Biomagnification of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls in a highly contaminated freshwater food web from South China

To evaluate the biomagnification extent of polybrominated diphenyls ethers (PBDEs) and polychlorinated biphenyls (PCBs) in a highly contaminated freshwater food web from South China, trophic magnification factors (TMFs) for 18 PBDE congeners and 53 PCB congeners were calculated. The TMF values ranged 0.26-4.47 for PBDEs and 0.75-5.10 for PCBs. Forty-five of 53 PCBs and BDEs 47, 100 and 154 had TMFs greater than one, suggesting their biomagnification in the present food web. The TMFs for PBDEs were generally smaller than those for PCBs with the same degree of halogenation, indicating a lower biomagnification potential for PBDEs compared to PCBs. For PCBs, it followed a parabolic relationship between TMFs and log K_OW (octanol-water partition coefficient). However, this relationship was not significant for PBDEs, possibly due to the more complex behaviors of PBDEs in the food web (e.g., metabolism), compared to that of PCBs.     

Diamondback terrapins as indicator species of persistent organic pollutants: Using Barnegat Bay, New Jersey as a case study

The diamondback terrapin’s (Malaclemys terrapin) wide geographic distribution, long life span, occurrence in a variety of habitats within the saltmarsh ecosystem, predatory foraging behavior, and high site fidelity make it a useful indicator species for contaminant monitoring in estuarine ecosystems. In this study fat biopsies and plasma samples were collected from males and females from two sites within Barnegat Bay, New Jersey, as well as tissues from a gravid female and blue mussels (Mytilus edulis), which are terrapin prey. Samples were analyzed for persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), chlorinated pesticides, and methyl-triclosan. Terrapins from the northern site, Spizzle Creek, closest to influences from industrial areas, had higher POP concentrations for both tissues than terrapins from the less impacted Forsythe National Wildlife Refuge. Sex differences were observed with males having higher contaminant concentrations in fat and females in plasma. PCB patterns in terrapin fat and plasma were comparable to other wildlife. An atypical PBDE pattern was observed, dominated by PBDEs 153 and 100 instead of PBDEs 47 and 99, which has been documented in only a few other turtle species. The typical PBDE patterns measured in mussels, terrapin prey, suggests that the terrapin may efficiently biotransform or eliminate PBDE 47 and possibly PBDE 99. Plasma contaminant concentrations significantly and positively correlated with those in fat. This study addresses several aspects of using the terrapin as an indicator species for POP monitoring: site and sex differences, tissue sampling choices, maternal transfer, and biomagnification.     

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in breast milk from the Pacific Northwest

Breast milk samples from 40 first-time mothers from the Pacific Northwest of the US and Canada were analyzed for polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). Total PBDEs (summation operator PBDEs), calculated by summing values for the 12 PBDEs congeners analyzed, ranged from 6 to 321 ppb (lipid weight) (mean=96 ppb; median=50 ppb). In approximately 40% of the women (15/40), summation operator PBDEs>100 ppb lw in their milk, and four samples had levels >250 ppb lw. PBDE 47 was the dominant congener in most samples, whereas PBDE 153 was predominant in a few (3/40). summation operator PCBs were calculated by summing values for the 82 PCB congeners analyzed, and ranged from 49 to 415 ppb (lipid weight) (mean=147 ppb; median=126 ppb). approximately 30% of the mothers (13/40) have summation operator PBDEs> summation operator PCBs in their milk samples, and approximately 65% (25/40) have BDE 47>PCB 153 in breast milk samples, with BDE 47 averaging 3-fold greater levels than PCB 153. Clearly, the lower brominated PBDEs are surpassing PCBs as a major environmental concern in North America, and are likely affecting significant portions of the populations in these regions. PBDEs have become a major persistent organic pollutant. However, there are no positive correlations between levels of summation operator PBDEs and summation operator PCBs, or between levels of PBDE 47 and PCB 153, suggesting there may be some differences in exposure pathways for PBDEs and PCBs in humans.     

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in human liver and adipose tissue samples from Belgium

Levels of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in paired human adipose tissue and liver samples (n=25) from Belgium. Average concentrations and standard deviation of sum PBDEs (congeners 28, 47, 99, 100, 153, 154 and 183) were 5.3+/-3.0 (range 1.4-13.2) and 3.6+/-2.1 (range 1.0-10.0)ngg(-1) lipid weight (lw) in adipose tissue and liver, respectively. These concentrations were similar to reported PBDE data from Belgium and were at the lower end of the concentration range reported elsewhere in the world. In both tissues under study, BDE 153 and BDE 47 were the most abundant PBDE congeners, contributing approximately 35% and 25% to the total PBDE content. Average concentrations and range of PCBs (sum of 23 congeners) were 490 (range 70-1130) and 380 (range 90-1140)ngg(-1)lw in adipose tissue and liver, respectively. No correlation between age and concentrations of PBDEs could be found (r=0.04), while PCB concentrations correlated significantly with age (r=0.62, p<0.01, for the sum PCBs; r=0.64, p<0.01 for PCB 153 alone). Factors, such as exposure pathways (food, dust and air), rates of bioaccumulation, metabolism and elimination, influence the concentrations of PBDEs differently than those of PCBs in humans.     

PBDE flame retardants and PCBs in migrating Steller sea lions (Eumetopias jubatus) in the Strait of Georgia, British Columbia, Canada

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in blubber biopsy samples from 22 live-captured Steller sea lions (Eumetopias jubatus) that had just entered the Strait of Georgia, British Columbia, Canada, for their overwintering feeding season. ∑PBDE ranged from 50 μg kg⁻¹ (lipid weight) in adult females to 3780 μg kg⁻¹ in subadult individuals. ∑PCBs ranged from 272 μg kg⁻¹ in adult females to 14 280 μg kg⁻¹ in subadult individuals. While most PBDE and PCB congeners were transferred through milk to pups, PCBs with log K_OW > 7.0 (PCBs 206, 207, 208 and 209) appeared constrained, resulting in a lighter mixture in pups compared to adult females. The ratio of individual PCB congeners by metabolic group (Groups I, II, III, IV and V) to PCB-153 regressed against length of males suggested poor biotransformation of these compounds (slopes did not differ from zero, p > 0.05). PBDE congeners 49, 99, 153 and 183 appeared bioaccumulative (slopes of ratio BDE/PCB 153 versus length were higher than zero, p < 0.05), but the dominance of the single congener, BDE-47 (64% of total PBDEs), likely due in part to debromination pathways, reduced our ability to explore congener-specific dynamics of PBDEs in these pinnipeds. With 80% of our Steller sea lions exceeding a recent toxicity reference value for PCBs, the fasting-associated mobilization of these contaminants raises concerns about a heightened vulnerability to adverse effects during annual migrations.     

Polychlorinated biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in surface sediments from Monastir Bay (Tunisia,Central Mediterranean): Occurrence,distribution and seasonal variations

An assessment of PCB and PBDE contamination of surface sediments in Monastir Bay was carried out in two contrasted seasons of the year. Samples were collected from 5 sites and analyzed for the ∑₇ marker PCBs (i.e. PCBs 28, 52, 101, 118, 138, 153 and 180) and ∑₄ PBDE congeners (PBDEs 47, 99, 119 and 153) by GC/ECD. Concentrations of both PCBs and PBDEs showed seasonal variations. PCB concentrations were in the range of 3.1–9.3 ng g⁻¹ and 1.1–8.1 ng g⁻¹ in wet and dry season respectively, and sediments were considered moderately contaminated with PCBs. All PCBs analyzed were detected in surface sediments. PCB 153 and 52 congeners showed the highest relative abundance in both winter and summer. PBDE concentrations ranged from not detect to 0.1 ng g⁻¹, with only BDE-47 congener detected in sediments and only in winter. Analysis of spatial and seasonal variations indicated that PCB distribution is governed by hydrodynamics and temporal variability of inputs. While the PCB contamination appeared to be mainly land-based, PBDEs are suspected to originate from atmospheric deposition.     

Predicting the bioavailability of sediment-associated polybrominated diphenyl ethers using a 45-d sequential Tenax extraction

A 45-d Tenax extraction was used to evaluate the bioavailability of polybrominated diphenyl ethers (PBDEs) in three spiked sediments. The effect of aging on desorption kinetics of PBDEs was investigated by incubating one of the sediments for 7, 14, 30 and 60 d at room temperature. Desorption kinetics were well described by a three-compartment model. The fraction of very slow desorption (Fvs) contributed the most of the desorbed PBDEs from sediments. The total desorption amount of PBDEs decreased with the increase of total organic carbon in the sediments, suggesting that organic matter is an important factor controlling the partition of PBDEs in sediments. The total desorption amount of PBDEs decreased while log [(Fslow+Fvs)/Frap] increased with logKow of PBDE congeners, indicating that the bioavailability of PBDEs in sediment decreases with logKow of the congeners. As the residential time of PBDEs in the sediment increased from 7 to 60 d, Frap of individual PBDE congeners decreased gradually with simultaneous increase of Fvs. There was a good positive correlation between Frap and F6/F24, indicating that either 6 h or 24 h Tenax extraction could be a proxy for Frap and bioavailability. In general, the results in present study suggest that the bioavailability of nona- and deca-BDEs in sediment is very low due to their strong hydrophobicity and large molecular size.     

Polybrominated diphenyl ethers (PBDEs) in farmed and wild salmon marketed in the Northeastern United States

Recently, we reported on the analysis of polychlorinated biphenyls (PCBs) and chlorinated pesticides in farmed Atlantic salmon (Salmo salar) from Maine, eastern Canada, and Norway, and wild Alaskan Chinook salmon (Oncorhynchus tshawytscha). In this paper, we extend the analysis to polybrominated diphenyl ethers (PBDEs) in these samples. Total PBDE concentrations in the farmed salmon (0.4-1.4ng/g, wet weight, ww) were not significantly different from those in the wild Alaskan Chinook samples (0.4-1.2ng/g, ww), nor were significant differences found among regions. However, significant intra-regional variations in concentrations of total PBDEs and tetra-BDE 47 were observed in the salmon from the Canadian farms (p<0.01). Congener profiles were dominated by BDE-47, followed by the penta-BDEs 99 and 100. PBDE concentrations in the Canadian samples were lower than those reported two years earlier. Removal of skin resulted in no overall reduction in PBDE concentrations in our farmed salmon, and in some cases, PBDE concentrations were higher in skin-off samples. PBDEs were correlated with lipids only in the skinned samples, suggesting that there is greater accumulation and retention of PBDEs in muscle lipids than in skin-associated fat. In skin-on samples, modest correlations were observed between concentrations of PBDEs and PCBs (R(2)=0.47) and mono-ortho PCBs (R(2)=0.50), whereas PBDEs were not correlated with non-ortho PCBs.     

Seasonal variability of polychlorinated biphenyls (PCBs) and polychlorinated diphenyl ethers (PBDEs) congener profiles in butter in Poland: Dietary risk evaluation

Various statistical methods have been employed to analyse in details seasonal diversification of polychlorinated biphenyl (PCB)/polybrominated diphenyl ether (PBDE) congener profiles found in butter fat. The variability of the PCB/PBDE congener profiles indicates the presence of various sources of the milk fat contamination. The obtained results suggest that the environmental chemical background has the highest share in the contamination sources pattern. Ion trap mass spectrometry coupled to high-resolution gas chromatography with semi-permeable membrane dialysis sample cleanup was used for determination of PCBs and PBDEs in milk fat. Determined butter fat PCB profiles were similar to the profiles characteristic for Aroclor 1254 technical mixture. Our data indicate that dietary intake of PCB/PBDE with milk and milk products may be estimated to be about 717.5 pg kg b.w.^?1 day^?1 for six-indicator PCBs, 0.329 (equivalent toxicity, TEQ) pg kg b.w.^?1 day^?1 for 12 DL PCBs and 50 pg kg b.w.^?1 day^?1 for PBDEs (sum of 14 congeners).     

Polybrominated diphenyl ethers (PBDEs) in marine fish and blue mussels from southern Greenland

Levels of polybrominated diphenyl ethers (PBDEs) have not previously been reported in Greenland. In this study shorthorn sculpins (Myoxocephalus scorpius) were sampled at three locations in southern Greenland; Usuk (no population), Igaliko (population 40) and Qaqortoq (population 3200). Furthermore uvak (Gadus ogac), spotted wolffish (Anarhichas minor), starry ray (Raja radiata), and blue mussels (Mytilus edulis) were collected at Usuk. Pooled samples of fish liver and blue mussel were analysed for lower brominated PBDEs (BDE-47, BDE-99, BDE-100 and BDE-153). The highest PBDE levels were found in Qaqortoq followed by Igaliko and Usuk. The measured sum PBDE concentrations in shorthorn sculpin collected at Qaqortoq, Igaliko and Usuk, were 8.2, 3.1 and 2.1 all in units of microg kg(-1) wet weight. In female and male uvak collected at Usuk PBDE levels of 7.1 and 12.0 microg kg(-1) wet weight were measured, while the concentrations were 1.2 microg kg(-1) in spotted wolffish, 1.4 microg kg(-1) in starry ray and 0.11 microg kg(-1) in blue mussels from the same locality all measured on a wet weight basis. The highest concentrations were measured in uvak, a top-predator on fish indicating that PBDEs are biomagnifying. The level of tetra-hexa BDEs is 15-24 times lower than PCB levels measured in the same samples, except for shorthorn sculpin collected at Qaqortoq, where the level of PBDEs was 40 times lower than the level of PCBs. The high concentration of PCBs relative to PBDEs in shorthorn sculpin collected at Qaqortoq signifies a local emission of PCBs, which is higher than the local emission of PBDEs.     

Spatial distribution of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs) in an e-waste dismantling region in Southeast China: Use of apple snail (Ampullariidae) as a bioindicator

Fengjiang is a large e-waste dismantling site located in southeast China. In this paper, apple snail and soil samples were collected from this e-waste dismantling site and 25 vicinal towns to investigate the contamination status, spatial distributions and congener patterns of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs). Total PCB concentrations in apple snails (3.78-1812 ng g⁻¹ dry weight (dw)) were significant higher than that in soil samples (0.48-90.1 ng g⁻¹ dw). PBDE (excluding BDE 209) concentrations in apple snail and soil samples ranged from 0.09 to 27.7 ng g⁻¹ dw and 0.06 to 31.2 ng g⁻¹ dw, respectively. Concentrations of PCBs and PBDEs in snails and soils correlated negatively with the distance from Fengjiang. Both the concentrations and profiles of the pollutants were significantly correlated (p < 0.05) between the snail and soil samples, indicating the suitability of apple snail as a reliable bioindicator for PCBs and PBDEs contamination in this region. Relatively high concentrations of PCBs and PBDEs at locations far from e-waste dismantling sites implied that these pollutants have been transported to surrounding regions.     

Spatial trends of polybrominated diphenyl ethers in avian species: utilization of stored samples in the Environmental Specimen Bank of Ehime University (es-Bank)

The present study determined concentrations and patterns of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in specimens of open sea, and Japanese coastal and inland avian species, which have been stored in the Environmental Specimen Bank of Ehime University (es-Bank), to examine the spatial trends. PBDEs and PCBs were detected in all the muscle samples analyzed, suggesting that PBDE pollution has spread even to the remote open sea areas, as in the case of PCBs. Japanese coastal and inland birds accumulated higher concentrations of PBDEs than open sea birds. In addition, higher PBDE/PCB concentration ratios were observed in Japanese coastal and inland birds than in open sea birds, indicating the input of PBDEs into the Japanese terrestrial environment. Compositions of PBDEs varied among avian species with a predominance of BDE47 or BDE153. This could be due to differences in their habitat, food habit and/or biotransformation capacity of PBDEs.     

Concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in milk of women from Catalonia, Spain

In this study, the concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in milk from women living in the vicinity of a new hazardous waste incinerator (HWI) in Catalonia, Spain, were determined. The study was performed after 4 years of regular operations in the facility and the present PCB levels were compared with baseline concentrations obtained in a pre-operational program. PCBs and PBDEs levels were determined by HRGC/HRMS in 15 samples. In the present study planar PCBs ranged from 1.3 to 6.3 pg WHO-TEQ/g fat with a mean value of 3.8 pg WHO-TEQ/g fat. After adding dioxin-like mono-ortho-PCBs the total PCB-TEQ concentrations ranged from 3.8 to 13.3 pg WHO-TEQ/g fat (mean value: 8.7 pg WHO-TEQ/g fat). A comparison of the current data with those obtained in the baseline study showed significant decreases for both planar and total WHO-TEQ of PCBs: 47.9% and 44.6%, respectively. PCB concentrations in milk of women living in urban zones were higher than those living near industrial areas (10.1 and 7.4 pg WHO-TEQ/g fat, respectively). Mean PBDE concentrations were 2.2 and 2.5 ng/g fat for women living in urban and industrial zones, respectively. Dietary intake of PCBs and PBDEs for a standard adult woman samples were 898 and 843 ng/day for PCBs, and 72 and 63 ng/day for PBDEs, for residents in urban and industrials areas, respectively. This study suggests that dietary intake is more relevant for human exposure to PCBs and PBDEs than living near the HWI.     

Influence of age,season, body condition and geographical area on concentrations of chlorinated and brominated contaminants in wild mink (Neovison vison) in Sweden

The wild mink has gained acceptance as a sentinel species in environmental monitoring. However, only limited data are available in the literature on factors driving variability in concentrations of organic pollutants in this species. This study characterizes the differences in contaminant concentrations in subcutaneous fat of male mink from four different areas in Sweden and demonstrates how age, season and body condition influence concentrations of polychlorinated biphenyl (PCB) congeners, polybrominated diphenyl ether (PBDE) congeners (including methoxylated forms, MeO-PBDEs), as well as the pesticides dichlorodiphenyldichloroethylene (DDE), chlordane and hexachlorobenzene (HCB). The data were statistically treated using multiple regression and principal component analysis. The ∑PCB concentration and concentrations of PCB congeners 138, 156, 157, 180, 170/190, 189, 194, 206, 209 as well as PBDE 153/154 varied with age. Season had an influence on ∑PCB, PBDE 47 and PBDE 153/154 concentrations, as well as concentrations of most PCB congeners, with the exception of PCB 101, 110, 141 and 182/187. Lean mink had higher concentrations of most PCBs and PBDEs than mink with larger fat depots. The analyzed pesticides (DDE, oxychlordane, HCB) showed no systematic variation with season, age or body condition. The concentrations of MeO-PBDEs were generally low and 6MeO-PBDE 47 was the most commonly detected MeO-PBDE in mink from marine, brackish and freshwater areas. The results indicate that age, season and body condition are factors that may influence the concentrations of PCBs and PBDEs, and it is thus recommended to take these factors into account when analyzing mink exposure data.     

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in milk from Italian women living in Rome and Venice

The levels of selected polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in human milk samples from the areas of Venice and Rome, primarily in order to characterize the current levels of infant exposure to PCBs and PBDEs due to breast feeding in Italy. Sixteen non-dioxin-like PCBs, including the traditional indicator congeners, and 11 PBDEs, comprising the relevant PBDE-47, PBDE-99, and PBDE-153, were determined. Congeners were selected for analysis according to their relative abundance in human tissues, toxicological relevance, and diffusion in the environment. Dietary habits of the milk donors were recorded by questionnaires; mothers of the Venice area were classified into three groups according to their consumption of local fish, molluscs, and other fishery products. Sigma(16)(PCBs) and Sigma(11)(PBDEs) (ng g(-1) fat) for the areas of Venice and Rome were respectively, 250-390 and 240, and 1.6-2.8 and 4.1. An increase of fish and fishery product consumption could not be associated with an increase of PCB and PBDE levels in milk.     

Occurrence of co-planar polybrominated/chlorinated biphenyls (PXBs), polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in breast milk of women from Spain

In this study, for the first time, levels and accumulation profiles of eight currently available polybrominated/chlorinated biphenyl congeners (PXBs; XB-77, -105, -118, -126A, -126B, -126C, -156 and -169, named according to IUPAC nomenclature) in human breast milk collected form Spanish women in 2005 were reported. Concentrations and congener specific profiles of polychlorinated biphenyls (PCBs), including co-planar PCBs, (co-PCBs) and polybrominated diphenyl ethers (PBDEs) were also reported.A concentration of 0.45 pg g⁻¹ lipid weight was found for total PXBs, and arithmetic mean concentrations of 125, 25 and 5.5 ng g⁻¹ lipid weight were determined for total PCBs, co-PCBs and total PBDEs respectively. Detectable levels of all congeners investigated, except CB-123 and XB-169 were found. Levels of PCBs were similar to those found in Spanish samples collected after 2000, and lower than those obtained before 2000. CB-138, -153 and -180 were the predominant PCB congeners. PBDE levels, dominated by BDE-47, -99, -100 and -209, were lower than PCB levels. PXB concentrations were the lowest, with XB-156 being the most abundant. The concentration levels of PCBs and PBDEs found in this study were in the same range as those from other European countries. Levels of PXBs were much lower than published values determined in Japan which were the only data found in the literature.     

Determination of potential sources of PCBs and PBDEs in sediments of the Niagara River

Sediments from Niagara River, an important waterway connecting two of the Great Lakes (Lake Erie to Lake Ontario), were analyzed for 14 congeners of polychlorinated biphenyls (PCBs) and 9 congeners of polybrominated diphenyl ethers (PBDEs) using accelerated solvent extraction and gas chromatography/mass spectrometry. Total concentrations of PCBs ranged from 1.7 to 124.6 ng/g were PCBs 138 and 153 were found in all samples. All sites but one showed PBDE in sediments with total concentrations as high as 148 ng/g, suggesting that PBDE is becoming an important class of POP. A land-use and coverage map was used to trace potential localized sources of PCB and PBDE contamination. Results indicate that the highest levels of PCBs and PBDEs were found in sediments collected from areas closest to the discharge locations of municipal wastewater treatment plants (WWTP) and local industries. This is the first study that suggests the importance of WWTP discharges as a potential source of PBDE contamination in the Great Lakes.     

Organochlorine levels in viperine snake Natrix maura carcasses from the ebro delta (NE Spain): Sexual and size-related differences

Organochlorine compounds (PCBs, DDTs and HCB) in carcasses from a population of the Viperine Snake (Natrix maura) living in the Ebro Delta were analyzed. This is a wetland area on the Mediterranean coast where the natural ecosystem has been partially substituted by rice fields. High levels of pollutants (mainly DDTs and PCBs) have been detected in several species living in this area, due to the production of these compounds by a former industrial activity upstream as well as agricultural activity in the Delta. Organochlorines were analyzed in adult males and females, and in immature snakes. DDTs (mainly p,p′-DDE) were the most abundant pollutant present. The DDT/PCB ratio was higher than expected, which is consistent with the position of the Viperine Snake in the trophic web as well as the type of prey consumed. Immature snakes had more organochlorines than adults. However, the broad range of concentrations shown by immature snakes, suggested that part of the organochlorine load is transferred from gravid females to their eggs. In adults, organochlorine concentrations increased with carcass weight in both males and females. This increase was higher in males since females lost contaminants through fat investment during vitellogenesis. Seasonally, PCBs and DDTs levels increased in spring when snakes showed higher feeding activity, whereas higher levels of HCB were present at the end of summer, when the river input increased. Furthermore, HCB does not seem to biomagnify well across the trophic chain. Organochlorine concentrations in Viperine Snake carcasses were high since: 1) the dry tissue had less than 5% of fat, and 2) snakes were caught many years after the DDT ban, supporting the fact that cleaning of the ecosystem does not occur easily. These results indicate that snakes are adequate as indicators of the contamination in natural ecosystems but sex and body size of the samples should be taken into account for interpretation of results.     

Distribution of polychlorinated biphenyls and polybrominated diphenyl ethers in birds of prey from Switzerland

Polychlorinated biphenyls (PCBs) and the structurally related polybrominated diphenyl ethers (PBDEs) have been associated with chronic neurotoxicity involving reduced motor activity and impaired attentiveness. Such neurobehavioral effects indicate that the central nervous system may represent an important target organ for the action of these persistent contaminants in wildlife. As a consequence, the brain of different terrestrial and aquatic birds collected in Switzerland was analysed for PCBs and PBDEs. In parallel, the same contaminants were examined in the accompanying adipose tissue. After clean-up by means of glass columns containing acidified silica, deactivated alumina and anhydrous sodium sulphate, the samples were analysed by high resolution gas chromatography/tandem mass spectrometry (HRGC-MS/MS). Median PCB concentrations in the brain (sum of PCB 28, PCB 52, PCB 101, PCB 118, PCB 138, PCB 153 and PCB 180) ranged between 13 ng g(-1) wet weight (ww) in blackbirds (Turdus merula) and 428 ng g(-1) ww in sparrow hawks (Accipiter nisus). Median PBDE concentrations in the brain (sum of BDE 28, BDE 47, BDE 99, BDE 100, BDE 153, BDE 154 and BDE 183) ranged from below the decision limit in buzzards (Buteo buteo) and blackbirds, to 14 ng g(-1) ww in sparrow hawks. After correction for the respective lipid content, higher PCB or PBDE concentrations in brain compared to adipose tissue, were found in three sparrow hawks, four buzzards and in all investigated blackbirds. These results suggest that a deficit in the neuroprotective function of the blood-brain barrier may cause unexpected levels of PCBs and PBDEs in the central nervous system.     

Levels and bioaccumulation of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in fishes from the Pearl River estuary and Daya Bay, South China

Fifty fish samples were collected from the Pearl River estuary (PRE) and Daya Bay, South China and were analyzed for DDTs, HCHs, chlordanes and polybrominated biphenyl ethers (PBDEs). Except the high concentrations of DDT observed in fishes, the concentrations of HCHs, chlordanes and PBDEs were low when compared to other regions. BDE-47 was the predominant PBDE congener and the BDE-209 concentrations were relatively low, despite its high concentration in surface sediments. The absence of significant increase of DDT, HCH, chlordane and PBDE concentrations towards higher delta15N values, as well as the lack of a significant correlation (p<0.1) between log concentrations (lipid normalized) and delta15N, may indicate a weak biomagnification of these chemicals in the food webs. Good agreement was observed between their concentrations and lipid contents of the organisms. Bioconcentration was suggested to be responsible for the accumulation of OCPs and PBDEs in the lower trophic organisms in the studied subtropical waters.