Low hepatic 7-ethoxyresorufin-O-deethylase (EROD) activity and minor alterations in retinoid and thyroid hormone levels in flounder (Platichthys flesus) exposed to the polychlorinated biphenyl (PCB) mixture, Clophen A50

The effect of the polychlorinated biphenyl (PCB) mixture Clophen A50 on hepatic cytochrome P4501A1 dependent EROD (7-ethoxyresorufin-O-deethylase) activity, plasma thyroid hormone levels and plasma, kidney and liver retinoid concentrations of the euryhaline flatfish flounder (Platichthys flesus) was determined 2 and 10 days after i.p. (intraperitoneal) injection with 20, 100 and 500 mg Clophen A50/kg body weight. No effect of Clophen A50 on total cytochrome P450 content in flounder liver was observed at both time points. A six-fold, dose-dependent, significant increase in EROD activity was found at exposure day 10 in flounder receiving 100 or 500 mg Clophen A50/kg body weight. Plasma retinol concentrations were not altered at both time points after Clophen A50 administration, whereas renal retinol levels showed a minor dose-related increase at day 2 and day 10 of exposure. Significant alterations in hepatic retinoid concentrations were observed, which were not dependent on the dose of PCB administered. In addition Clophen A50 administration did not result in a dose-related alteration of total T4 concentrations in plasma. Total T3 concentrations in plasma were only significantly increased at day 2 after exposure, whereas free T4 concentrations were increased at both time points after Clophen A50 administration. These data indicate that with regard to the parameters investigated and in contrast to other fish species studied, the flounder is not a sensitive species to PCB exposure.     

The toxicity of tetrachlorobenzyltoluenes (Ugilec 141) and polychlorobiphenyls (Aroclor 1254 and PCB-77) compared in Ah-responsive and Ah-nonresponsive mice

The toxicity of the PCB substitute Ugilec 141, a mixture of tetrachlorobenzyltoluenes (TCBTs), is compared with the toxicity of a commercial mixture of polychlorobiphenyls (Aroclor 1254) and with the model toxic PCB-congener 3,3',4,4',-tetrachlorobiphenyl (PCB-77) as a positive control. Alterations in liver weight, hepatic cytochrome P450 content and EROD and PROD activity, plasma thyroxin and retinol level, hepatic retinoid level and liver and thyroid pathology, have been studied in Ah-responsive and Ah-nonresponsive mice. Ugilec 141 proved to induce similar toxicological changes, qualitatively and quantitatively, to Aroclor 1254. Therefore Ugilec may pose a similar environmental and health risk as PCBs. The criteria for acceptance of new substances, like Ugilec 141, on the European market are discussed.     

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.     

Levels, distributions and profiles of polychlorinated biphenyls in surface soils of Dalian, China

Surface soil (0-5cm) samples from 14 sampling sites including rural and urban areas of Dalian, a coastal city in Liaoning Province, China, were collected and analyzed for 84 polychlorinated biphenyls (PCBs). Total 57 PCB congeners were identified and mean concentration of total PCBs among all the sites was 2.8mugkg(-1) dry weight (dw) with a range of 1.3 (rural site) to 4.8mugkg(-1)dw (urban site). For the urban sites, total PCB concentrations in the soil samples collected in industrial area are highest, followed by those from business/residential sites and the garden sites, but the differences are not significant. Higher percentage of lighter weighted molecular PCBs were found in the rural site than urban sites in Dalian, possibly indicating the "urban fractionation effect". Total seven dioxin-like PCBs (CB-77, 81, 105, 114, 118, 123, and 126) have been found in Dalian soils and the mean concentration (in mugkg(-1)dw) among all the sites of CB-105 (0.17) is higher than any other dioxin-like PCBs, followed by that for CB-81 (0.14) and for 118 (0.06). No significant correlation relationship between the concentrations of dioxin-like PCBs and those of total PCBs was found. The toxic equivalency (TEQ) concentrations (in ngkg(-1)dw) of these seven dioxin-like PCBs in 14 soil samples range from 0.006(7) to 4.885(7) (with a mean 1.372(7)) for humans and mammals, from 0.001(7) to 0.37(7) (with a mean 0.14(7)) for fish, and from 0.01(7) to 31.47(7) (with a mean 17.23(7)) for birds.     

Uptake and depuration of toxic halogenated aromatic hydrocarbons by the American oyster (Crassostrea virginica): a field study

Uptake and depuration of toxic chlorinated compounds such as planar polychlorinated biphenyls (PCBs 77, 126, 169), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) were monitored during a 50-day field study where American oysters (Crassostrea virginica) were transplanted back and forth between a heavily polluted area (Houston Ship Channel, SC) and a relatively unimpacted area (Hanna's Reef, HR) within Galveston Bay, TX. In general, low molecular weight, less lipophilic compounds accumulated in the oysters to a larger extent than high molecular weight ones. Estimated half-lives for planar PCB congeners 77 and 126 were 28 and 51 days, respectively for depuration of newly contaminated oysters (HR-SC-HR) while longer half-lives (42 and 60 days, respectively) were observed for the same compounds as they were eliminated from chronically contaminated individuals (SC-HR). Estimated half-lives for 2,3,7,8-TCDD and 2,3,7,8-TCDF were 35 and 36 days, respectively and were similar to the tetrachlorinated biphenyls (PCBs 77 and 81). Compared with ortho-substituted PCB congeners of the same chlorination level, the more toxic PCBs take longer to depurate from the oysters. With few exceptions, elimination of all toxic compounds investigated proceeded at a slower rate from the chronically exposed population that from the newly contaminated one.     

Embryotoxicity of polycyclic aromatic hydrocarbons (PAHs) in three domestic avian species, and of PAHs and coplanar polychlorinated biphenyls (PCBs) in the common eider

The embryotoxicity of an artificial mixture of 18 polycyclic aromatic hydrocarbons (PAHs) was tested by injection into the yolk sacs of eggs of four avian species: chicken Gallus domesticus, turkey Meleagris gallopavo, domestic duck Anas platyrhynchos and common eider Somateria mollissima. A dose of 2.0 mg kg egg(-1) of the PAH mixture increased the mortality among the embryos of all four species. In the domestic duck, but not in the three other species, there was a significantly increased embryonic mortality at a dose of 0.2 mg kg(-1) of this mixture. All 18 individual compounds in the mixture were tested for embryotoxicity in the chicken. The compound most toxic to chick embryos was benzo[k]fluoranthene. This substance also proved to be highly embryotoxic in the three other species. Previous studies have shown coplanar polychlorinated biphenyls (PCBs) to be much more embryotoxic in the chicken than in other avian species studied. In accordance with this, eider duck embryos proved to be considerably less sensitive to 3,3',4,4'-tetrachlorobiphenyl and 3,3',4,4',5-pentachlorobiphenyl than was previously found for chick embryos. For PAHs, however, chick embryos did not have a higher sensitivity than the other species tested.     

Polychlorinated biphenyls and organochlorine pesticides in various bird species from northern China

Little data are available on organochlorine contamination in Chinese terrestrial birds of prey. This study examined the presence of PCBs, DDTs and other organochlorine pesticides in various raptors from northern China. DDE exhibited the highest concentrations among targeted compounds. Greatest levels (23.5-1020 mg/kg lipid weight) were observed in Eurasian sparrowhawks. This may be due to their stopover in southeastern China, where high DDT and dicofol applications have been documented. Residential kestrels exhibited much lower DDE, but similar PCB and HCH concentrations. ΣTEQs and PCB-126/-77 concentration ratios exhibited significant positive correlations with ΣPCB concentrations, respectively. Similar results were also demonstrated by a meta-analysis of previously published data across avian species. Possible hepatic sequestration of coplanar PCB-77, -126, -169 and -118 was observed as liver TEQs increased in Eurasian sparrowhawks. These observations may indicate an induction of CYP1A enzymes, as a result of elevated contamination in some species.     

Polybrominated diphenyl ethers and traditional organochlorine pollutants in fulmars (Fulmarus glacialis) from the Faroe Islands

The observed high-level burdens of organohalogens among the residents of the Faroe Islands, needs to be explained. Long-finned pilot whale (Globicephala melas) blubber and meat are known sources of environmental exposure. The present study focus on the organohalogen contamination of the fulmar (Fulmarus glacialis). The compounds quantified in fulmar muscle, fat, and egg are PCBs, DDTs, hexachlorobenzene (HCB), and polybrominated diphenyl ethers (PBDEs). The dominating pollutants are the 4,4'-DDT metabolite 4,4'-DDE and the two PCB congeners, CB-153 and CB-180, which are present in geometric mean concentrations of 7100, 4700 and 2500 ng/g lipid weight (l.w.), respectively, in adult fulmar muscle. 4,4'-DDT and HCB concentrations are approximately 250 ng/gl.w., each. Concentrations in the eggs are about 50% of the fulmar muscle levels, due to differences in lipid amounts, 4% in muscle and 10% in the eggs, the exposure contribution on a fresh weight basis is almost the same. As a result, both the egg and the adult fulmar muscle may lead to a significant exposure risk, if consumed by humans. BDE-153, the most abundant PBDE congener in fulmar muscle, with a geometric mean concentration of 6.5 ng/gl.w., is much lower than the individual PCB congeners and 4,4'-DDE concentrations. In the adult fulmar muscle, the relative PBDE congener pattern is different from that previously observed in biota, with BDE-153 and BDE-154 as the dominating congeners, rather than BDE-47. In contrast, BDE-47 is the most abundant congener in juvenile muscle and subcutaneous fat. The summation operatorPBDE concentrations are almost the same in egg, muscle (adult and juvenile) and subcutaneous fat (juvenile). For the polybrominated biphenyl (BB-153) the concentrations are considerably higher in the adult bird and egg than in the juvenile bird; this is also seen for the PCB and 4,4'-DDE concentrations. PCB concentrations found in fulmar egg and muscle are in the same range as seen in the pilot whale, i.e. 590-5700 ng/gl.w. for CB-153. Hence humans are also exposed to PCBs at a reasonable degree via intake of fulmar and/or fulmar egg and not only via pilot whale blubber.     

Dietary antioxidants (selenium and N-acetylcysteine) modulate paraoxonase 1 (PON1) in PCB 126-exposed rats

Environmental pollutants polychlorinated biphenyls (PCBs), especially dioxin-like PCBs, cause oxidative stress and associated toxic effects, including cancer and possibly atherosclerosis. We previously reported that PCB 126, the most potent dioxin-like PCB congener, not only decreases antioxidants such as hepatic selenium (Se), Se-dependent glutathione peroxidase, and glutathione (GSH) but also increases levels of the antiatherosclerosis enzyme paraoxonase 1 (PON1) in liver and serum. To probe the interconnection of these three antioxidant systems, Se, GSH, and PON1, we examined the influence of varying levels of dietary Se and N-acetylcysteine (NAC), a scavenger of reactive oxygen species (ROS) and precursor for GSH synthesis, on PON1 in the absence and presence of PCB 126 exposure. Male Sprague–Dawley rats, fed diets with differing Se levels (0.02, 0.2, or 2 ppm) or NAC (1 %), were treated with a single intraperitoneal injection of corn oil or various doses of PCB 126 and euthanized 2 weeks later. PCB 126 significantly increased liver PON1 mRNA, protein level and activity, and serum PON1 activity in all dietary groups but did not consistently increase thiobarbituric acid levels (thiobarbituric acid reactive substances, TBARS), an indicator of lipid oxidation and oxidative stress, in liver or serum. Inadequate (high or low) dietary Se decreased baseline and PCB 126-induced aryl hydrocarbon receptor (AhR) expression but further increased PCB 126-induced cytochrome P450 1A1 (CYP1A1) expression, the enzyme believed to be the cause for PCB 126-induced oxidative stress. In addition, a significant inverse relationship was observed not only between dietary Se levels and PON1 mRNA and PON1 activity but also with TBARS levels in the liver, suggesting significant antioxidant protection from dietary Se. NAC lowered serum baseline TBARS levels in controls and increased serum PON1 activity but lowered liver PON1 activities in animals treated with 1 μmol/kg PCB 126, suggesting antioxidant activity by NAC primarily in serum. These results also show an unexpected predominantly inverse relationship between Se or NAC and PON1 during control and PCB 126 exposure conditions. These interactions should be further explored in the development of dietary protection regimens.     

A synchronized amphibian metamorphosis assay as an improved tool to detect thyroid hormone disturbance by endocrine disruptors and apolar sediment extracts

Amphibian metamorphosis assays are used to evaluate potential effects of endocrine disrupting compounds on the thyroid hormone axis. In this study, Xenopus laevis tadpoles are kept in a solution of 0.2% thiourea (TU) to arrest and synchronise them in their development. The advantage of this synchronized amphibian metamorphosis assays is that synchronised tadpoles are available at any time to start metamorphosis experiments, and experimental groups are much more homogenous at the start of experimental exposure compared with groups selected from an untreated pool of animals. The water volume per animal was kept constant throughout the experimental period to overcome the influence of declining numbers of animals per aquarium due to metamorphosis and mortality on the density dependent development of the remaining tadpoles. Clophen A50 (a technical PCB mixture), the single congener 3,3',4,4'-tetrachlorobiphenyl (PCB 77) and apolar sediment extracts that were previously tested positive in the T-Screen, an in vitro proliferation assay for thyroid hormone disruption, were tested in the Synchronized Amphibian Metamorphosis Assay. Endpoints studied were mortality, malformations, body weight, and percentage of metamorphosed froglets at the end of the 60-day experimental period, percentage of tadpoles in different developmental stages, and developmental stage-dependent awarded penalty points. Dietary exposure to Clophen A50 (0.2-50mg/kg food) resulted in a significant increased percentage of tadpoles that did not pass metamorphosis at concentrations higher than 2mg/kg food. Time until metamorphosis in those animals that were able to metamorphose after the 60-days experimental period was significantly decreased. Dietary exposure to PCB 77, a congener that can be readily metabolised, did not result in significant effects in any exposure group (2-500 microg/kg food). Apolar sediment extracts from two of the three sites that are contaminated with a wide variety of chemicals significantly decreased the percentage of metamorphosed animals and significantly increased the number of tadpoles that remained in early and late metamorphic stages. These effects already occurred when the extracts where diluted more than 1000 times (on an organic carbon base) compared to environmental concentrations. The rank of potency was comparable to results obtained with the T-screen. This suggests the presence of thyroid hormone disrupting compounds in the aquatic environment and possible effects of such compounds on animal development in the wild.     

Tissue distribution and effects on hepatic xenobiotic metabolising enzymes of 2,3,3',4,4'-pentachlorobiphenyl (PCB-105) in COD (Gadus morhua) and rainbow trout (Oncorhynchus mykiss)

2,3,3',4,4'-Pentachlorobiphenyl, PCB-105 (IUPAC no. 105) was orally administered twice with a 4-day interval between dosings (total dose 10 mg kg(-1) body weight) to gonadally immature cod and rainbow trout of both sexes. The fish were killed 9 and 17 days after the first treatment, and the effects of PCB-105 on hepatic xenobiotic metabolising enzymes were determined by examining the cytochrome-P450-dependent ethoxyresorufin-O-deethylase (EROD) and aldrin epoxidase activities, and the EROD-catalysing P450 1A1 protein by indirect enzyme-linked immunosorbent assay (ELISA). Glutathione S-transferase activity towards 1-chloro-2,4-dinitrobenzene was included. The hepatic levels of the compound were determined. In addition, the distribution patterns of radio-labelled PCB-105 were studied by whole-body autoradiography. In exposed rainbow trout EROD activity and P450 1A1 by enzyme linked immunosorbent assay (ELISA) were significant induced, while GST activity was significant reduced. Exposed cod did not show significantly different enzyme values from controls, but percentage fat in the liver was significantly reduced. The whole cod liver contained about 1000 times more PCB-105 than the corresponding trout liver, and on a fat-weight basis the PCB level was five to six times higher in cod liver than in the rainbow trout liver. The autoradiographical investigation revealed high concentrations of radiolabelled compound in the liver and the brain of cod, while in rainbow trout the radiolabel was mainly confined to extrahepatic fat depots. These results demonstrate that the mono-ortho chlorinated coplanar analogue, PCB-105, has a different distribution pattern in the two fish species and that the potential for induction of the hepatic xenobiotic metabolising enzyme system seems to be lower in the cod than in the rainbow trout.     

Association between biomarkers of exposure to persistent organochlorine compounds (POCs)

Serum concentrations of CB-153 and p,p'-DDE were assessed for 354 men and women from the Swedish Fishermen's Families Cohort, and were found to correlate very well (Pearson's r=0.72). In this particular cohort the main source of exposure to persistent organochlorine compounds are consumption of contaminated fatty fish. High correlations between total PCB/CB-153 and p,p'-DDE have also been found in other population with similar exposure, but not in populations whose major source of exposure to persistent organochlorine compounds is not necessarily through the consumption of contaminated sea food. The authors suggest that when investigating a possible relation between exposure to persistent organochlorine compounds and different health outcomes in populations with exposure similar to the Swedish Fishermen's Families Cohort, there may be no need to analyze more than either CB-153 or p,p'-DDE.     

Perfluorooctane sulfonic acid and organohalogen pollutants in liver of three freshwater fish species in Flanders (Belgium): relationships with biochemical and organismal effects

A perfluorooctane sulfonic acid (PFOS) assessment was conducted on gibel carp (Carassius auratus gibelio), carp (Cyprinus carpio), and eel (Anguilla anguilla) in Flanders (Belgium). The liver PFOS concentrations in fish from the Ieperlee canal (Boezinge, 250-9031 ng/g wet weight, respectively) and the Blokkersdijk pond (Antwerp, 633-1822 ng/g wet weight) were higher than at the Zuun basin (Sint-Pieters-Leeuw, 11.2-162 ng/g wet weight) and among the highest in feral fish worldwide. Eel from the Oude Maas pond (Dilsen-Stokkem) and Watersportbaan basin (Ghent) had PFOS concentrations ranging between 212 and 857 ng/g wet weight. The hepatic PFOS concentration was significantly and positively related with the serum alanine aminotransferase activity, and negatively with the serum protein content in eel and carp. The hepatic PFOS concentration in carp correlated significantly and negatively with the serum electrolyte concentrations whereas a significant positive relation was found with the hematocrit in eel. Although 13 organochlorine pesticides, 22 polychlorinated biphenyl (PCB) congeners and 7 polybrominated diphenyl ethers (PBDEs) were also measured in the liver tissue, only PCB 28, PCB 74, gamma-hexachlorocyclohexane (gamma-HCH) and hexachlorobenzene (HCB) were suggested to contribute to the observed serological alterations in eel.     

Biochemical study on the protective role of folic acid in rabbits treated with chromium (VI)

Deleterious effects of chromium (VI) compounds are diversified affecting almost all the organ systems in a wide variety of animals. Therefore, the present study was carried out to determine the effectiveness of folic acid (FA) in alleviating the toxicity of chromium (VI) on certain biochemical parameters, lipid peroxidation, and enzyme activities of male New Zealand white rabbits. Six rabbits per group were assigned to one of four treatment groups: 0 mg FA and 0 mg Cr(VI)/kg BW (control); 8.3 microg FA/kg BW; 5 mg Cr(VI)/kg BW; 5 mg Cr(VI) plus 8.3 microg FA/kg BW, respectively. Rabbits were orally administered their respective doses every day for 10 weeks. Results obtained showed that Cr(VI) significantly (P < 0.05) increased the levels of free radicals and the activity of glutathione S-transferase (GST), and decreased the content of sulfhydryl groups (SH groups) in liver, testes, brain, kidney, and lung. The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AlP), acid phosphatase (AcP), and lactate dehydrogenase (LDH) were significantly decreased in liver and testes due to Cr(VI) administration. Also, AlP and AcP activities were significantly decreased in kidney and lung. The activity of acetylcholinesterase (AChE) was significantly decreased in brain and plasma. Contrariwise, the activities of AST and ALT were significantly increased in plasma, while AlP and AcP decreased. Chromium (VI) treatment caused a significant decrease in plasma total protein (TP) and globulin, and increased total lipids (TL), cholesterol, glucose, urea, creatinine, and bilirubin concentrations. Folic acid alone significantly decreased the levels of free radicals in liver, brain, and kidney, and increased the content of SH-group. The activities of AST, ALT, and LDH in liver; AST, ALT, AlP, AcP, and LDH in testes; AcP in kidney; AlP and AcP in lung, and LDH in brain were significantly increased. Plasma TP and albumin were increased, while urea and creatinine were decreased. The presence of FA with Cr(VI) restored the changes in enzyme activities and biochemical parameters. In conclusion, folic acid could be effective in the protection of chromium-induced toxicity.     

Effects of polychlorinated biphenyls on whole animal energy mobilization and hepatic cellular respiration in rainbow trout, Oncorhynchus mykiss

The production of polychlorinated biphenyls (PCBs) was banned in 1977 but these chemicals persist in the environment and threaten aquatic organisms. PCB exposure often results in activation of the aryl hydrocarbon receptor (AhR) and increases in hepatic detoxification mechanisms. Activation of these detoxification mechanisms is believed to be associated with energetic demands that may come at the expense of other physiological processes such as growth, activity and reproduction. We tested the hypothesis that exposure to sub-lethal levels of PCBs results in increased energy demand and energy mobilization using both an in vivo and in vitro approach. Rainbow trout (Oncorhynchus mykiss) received a single intraperitoneal sub-lethal dose (50 μg kg⁻¹) of 3,3’,4,4’,5-pentachlorobiphenyl (PCB 126) and left for 10 d after which standard oxygen consumption and plasma and liver metabolites were assessed. PCB 126 exposed trout did not alter standard oxygen consumption but did increase plasma glucose concentration implying the mobilization of glucose to cope with this exposure regime. Cellular respiration was assessed in trout hepatocytes exposed to PCB 126 or PCB 77 (3,3′4,4′-tetrachlorobiphenyl) two AhR activators but with different potencies (PCB 126 ? PCB 77). Mitochondrial respiration was assessed by stimulating complex II with succinate and although no increases in respiration were associated with PCB exposure in non-stimulated cells, PCB 77 impaired mitochondrial respiration by preventing stimulation of complex II respiration and potentially masking any actual energetic costs of PCB exposure. These studies suggest that energy is mobilized upon exposure to PCBs, however, actual increases in energy demand may be overshadowed by impaired mitochondrial respiration.     

Polychlorinated biphenyl (118) activates osteoclasts and induces bone resorption in goldfish

To analyze the effect of polychlorinated biphenyl (PCB) 118 on fish bone metabolism, we examined osteoclastic and osteoblastic activities, as well as plasma calcium levels, in the scales of PCB (118)-injected goldfish. In addition, effect of PCB (118) on osteoclasts and osteoblasts was investigated in vitro. Immature goldfish, in which the endogenous effects of sex steroids are negligible, were used. PCB (118) was solubilized in dimethyl sulfoxide at a concentration of 10 ppm. At 1 and 2 days after PCB (118) injection (100 ng/g body weight), both osteoclastic and osteoblastic activities, and plasma calcium levels were measured. In an in vitro study, then, both osteoclastic and osteoblastic activities as well as each marker mRNA expression were examined. At 2 days, scale osteoclastic activity in PCB (118)-injected goldfish increased significantly, while osteoblastic activity did not change significantly. Corresponding to osteoclastic activity, plasma calcium levels increased significantly at 2 days after PCB (118) administration. Osteoclastic activation also occurred in the marker enzyme activities and mRNA expressions in vitro. Thus, we conclude that PCB (118) disrupts bone metabolism in goldfish both in vivo and in vitro experiments.     

Distribution of organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) in marine sediments directly exposed to wastewater from Cortiou, Marseille

Introduction

The future ??Calanque National Park?? coastlines of the Bouches-du-Rh?ne and Var departments in France, constitute one of the ten biodiversity hot spots identified in the Mediterranean basin that receives industrial and urban wastewaters discharged from Marseille and its suburbs.

Materials and methods

Organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) were measured in sediments collected from 12 sampling sites (C1?CC12) of sewage discharge to the sea from the wastewater treatment plant of Cortiou-Marseille. This study aims to determine the extent of these compounds in the sediments and to establish the possible sources of these contaminants.

Results and discussion

Total pesticides in the sediments ranged from 1.2 to 190.6 ng g^-1 dry weight of sediment. The highest value was found at station C1, with a decreasing trend in total OC concentrations seaward. Among these compounds, the concentrations of the sum of dichlorodiphenyltrichloroethane (??DDT) were the highest, ranging from 0.7 to 114.3 ng g^-1. PCB concentrations, expressed as equivalent to Arochlor 1260, varied from 9.1 to 226.9 ng g^-1. Individually, the dominant coplanar PCB congeners CB-153, CB-138 and CB-101. Generally, PCB concentrations at stations C2, C3, C5 and C7 were higher than those at stations C10, C11 and C12. Through some pollution indices, we showed the long-term contamination input of these OCs (DDT, endosulfan, HCH and heptachlor cases) rather than a recent release resulting from degradation and long-term weathering (dieldrin, aldrin and methoxychlor cases). Occurrence of PCBs might be due to their resistance to degradation processes or/and chronic inputs.

Conclusions

By comparison with available sediment quality guideline (SQG) values, the environmental significance and toxicological implications of PCBs and OCs (i) reveal the probable adverse effects for the sediments from C1, C5, C6, C9 and (ii) confirm the adverse effect for marine biota and more particularly for benthic communities at C2?CC4, C7 and C8.     

Cyanide phytoremediation by water hyacinths (Eichhornia crassipes)

Although cyanide is highly toxic, it is economically attractive for extracting gold from ore bodies containing only a few grams per 1000 kg. Most of the cyanide used in industrial mining is handled without observable devastating consequences, but in informal, small-scale mining, the use is poorly regulated and the waste treatment is insufficient. Cyanide in the effluents from the latter mines could possibly be removed by the water hyacinth Eichhornia crassipes because of its high biomass production, wide distribution, and tolerance to cyanide (CN) and metals. We determined the sodium cyanide phytotoxicity and removal capacity of E. crassipes. Toxicity to 5-50 mg CN L(-1) was quantified by measuring the mean relative transpiration over 96 h. At 5 mgCNL(-1), only a slight reduction in transpiration but no morphological changes were observed. The EC(50) value was calculated by probit analysis to be 13 mgCNL(-1). Spectrophotometric analysis indicated that cyanide at 5.8 and 10 mgL(-1) was completely eliminated after 23-32 h. Metabolism of K(14)CN was measured in batch systems with leaf and root cuttings. Leaf cuttings removed about 40% of the radioactivity from solution after 28 h and 10% was converted to (14)CO(2); root cuttings converted 25% into (14)CO(2) after 48 h but only absorbed 12% in their tissues. The calculated K(m) of the leaf cuttings was 12 mgCNL(-1), and the V(max) was 35 mg CN(kg fresh weight)(-1)h(-1). Our results indicate that E. crassipes could be useful in treating cyanide effluents from small-scale gold mines.     

Levels of PCB 126 and PCB 153 in plasma and tissues in goats exposed during gestation and lactation

The aim of the present study was to gain knowledge about the disposition of the PCB congeners 126 and 153 in a goat model where pregnant does were given oral doses of PCB from day 60 of gestation until delivery. The goat kids were thus exposed to PCB during gestation and lactation. The doses of PCB 153 and PCB 126 were 98 and 49 ng/kg body wt/day, respectively. PCB levels were measured in plasma from the does at day 90 of gestation and at delivery, and in plasma from the kids at birth and four weeks post partum. Concentrations of PCB were analysed in brain, liver and fat tissue from the does six weeks after delivery and in liver and fat tissue from the kids at nine months of age. The ratio of estimated body burden to ingested dose in the does, was 0.95 +/- 0.07 for PCB 153 and 0.41 +/- 0.03 for PCB 126. Approximately 9% of PCB 153 and 6% of PCB 126 was transferred from the mothers to their kids during gestation and lactation. Prenatal exposure contributed to a much lower fraction of the body burden than postnatal PCB intake via milk, due to the fact that almost 100% of the PCB 153 transferred from the does to kids was transferred via milk, and the PCB 126 intake via milk was threefold higher than the calculated body burden. The hepatic PCB 126 concentration in both does and kids was significantly higher than the concentration in fat, in contrast to PCB 153, where the highest concentrations were found in fat. A significant difference in body burden between the does at delivery, the newborn kids, and the kids at four weeks of age, did not influence the plasma concentration of PCB 153 on a fat weight basis, which showed no difference with sampling time. Our results suggest that PCB 126 and PCB 153 have different pharmacokinetic properties. The higher levels of PCB 126 in liver tissue compared to fat tissue confirm the concept of hepatic sequestration. The similar blood concentration of PCB 153 in the does at delivery and their newborn kids despite the considerable difference in body burden, suggests a high degree of placental transfer. This supports previous observations that low molecular weight, lipid-soluble, non-polar chemicals reach the fetus to the greatest possible extent. For PCB 153, the body burden may provide the appropriate dose metric at steady state, but may give a minor underestimation of PCB 126 at low environmental exposure levels due to hepatic sequestration.     

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.