Concentrations of organochlorine pesticides and polychlorinated biphenyls in human serum and their relation with age,gender, and BMI for the general population of Bizerte,Tunisia

Human serum samples (n?=?113) from Bizerte, northern Tunisia, collected between 2011 and 2012 were analyzed for 8 organochlorine pesticides (OCPs) including p,p′-dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), hexachlorocyclohexane isomers, dieldrin, and heptachlor and 12 polychlorinated biphenyls (PCBs) congeners. Concentrations of these residues in serum were determined by gas chromatography with electron capture detector and total cholesterol (CHOL) and triglycerides (TG) levels were evaluated by enzymatic colorimetric method. HCB, p,p′-DDE, PCB-138, PCB-153, and PCB-180, were the most abundant organochlorine compounds (OCs) detected in >95 % of the study subjects. The mean levels of p,p′-DDE and HCB in serum were 168.8 and 49.1 ng?g^?1 lipid, respectively. The sum PCBs concentrations ranged from 37.5 to 284.6 ng?g^?1 lipid in the samples, with mean and median value of 136.1 and 123.2 ng?g^?1 lipid, respectively. The PCB profile consisted of persistent congeners, such as PCB-138, PCB-153, and PCB-180 which contributed for approximately 82.7 % to the ∑PCBs. Statistical analysis showed that most OCs correlated significantly with age, considering all samples together or with gender differentiation. The present study shows that the levels of p,p′-DDE and ∑DDTs were significantly higher in females than in males (p?<?0.05), while PCBs levels were significantly higher in male (p?<?0.05) than in females. No statistically significant association was found between body mass index and concentration of any organochlorine pesticide or PCB congeners 153, 138, 180, or ∑PCBs.     

Comparison of seven indicator PCBs and three coplanar PCBs in beef, pork, and chicken fat

The risk assessment of polychlorinated biphenyls (PCBs) is difficult since complex congeners were used in many industrial applications for a long period of time and the residue monitoring in foods of animal origin and the environment were not established in comparable systems. The relationships of determined concentrations in indicator PCB congeners (mono- and di-ortho PCBs) and coplanar PCB congeners (non-ortho PCBs) in livestock products are presented in this study. The concentrations of seven indicator PCBs were compared with three coplanar PCBs in beef, pork, and chicken fat. Distributions of concentration for the indicator PCBs in three different animal species were similar except for that of PCB-118 (2,3',4,4',5-pentachlorobiphenyl) in pork fat. The congeners with the highest concentration were PCB-138 (2,2',3,4,4',5'-hexachlorobiphenyl) in beef and pork fat and PCB-28 (2,4,4'-trichlorobiphenyl) in chicken fat. The bioaccumulation and metabolism of PCBs in animal species represent different congener profiles in livestock products. The percentage of the total concentration of three coplanar PCBs was about 2% of the total concentration of the seven indicator PCBs. Relatively high concentration of mono-ortho and di-ortho PCBs in fat samples of livestock products may be calculated with the concentration of coplanar PCBs that can be usually determined on a sequential procedure with dioxin analysis. Therefore, the relationship of the amounts between seven indicator PCBs and three coplanar PCBs may be useful to derive the composition and level of contaminants in beef, pork, and chicken.     

Highly toxic coplanar PCBs: occurrence, source, persistency and toxic implications to wildlife and humans

Isomer-specific determinations of PCB congeners in a wide variety of animal species such as fish, marine mammals (whale, dolphin and porpoise) and terrestrial mammals (dog, cat and human) revealed the environmental occurrence of highly toxic coplanar 3,3',4,4'-tetrachlorobiphenyl (T(4)CB), 3,3',4,4',5-pentachlorobiphenyl (P(5)CB) and 3,3',4,4',5,5'-hexachlorobiphenyl (H(6)CB) within a range of few pg g(-1) to several ten ng g(-1) in fat tissues (except fish) on a wet weight basis. Detection of these toxic residues in wild specimens collected from remote areas such as the North Pacific suggests the already widespread distribution of coplanar PCBs as in the case of general PCB pollution. The clear positive correlations between concentrations of total PCBs and each of the three coplanar PCBs obtained in all mammals analysed suggest that the sources of coplanar PCB contamination to the environment are mainly commercial PCB preparations. Comparison of the composition of three toxic coplanar PCBs in commercial PCB mixtures and in the various animals indicates the relative metabolisability of these congeners as follows: 3,3',4,4'-T4CB>3,3',4,4',5-P5CB>3,3',4,4',5,5'-H6CB. Moreover, marine mammals seem to have lower potency to metabolise the coplanar PCBs in comparison with terrestrial mammals. In human adipose tissues, the concentrations of coplanar PCBs were found to be much higher than 2,3,7,8-tetrachlorodibenzo-p-dioxin (T(4)CDD), 2,3,4,7,8-pentachlorodibenzofuran (P(5)CDF) and other toxic congeners. 'T(4)CDD-equivalent' analysis based on the enzyme induction potencies and the residues of these toxic chemicals indicates that 3,3',4,4',5-P(5)CB may impose a greater toxic threat than dioxins and furans to the humans and probably to wildlife also.     

Accumulation status of persistent organochlorines in albatrosses from the North Pacific and the Southern Ocean

Current status of contamination by persistent organochlorines (OCs) such as polychlorinated biphenyles (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), isomers of hexachlorocyclohexane (HCHs), hexachlorobenzene (HCB) and chlordane compounds (CHLs) were examined in 61 individuals belonging to eight albatross species collected from the North Pacific and the Southern Ocean. Generally high OC concentrations were found in albatrosses from the North Pacific than those from the Southern Oceans. Black-footed albatrosses had noticeably high PCBs and DDTs concentrations with mean values of 92 and 33 micrograms/g wet weight in subcutaneous fat, respectively. Among the other OCs, concentration of CHLs was higher than that of HCB in North Pacific albatrosses. HCHs accumulation was the lowest among all the OCs analyzed. Species-specific differences were observed for HCB, CHLs and DDTs in some species in the Southern Ocean. No significant difference of gender and age-related accumulation was observed in total OCs. However, PCB concentrations were higher in mature birds than those from immature ones in the Southern Ocean. Species-specific accumulation patterns of OCs in albatrosses were closely related with their feeding, migration, age and geographical ranges.     

Long-term trends of continental-scale PCB patterns studied using a global atmosphere–ocean general circulation model

Continental-scale distribution and inter-continental transport of four polychlorinated biphenyl (PCB) congeners (28, 101, 153, 180) from 1950 to 2010 were studied using the global multicompartment chemistry transport model MPI-MCTM. Following identical primary emissions for all PCB congeners into air, most of the burden is stored in terrestrial (soil and vegetation) compartments. Thereby, PCB-28, PCB-101 and PCB-153 show a shift of the soil burden maxima from source to remote regions. This shift is downwind with regard to the westerlies for Eurasia and upwind for North America and more prominent for the lighter PCBs than for PCB-153 or PCB-180. In meridional direction, all congeners' distributions underwent a northward migration in Eurasia and North America since the 1950s. Inter-continental transport from Eurasian sources accounts largely for contamination of Alaska and British Columbia and determines the migration of the PCB distribution in soil in North America. Trans-Pacific transport occurs mainly in the gas phase in boreal winter (December-January-February) at 3-4 km altitude and is on a multi-year time scale strongly linked to the atmospheric pressure systems over the Pacific. Inter-continental transport of the lighter, more volatile PCBs is more efficient than for the heavier PCBs.     

A survey of PCB congeners in U.K. cows'' milk

Samples of unpasteurised bulked milk, taken directly from ten herds of dairy cattle on rural and urban farms in the north west of England on five separate sampling occasions, were analysed for a range of PCB congeners. ΣPCB concentrations (sum of 37 congeners) ranged from 3.4–16.4 ng/g milk fat with a mean ΣPCB concentration of 8.4 ng/g milk fat. The dominating congeners were 118, 153, 138 and 180, which contributed 15%, 20%, 17% and 9% of the ΣPCB load respectively. The chlorine pattern of the congeners which made moderate or major contributions to the ΣPCB concentration were typically substituted at both para positions (4, 4′), while the PCB congeners not detected in the milk had at least one ring that was not 4-substituted. These results indicate the 4,4′ substitution pattern as being the key to PCB persistence in cows. It is estimated that consumption of typical daily intakes of milk with the PCB concentrations measured in this study would contribute 11 % of the average daily ΣPCB intake for individuals in the UK. This contribution would increase to 30% when exposure through the consumption of dairy products prepared from such milk (e.g. cheese, butter) is taken into account. It is estimated that the inclusion of the TEF assigned PCBs would typically increase the TEQ rating of cows' milk by approximately 40% over that attributed to PCDD/Fs alone.     

Profile of persistent chlorinated contaminants,including selected chiral compounds,in wolverine (Gulo gulo) livers from the Canadian Arctic

Wolverines (Gulo gulo) are circumpolar omnivores that live throughout the alpine and arctic tundra ecosystem. Wolverine livers were collected at Kugluktuk (Coppermine), NU (n=12) in the western Canadian Arctic to report, for the first time, the residue patterns of persistent organochlorine contaminants (OCs) in this species. The enantiomer fractions (EFs) of several chiral OCs, including PCB atropisomers, in wolverines were also determined. Results were compared to OC concentrations and EFs of chiral contaminants in arctic fox (Alopex lagopus) from Ulukhaqtuuq (Holman), NT (n=20); a closely related species that scavenges the marine and terrestrial arctic environment. The rank order of hepatic concentrations for sum ( summation operator ) OC groups in wolverines were polychlorinated biphenyls ( summation operator PCB)>chlordane-related components ( summation operator CHLOR)>DDT-related compounds ( summation operator DDT)>hexachlorocyclohexane isomers ( summation operator HCHs). The most abundant OC analytes detected in wolverine liver were PCB-153, PCB-180, and oxychlordane (OXY). Wolverine age and gender did not influence OC concentrations, which were comparable to lipid-normalized values in arctic fox. The EFs of several chiral OCs (alpha-HCH, cis- and trans-chlordane, OXY, heptachlor exo-epoxide) and PCB atropisomers (PCB-136, 149) were nonracemic in arctic fox and wolverine liver and similar to those previously calculated in arctic fox and polar bears from Iceland and the Canadian Arctic. Results suggest that these species have similar ability to biotransform OCs. As well, contaminant profiles suggest that terrestrial mammals do not represent the major source of OC exposure to wolverines and that wolverines are scavenging more contaminated prey items, such as marine mammals. While summation operator PCB did not exceed the concentrations associated with mammalian reproductive impairment, future research is required to properly evaluate the potential affect of other OCs on the overall health of wolverines.     

Polychlorinated biphenyls in small mammals from contaminated landfill sites

PCBs in small mammals living in a contaminated landfill site varied in both concentration and congener composition, reflecting both the feeding strategy of each species and the chlorination of the congeners. Body concentrations of SigmaPCB on a 1:1:1 Arochlor (1242:1254:1260) basis gave a rank order of Sorex araneus > Apodemus sylvaticus > Microtus agrestis. Comparisons with data for other PCB-contaminated sites suggest that the SigmaPCB values in S. araneus from the landfill site may be of sufficient magnitude to inhibit reproductive capability and to cause other major organ dysfunction. There were also inter-specific differences in the whole body concentrations of the individually quantified congeners. For S. araneus, the rank order of concentrations of the selected ICES 7 marker PCB congeners was: No. 153>138>180>118>28>101>52. In M. agrestis the rank order was: No. 28>118>153>138>180, 52>101. The congener order for A. sylvaticus differed from both S. araneus and M. agrestis, but was more similar to the latter, being: No. 153>138>118>180>28>52, 101. The contribution of the different congeners to SigmaPCB in the mammals reflects the degree of chlorination of different congeners but varies with feeding strategy of the species. In the insectivorous S. araneus, heavily chlorinated congeners (Nos 153, 138 and 180) are most abundant, whereas the herbivore, M. agrestis showed congeners Nos 28 and 118 to be present in the highest amounts, whilst the equivalent pattern for the more omnivorous A. sylvaticus was intermediate between S. araneus and M. agrestis. The high concentrations of PCBs in S. araneus relative to the other species, suggests that it may serve as a useful biomarker of terrestrial environmental pollution by organochlorines.     

Concentration levels and congener profiles of polychlorinated biphenyls, pentachlorobenzene, and hexachlorobenzene in commercial pigments

The concentration levels and congener profiles of polychlorinated biphenyls (PCBs), pentachlorobenzene (PeCBz), and hexachlorobenzene (HxCBz) were assessed in commercially available organic pigments. Among the azo-type pigments tested, PCB-11, which is synthesized from 3,3′-dichlorobendizine, and PCB-52, which is synthesized from 2,2′,5,5′-tetrachlorobendizine, were the major congeners detected. It is speculated that these were byproducts of chlorobendizine, which has a very similar structure. The total PCB concentrations in this type of pigment ranged from 0.0070 to 740 mg/kg. Among the phthalocyanine-type pigments, highly chlorinated PCBs, mainly composed of PCB-209, PeCBz, and HxCBz were detected. Their concentration levels ranged from 0.011 to 2.5 mg/kg, 0.0035 to 8.4 mg/kg, and 0.027 to 75 mg/kg, respectively. It is suggested that PeCBz and HxCBz were formed as byproducts and converted into PCBs at the time of synthesizing the phthalocyanine green. For the polycyclic-type pigments that were assessed, a distinctive PCB congener profile was detected that suggested an impact of their raw materials and the organic solvent used in the pigment synthesis. PCB pollution from PCB-11, PCB-52, and PCB-209 pigments is of particular concern; therefore, the monthly variations in atmospheric concentrations of these pollutants were measured in an urban area (Sapporo city) and an industrial area (Muroran city). The study detected a certain level of PCB-11, which is not included in PCB technical mixtures, and revealed continuing PCB pollution originating from pigments in the ambient air.     

Formation of polychlorobiphenyls in silicone rubber

In silicone rubber crosslinked with bis(2,4-dichlorobenzoyl) peroxide (DCBP) as initiator about 0.1% of DCBP is converted into polychlorobiphenyls (PCBs). The PCB content in silicone rubber determined by high resolution gas chromatography (HRGC) after its destruction by HF is around 10 mg/kg. 29 PCB congeners were detected. Instead of the expected PCB-47, lower chlorinated congeners are predominant. Some possible pathways of their origin are presented.     

Accumulation and tissue distribution of selected polychlorinated biphenyl congeners in chickens

During one to three consecutive periods of 2 weeks, broiler chickens (n = 108) received test dies to which different amount of PCBs (7 congeners) were added. The relationship between exposure time and accumulation of individual congeners in different chicken tissues, such as breast, thigh and abdominal fat tissue, was observed. In all tissues, the vast majority of the PCB accumulation occurred during the first 2 weeks of exposures. After that, PCB concentrations only increased in the abdominal fat tissue of the animals. The individual PCBs were distributed differently in the various tissues. While CBs 28, 118, 138, 153 and 180 accumulated in the chickens, CBs 52 and 101 were metabolized, but no methyl sulphone metabolites of these congeners could be detected. Our results provide information on the absorption, tissue distribution and biotransformation of the individual PCB congeners and confirm the structure-activity relationships for metabolism of PCBs in birds, which are different from those in fish or mammalian species.     

Olive tree, Olea europaea L., leaves as a bioindicator of atmospheric PCB contamination

Olive tree leaf samples were collected to investigate their possible use for biomonitoring of lipophilic toxic substances. The samples were analyzed for 28 polychlorinated biphenyls (PCB) congeners. Twelve congeners were detected in the samples. PCB-60, 77, 81, 89, 105, 114, and 153 were the most frequently detected congeners ranging from 32 % for PCB-52 to 97 % for PCB-81. Σ₁₂PCBs concentration varied from below detection limit to 248 ng/g wet weight in the sampling area, while the mean congener concentrations ranged from 0.06 ng/g (PCB-128?+?167) to 64.2 ng/g wet weight (PCB-60). Constructed concentration maps showed that olive tree leaves can be employed for the estimation of spatial distrubution of these congeners.     

Temporal and spatial trends of PCB congeners in UK gannet eggs

Gannet (Sula bassana) eggs collected from Ailsa Craig, Western Scotland between 1977-1998 have been analyzed retrospectively for several PCB congeners. Concentrations of a range of congeners were determined in 8-10 eggs analyzed separately for several individual years. All congeners declined in concentrations throughout the time period, but the rates of decline differed for different congeners. Declines were first order and half-lives varied between 5.4 years for PCB-101 to 10.1 years for PCB-180. Egg concentrations reflect the maternal body burden, which itself is controlled by the birds rate of intake (principally via the diet) and losses (via metabolism and other clearance mechanisms). The declining concentrations in eggs, therefore, broadly reflect reductions in prey concentrations (principally herring and mackerel) and--in turn--water column concentrations. Rates of change in PCB concentrations from this study were similar to those noted in fish-eating birds from the Baltic Sea and North American Great Lakes, and ambient air in the UK. This provides indirect evidence that gannet eggs are broadly reflecting regional/global scale clearance/removal mechanisms which are controlling ambient PCB concentrations.     

Study of transportation and distribution of PCBs using an ecologically simulated growth chamber

This study was designed to investigate the transportation, distribution, and bioaccumulation of PCBs in various environmental media and compartments using an ecologically simulated growth chamber. Spatial and temporal trends of PCBs in the growth chamber were discussed. The release of PCB congeners in soil was affected by the amount of rainfall with the transporting direction moving away from PCBs contaminated point. Two pathways of PCBs accumulation in plants were the uptake of roots and the deposition on shoots/leaves. There were 29 PCB congeners been found in the lalang grass. Higher concentrations of lower chlorinated PCBs were identified than higher chlorinated PCBs because of relatively higher vapor pressure for lower chlorinated congeners. After 10months of monitoring, PCBs were detected in water samples which were contributed by the release of PCBs from leached soil. Analysis of sediment showed that the percentages of low- and mid-chlorinated biphenyls were decreased 1% and 13%, respectively compared to the increase (14%) of high-chlorinated biphenyls. The increase of high-chlorinated PCBs was possibly caused by their low hydrophilicity which had resulted higher adsorption rate in sediment. All of five species of fish had been found significant amount of PCBs accumulation ( summation operatorPCBs: 21.7-102.1 microg/g-lipid). The concentrations of PCBs in fish were varied significantly among species. The range of bioaccumulation factors (BAFs) among different species of fish could be as much as 5 times depending on the consumption habits of fish. The mass balance of PCBs distribution in the growth chamber was also discussed.     

Polychlorinated biphenyls (PCBs) in marine fishes from China: Levels, distribution and risk assessment

Muscle tissues of large yellow croakers (Pseudosciaena crocea) and sliver pomfret (Pampus argenteus) from nine coastal cities of East China including Dalian, Tianjin, Qingdao, Shanghai, Zhoushan, Wenzhou, Fuzhou, Quanzhou and Xiamen were analyzed for polychlorinated biphenyl (PCB) concentrations. Thirty-six PCB congeners were quantified in the fishes, of which 11 congeners were dioxin-like PCBs. The total PCB concentrations of the present study were at the low end of the global range, which may be related to the smaller usage and shorter consumption history of PCBs in China. PCBs 18, 29, 52, 66, 101, 104, 138, 153, 180 and 194 were the major constituents found in the fish samples. Regression analysis showed a strong positive correlation (R² = 0.800; p < 0.001) between total dioxin-like PCBs and total PCB concentrations, and that total PCB concentrations explain 80% of the variability in total dioxin-like PCB concentrations. Among the species investigated, significantly higher concentrations of total PCBs were found in croakers than in pomfrets, which may be attributed to their different feeding and living habits. No significant difference in total PCB concentrations among the cities was observed; principal component analysis (PCA) of PCB profiles indicated that PCB pollution came from similar sources in the sampling areas and that there may be other PCB sources in Dalian and Wenzhou. The calculated carcinogenic risks (CRs) from the two species based on a low consumption group and high consumption group were all greater than 10⁻⁶, suggesting that daily exposure to dioxin-like PCBs via fish consumption results in a lifetime cancer risk of greater than one in one million. In contrast, the hazard quotients (HQs) of noncancer risks were all less than unity.     

Concentrations and compositions of organochlorine contaminants in sediments, soils, crustaceans, fishes and birds collected from Lake Tai, Hangzhou Bay and Shanghai city region, China

Contamination by persistent organochlorines (OCs), such as DDTs, hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs) were examined in sediments, soils, fishes, crustaceans, birds, and aquaculture feed from Lake Tai, Hangzhou Bay, and in the vicinity of Shanghai city in China during 2000 and 2001. OCs were detected in all samples analyzed, and DDT and its metabolites were the predominant contaminants in most sediments, soils and biota. Concentrations of p,p'-DDT and ratio of p,p'-DDT to SigmaDDTs were significantly higher in marine fishes than those in freshwater fishes. While the use of DDTs has been officially banned in China since 1983, these results indicate a recent input of technical DDTs into the marine environment around Hangzhou Bay. Comparison of organochlorine concentrations in fishes collected from Lake Tai and Hangzhou Bay suggests the presence of local sources of HCHs, chlordanes and PCBs at Lake Tai. Higher proportions of penta- and hexa-PCB congeners in fishes at Lake Tai may suggest the use of highly chlorinated PCB product, such as PCB(5), around this lake. To our knowledge, this is a first comprehensive study to examine the present status of organochlorine contamination in various environmental media, such as sediments, soils and wildlife, in China.     

Polychlorinated biphenyls in different trophic levels from a shallow lake in Argentina

Polychlorinated biphenyls (PCBs) were determined in a aquatic community from Los Padres Lake, Argentina. Twenty four PCB congeners from tri- to octa-chlorinated isomers were detected and quantified using conventional gas chromatography with electron capture detector (GC-ECD). The aim of this study was to investigate the concentrations of PCBs in freshwater organisms from a shallow lake of Argentina. Stems of bulrush (Schoenoplectus californicus), whole tissues of false loosestrife (Ludwigia sp.) and grass shrimp (Palaemonetes argentinus), and liver, gonads, muscle and mesenteric fat (if present) of fish species (Rhamdia sapo) and (Oligosarcus jenynsi) were analyzed. Two areas were selected to macrophytes sampling: the input area, main PCB source of the lake (Station 1), and the output area, a potential anoxic zone (Station 2). Macrophytes from Station 1 bioconcentrated higher total PCB levels than Station 2, showing that the former have received PCBs washed down from upstream areas. Penta- and hexa-congeners were enriched relative to other congeners in animal biota and macrophytes from Station 1, consistent with commercial mixture of Aroclor 1254 used in this region. In bulrush from Station 2 a predominance of tri- and tetra-chlorinated congeners was observed. Grass shrimp showed the lowest PCB values among animal biota. PCB concentrations in fish tissues varied with the species and the gonadal development. Mesenteric fat, only present in post-spawning organisms of R. sapo, had the highest values of PCBs relative to other tissues. A clearance of total PCBs in ovaries of post-spawning females of R. sapo was observed, but not in testes. O. jenynsi/P. argentinus biomagnification factor (BMF) had a mean value of 18.7. Congeners 44, 52 and 151, showed the highest BMF values, being 64, 66 and 62, respectively. These values would be a consequence of the low depuration rate of 44 and 52 congeners with orthochlorine substitution conducted by O. jenynsi and the high depuration rate of congener 151, which lacks 4 4^′- chlorine substitution, carried out by grass shrimp. Although the most of congeners have been biomagnified, they did not clearly displayed a concomitantly increasing with log K_ow.     

Patterns of PCBs and PCDD/PCDFs in chicken and pork fat following a Belgian food contamination incident

A food contamination incident involving polychlorobiphenyls (PCBs) and PCDD/Fs occurred in 1999 in Belgium. On heavily affected farms, concentrations of PCBs in chicken or pork fat exceeded the Belgium tolerance limit of 200 ng/g lipid weight for the sum of seven marker PCBs. Analysis of contaminated samples showed that the patterns for PCB and PCDD/F congeners differed among feed, chicken fat and pork fat. Lower chlorinated PCBs and polychlorodibenzofurans (PCDFs) including those with high TEFs (PCBs 105, 118, 126 and 2,3,4,7,8-PeCDF) were shown to either bioaccumulate more in chicken fat or to be eliminated more readily in pork. This leads to the possibility that consumption of chicken would result in a higher TEQ human body burden than that from the same consumption of pork. In addition, PCDF congeners with non-2,3,7,8-substitution (e.g., 1,2,4,7,8-PeCDF) were present in chicken fat but absent in pork fat. Since the residue pattern in this commercial episode changes less in the avian species, these results reinforce the value of birds rather than mammals as markers of the source of contamination with persistent organochlorine pollutants.     

Bioaccumulation of PCBs in Arctic seabirds: influence of dietary exposure and congener biotransformation

Four seabird species and their prey (zooplankton or fish) were collected in the Barents Sea to determine how dietary exposure, cytochrome P450 (CYP) enzyme activities and sex influenced their hepatic PCB concentrations and accumulation patterns. Five males and five females from each seabird species (little auk (Alle alle), Brunnich's guillemot (Uria lomvia), black guillemot (Cepphus grylle) and black-legged kittiwake (Rissa tridactyla)) were analysed. PCB concentrations could not be explained directly by carbon source (delta13C) or trophic position (delta15N), but by a combination of dietary parameters (delta13C, delta15N, migratory pattern, age) and contaminant metabolism. Contrary to previous studies, the PCB pattern differed among seabirds, with a higher proportion of persistent congeners (% of PCB-153, RPCB-153) in black-legged kittiwake than in auks. The PCB pattern also differed among auks, with little auk as the most efficient biotransformer (highest RPCB-153 values of persistent congeners). Based on high RPCB-153 values, Brunnich's guillemot poorly metabolised ortho-meta-unsubstituted congeners, whereas black guillemot poorly metabolised meta-para unsubstituted congeners. Species-specific differences in PCB biotransformation were confirmed by metabolic indices, where PCB patterns in seabirds were adjusted for PCB pattern in prey. The relative contribution of ortho-meta-unsubstituted congeners to SigmaPCBs decreased with increasing EROD activity. There were no differences in PCB concentrations, PCB patterns or cytochrome P450 enzyme activities between males and females. CYP P450 activities (CYP1A- and CYP2B/3A-like: EROD and testosterone 6beta-hydroxylation, respectively) were low and did not correlate with concentrations of non- or mono-ortho Cl-substituted PCBs (NO- and MO-PCBs), or with total toxic equivalent concentrations (TEQs) for dioxin-like effects of NO- and MO-PCBs.     

Determination of coplanar and ortho substituted PCBs in some sewage sludges of Switzerland using HRGC/ECD and HRGC/MSD

The three most toxic coplanar PCB congeners PCB 77, 126 and 169 as well as 7 mono-and di-ortho-PCBs (PCB 28, 52, 101, 118, 153, 138, 180) were measured in 19 sewage sludges. Concentrations of the coplanar PCBs ranged between 231–5050 ng/kg dw for PCB 77, 43–1511 ng/kg dw for PCB 126 and 29–273 ng/kg dw for PCB 169. Comparable results were obtained with mass selective detection in the single ion monitoring mode (MSD-SIM) except for PCB 169, where MSD-SIM was less sensitive than ECD. The sum of the 7 mono-and di-ortho-PCBs, which are routinely measured as representatives of the PCB fraction, reached levels between 43–550 μg/kg dw and agreed well with results previously obtained in our laboratory. Based on our data, a selective accumulation of the coplanar PCBs could not be observed. Sludges that received industrial effluents clearly showed higher PCB levels than rural ones. Finally, calculation of TEQ equivalents of the coplanar PCBs in the sewage sludges revealed that, based on application rates normally used in Switzerland, the contribution of the sludges to soil pollution seems to be of minor importance.