Polychlorinated Biphenyl

model for gas-phase persistent organic compounds over Lake Michigan has been constructed. Using air temperature, wind direction and atmospheric PCB concentration collected around and over the lake, the model predicts the concentration of PCB congeners (~100) and trans-nonachlor over the lake and gas exchange fluxes. The model shows that gas-phase PCB and trans-nonachlor concentrations over Lake Michigan vary considerably as a function of temperature, wind direction, and distance from the urban-industrial region of southwest Lake Michigan. The combined effects of southerly winds and high temperatures cause a large 'plume ' of gas-phase PCBs from Chicago. The Chicago urban air toxics plume can impact the whole lake when warm southerly winds are strong. In this paper, we examine the magnitude of the Chicago plume on gas deposition of these potentially toxic compounds to the lake. Findings-PCBs 1. The LMMB atmospheric modeling shows that Chicago is a source of gas-phase PCBs. ...

As part of the U.S. EPA's Lake Michigan Mass Balance Study, a predictive model for gas-phase persistent organic compounds over Lake Michigan has been constructed. Using air temperature, wind direction and atmospheric PCB concentration collected around and over the lake, the model predicts the concentration of PCB congeners (~100) and trans-nonachlor over the lake and gas exchange fluxes. The model shows that gas-phase PCB and trans-nonachlor concentrations over Lake Michigan vary considerably as a function of temperature, wind direction, and distance from the urban-industrial region of southwest Lake Michigan. The combined effects of southerly winds and high temperatures cause a large 'plume' of gas-phase PCBs from Chicago. The Chicago urban air toxics plume can impact the whole lake when warm southerly winds are strong. In this paper, we examine the magnitude of the Chicago plume on gas deposition of these potentially toxic compounds to the lake. Findings-PCBs 1. The LMMB atmospheric modeling shows that Chicago is a source of gas-phase PCBs. The Chicago region contributes 2 to 20% of the total deposition of PCB to the lake, depending on the congener and time of year. For an annual year the total gas-phase depositon of ΣPCBs is ~3200 kg and the Chicago contribution is ~330 kg. 2. The Chicago source behaves like a non-point release by volatilization from contaminated sites open to the atmosphere and subject to the same temperature fluctuations as the air temperature. Recommendations -PCBs 1. Reduce the deposition of PCBs to Lake Michigan by: a. Covering land surfaces contaminated with PCBs b. Removing structures contaminated with PCBs c. Conduct remediation activities in cool weather Findings -trans-nonachlor 1. The Chicago source of trans-nonachlor is most important in the winter. During the summertime, the source of trans-nonchlor is more diffuse. 2. The trans-nonachlor signal is not consistent with current use of the pesticide or of seasonal application. 3. Sources of trans-nonachlor are associated with high temperatures and southern winds. This model cannot identify the range of transport. Recommendations -trans-nonachlor 1.Reduce the deposition of trans-nonachlor to Lake Michigan: a. Prevent new application of trans-nonachlor inside and outside the Great Lakes basin b. Conduct remediation activities in cool weather.

Persistent organochlorine pollutants (POPs) are analyzed for the dropping-amended soils from the habitats of Antarctic seabirds and seals in Fildes Peninsula and Ardley Island. The concentration ranges are 0.21 to 3.85 ng/g for polychlorinated biphenyls (ΣPCBs), 0.09 to 2.01 ng/g for organochlorine pesticides (ΣDDT), and 0.06 to 0.76 ng/g for hexachlorocyclohexanes (HCHs). Among these, hepatachlorobiphenyls, hexachlorobiphenyls, p,p′-DDE and α-HCH compounds are dominant. The concentration ranges of ΣPCB, DDT and HCH in the eggs of skuas were 91.9-515.5 ng/g, 56.6-304.4 ng/g and 0.5-2.0 ng/g respectively; those in the eggs of penguins were 0.4-0.9 ng/g, 2.4-10.3 ng/g and 0.1-0.4 ng/g; and those in the eggs of giant petrel were 38.1-81.7 ng/g, 12.7-53.7 ng/g and 0.5-1.5 ng/g respectively. The dominant POP compounds in the eggs are PCB180, PCB153, p,p′-DDE and hexachlorobenzene (HCB). The present study shows that the concentration of POPs in the seabird-inhabited-dropping-amended soil varies with the extent of predation and nest occupancy of different seabird populations. Statistical analysis on the POP concentrations from the different seabird eggs implies that the difference in the bio-concentration levels of the birds depends on the bio-habits of the species, such as the range of activity, distance of immigration, feeding pattern, and nest occupation. Among these, the most important factor is the location of the seabirds in the food chain and their feeding pattern. This shows that POPs accumulated in the seabirds resulted from the bio-concentration through the food chain. In addtion, 210 Pb dating for the dropping-amended soils (AD1-a and AD2) was performed, which provided the POP accumulation rate and the historic record for the soil profile. It indicates that POP will continuously affect the Antarctic ecosystem for a long time. persistent organochlorine pollutant, animal habitats, dropping-amended soil, seabird egg, Antarctica Polychlorinatedbiphehyls (PCBs) and organochlorine pesticides (OCPs) are persistent organochlorine pollutants (POPs), with stable chemical structures, resistant to degradation, lipophilic, high toxicity, and accumulationprone in organisms through the food web. POPs can also enter animals through their feeding on phytoplankton that assimilate the compounds in the ocean. POPs are transferred across the food chain and accumulated in the high trophic levels of the aquatic food web, which result in long-term toxic effects on living organisms. Therefore they are generally considered primary pollutants of the Earth, so the study on it has become a hot issue in environmental science. Sladen et al. first showed the environmental pollu-

Je tiens à remercier le Dr. Christian Blaise pour m'avoir accepté au sein de I'Unité de recherche en bioanalyse, de sa confiance, de sa patience et de ces précieux conseils, comme co-directeur, dans le déroulement de ma recherche sur les méthodes altematives en écotoxicologie. J'exprime toute ma gratitude au Professeur Paule Vasseur de I'Université de Metz qui a accepté de co-diriger mes travaux du coté français. Pour son intérêt intrinsèque à l'égard de ma recherche et pour la confiance qu'elle a bien voulu m'accorder, je lui suis profondément reconnaissant. Je suis également reconnaissant aux autres membres du jury -Messieurs les Professeurs F. Ramade, G. Dirheimer et J.F. Férard,

The effects of chronic exposure to dioxin (2,3,7,8,-tetrachlorodibenzo-pdioxin [TCDD]) and a dioxin-like compound ) on the cardiovascular system were evaluated in female Harlan Sprague-Dawley rats as part of an ongoing National Toxicology Program investigation. The animals were gavage treated 5 d per week with up to 1000 ng of PCB126 per kilogram of body weight per day or up to 100 ng of TCDD per kilogram of body weight per day for up to 2 yr. The control animals received only a corn oil/acetone vehicle (99:1 mixture). The corresponding stop-study groups received the highest doses for 31 wk and then received only the vehicle for the remainder of the study. After a full necropsy of all animals, a complete set of tissues was examined microscopically. Administration of each compound was associated with treatment-related increases in the incidences of degenerative cardiovascular lesions. Cardiomyopathy and chronic active arteritis increased in a dose-related manner in all groups treated with PCB126 or with TCDD. Increased incidences were also observed in the stop-study groups, indicating that a shorter term exposure may produce some effects. The average severity of cardiomyopathy was minimal or slightly greater in all dose groups, including the controls. Chronic active arteritis occurred primarily in the mesentery and pancreas, although the rectum, liver, heart, ovary, uterus, and glandular stomach in the PCB126 study and the liver and ovary in the TCDD study were affected in a few of the dosed animals. The authors' investigations indicate that the rat cardiovascular system is a target for dioxin toxicity, which increases the incidence of spontaneous cardiomyopathy and arteritis.

The effects of chronic exposure to dioxin (2,3,7,8,-tetrachlorodibenzo-pdioxin [TCDD]) and a dioxin-like compound ) on the cardiovascular system were evaluated in female Harlan Sprague-Dawley rats as part of an ongoing National Toxicology Program investigation. The animals were gavage treated 5 d per week with up to 1000 ng of PCB126 per kilogram of body weight per day or up to 100 ng of TCDD per kilogram of body weight per day for up to 2 yr. The control animals received only a corn oil/acetone vehicle (99:1 mixture). The corresponding stop-study groups received the highest doses for 31 wk and then received only the vehicle for the remainder of the study. After a full necropsy of all animals, a complete set of tissues was examined microscopically. Administration of each compound was associated with treatment-related increases in the incidences of degenerative cardiovascular lesions. Cardiomyopathy and chronic active arteritis increased in a dose-related manner in all groups treated with PCB126 or with TCDD. Increased incidences were also observed in the stop-study groups, indicating that a shorter term exposure may produce some effects. The average severity of cardiomyopathy was minimal or slightly greater in all dose groups, including the controls. Chronic active arteritis occurred primarily in the mesentery and pancreas, although the rectum, liver, heart, ovary, uterus, and glandular stomach in the PCB126 study and the liver and ovary in the TCDD study were affected in a few of the dosed animals. The authors' investigations indicate that the rat cardiovascular system is a target for dioxin toxicity, which increases the incidence of spontaneous cardiomyopathy and arteritis.

Polychlorinated biphenyls from transformer oil were degraded in liquid culture under aerobic conditions using a mixed bacterial culture isolated from a transformer oil sample with a high content of polychlorinated biphenyls and other hydrocarbons. Four strains were identified, three of them corresponded to genus Bacillus, the other one to Erwinia. Bacteria in the transformer oil could remove as much as 65 % of polychlorinated biphenyls (88 % W/V in the transformer oil). Additional data showed that the two isolated strains of B. lentus were able to grow on transformer oil and degrade polychlorinated biphenyls by 80 and 83 %. Our results provide evidence that microorganisms occurring in transformer oil have the potential to degrade polychlorinated biphenyls.

The seasonal variations in PCB and DDT accumulation levels in carp and eels from the Ebro Delta troughout an annual cycle are described. The two types of organochlorine compounds are ubiquitous in the samples analyzed. Variations in accumulation patterns are related to biological events (e.g. reproduction) and environmental changes (water flow, pesticide treatment, etc.). When comparing the levels of pollutant accumulation in carp (detritivore-herbivore) and eels (carnivore), PCB levels reached in the two species are very similar, while DDTs display an important variation, being higher for eels than carp. The total organochlorine load in eels from the Ebro Delta is lower than in eels from a similar ecosystem, the Venice Lagoon. This différence is mainly due to a greater PCB load in Venetian eels. Conversely, DDT concentrations are higher (double) in eels from the Ebro Delta. The PCB and DDT concentrations in carp and eels from the Ebro Delta are lower than the tolérance levels set by the U.S.F.D.A., but controls extended to further species are needed in order to assess risk factors associated with organochlorine pollution in this area. Anguilles du delta de l'Ebre sont suivies pendant un cycle annuel. Les deux types de composés organochlorés sont omniprésents dans les échantillons analysés. Les niveaux d'accumulation sont mis en relation avec les différentes phases du cycle biologique des deux espèces de Poissons (reproduction) et aussi par les changements d'ordre écologique (flux aquatique, traitements phytosanitaires). Quand on compare les niveaux d'accumulation des Carpes (détritivores-herbivores) et des Anguilles (carnivores), on constate que les niveaux de PCB des deux espèces sont très similaires. Au contraire, les DDT montrent une variation importante, présentant une concentration plus élevée pour les Anguilles que pour les Carpes. La quantité totale de pesticides organochlorés des Anguilles du delta de l'Èbre ne dépasse pas les niveaux de tolérance donnés par l'U.S.F.D.A., mais les contrôles doivent être étendus à d'autres espèces pour pouvoir évaluer les facteurs de risque associés avec la pollution par des organochlorés dans cette zone méditerranéenne.

stati studiati per la determinazione del loro contenuto di pesticidi. Nonostante le influenze dovute alle caratteristiche orografiche, vegetazionali e pedologiche e alle differenze meteorologiche, è stato possibile misurare i gradienti regionali della contaminazione del suolo con pesticidi i quali presentano un andamento decrescente dall'estremità nord agli Alpi Centrali. Si osserva inoltre che gli aghi e l'humus si comportano in modo leggermente diverso. Per ultimo è stato riscontrato che alcuni pesticidi mostrano un incremento delle concentrazioni con la quota.

We investigated the occurrence, origin, and potential ecological risk of dissolved polycyclic 28 aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCBs) and organochlorine 29 pesticides (OCPs) in 27 surface water samples collected from a highly anthropized and 30 industrialized area in the Gulf of Gabès (Tunisia, Southern Mediterranean Sea) in October-31 November 2017. The results demonstrated a wide range of concentrations (ng L -1 ) with the 32 following decreasing order: Ʃ16 PAHs (17.6-71.2) > Ʃ20 PCBs (2.9-33.7) > Ʃ6 DDTs (1.1-33 12.1) > Ʃ4 HCHs (1.1-14.8). Selected diagnostic ratios indicated a mixture of both pyrolytic 34 and petrogenic sources of PAHs, with a predominance of petrogenic sources. PCB 35 compositions showed distinct contamination signatures for tetra-to hepta-chlorinated PCBs, 36 characteristic of contamination by commercial (Aroclor) PCB mixtures. The dominant OCP 37 congeners were γ-HCH, 2,4′-DDD and 2,4′-DDE, reflecting past use of Lindane and DDTs in 38 the study area. Agricultural, industrial and domestic activities, as well as atmospheric 39 transport are identified as potential sources of PAHs, PCBs and OCPs in surface waters of the 40 Gulf of Gabès. Toxic equivalents (TEQs) suggested a low carcinogenic potential for PAHs in 41 seawater samples (mean of 0.14 ng TEQ L -1 ). Evaluation of risk coefficients revealed low risk 42 for PAHs and PCBs, and moderate to severe risk for OCPs.

In the first Flemish Environment and Health survey run by the Flemish Centre of Expertise on Environment and Health (FLEHS I 2002-2006) increased concentrations of PCBs, dioxin-like substances and chlorinated pesticides (a metabolite of DDT and hexachlorobenzene) were observed in cord blood of newborns and in blood of 14-15 year-old adolescents and 50-65 year-old adults living in low populated rural communities of East and West Flanders and Flemish Brabant compared to other Flemish regions. Due to the health concern associated with chlorinated compounds follow-up of pollutant levels in this area is of importance. Therefore, human breast milk from mothers living in these regions was collected (2009-2010) for analysis of different POPs. For the quantification of PCDD/Fs and/or dioxin-like PCBs in (human) milk samples both GC-HRMS and the CALUX bioassay are used in routine analysis. However, most CALUX methods use high amounts of milk (varying between 10 and 60 mL) 1, 2 . Since for the Flemish human breast milk survey in the rural areas not only PCDD/Fs and dioxin-like PCBs were analyzed, but also other POPs like p,p'-DDE, PBDEs, marker PCBs, HCB, HCH, perfluorinated compounds, etc., the amount of milk available for the each assay was limited. Therefore, the CALUX bioassay was used for the analysis of PCDD/Fs and dl-PCBs in the individual milk samples, while GC-HRMS was used to define the concentration level of a pooled human milk sample. In this study, 5 mL human breast milk samples obtained from 84 18-35 year-old breastfeeding mothers residing in the rural areas of Flanders (24 low-populated rural communities in East and West Flanders), were analyzed for PCDD/Fs and dl-PCBs with a new sensitive CALUX mouse hepatoma cell line. Additionally, from each of the 84 individual samples, 10 mL was taken to compose a pooled sample, which was analyzed with both the CALUX assay (VUB, ANCH, Brussels, Belgium) and by GC-HRMS (WHO reference laboratory, State Institute for Chemical Analysis and Veterinary of Food, Freiburg, Germany). Details about inclusion criteria and characteristics of the study population are described by Colles et al., 2011 3 . CALUX analysis was performed at the VUB, using the methodology described by Croes et al. (2011 and submitted) . Methods used for analysis of the pooled milk sample by the WHO reference laboratory (State Institute for Chemical Analysis of Food) in Freiburg, Germany, are described elsewhere . Five millilitre milk samples were analyzed with the CALUX bioassay for all 84 mothers participating in the study. All samples were above the LOQ, both for the PCDD/Fs and the dl-PCBs. The geometric mean PCDD/F and dioxin-like PCB concentrations (raw data) in the total study population were respectively 10.4 (95% CI: 9.4-11.4) pg CALUX-BEQ per g fat or 0.41 (95% CI: 0.37-0.45) pg CALUX-BEQ per g milk for the PCDD/Fs and 1.73 (1.57-1.91) pg CALUX-BEQ per g fat or 0.07 (95% CI: 0.06-0.08) pg CALUX-BEQ per g milk for the dioxin-like PCBs. Univariate analysis of the raw data showed that participants who lost weight after the pregnancy had significant higher values of dioxin-like PCBs (p=0.02) and PCDD/Fs (p=0.002) compared to participants who gained

1Al Farabi Kazakh National University, 71 av. Al Farabi, 050038 Almaty, Kazakhstan, 2UR AFPA, Université de Lorraine, INRA-USC 340, 54505 Vandoeuvre cedex, France 3CIRAD Département Environnements et Sociétés, Campus International de Baillarguet, TA C-DIR / B, 34398 Montpellier cedex 5, France stefan.jurjanz@univ-lorraine.fr Moldir Nurseitova1, Gaukhar Konuspayeva1, Cyril Feidt2*, Bernard Faye3, Stefan Jurjanz2

The study aimed to determinate the mechanisms of bioaccumulation and decontamination of Polychlorinated biphenyls (PCBs), in the body of two-humped camels Camelus bactrianus, following an oral exposure. The experiment has been carried out in Sozak region of South Kazakhstan. Four lactating two humped camels (Camelus bactrianus) received 0.8 mg of indicator PCBs (Aroclor 1254, 1.3 μg/kg body weight) during two months and followed by a 4-month decontamination period. Milk and hump fat of experimental camels have been sampled. Milk samples were analyzed using a liquid-liquid and hump fat using solid extraction by gas chromatography and mass spectrometry method. Concentrations of PCBs in milk and hump reached a plateau at the end of the 2 months exposure period. Transfer rates into milk ranged between 2 for PCB 101 and 71 % for PCB 180 of the daily dose, which was generally lower than rates observed in ruminants. In the same time, the most important part of the contaminants has been sto...

1 Department Ecology and Energy, al-Farabi Kazakh National University, 71 Al-Farabi avenue, 050040, Almaty, Kazakhstan; 2 Al-Kharj FAO Camel project, Center for agriculture project P.O.Box n°761 Al-Kharj 11942 Saudi Arabia; 3 CIRAD-ES. Campus international de Baillarguet. TA C/112A, 34398 Montpellier. France; 4 INRA-URAFPA, Université de Lorraine, 2 avenue de la forêt-de-Haye, TSA 40602, 54518 Vandoeuvre cedex, France; 5 al-Farabi Kazakh National University, Center of Physical Chemical Methods of Research and Analysis, laboratory “Ecology of Biosphere”, 96A Tole bi street, 050012, Almaty, Kazakhstan.

Polychlorinated biphenyls (PCBs) accumulate in mammals via the food chain because of their characteristics such as slow degradation and high hydrophobicity. One of the 209 PCB congeners, 2,3',4,4',, is abundantly found in the environment and in mammals. Understanding the metabolic fate of CB118 can provide important information toward evaluating its toxicity. In vitro studies on the metabolism of CB118 by cytochrome P450 enzymes (P450 or CYP) revealed that human CYP2B6 and rat CYP2B1 primarily metabolized it to 3-hydroxy (OH)-CB118, whereas rat CYP1A1 metabolized CB118 to 4-hydroxy-2,3,3',4',5-pentachlorobiphenyl (4-OH-CB107). Docking models of CYP2Bs with CB118 revealed a short distance between the 3-position of CB118 and the heme iron caused by polarization of the substrate-binding cavity, and maintenance of this pose through interaction with the peripheral amino acids determines the activity and position of hydroxylation. 4-Hydroxylation by rat CYP1A1 occurs owing to the longitudinal shape of the substrate-binding cavity toward the heme of CYP1A1. The metabolites 3-OH-CB118 and 4-OH-CB107 decreased potential for activating the aryl hydrocarbon receptor compared to that of CB118, thereby leading to a decrease in dioxin-like toxicity; however, the neurodevelopmental toxicity of 4-OH-CB107 has been previously reported. The results suggest that these three P450 isoforms play an important role in determining the extent of CB118 toxicity. This study will contribute to understanding of the metabolic fates and toxicity of CB118 in vivo.

A microorganism whose growth is linked to the dechlorination of polychlorinated biphenyls (PCBs) with doubly flanked chlorines was identified. Identification was made by reductive analysis of community 16S ribosomal DNA (rDNA) sequences from a culture enriched in the presence of 2,3,4,5-tetrachlorobiphenyl (2,3,4,5-CB), which was dechlorinated at the para position. Denaturing gradient gel electrophoresis (DGGE) analysis of total 16S rDNA extracted from the culture led to identification of three operational taxonomic units (OTUs 1, 2, and 3). OTU 1 was always detected when 2,3,4,5-CB or other congeners with doubly flanked chlorines were present and dechlorinated. Only OTUs 2 and 3 were detected in the absence of PCBs and when other PCBs (i.e., PCBs lacking doubly flanked chlorines) were not dechlorinated. Partial sequences of OTUs 2 and 3 exhibited 98.2% similarity to the sequence of "Desulfovibrio caledoniensis" (accession no. DCU53465). A sulfate-reducing vibrio isolated from the culture generated OTUs 2 and 3. This organism could not dechlorinate 2,3,4,5-CB. From these results we concluded that OTU 1 represents the dechlorinating bacterium growing in a coculture with a Desulfovibrio sp. The 16S rDNA sequence of OTU 1 is most similar to the 16S rDNA sequence of bacterium o-17 (89% similarity), an ortho-PCB-dechlorinating bacterium. The PCB dechlorinator, designated bacterium DF-1, reductively dechlorinates congeners with doubly flanked chlorines when it is supplied with formate or H 2 -CO 2 (80:20). Polychlorinated biphenyls (PCBs) remain an environmental concern because of their chemical stability and potential toxicity to humans and wildlife. Although production of PCBs has been banned in much of the industrial world, these compounds are still used to some extent in electrical equipment and can be found in the environment many years after they are released. For these reasons microbial degradation and dechlorination of PCBs have been investigated in great detail (reviewed in references 1, 5, 24, and 25). Aerobic PCB-degrading microorganisms degrade the biphenyl ring, but usually they do not transform the more extensively chlorinated PCB congeners that dominate many commercial PCB mixtures. In contrast, microbial dechlorination of PCBs under anaerobic conditions results in the dechlorination of PCB congeners that are more extensively chlorinated and more resistant to aerobic attack. Although there have been several reports concerning the microbes that catalyze the aerobic biodegradation of PCBs, dechlorinating anaerobes have eluded isolation and identification. This has impeded further research into the mechanisms of anaerobic PCB dechlorination. Recently, two PCB-dechlorinating enrichment cultures derived from estuarine sediment were established in a defined and sediment-free medium. One of these cultures is capable of A defined estuarine medium (E-Cl medium) was prepared under anaerobic conditions as described by Berkaw et al. (6), except that Na 2 S • H 2 O was not added. The final pH of the medium was 7.0, and the medium was sterilized by autoclaving it at 121°C for 30 min.

Polychlorinated biphenyls (PCBs) accumulate and persist in sediments posing a risk to human health and the environment. Highly chlorinated PCBs are reductively dechlorinated in anaerobic sediments and two bacteria, designated o-17 and DF-1, from a novel phylogenetic group that reductively dechlorinate PCBs have recently been identified. However, there is a paucity of knowledge about the distribution, diversity and ecology of PCB-dechlorinating bacteria due to difficulty in obtaining pure cultures and the lack of detection by universal PCR 16S rRNA gene primer sets in sediments. A specific PCR primer was developed and optimized for detection of o-17/DF-1 and other closely related bacteria in the environment. Using this primer set it was determined that bacteria of this group were enriched in sediment microcosms from Baltimore Harbour concurrent with active dechlorination of 2,2′,3,4,4′,5′-hexachlorobiphenyl. Additional 16S rRNA gene sequences that had high levels of similarity to des...

A microorganism whose growth is linked to the dechlorination of polychlorinated biphenyls (PCBs) with doubly flanked chlorines was identified. Identification was made by reductive analysis of community 16S ribosomal DNA (rDNA) sequences from a culture enriched in the presence of 2,3,4,5-tetrachlorobiphenyl (2,3,4,5-CB), which was dechlorinated at the para position. Denaturing gradient gel electrophoresis (DGGE) analysis of total 16S rDNA extracted from the culture led to identification of three operational taxonomic units (OTUs 1, 2, and 3). OTU 1 was always detected when 2,3,4,5-CB or other congeners with doubly flanked chlorines were present and dechlorinated. Only OTUs 2 and 3 were detected in the absence of PCBs and when other PCBs (i.e., PCBs lacking doubly flanked chlorines) were not dechlorinated. Partial sequences of OTUs 2 and 3 exhibited 98.2% similarity to the sequence of “ Desulfovibrio caledoniensis ” (accession no. DCU53465 ). A sulfate-reducing vibrio isolated from th...

This research is intended to study the possible transfer of the residual chemical contamination from treated wastewaters reused for irrigation purposes of Fragaria x ananassa strawberry (cv. Camarosa). Different sewages from urban, and mixed urban-textile origins treated according to different treatment trainswere used for the irrigation of strawberry in pots. Organic and inorganic chemical contamination indicators, i.e.: PCBs, including dioxin-like congeners, PAHs, and Cr(VI), were monitored along the whole agricultural production chain (wastewater treatment effluents, soil and crop). Robust analytical procedures were specifically developed for the determination of contaminants in the above-mentioned matrices with quantitation limits (MQLs) ranging from 1.3 (Phe) to 11.0 ng/L (PCB169) for wastewaters; from 3 (PCB180) to 10 g/kg (BbFl) for soils; from 1.0 (Phe) to 10.9 g/Kg (PCB169) for strawberries. For Cr(VI), limits were 0.15 g/L (waters) and 0.018mg/kg (soils). These performance...

Over this period of time, the role of a Native Americans and a range of stakeholders (including government, private and commercial interests) has changed from the provision of information to inclusion of different entities in both the development and the execution of the research that has led to closure of sites (Amchitka Island) or to facilitate the necessary steps to reach Records of Decision (RODs). Several models developed by CRESP have shown success, including 1) combining the assessment of perceptions and consumption patterns of fisherfolk with examination of mercury loads in fish to provide site-specific information that could lead to risk reduction and the creation of a fish fact sheet that informed those most at risk (Savannah River Site, Oak Ridge), 2) assessing perceptions of appropriate land use and recreational rates to address future land use (Savannah River Site,

An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polchlorinated dibenzo-p-dioxins (PCDDs) and dibenzofirans (PCDFs) and dioinlike polhiorinated biphenyls (PCBs) for both human, fish, and wildlife risk assessment. Based on existing literature data, TEFs were (re)evaluated and either revised (mammals) or established (fish and birds). A few mammalian WHO-TEFs were revised, induding 1,2,3,7,8-pentachiornated DD, octachiorinated DD, octachlorinated DF, and PCB 77. These mammalian TEFs are also considered applicable for humans and wild mammalian species. Furthermore, it was concuded that there was insufficient in vivo evidence to continue the use of TEFs for some di-ortho PCBs, as suggested earlier by Ahlborg et al. [Chemosphere 28:1049[Chemosphere 28: -1067[Chemosphere 28: (1994))1. In addition, TEFs for fish and birds were determined. The WHO work- ing group attempted to harmonize TEFs across different tana to the extent possible. However, total synchronization ofTEFs was not feasible, as there were orders of a mnde difference in TEFs between tan for some compounds. In this respect, the absent or very low response of fish to mono-ortho PCBs isnmost noticeable compared to mamas and birds. Uncerta iies that could compromise the TEF concept were albo reviewed, interactions, differences in shape of the dose-response curve, and species responsiveness. In spite of these uncer- tainties, it was concluded that the TEF concept is still the most plausible and feasible approach for risk assessment ofhalogenated aromatic hydrocarbons with dio properties. Key work dioxins, humans, PCBs, polychlorinated biphenyls, TEFs, toxic equivalency, uncertainties, wildlife.

This study was carried out to determine the ameliorative effect of ethanolic extract of brassica oleracea of naphthalene induced toxicity on the hippocampus and cerebellum of male adult wistar rats. Thirty three (33) adult wistar rats weighing 250-260g were used for the whole experiment. 8 rats were initially used to carry out the toxicity test for Brassica oleracea. The 8 rats were grouped into 4 different groups of 2 rats each. The groups were given 2000mg/kg, 3000mg/kg, 4000mg/kg and 5000mg/kg body weight of ethanolic Brassica oleracea extract respectively. The toxicity signs on the rats like weakness, and death within 24 hours were closely monitored, noted and recorded. From observation, Maximum dose with 100% mortality = >5000mg/kg, Minimum dose with 0% mortality = <2000mg/kg, LD50 of Brassica oleracea is >5000mg/kg. The remaining twenty five (25) rats were then divided into five (5) groups of five (5) animals each. The groups were designated as A, B, C, D, and E. The rats were acclimatized for a period of seven days. The rats in group B, C and D were administered 15mg/kg of naphthalene dissolved in 10mls of soya oil every day between the hours of 8am – 9am for seven days. After the period of the seven (7) days, the extracts were administered once a day at same time, and it lasted for fourteen (14) days. All the administrations were done orally by inserting a syringe into the oral cavity of the rats. Group A served as the control group, with only administration of distilled water given to them. Group B was administered 15mg/kg of naphthalene only. Group C was administered 15mg/kg of naphthalene and 200mg/kg of ethanolic extract of Brassica oleracea. Group D was administered 15mg/kg of naphthalene and 400mg/kg of ethanolic extract of Brassica oleracea. Group E was administered 400mg/kg of ethanolic extract of Brassica oleracea only. The full duration of this experiment lasted for twenty eight days. At the end of the experimental period, the animals were weighed and sacrificed by cervical dislocation method and dissected. The hippocampus and cerebellum organs of the different groups were harvested and trimmed down for histological studies. Histological and histochemical observations showed that following the administration of ethanolic extract of Brassica oleracea, there was no degeneration of cells in the hippocampus and cerebellum while naphthalene exposed animals showed distortion of cells. The result of this study showed that Brassica oleracea extract contains high anti-histopathological and histochemical properties. I therefore recommend that Brassica oleracea should be consumed in adequate proportions for a healthy cellular functioning of the body.

Polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) and dioxin-like and non-dioxin-like (indicator) polychlorinated biphenyls (PCBs) were monitored in various foodstuffs of animal origin and edible oil samples obtained from two different cities in Turkey both rural and industrial. Total dioxinþdioxin-like PCBs and indicator PCB concentrations of pooled samples ranged 0.20-4.19 pg World Health Organization-Toxic Equivalency (WHO-TEQ) (1998) /g fat and 57.2-1710 pg/g fat, respectively. The dominant congeners were 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD, 2,3,7,8-TCDD and PCB126. Dietary intake of dioxinþdioxin-like PCBs and indicator PCBs from fish, dairy products, edible oil, egg and meat was 0.509 pg WHO-TEQ 1998 /kg bw (body weight)/day and 839 pg/kg bw/day in Afyon and 0.588 pg WHO-TEQ 1998 / kg bw/day and 1070 pg/kg bw/day in Kocaeli, respectively. The major contributors to total exposure were dairy products and fish. Despite the unexplained high contamination level in an individual egg sample from Kocaeli, average concentration levels in Turkey, even in industrialized regions, were low compared to reported concentrations in Western Europe. Exposure levels were well below the tolerable daily intake (TDI) of 2 pg WHO-TEQ 1998 /kg body weight.

This study explores a retrospective non-targeted analysis (NTA), based on Ultra High-Performance Liquid Chromatography coupled to High-Resolution Mass Spectrometry (UHPLC-HRMS), to assess hidden chemicals of emerging concern (CECs) in marine model organisms. Conventional ecotoxicological studies do not include evaluating the natural habitats of the collected organisms, missing the possibility of highlighting unexpected pollutants, and thus compromising the correctness and reliability of the experimental results. In this paper we reprocessed samples previously collected from the Venice Lagoon for ecotoxicological studies and used for targeted analysis of three bisphenols-related compounds (i.e. BPS, BPF and BPAF) on seawater and specimens of the clam Ruditapes philippinarum. Results from the validation were the following: accuracy, expressed as percentage recoveries (R%), in the range 80%<R%<120% for all the considered compounds and matrices, and precision, expressed as relative standard deviation of the absolute areas of IS, was <20% for clams (N = 24) and <15% for seawater (N = 30). LODs ranged from 5 to 50 ng/L for seawater and 5-12 ng/g for clam tissues.

The experiment was planned to study the influence of different seasons on physiological parameters of crossbred dairy cattle. Physiological variables like pulse rate (PR), rectal temperature (RT) and respiration rate (RR) of individual animals were measured and recorded at a week interval to observe the seasonal variation during different season which were divided into dry hot summer (DHS), humid hot summer (HHS) and winter (W). Data were analyzed by suitable statistical methods. Analysis of variance (ANOVA) showed that seasons had highly significant (P&lt;0.01) effect of on all the physiological parameters under study. The mean values for PR, RT and RR were 58.500 ± 0.619, 38.617 ± 0.070 & 30.000 ± 0.516; 52.167 ± 0.601, 38.490 ± 0.020 & 27.667 ± 0.333 and 50.833 ± 0.477, 38.083 ± 0.060 & 25.000 ± 0.365, respectively for DHS, HHS and W seasons. During DHS all the physiological parameters of crossbred cattle increases significantly compared to other two seasons. Different management...

Endophytic fungi have become potential sources of antitumor agents, particularly against antineoplastic-resistant cancer cells, with marginal or nil adverse effects for the oncological patient. Endophytic fungi were isolated from stems of the Lophocereus marginatus cactus, commonly found in Mexico. Methanol extracts were then obtained from fungus liquid cultures and their effects on tumor cell growth against murine lymphoma (L5178Y-R), human colorectal adenocarcinoma (HT-29), and human breast cancer (MCF-7) cells were evaluated at concentrations ranging from 31 µg/mL to 250 µg/mL via the colorimetric 3- [4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide reduction assay, using monkey kidney epithelial (MA-104) and human peripheral mononuclear (PBMC) cells as controls. Furthermore, we obtained the IC50 and the selectivity index (SI) was calculated from the IC50 ratio of normal and tumor cells. In addition, molecular identification of fungi showing cytotoxic activity was determi...

Oily seafood is an important food source which contains several key nutrients beneficial for human health. On the other hand, oily seafood also contains persistent organic pollutants (POPs), including the dioxin-like compounds (DLCs) polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) and dioxin-likepolychlorinated biphenyls (dl-PCBs), potentially detrimental to human health. For a comprehensive comparison of the beneficial and potentially adverse health effects of seafood consumption, risk-benefit analyses are necessary. Risk-benefit analyses require reliable quantitative data and sound knowledge of uncertainties and potential biases. Our dataset comprised more than 4000 analyses of DLCs and more than 1000 analyses each of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and vitamin D in the three most important Norwegian commercial oily seafood species: Atlantic herring (Clupea harengus), Atlantic mackerel (Scomber scombrus) and farmed Atlantic salmon (Salmo salar). The levels of several DLC congeners were below the limit of quantification (LOQ), making estimation of true levels challenging. We demonstrate that the use of upper bound substitution of censored data will overestimate, while lower bound substitution will underestimate the actual levels of DLCs. Therefore, we implement an alternative robust statistical method by combining Maximum Likelihood Estimation, Regression on Order Statistics and Kaplan-Meier analyses, which is better suited for providing estimations of levels of these contaminants in seafood. Moreover, we illustrate the impact of the toxic equivalency factor (TEF) system on estimation of the sums of DLCs by comparing the TEF system to an alternative system of relative effect potency (REP) factors (Consensus Toxicity Factors). The levels of nutrients and contaminants were related to adequate intake (AI) and tolerable weekly intake (TWI), respectively. We used AI and the TWI values established by the European Food Safety Authority (EFSA). The benefit and the risk were further viewed in the context of the Norwegian average intake of oily fish, and the Norwegian governmental official dietary recommendations of oily fish. Our results showed that both benefit and risk are met at the levels found of nutrients and DLCs in oily seafood. The comprehensive quantitative data presented here will be a key for future risk-benefit assessment of oily fish consumption. Together, our results underline that a refined formalized integrative risk-benefit assessment of oily fish in the diet is warranted, and that the data and methodology presented in this study are highly relevant for future integrated and multidisciplinary assessment of both risks and benefits of seafood consumption for human health.

Persistent organic pollutants (POPs) are highly lipophilic and can accumulate and biomagnify in food chains. Characterized as a public health problem, exposure to these compounds enables the development of diseases like cancer, cardiovascular disease, diabetes, and obesity. The objective of this study was to estimate the plasma levels of organochlorine pesticides and PCBs in hospitalized individuals in Petropolis, Brazil. Individuals over 18 years of age and residing for at least two years in the mountainous region of the State of Rio de Janeiro, Brazil, participated in a cross-sectional study. Interviews using a structured questionnaire and blood samples to estimate plasma levels of persistent organic pollutants provided data. Gas chromatography coupled with triple quadrupole mass spectrometry provided the levels of organochlorine pesticides and PCBs. Compared to data present in the literature, the concentration of POPs was lower, and individuals from 55 to 64 years of age (3.28 ng...

Persistent organic pollutants (POPs) are highly lipophilic and can accumulate and biomagnify in food chains. Characterized as a public health problem, exposure to these compounds enables the development of diseases like cancer, cardiovascular disease, diabetes, and obesity. The objective of this study was to estimate the plasma levels of organochlorine pesticides and PCBs in hospitalized individuals in Petropolis, Brazil. Individuals over 18 years of age and residing for at least two years in the mountainous region of the State of Rio de Janeiro, Brazil, participated in a cross-sectional study. Interviews using a structured questionnaire and blood samples to estimate plasma levels of persistent organic pollutants provided data. Gas chromatography coupled with triple quadrupole mass spectrometry provided the levels of organochlorine pesticides and PCBs. Compared to data present in the literature, the concentration of POPs was lower, and individuals from 55 to 64 years of age (3.28 ng mL - 1 ) and women (2.52 ng mL - 1 ) presented a higher average concentration of organochlorine pesticides; men (0.05 ng mL - 1 ) also presented a high concentration of PCBs. This is the rst Brazilian study to estimate the concentration of several POPs in a hospital-based sample that includes men and women, thus contributing to the characterization of our population regarding environmental exposures relevant to health.

Introduction: The hypothalamus is an important integrative center of information that ensures homeostasis, coordination of visceral functions and initiation of behaviors, as the reproduction. Review of Literature: In mammals, including humans, there are several structural and functional sexual differences throughout the brain, especially in the hypothalamus and surrounding anatomical structures that sustain physiological and behavioral sexual dimorphism. These regions may differ in size or volume (for example, the sexually dimorphic nucleus of the preoptic area - SDN-POA is higher in males and anteroventral periventricular nuclei - AVPV that is larger in females) and even as the expression of estrogen receptors which are associated with masculinization and defeminization these regions. The development and differentiation of the brain involve a series of events that begin during pregnancy and continue during the first hours of postnatal life in rodents. Steroid hormones are essential...

Pseudomonas pseudoalcaligenes KF707 is a soil polychlorinated biphenyl (PCB) degrader, able to grow both planktonically and as a biofilm in the presence of various toxic metals and metalloids. Here we report the genome sequence (5,957,359 bp) of P. pseudoalcaligenes KF707, which provides insights into metabolic degradation pathways, flagellar motility, and chemotaxis.

Milk samples of 14 women were analyzed for PCBs (polychlorinated biphenyls), p,p'-DDE, and HCB (hexachlorobenzene) during 11 intervals of a 120 day-lactation period. A general downward trend in residue levels was evident, and a statistically significant decline was observed for residue levels ofPCBs (P < 0.01) and HCB (P = 0.02) on the milk fat basis. Primipara (n = 9) had from 1.5 to 2.1 times higher mean residue levels than mothers nursing their second or third child (n = 9). Significant declines in residue levels during lactation of the first child were found, while no pronounced changes in residue levels were observed during lactation of the second or third child. Overall, residue levels in this study were lower than corresponding levels found earlier in Norway, and within the range of the corresponding levels found in another Norwegian human milk survey done at the same time.

This paper presents concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in marine water samples of Porto-Romano area. Porto-Romano is situated in Adriatic Sea, near city of Durres, in central Albania. It was considered Hot-spot area because before 90&#39; there was located chemical plant for Lindane production. Landfill near Porto-Romano and elevated activity for industrial development of this area can be the main sources of water pollution in recent years. Water samples were taken in December 2018 and April 2019 in nine stations of Porto-Romano. Liquid-liquid extraction was used for isolate organic pollutants from water samples. Clean-up procedure for chlorinated pollutants was realized in a Florisil column. Qualitative and quantitative analyzes of pesticides and PCBs were performed in HP 6890 Series II, gas chromatograph equipped with p-ECD detector. For separation of organochlorine pollutants was used Rt...

SummaryThis study was performed to assess the association between labour and the mode of delivery with the umbilical cord plasma thyroxine (T4) and thyroid‐stimulating hormone (TSH) concentrations in full‐term uncomplicated pregnancies delivered in our hospital. Babies born vaginally had statistically significantly higher umbilical cord plasma TSH but similar T4 concentrations than babies born by caesarean section. Labour was not associated with either higher TSH or T4 concentrations. All the babies with an elevated TSH concentration (&gt;20 miu/1) were born vaginally. Our findings indicate that the mode of delivery should be taken into consideration in the interpretation of umbilical cord plasma TSH results.

The biphenyl dioxygenase of Burkholderia xenovorans LB400 is a multicomponent Rieske-type oxygenase (RO) that catalyzes the dihydroxylation of biphenyl and many polychlorinated biphenyls (PCBs). The structural bases for the substrate specificity of the enzyme's oxygenase component (BphAE LB400 ) are largely unknown. BphAE p4 , a variant previously obtained through directed evolution, transforms several chlorobiphenyls, including 2,6-dichlorobiphenyl, more efficiently than BphAE LB400 yet differs from the parent oxygenase at only two positions: T335A/ F336M. Herein, we compare the structure of BphAE LB400 and BphAE p4 and examine the biochemical properties of two BphAE LB400 variants with single substitutions, T335A or F336M. Our data show that residue 336 contacts the biphenyl and influences the regiospecificity of the reaction, but does not enhance the enzyme's reactivity toward 2,6-dichlorobiphenyl. By contrast, residue 335 did not contact biphenyl, but contributed significantly to expansion of the enzyme's substrate range. Crystal structures indicate that Thr335 imposes constraints through hydrogen bonds and non-bonded contacts to the segment from Val320 to Gln322. These contacts are lost when Thr is replaced by Ala, relieving intramolecular constraints and allowing for significant movement of this segment during binding of 2,6-dichlorobiphenyl, increasing the space available to accommodate the doubly-ortho-chlorinated congener 2,6-dichlorobiphenyl. This study provides important insight about how ROs can expand substrate range through mutations that increase the plasticity and/or mobility of protein segments lining the catalytic cavity.

White-footed mice (Perornyscus leucopus) chronically exposed to polychlorinated biphenyls (PCBs) in the diet at a level of l0 ppm (jxg/g) through the second generation were evaluated in regard to reproductive success, growth (body weight) and development of reproductive organs. PCBs-treated second generation mice exhibited poor reproductive success in comparison with second generation controls and the parental generation. Although young from second generation control and PCBs-treated litters did not differ in weight at birth, PCBs-treated young were significantly smaller at 4, 8, and 12 weeks of age. Similarly, reproductive organs of females (uteri, ovaries) and accessory glands of males were smaller in PCBs-treated mice at 8 and 12 weeks of age. Testes weights were unaffected by PCBs exposure. These results provide insight into the cumulative effects of chronic PCBs exposure.

In this study, a continuous-flow UV-induced mutation (CUM) device and the CUM device coupled to a selector (CUMS) reactor were fabricated and tested for tlheir ability to enhance the probability of obtaining populations capable of chlorinated organic biodegradation. A mixed culture of bacteria were used as the starting strain for both the CUM and CUMS processes. Populations were obtained from the CUM and CUMS systems capable of 4-chlorobenzoic acid, 2,4-dichlorobenzoic acid and chlorendic acid biodegradation. Non-UV irradiated population served as controls for the experiments and did not demonstrate chlorinated organic biodegradation over the test duration.

Feline hyperthyroidism is the most commonly diagnosed endocrine-related disease among senior and geriatric housecats, but the causes remain unknown. Exposure to endocrine-disrupting compounds with thyroid targets, such as flame retardants (FRs), may contribute to disease development. Silicone passive sampling devices, or pet tags, quantitatively assessed the bioavailable FR exposures of 78 cats (≥7 y) in New York and Oregon using gas chromatography-mass spectrometry. Pet tags were analyzed for 36 polybrominated diphenyl ethers, six organophosphate esters (OPEs), and two alternative brominated FRs. In nonhyperthyroid cats, serum free thyroxine (fT 4 ), total T 4 (TT 4 ), total triiodothyronine, and thyroid-stimulating hormone concentrations were compared with FR concentrations. Tris(1,3-dichloro-2-isopropyl) phosphate (TDCIPP) concentrations were higher in hyperthyroid pet tags in comparison to nonhyperthyroid pet tags (adjusted odds ratio, p < 0.07; Mantel-Cox, p < 0.02). Higher TDCIPP concentrations were associated with air freshener use in comparison to no use (p < 0.01), residences built since 2005 compared to those pre-1989 (p < 0.002), and cats preferring to spend time on upholstered furniture in comparison to no preference (p < 0.05). Higher TDCIPP concentrations were associated with higher fT 4 and TT 4 concentrations (p < 0.05). This study provides proof-ofconcept data for the use of silicone pet tags with companion animals and further indicates that bioavailable TDCIPP exposures are associated with feline hyperthyroidism.

Feline hyperthyroidism is the most commonly diagnosed endocrine-related disease among senior and geriatric housecats, but the causes remain unknown. Exposure to endocrine-disrupting compounds with thyroid targets, such as flame retardants (FRs), may contribute to disease development. Silicone passive sampling devices, or pet tags, quantitatively assessed the bioavailable FR exposures of 78 cats (≥7 y) in New York and Oregon using gas chromatography-mass spectrometry. Pet tags were analyzed for 36 polybrominated diphenyl ethers, six organophosphate esters (OPEs), and two alternative brominated FRs. In nonhyperthyroid cats, serum free thyroxine (fT 4 ), total T 4 (TT 4 ), total triiodothyronine, and thyroid-stimulating hormone concentrations were compared with FR concentrations. Tris(1,3-dichloro-2-isopropyl) phosphate (TDCIPP) concentrations were higher in hyperthyroid pet tags in comparison to nonhyperthyroid pet tags (adjusted odds ratio, p < 0.07; Mantel-Cox, p < 0.02). Higher TDCIPP concentrations were associated with air freshener use in comparison to no use (p < 0.01), residences built since 2005 compared to those pre-1989 (p < 0.002), and cats preferring to spend time on upholstered furniture in comparison to no preference (p < 0.05). Higher TDCIPP concentrations were associated with higher fT 4 and TT 4 concentrations (p < 0.05). This study provides proof-ofconcept data for the use of silicone pet tags with companion animals and further indicates that bioavailable TDCIPP exposures are associated with feline hyperthyroidism.

Objective: To investigate possible exposure to polybrominated diphenyl ethers (PBDEs) in US professional airline workers. Methods: We recruited 30 healthy US professional airline workers who lived in the Dallas, Texas, area to test their blood PBDE levels. We examined the relationship between hours worked in an airplane and total PBDE blood levels. Results: Total PBDE blood levels from the 30 volunteers were unremarkable despite minor elevations of certain congeners in a few volunteers. No statistically significant correlations were noted between hours in airplanes in the past 1 or 5 years and levels of individual brominated diphenyl ethers congeners or total PBDEs. Conclusions: We hypothesized that elevated PBDE levels in commercial aviation workers could be found associated with time spent in airliners. Our findings do not support such an association. P olybrominated diphenyl ethers (PBDEs) are brominated flame retardants widely used in the United States since the 1970s. 1 They are persistent organic pollutants used in a variety of applications, such as in the manufacture of foam used in sofas, chairs, and mattresses, and in electronics and plastic casings, such as television sets, computers, and computer monitors. 2 Because they are additive compounds and not covalently bound, they can dissociate from products and accumulate at low levels in air and at much higher levels in dust. They are found in food, such as fruits and vegetables, and in much higher levels in meat, fish, and dairy products. Human intake is primarily from food and dust. Polybrominated diphenyl ethers have similar chemical structure and toxic profiles as polychlorinated biphenyls 1 and have been associated with cancer, 15 reproductive and developmental pathology, decreased thyroid function, 17 endocrine disruption, and neurotoxicological effects. Recently, prenatal exposure to PBDEs has been associated with effects on neurodevelopment, including reduced scores on mental development, psychomotor development, and intelligence quotient tests. Serum PBDE concentrations have also been associated with a decrease in fecundity, as measured by time to pregnancy. Polybrominated diphenyl ethers have been increasing in blood and milk in the general population worldwide in industrial countries during the past few decades. Body burden of PBDEs is orders of magnitude higher in the US population than in the European population because of greater use in the United States. Certain exposed workers, especially in less-developed countries, have marked elevation of PBDEs; 30 other workers have less striking PBDE elevations. In the United States and European Union countries, PBDEs are being phased out either by regulations or consent decrees ; however, PBDEs will remain in the environment for a considerable amount From the

Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) have been shown to act as tumor promoters in liver; however, the exact mechanisms of their action are still only partially understood. One of the interesting effects of NDL-PCBs is the acute inhibition of gap junctional intercellular communication (GJIC), an effect, which has been often found to be associated with tumor promotion. As previous studies have suggested that NDL-PCB-induced disruption of lipid signalling pathways might correspond with GJIC inhibition, we investigated effects of PCBs on the release of arachidonic acid (AA) in the rat liver epithelial WB-F344 cell line, a well-established model of liver progenitor cells. We found that both 2,2′,4,4′-tetrachlorobiphenyl (PCB 47) and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153), but not the dioxin-like, non-ortho-substituted, 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), induce a massive release of AA. The AA release, induced by PCB 153, was partially inhibited by extracellular signal-regulated kinases 1/2 (ERK1/2) signalling inhibitor, U0126, and by cytosolic phospholipase A 2 (cPLA 2 ) inhibitor, AACOCF 3 . Although PCB 153 induced both ERK1/2 and p38 activation, the specific p38 kinase inhibitor, SB203580, had no effect on AA release. Inhibitors of other phospholipases, including phosphatidylcholine-specific phospholipase C or phosphatidylinositol-specific phospholipase C, were also without effect. Taken together, our findings suggest that the AA release, induced by non-dioxin-like PCBs in liver progenitor cell line, is partially mediated by cytosolic PLA 2 and regulated by ERK1/2 kinases. Our results suggest that more attention should be paid to cell signalling pathways regulated by AA or eicosanoids after PCB exposure, which might be involved in their toxic effects.