 130 C for 5 h before use. Anhydrous sodium sulfate suitable for use in pesticide analysis was purchased from Fluka, heated at 300 C and stored in a 130 C oven. Individual standard solutions of PBDEs (BDE-28, BDE-47, BDE66, BDE-85, BDE-99, BDE-119, BDE-138, BDE-153, BDE-154, and BDE-183) at 50 mg mL1 in isooctane were purchased from Supelco (CIL, USA). The MeO-PBDE analytical mixture standard solution was
Fig. 1. Map showing sampling areas.
260
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
Table 1 Details of samples from the Bizerte Lagoon (BL) and the Mediterranean Sea (MS). Common name
Mullet Sea bass
Scientific name
Mugil cephalus Dicentrarchus labrax
Number of samples
Weight g (SD)
Length cm (SD)
Lipid % (SD)
BL
MS
BL
MS
BL
MS
BL
MS
15 15
5 5
265.8 (83.4) 265.3 (52.6)
185 (15.0) 290 (10.0)
30.5 (3.5) 29.4 (1.3)
26.7 (1.7) 30.7 (1.0)
6.30(5.4) 4.60 (3.1)
5.70 (1.6) 6.10 (4.4)
SD: standard deviation.
purchased from Wellington Laboratories (Guelph, ON, Canada) containing 6-MeO-BDE-47, 20 -MeO-BDE-68, 5-MeO-BDE-47, 4MeO-BDE-49, 5-MeO-BDE-100, 4-MeO-BDE-103, 5-MeO-BDE-99, and 4-MeO-BDE-101 at 5 mg mL1 in nonane. These standard solutions were further diluted by n-hexane to obtain mixed fortifying and GC calibration standard solutions for all compounds. 2.3. Sample preparation PBDEs and MeO-PBDEs were analyzed following the method described by Guo et al. (2008) with slight modifications. Samples of freeze dried muscle tissues (10 g) was Soxhlet extracted with nhexane:acetone (4:1; v/v) for 16 h at a rate of five cycles per hour. The extract was concentrated with a rotary evaporator. An aliquot of 1 mL was used for gravimetric determination of the extractable lipid content. The remaining lipids, after adding BDE-77 as internal standard were removed by treatment with concentrated sulfuric acid (4 10 mL). Further, cleanup was done on a column (40 cm 0.5 cm ID) packed with 5 g of activated Florisil and topped with 1 g of anhydrous sodium sulfate. The extract was eluted with 50 mL of dichloromethane and n-hexane (1:9; v/v). The eluate was finally concentrated to incipient dryness and re-dissolved with 50 mL of hexane prior to the analysis by gas chromatography coupled with electron capture negative ionization mass spectrometry (GCeECNI-MS).
methodology, recoveries ranged from 46 to 72% for PBDEs and from 53 to 90% for MeO-PBDEs. All samples were recovery corrected. The limit of detection (LOD) calculated as three times the signal-tonoise ratio, ranged from 57 to 695 pg g1 lipid weight (lw) for PBDEs and from 35 to 645 pg g1 lw for MeO-PBDEs. Relative standard deviations of the method (n ¼ 3) were in the range of 1e13%. Moreover, procedural blanks were carried out and no analytes of interest were detected. Multi-level calibration curves in the linear response interval of the detector were created for the quantification and good correlation (r2 > 0.999) was achieved. 2.6. Statistical analysis Statistical treatment of the obtained results was performed with SPSS software (SPSS 10.0 for Windows, SPSS Inc.). Our data were not normally distributed. In the first step we tried to log-transform the data, but even then most of them were still not normally distributed. Therefore we further used non-parametric tests for these data. For general comparisons, we used k-independent sample and if difference was significant (p < 0.05), subsequent multiple comparisons between fish groups and sites were tested using ManneWhitney U-test. Spearman rank correlation was used to examine the strength of associations between parameters. Statistical significance was accepted at p < 0.05. 3. Results
2.4. Instrumental analysis 3.1. Polybrominated diphenyl ethers GCeECNI-MS analyses were performed on a gas chromatograph Agilent 6890 connected to a mass spectrometer Agilent 5973 a, Madrid, Spain). An HP-5ms Network (Agilent Technologies Espan (30 m 0.25 mm i.d., 0.25 mm film thickness) containing 5% phenyl methyl siloxane (model HP 19091S-433) capillary column was used for the determination of the PBDEs and MeO-PBDEs. The temperature program was from 110 C (held for 1 min) to 180 C (held for 1 min) at 8 C/min, then from 180 C to 240 C (held for 5 min) at 2 C/min, and then from 240 C to 265 C (held for 6 min) at 2 C/ min, using the splitless injection mode during 1 min, and injection volume of 2 mL. The operating conditions were as follows: ion source temperature ¼ 250 C, ammonia as chemical ionization moderating gas at an ion source pressure of 1.9 104 torr. Experiments were carried out monitoring the two most abundant isotope peaks from the mass spectra corresponding to m/z ¼ 79 and 81 ([Br]) (Eljarrat et al., 2002). 2.5. Quality assurance and quality control Confirmation criteria for the detection and quantification of PBDEs and MeO-PBDEs should include the following: (1) the retention time should match that of the standard compound within 1 s, (2) the signal-to-noise ratio (S/N) should be 3, and (3) the deviation of the two monitored ions intensities ratio should be within 15% of that of the standard compound. Quantification of the target compounds was carried out by internal standard procedure with the BDE-77 as internal standard. Using the described
Of the 10 PBDE congeners measured, seven compounds (BDE28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-183) were frequently detected in the fish samples. Therefore, only data for these seven PBDE congeners are reported herein. The concentrations of PBDEs expressed in nanograms per gram lipid weight (ng g1 lw) in the muscle of the analyzed species are presented in Table 2. PBDEs were detected in all samples, indicating ubiquitous contamination by these compounds in aquatic biota from the BL. P At both sampling areas, the PBDE concentrations in sea bass are higher than those of mullet, with values ranging from 37.3 to 218 ng g1 lw for sea bass, and 8.01e98.8 ng g1 lw for mullet in BL, and from 20.8 to 36.6 ng g1 lw for sea bass, and 5.52e10.4 ng g1 lw for mullet in the MS. However no statistically significant differences in concentration existed between mullet and sea bass (p ¼ 0.28). On the other hand and comparing the two P sampling sites, PBDEs in the two studied species were higher in BL than in the MS. However, although the concentrations were found to be different between the two areas, no statistically significant differences in concentration were observed between sites (p ¼ 1.000 mullet; p ¼ 0.99 sea bass). The compounds analyzed in the current work were constituents of the PBDE Penta-mixture (BDE-28, BDE-47, BDE-66, BDE-99, BDE100, BDE-138, BDE-153 and BDE-154) and Octa-mixture (BDE-153, BDE-154 and BDE-183). The PBDE profiles measured in BL fish and in MS fish are presented in Fig. 2. As is shown, very similar patterns were obtained for mullet and sea bass samples in both studied sites.
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
261
Table 2 PBDE and MeO-PBDE concentrations (ng g1 lw) in fishes from Bizerte Lagoon (BL) and the Mediterranean Sea (MS). Compound
Mugil cephalus
Dicentrarchus labrax
BL
MS
BL
MS
Mean
Range
Mean
Range
Mean
Range
Mean
Range
BDE-28 BDE-47 BDE-99 BDE-100 BDE-153 BDE-154 BDE-183 P PBDEs
3.01 26.8 0.48 0.31 3.47 3.41 7.86 45.3
(3.20) (20.9) (1.05) (1.07) (3.45) (4.81) (8.14) (31.12)
nde8.80 4.66e68.8 nde3.07 nde3.70 nde10.2 nde14.1 nde21.6 8.01e98.8
0.57 (0.51) 4.83 (1.44) 0.12 (0.20) 0.17 (0.29) 0.44 (0.47) 0.38 (0.93) 1.25 (0.41) 7.80(2.44)
nde1.00 3.74e6.46 nde0.35 nde0.50 nde0.93 nde0.90 0.95e1.27 5.52e10.4
9.40 49.4 2.59 1.74 9.57 11.4 12.1 96.2
(16.0) (26.1) (4.61) (8.71) (8.71) (18.4) (4.41) (48.1)
nde39.3 20.3e98.7 nde14.0 nde15.5 nde26.8 nde63.9 1.63e16.1 37.3e218
2.92 14.6 0.44 0.92 1.28 1.79 5.90 27.9
(2.79) (4.48) (0.77) (1.59) (0.91) (0.81) (3.20) (8.03)
nde5.57 9.45e17.8 nde1.33 nde2.75 0.42e2.23 1.30e2.73 2.26e8.26 20.8e36.6
6-MeO-BDE-47 20 -MeO-BDE-68 5-MeO-BDE-47 SMeO-PBDEs
72.5 28.2 4.56 105
(97.3) (40.1) (4.33) (114)
nde220 nde96.3 nde32.1 6.46e286
211 82.1 23.7 317
130e253 60.3e109 nde71.1 190e401
223 34.3 43.1 300
(152) (47.7) (77.4) (218)
45.9e530 nde115 nde267 49.4e798
242 189 51.4 482
(54.1) (252) (44.8) (117)
180e281 100e252 nde81.7 353e578
(70.9) (109) (41.0) (112)
nd ¼ not detected, and assumed as 0 for the calculation of total PBDE and total MeO-PBDE values. Values in parentheses represent the standard deviation.
In all the samples, BDE-47 was the predominant among the seven P detected congeners. For instance, its contribution to PBDEs ranged from 24.2% to 82.7% in mullet and from 25.3% to 92.6% in sea bass from BL. 3.2. Methoxylated polybrominated diphenyl ethers Only three out of the 8 targeted MeO-PBDE congeners were found at measurable levels in the studied fish samples (Table 2). The MeO-PBDEs detected in fish samples were 20 -MeO-BDE-68, 6MeO-BDE-47 and 5-MeO-BDE-47. Concentrations of MeO-PBDEs in mullet and sea bass from BL ranged from 6.46 to 286 ng g1 lw and from 49.4 to 798 ng g1 lw respectively, while the concentrations of these compounds in mullet and sea bass from MS ranged from 190 to 401 ng g1 lw and from 353 to 578 ng g1 lw respectively. The P MeO-PBDEs were shown to be significantly higher for sea bass compared with mullet for both studied areas (p ¼ 0.03 BL; p ¼ 0.001 MS). Moreover, concentrations of MeO-PBDEs in the two species were significantly higher in the MS than in BL (p ¼ 0.02). 20 -MeO-BDE-68, 6-MeO-BDE-47 and 5-MeO-BDE-47 accounted P for 68.9%, 26.8% and 4.33% of the MeO-PBDE concentration in P mullet from BL and 74.4%, 11.3% and 14.4% of the MeO-PBDE concentration in sea bass from BL respectively. MeO-PBDE profiles were similar in the two investigated groups for the two studied areas, with 20 -MeO-BDE-68, 6-MeO-BDE-47 and 5-MeO-BDE-47 P contributing with almost 90.7% and 91.0% of the MeO-PBDEs in fish from BL and MS respectively. 5-MeO-BDE-47 contribution to P the MeO-PBDEs in fish from BL and MS was 9.30% and 9.00% respectively.
Fig. 2. PBDE congener profiles in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) from the Bizerte Lagoon (BL) and the Mediterranean Sea (MS).
In our study there was no significant correlation between the levels of BDE-47 and 6-MeO-BDE-47 in mullet (rs ¼ 0.23, p ¼ 0.48), and in sea bass (rs ¼ 0.37, p ¼ 0.22) from BL. The levels of 6-MeOBDE-47 were highly correlated with the levels of 20 -MeO-BDE-68 in mullet and sea bass from BL (rs ¼ 0.93, p ¼ 0.03) and (rs ¼ 0.99, p ¼ 0.01). 3.3. Correlation of characteristics
P
PBDEs and
P
MeO-PBDEs with fish
Levels of PBDEs in mullet and sea bass from BL were not correlated with weight (rs ¼ 0.38, p ¼ 0.21 and rs ¼ 0.5, p ¼ 0.89 respectively) or length (rs ¼ 1.55, p ¼ 0.63 and rs ¼ 0.32, p ¼ 0.31 respectively) or with lipid percentage (rs ¼ 0.41, p ¼ 0.18 and rs ¼ 0.38, p ¼ 0.22 respectively). Moreover, levels of MeO-PBDEs in biota from BL were not correlated with weight (rs ¼ 0.89, p ¼ 0.79 and rs ¼ 0.50, p ¼ 0.45 respectively) or length (rs ¼ 0.35, p ¼ 0.91 and rs ¼ 1.55, p ¼ 0.78 respectively) or with lipid percentage (rs ¼ 0.47, p ¼ 0. 85 and rs ¼ 0.50, p ¼ 0.76 respectively). 4. Discussion 4.1. Polybrominated diphenyl ethers The interspecies differences in PBDE levels are possibly related to their feeding habits, their trophic position in the food chain and to the difference in the metabolic capacity of both species (Johnson and Olson, 2001; Wan et al., 2010). The low concentrations of PBDEs in mullet may be attributed to its feeding habits being omnivorous and consuming mostly phytoplankton, and to its low trophic position in the food chain (Nyunja et al., 2009). In contrast, the sea bass is a top predator (carnivorous fish) and has a high trophic position in the food chain (Pasquaud et al., 2008). The lack of inter-site variability in PBDE levels may partly be due to large variations in concentrations between individual fish specimens. This high variability in concentrations of persistent chemicals has been reported in a similar study (Gevao et al., 2010), even when samples were collected within a small geographical region, as was the case in this study. Also, it is may be due to the low number of samples and the relatively high standard deviation of weight values. The relatively high PBDE levels in BL may be caused by the industrial development and population growth. The most obvious sources are effluents from factories producing textile and plastic products and from local wastewater discharges.
262
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
The similarity of PBDE abundances across the two fish species indicates that the seven congeners are accumulated in the fish to the same extent. The dominance of BDE-47 in the present study was consistent with the general pattern found in fish samples collected from Anoia and Cardener River, Spain (Labandeira et al., 2007). In this study, the aquatic biota from the BL seemed to accumulate higher proportion of tri-BDEs (BDE-28) than penta-BDEs (BDE100, BDE-99). This result was in line with results in the Yangtze River Delta (Xian et al., 2008) and Pearl River Delta (Guo et al., 2008). The congener pattern observed in this study was similar to those described in previous studies conducted for fish samples (Xian et al., 2008; Gao et al., 2009). These profiles do not reflect the composition of Penta-mixture or Octa-mixture formulations, but this might be explained, for example, by the differences in the uptake and clearance efficiency of particular congeners. Table 3 shows a global view of the PBDE levels in fish samples P from other studies located in different geographical areas. PBDE concentrations and concentrations of an individual congener (BDE47, commonly the most abundant congener in biological samples) are shown. Concentrations observed in BL samples were comparable to those obtained in fish from Georgia coast, USA (Sajwan et al., 2008), from Gironde Estuary, France (Tapie et al., 2011) and from Sydney Harbor, Australia (Losada et al., 2009). However, concentrations in the present study were relatively lower to those from Anoia and Cardener River, Spain (Labandeira et al., 2007) and from Tokyo Bay, Japan (Mizukawa et al., 2009), while these concentrations were much lower to those found in fishes from Hardley Lake, USA (Dodder et al., 2002) and from Virginia watersheds, USA (Hale et al., 2001). The concentrations observed in BL were relatively higher to those from Northwestern Arabian Gulf (Gevao et al., 2010) and much higher to those from Eastern China coastline (Xia et al., 2011) and from Storfjorden, Svalbard Islands, Norway (Wolkers et al., 2004). Mean BDE-47 concentration in fish from BL was lower than that found in fish collected from Northwestern Arabian Gulf (Gevao et al., 2010), Eastern China coastline (Xia et al., 2011) and from Storfjorden, eastern Svalbard (Wolkers et al., 2004). Moreover this concentration was lower to that found in fish sampled from Yakima River, USA (Johnson and Olson, 2001) and from Hardley Lake, USA (Dodder et al., 2002). However this mean concentration was similar to that found in fish caught from
Georgia coast, USA (Sajwan et al., 2008) and from Sydney Harbour, Australia (Losada et al., 2009). 4.2. Methoxylated polybrominated diphenyl ethers The MeO-PBDEs found in fish muscle from this study have been also detected in previous studies (Pena-Abaurrea et al., 2009; Su et al., 2010). As in the case of PBDEs, the interspecies differences in MeOPBDE levels are possibly related to their feeding habits, their trophic position in the food chain and to the difference in the metabolic capacity of both species (Johnson and Olson, 2001; Wan et al., 2010). The existence of a difference in MeO-PBDE levels between the two investigated locations is in accordance with a result obtained in a work conducted in Brazil that showed that concentration levels of MeO-PBDEs are higher in samples collected from oceanic waters than those collected from coastal waters (Dorneles et al., 2010). The MeO-PBDE profiles in fish from the investigated areas agree with published literature for marine species (Pena-Abaurrea et al., 2009). The lower level of 5-MeO-BDE-47 in fish simple compared to that of 6-MeO-BDE-47 and 20 -MeO-BDE-68 is in accordance with results obtained by Pena-Abaurrea et al. (2009) and by Wan et al. (2010). P The MeO-PBDEs concentrations in the two fish species are P higher than the PBDEs in both areas. These results are similar to those reported by Strid et al. (2010) and by Su et al. (2010) and may indicate the natural origin of the MeO-PBDEs. According to Malmvärn et al. (2005), the fact that MeO-BDEs are present at much higher concentrations than the PBDEs in both the alga and mussel samples may also provide further evidence supporting a natural origin for these compounds. Our result showed a difference in MeO-PBDE concentrations for both species between the BL and the MS. Because there is no anthropogenic source of these MeO-PBDEs, the difference in the concentrations may possibly be due to the difference in the distribution of marine sponge, algae, and other aquatic organisms that are known to synthesize these compounds. The absence of significant correlation between the levels of BDE47 and 6-MeO-BDE-47 in the two fish species suggests that 6-MeOBDE-47 is not only a possible metabolic product of BDE-47 in fish but could also come from other marine sources. This fact is also supported by Vetter et al. (2001) who did not detect significant amounts
Table 3 Global PBDE levels in fish muscles (ng g1 lw). Location
Species
Georgia coast, USA
Anchovy, Flounder, Rock sea bass, Silver Perch, Spot and Spade fish Eel Flounder, tailor, yellowfin bream, luderick, fanbelly leatherjacket and sea mullet Carp Japanese sea bass Ureogenic goby Carp Carp Carp Mullet, tonguesole and yellowfin seabream Yellow croaker and silver pomfret Polar cod Carp Mullet and sea bass
Gironde Estuary, France Sydney Harbour, Australia
Anoia and Cardener River, Spain Tokyo Bay, Japan Yakima River, USA Hardley Lake, USA Virginia watersheds, USA Northwestern Arabian Gulf Eastern China coastline Storfjorden, eastern Svalbard Yangtze River, China Bizerte Lagoon, Tunisia nr ¼ not reported.
P
PBDE Mean (min-max)
BDE-47 Mean (min-max)
Number of measured PBDE congeners
References
77.5 (9.9e337)
27.4 (10e241)
6
Sajwan et al. (2008)
(24e237) (24e115)
(97e121) (13.2e78.2)
12 9
Tapie et al. (2011) Losada et al. (2009)
160 (29e744) 130 (nde177) 960 1600 (760e2500) 7200 (5e47900) 19.5 (2,80e190)
105 (20e565) 66.5 910 400e1200 74 12.5 (1,8e130)
40 21 nr nr nr 4
Labandeira et al. (2007) Mizukawa et al. (2009) Johnson and Olson (2001) Dodder et al. (2002) Hale et al. (2001) Gevao et al. (2010)
3.04 (1.11e5.28) 3.55 (2.53e4.98) 140 (17e1100) 70.8 (8.01e218)
1.79 (0.47e4.29) 2.09 (1.33e3.28) 8.3e160 38.1 (4.66e98.7)
9 6 nr 10
Xia et al. (2011) Wolkers et al. (2004) Xian et al. (2008) This study
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
of parent compounds (PBDEs) in marine mammals from northeastern Australia despite the high levels found of 60 -MeO-BDE-47. Since the levels of 6-MeO-BDE-47 were highly correlated with the levels of 20 -MeO-BDE-68, it is highly plausible that these compounds have both accumulated from similar sources. The literature on MeO-PBDEs in fish from different locations is rather scarce and only a few reports of these compounds in other aquatic organisms are available. The mean MeO-PBDEs concentration found in our study, 203 ng g1 lw, is similar to that found in wild bluefin tuna (Thunnus thynnus) from the Mediterranean Sea, 150 ng g1 lw (Pena-Abaurrea et al., 2009) and it was higher than that found in anchovy (coila sp.) from the Yangtze River Delta, 9.10 ng g1 lw (Su et al., 2010) and to that found in marine species from the Sydney Harbor, 26.7 ng g1 lw (Losada et al., 2009). However, and compared with those obtained in Brazilian waters, the mean MeO-PBDEs concentrations in the present study were lower than those found in dolphin (Pseudorca crassidens), mean 148 700 ng g1 lw (Dorneles et al., 2010). 4.3. Correlation of characteristics
P
PBDEs and
P MeO-PBDEs with fish
The PBDE levels in BL fish were not significantly correlated either with fish size, or with fish weight and or with lipid percentage. These results were similar to those found by Mariottini et al. (2008); Borghesi et al. (2009); by Gao et al. (2009) and by Strid et al. (2010). The absence of significant correlation between MeOPBDE concentrations and lipid percentage, between MeO-PBDE concentration and fish length was in accordance with the results obtained by Valters et al. (2005) and by Strid et al. (2010). This suggests that these characteristics were not large determinants of contaminant burdens. 5. Conclusions PBDEs and MeO-PBDEs were detected in mullet and sea bass from the Bizerte Lagoon. This is the first report of these compounds in P P marine fishes of Tunisia. PBDEs and MeO-PBDEs in sea bass were higher than those in mullet in both investigated areas, a pattern which may be related to the different feeding habits and trophic position in the food chain of the two species. Similar profiles of anthropogenic and naturally-produced organobrominated compounds were observed in the two studied species from the both areas. The PBDE and MeO-PBDE concentrations in biota from the Bizerte Lagoon were similar to or slightly lower than those reported for other species from other locations around the world. The results of this study as well as those of other studies suggest that PBDEs in both fish species are primarily of synthetic origin and released by human activities around Bizerte Lagoon, while MeO-PBDEs in the two studied species are primarily from nature as natural products from the sea instead of metabolism of PBDEs in these fishes. Acknowledgments The authors are grateful to R. Chaler, D. Fangul and M. Comesaña for their assistance with the gas chromatographyemass spectrometry (GCeMS) analyses. We thank also the anonymous referees for their helpful comments, which will improve the paper. References An, J., Li, S., Zhong, Y., Wang, Y., Zhen, K., Zhang, X., Wang, Y., Wu, M., Yu, Z., Sheng, G., Fu, J., Huang, Y., 2010. The cytotoxic effects of synthetic 6-
263
hydroxylated and 6-methoxylated polybrominated diphenyl ether 47 (BDE47). Environ. Toxicol. doi:10.1002/tox.20582. Birnbaum, L., Staskal, D., 2004. Brominated flame retardants: cause for concern? Environ. Health Persp 112, 9e17. Borghesi, N., Corsolini, S., Leonards, P., Brandsma, S., de Boer, J., Focardi, S., 2009. Polybrominated diphenyl ether contamination levels in fish from the Antarctic and the Mediterranean Sea. Chemosphere 77, 693e698. Darnerud, P.O., 2003. Toxic effects of brominated flame retardants in man and wildlife. Environ. Int. 29, 841e853. de Wit, C., 2002. An overview of brominated flame retardants in the environment. Chemosphere 46, 583e624. Department of Health and Human Services (US), Public Health Service, Agency for Toxic and disease registry, September 2004. Toxicological Profile for Polybrominated Biphenyls and Polybrominated Diphenyl Ethers. Dodder, N.G., Strandberg, B., Hites, R.A., 2002. Concentrations and spatial variations of polybrominated diphenyl ethers and several organochlorine compounds in fishes from the northeastern United States. Environ. Sci. Technol. 36, 146e151. Dorneles, P.R., Lailson-Brito, J., Dirtu, A.C., Weijs, L., Azevedo, A.F., Torres, J.P., Malm, O., Neels, H., Blust, R., Das, K., Covaci, A., 2010. Anthropogenic and naturally-produced organobrominated compounds in marine mammals from Brazil. Environ. Int. 36, 60e67. Eljarrat, E., Lacorte, S., Barceló, D., 2002. Optimization of congener-specific analysis of 40 polybrominated diphenyl ethers by gas chromatography/mass spectrometry. J. Mass Spectrom 37, 76e84. Feng, C., Xu, Y., He, Y., Luo, Q., Zha, J., Wang, Z., 2010. Debrominated and methoxylated polybrominated diphenyl ether metabolites in rainbow trout (Oncorhynchus mykiss) after exposure to decabromodiphenyl ether. J. Environ. Sci. (Beijing, China) 22, 1425e1434. Gao, Z., Xu, J., Xian, Q., Feng, J., Chen, X., Yu, H., 2009. Polybrominated diphenyl ethers (PBDEs) in aquatic biota from the lower reach of the Yangtze River, East China. Chemosphere 75, 1273e1279. Gevao, B., Jaward, F.M., Al-Bahloul, M., Uddin, S., Beg, M.U., Zafar, J., 2010. Polybrominated diphenyl ethers in three commercially important fish from the Northwestern Arabian Gulf: occurrence, concentration, and profiles. Arch. Environ. Contam. Toxicol. 60, 636e642. Gill, U., Chu, I., Ryan, J.J., Feeley, M., 2004. Polybrominated diphenyl ethers: human tissue levels and toxicology. Rev. Environ. Contam. T. 183, 55e97. Gribble, G.W., 2000. The natural production of organobromine compounds. Environ. Sci. Pollut. Res. Int. 7, 37e49. Guo, L., Qiu, Y., Zhang, G., Zheng, G.J., Lam, P.K., Li, X., 2008. Levels and bioaccumulation of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in fishes from the Pearl River estuary and Daya Bay, South China. Environ. Pollut. 152, 604e611. Hale, R.C., La Guardia, M.J., Harvey, E.P., Mainor, T.M., Duff, W.H., Gaylor, M.O., 2001. Polybrominated diphenyl ether flame retardants in Virginia freshwater fishes (USA). Environ. Sci. Technol. 35, 4585e4591. Johnson, A., Olson, N., 2001. Analysis and occurrence of polybrominated diphenyl ethers in Washington state freshwater fish. Arch. Environ. Contam. Toxicol. 41, 339e344. Kuniyoshi, M., Yamada, K., Higa, T., 1985. A biologically active diphenyl ether from the green algae Cladophora fascicularis. Experientia 41, 523e524. Labandeira, A., Eljarrat, E., Barceló, D., 2007. Congener distribution of polybrominated diphenyl ethers in feral carp (Cyprinus carpio) from the Llobregat River, Spain. Environ. Pollut. 146, 188e195. Legler, J., Brouwer, A., 2003. Are brominated flame retardants endocrine disruptors? Environ. Int. 29, 879e885. Losada, S., Roach, A., Roosens, L., Santos, F.J., Galceran, M.T., Vetter, W., Neels, H., Covaci, A., 2009. Biomagnification of anthropogenic and naturally-produced organobrominated compounds in a marine food web from Sydney Harbour, Australia. Environ. Int. 35, 1142e1149. Malmvärn, A., Marsh, G., Kautsky, L., Athanasiadou, M., Bergman, A., Asplund, L., 2005. Hydroxylated and methoxylated brominated diphenyl ethers in the red algae Ceramium tenuicorne and blue mussels from the Baltic Sea. Environ. Sci. Technol. 39, 2990e2997. Mariottini, M., Corsi, I., Della Torre, C., Caruso, T., Bianchini, A., Nesi, I., Focardi, S., 2008. Biomonitoring of polybrominated diphenyl ether (PBDE) pollution: a field study. Comp. Biochem. Physiol. C. Toxicol. Pharmacol. 148, 80e86. Mizukawa, K., Takada, H., Takeuchi, I., Ikemoto, T., Omori, K., Tsuchiya, K., 2009. Bioconcentration and biomagnification of polybrominated diphenyl ethers (PBDEs) through lower-trophic-level coastal marine food web. Mar. Pollut. Bull. 58, 1217e1224. Nyunja, J., Ntiba, M., Onyari, J., Mavuti, K., Soetaert, K., Bouillon, S., 2009. Carbon sources supporting a diverse fish community in a tropical coastal ecosystem (Gazi Bay, Kenya). Estuar. Coast. Shelf Sci. 83, 333e341. Pasquaud, S., Elie, P., Jeantet, C., Billy, I., Martinez, P., Girardin, M., 2008. A preliminary investigation of the fish food web in the Gironde estuary, France, using dietary and stable isotope analyses. Estuar. Coast. Shelf Sci. 78, 267e279. Pena-Abaurrea, M., Weijs, L., Ramos, L., Borghesi, N., Corsolini, S., Neels, H., Blust, R., Covaci, A., 2009. Anthropogenic and naturally-produced organobrominated compounds in bluefin tuna from the Mediterranean Sea. Chemosphere 76, 1477e1482. Sajwan, K.S., Kumar, K.S., Nune, S., Fowler, A., Richardson, J.P., Loganathan, B.G., 2008. Persistent organochlorine pesticides, polychlorinated biphenyls,
264
W. Ben Ameur et al. / Marine Environmental Research 72 (2011) 258e264
polybrominated diphenyl ethers in fish from coastal waters off Savannah, GA, USA. Toxicol. Environ. Chem. 90, 81e96. Strid, A., Athanassiadis, I., Athanasiadou, M., Svavarsson, J., Päpke, O., Bergman, A., 2010. Neutral and phenolic brominated organic compounds of natural and anthropogenic origin in northeast Atlantic Greenland shark (Somniosus microcephalus). Environ. Toxicol. Chem. 29, 2653e2659. Su, G.Y., Gao, Z.S., Yu, Y., Ge, J.C., Wei, S., Feng, J.F., Liu, F.Y., Giesy, J.P., Lam, M.H., Yu, H.X., 2010. Polybrominated diphenyl ethers and their methoxylated metabolites in anchovy (Coilia sp.) from the Yangtze River Delta, China. Environ. Sci. Pollut. Res. Int. 17, 634e642. Tapie, N., Menach, K.L., Pasquaud, S., Elie, P., Devier, M.H., Budzinski, H., 2011. PBDE and PCB contamination of eels from the Gironde estuary: from glass eels to silver eels. Chemosphere 83, 175e185. Teuten, E.L., Xu, L., Reddy, C.M., 2005. Two abundant bioaccumulated halogenated compounds are natural products. Science 307, 917e920. Valters, K., Li, H., Alaee, M., D’Sa, I., Marsh, G., Bergman, A., Letcher, R.J., 2005. Polybrominated diphenyl ethers and hydroxylated and methoxylated brominated and chlorinated analogues in the plasma of fish from the Detroit river. Environ. Sci. Technol. 39, 5612e5619. Vetter, W., Hiebl, J., Oldham, N.J., 2001. Determination and mass spectrometric investigation of a new mixed halogenated persistent component in fish and seal. Environ. Sci. Technol. 35, 4157e4162.
Vetter, W., Stoll, E., Garson, M.J., Fahey, S.J., Gaus, C., Müller, J.F., 2002. Sponge halogenated natural products found at parts-per-million levels in marine mammals. Environ. Toxicol. Chem. 21, 2014e2019. Wan, Y., Liu, F., Wiseman, S., Zhang, X., Chang, H., Hecker, M., Jones, P.D., Lam, M.H.W., Giesy, J.P., 2010. Interconversion of hydroxylated and methoxylated polybrominated diphenyl ethers in Japanese Medaka. Environ. Sci. Technol. 44, 8729e8735. Weijs, L., Losada, S., Das, K., Roosens, L., Reijnders, P.J., Santos, J.F., Neels, H., Blust, R., Covaci, A., 2009. Biomagnification of naturally-occurring methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in a fish-marine mammal food chain from the North Sea. Environ. Int. 35, 893e899. Wolkers, H., Van Bavel, B., Derocher, A.E., Wiig, O., Kovacs, K.M., Lydersen, C., Lindström, G., 2004. Congener-specific accumulation and food chain transfer of polybrominated diphenyl ethers in two Arctic food chains. Environ. Sci. Technol. 38, 1667e1674. Xia, C., Lam, J.C., Wu, X., Sun, L., Xie, Z., Lam, P.K., 2011. Levels and distribution of polybrominated diphenyl ethers (PBDEs) in marine fishes from Chinese coastal waters. Chemosphere 82, 18e24. Xian, Q., Ramu, K., Isobe, T., Sudaryanto, A., Liu, X., Gao, Z., Takahashi, S., Yu, H., Tanabe, S., 2008. Levels and body distribution of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in freshwater fishes from the Yangtze River, China. Chemosphere 71, 268e276.