Presence Of Polychlorinated Biphenyls Research Articles

Under explored roles of microbial ligninolytic enzymes in aerobic polychlorinated biphenyl transformation.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants in the environment that are responsible for many adverse health effects. Bioremediation appears to be a healthy and cost-effective alternative for remediating PCB-contaminated environments. While some microbial species have been observed to be capable of transforming PCBs, only two different microbial pathways (rdh and bph pathways) have been described to be involved in PCB transformations. Ligninolytic enzymes have been observed or are under suspicion in some microbial PCB transformations. However, the role of these promising PCB-transforming enzymes, which are produced by fungi and some aerobic bacteria, is still unclear. The present review describes their role by identifying microbial PCB-transforming species and their reported ligninolytic enzymes whether proven or suspected to be involved in PCB transformations. There are several lines of evidence that ligninolytic enzymes are responsible for PCB transformations such as (1) the ability of purified laccases from Myceliophthora thermophila, Pycnoporus cinnabarinus, Trametes versicolor, Cladosporium sp, and Coprinus cumatus to transform hydroxy-PCBs; (2) the increased production of laccases and peroxidases by many fungi in the presence of PCBs; and (3) the enhanced PCB transformation by Pseudomonas stutzeri and Sinorhizobium meliloti NM after the addition of ligninolytic enzyme enhancers. However, if the involvement of ligninolytic enzymes in PCB transformation is clearly demonstrated in some fungal species, it does not seem to be implicated in all microbial species suggesting other still unknown metabolic pathways involved in PCB transformation and different from the bph and rdh pathways. Therefore, PCB transformation may involve several metabolic pathways, some involving ligninolytic enzymes, bph or rdh genes, and some still unknown, depending on the microbial species. In addition, current knowledge does not fully clarify the role of ligninolytic enzymes in PCB oxidation and dechlorination. Therefore, further studies focusing on purified ligninolytic enzymes are needed to clearly elucidate their role in PCB transformation.

Polychlorinated Biphenyl Transformation, Peroxidase and Oxidase Activities of Fungi and Bacteria Isolated from a Historically Contaminated Site.

Causing major health and ecological disturbances, polychlorinated biphenyls (PCBs) are persistent organic pollutants still recovered all over the world. Microbial PCB biotransformation is a promising technique for depollution, but the involved molecular mechanisms remain misunderstood. Ligninolytic enzymes are suspected to be involved in many PCB transformations, but their assessments remain scarce. To further inventory the capabilities of microbes to transform PCBs through their ligninolytic enzymes, we investigated the role of oxidase and peroxidase among a set of microorganisms isolated from a historically PCB-contaminated site. Among 29 isolated fungi and 17 bacteria, this work reports for the first time the PCB-transforming capabilities from fungi affiliated to Didymella, Dothiora, Ilyonectria, Naganishia, Rhodoturula, Solicoccozyma, Thelebolus and Truncatella genera and bacteria affiliated to Peribacillus frigotolerans, Peribacillus muralis, Bacillus mycoides, Bacillus cereus, Bacillus toyonensis, Pseudarthrobacter sp., Pseudomonas chlororaphis, Erwinia aphidicola and Chryseobacterium defluvii. In the same way, this is the first report of fungal isolates affiliated to the Dothiora maculans specie and Cladosporium genus that displayed oxidase (putatively laccase) and peroxidase activity, respectively, enhanced in the presence of PCBs (more than 4-fold and 20-fold, respectively, compared to controls). Based on these results, the observed activities are suspected to be involved in PCB transformation.

Occurrence of OCPs & PCBs and their effects on multitrophic biological communities in riparian groundwater of the Beiluo River, China

Persistent Organic Pollutants (POPs) may exert adverse effects on human and ecosystem health. However, as an ecologically fragile zone with strong interaction between river and groundwater, the POPs pollution in the riparian zone has received little attention. The goal of this research is to examine the concentrations, spatial distribution, potential ecological risks, and biological effects of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the riparian groundwater of the Beiluo River, China. The results showed that the pollution level and ecological risk of OCPs in riparian groundwater of the Beiluo River were higher than PCBs. The presence of PCBs (Penta-CBs, Hexa-CBs) and CHLs, respectively, may have reduced the richness of bacteria (Firmicutes) and fungi (Ascomycota). Furthermore, the richness and Shannon’s diversity index of algae (Chrysophyceae and Bacillariophyta) decreased, which could be linked to the presence of OCPs (DDTs, CHLs, DRINs), and PCBs (Penta-CBs, Hepta-CBs), while for metazoans (Arthropoda) the tendency was reversed, presumably as a result of SULPHs pollution. In the network analysis, core species belonging to bacteria (Proteobacteria), fungi (Ascomycota), and algae (Bacillariophyta) played essential roles in maintaining community function. Burkholderiaceae and Bradyrhizobium can be considered biological indicators of PCBs pollution in the Beiluo River. Note that the core species of interaction network, playing a fundamental role in community interactions, are strongly affected by POPs pollutants. This work provides insights into the functions of multitrophic biological communities in maintaining the stability of riparian ecosystems through the response of core species to riparian groundwater POPs contamination.

Interaction mechanisms of the binding of polychlorinated biphenyls to thyroid hormone transporters revealed based on quantum chemistry and spectroscopy

Polychlorinated biphenyls (PCBs) are a kind of persistent, bioaccumulative and refractory environmental pollutants. In this work, three typical PCBs (CB54, CB125, CB152) were selected to investigate the interaction between thyroid hormone (TH) transporter and PCBs by combining spectroscopy and calculation. The fluorescence results showed that PCBs had a high binding affinity to TH transport proteins and strongly quenched the intrinsic fluorescence of TH transport proteins through a static quenching mechanism. Analysis of thermodynamic parameters revealed that hydrophobic interactions played an important role in the complex formation. Furthermore, the microenvironment and conformation of transthyretin (TTR) and thyroxine binding globulin (TBG) were altered in the presence of PCBs, which was confirmed by Fourier transform infrared (FT-IR) spectroscopy and quantum chemical analysis. Finally, the optimal binding mode of PCBs to TH transport proteins and the stability of the complexes were studied through molecular docking and molecular dynamics simulations.

Organochlorine residues in muscle of European eels (Anguilla anguilla) from four Spanish Mediterranean wetlands and coastal lagoons

European eels (Anguilla anguilla) are an endangered species throughout their range, and chlorine organic compounds are some of the most important pollutants for marine species. Data on contaminants in eel stocks remain incomplete, so organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in muscle of European eels from four Spanish Mediterranean ecosystems were analyzed. COPs are presents in eels from all areas, but some compounds are not detected: HCH α, β and γ (lindane), endosulfan sulfate, heptachlor, and PCBs 28, 52 and 180. The high percentage of DDT 2,4′ in eels from S'Albufera des Grau Natural Park, an ecosystem with good ecological status according to the Water Framework Directive, and the presence of PCBs in S'Albufereta Natural Reserve indicate the need to carry out further studies in the future. The results obtained can improve the management of this species in the studied areas.

Presence of novel and legacy flame retardants and other pollutants in an e-waste site in China and associated risks

Electrical and Electronic Equipment (EEE) residues and their management have been widely identified as potential sources of plasticizers and flame retardants to the environment, especially in non-formal e-waste facilities. This study evaluates the distribution, partitioning and environmental and human impact of organophosphate esters (OPEs), legacy polychlorinated biphenyls (PCBs), polybromodiphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in the e-waste recycling area of Baihe Tang village, in the Qingyuan county, Guangdong province, China. A plastic debris lump accumulated in a small pond during years was identified as the main source of pollution with ∑pollutants of 8400 μg/g dw, being OPEs the main contaminants detected, followed by PBDEs. This lump produced the contamination of water, sediments, soils and hen eggs in the surrounding area at high concentrations. Plastic-water and water-sediment partitioning coefficients explained the migration of OPEs to the water body and accumulation in sediments, with a strong dependence according to the KOW. Triphenyl phosphate (TPhP), tricresyl phosphate (TCPs) and high chlorination degree PCBs produced a risk in soils and sediments, considering the lowest predicted no effect concentration, while the presence of PCBs and PBDEs in free range hen eggs exceeded the acceptable daily intake. OCPs were detected at low concentrations in all samples. The presence of organic contaminants in e-waste facilities worldwide is discussed to highlight the need for a strict control of EEE management to minimize environmental and human risks.

La sobre-expresión de PtCSP4 del álamo promueve un mayor potencial para la fitorremediación de PCB

La fitorremediación es un método biotecnológico ampliamente aceptado que reduce, absorbe y degrada los contaminantes tóxicos. Los bifenilos policlorados (PCB) son contaminantes orgánicos persistentes que causan efectos nocivos para el medio ambiente. Se reconoce que el álamo (Populus trichocarpa) tiene un crecimiento rápido, alta transpiración y se tiene una secuencia completa de su genoma; por lo que se considera un modelo perfecto en fitorremediación. Las plantas genéticamente modificadas pueden ser más eficientes en la remediación de sitios, cuyos suelo y agua están contaminados con bifenilos policlorados (PCB). Yb-1 es una proteína multifuncional involucrada en la regulación de la transcripción, traducción, empalme de ARNm y reparación de ADN. El factor de transcripción Yb1 se conoce en humanos y mamíferos, pero muy poco en plantas. Yb-1 en plantas es más conocido como CSP (proteínas de choque frío). En este trabajo, el gen PtCSP4 (Potri.004G172600) se aisló y amplificó a partir del álamo. El sistema de recombinación de puerta de enlace se usó para clonar PtCSP4 en un vector binario con un promotor constitutivo. PtCSP4 se introdujo en Arabidopsis thaliana y se probó su tolerancia en presencia de PCB (Aroclor 1221). Ocho líneas transgenicas de Arabidopsis cultivadas in vitro fueron expuestas a PCB. Todos los resultados sugieren que PtCSP4 es un buen candidato para la fitorremediación de PCB.

Polychlorinated biphenyls in settled dusts from an end-of-life vehicle processing area and normal house dusts in northern Vietnam: Occurrence, potential sources, and risk assessment

Concentrations and congener-specific profiles of total 209 polychlorinated biphenyls (PCBs) were investigated in settled dust samples collected from end-of-life vehicle (ELV) processing, urban, and rural areas in northern Vietnam. Concentrations of total 209 PCBs, seven indicator congeners, and twelve dioxin-like PCBs decreased in the order: ELV working > ELV living ≈ urban > rural dusts. Penta- and hexa-CBs dominated the homolog patterns in all the samples with higher proportions in the ELV dusts compared to the urban and rural house dusts. The abundance and pattern of PCBs in the ELV dusts suggest on-going emissions of these compounds related to processing of vehicular oils and lubricants containing PCBs, whereas the presence of PCBs in the urban and rural house dusts indicate long-time releases. However, levels of some PCBs identified as by-products of pigment manufacturing (e.g., PCB-11 and PCB-209) were higher in the urban house dusts than those from other locations, resulting from human activities utilizing paints and pigments. Daily intake doses (ID), non-carcinogenic hazard quotient (HQ), and lifetime cancer risk (CR) of PCBs through dust ingestion were estimated for ELV workers and residents in the studied areas. The workers and children in the ELV sites were estimated to be at higher risk of PCB exposure, however almost all of the HQ < 1 and CR < 10−4 indicate no serious risk related to dust-bound PCBs.

Nivoi nekih organskih zagađivača u uzorcima vode Jadranskog mora - studija slučaja - žarište Porto-Romana, Albanija

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' 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 Rtx-5 capillary column. Analyzes of PAH were realized in Varian 450 GC, gas chromatograph equipped with FID detector and VF-1ms capillary column. The most frequent organic pollutants in water samples of Porto-Romano were found organochlorine pesticides because of ex-chemical plants impact in this area. Note, that Lindane and its isomers weren't found in high concentration. PCB 28, volatile congener, was found in higher concentrations because of their atmospheric origin. Presence of PCB 138 show terrestrial origin of PCBs in this area. PAH were found in higher concentrations inside of hydrocarbon port. Their concentrations were due to industrial activity and ship transport in this area. Mismanagement of Lindane plant wastes, urban pollution and recent industrial activity are factors of continues pollution in Porto-Romano area. Presence of organic pollutants in water samples of Porto-Romano indicates that monitoring of this Hot-spot should be continuous.

Health Risks of Polychlorinated Biphenyls (PCBs) Levels in Fish and Sediment from River Niger (Onitsha Axis)

ABSTRACTThe health risks of polychlorinated biphenyls (PCBs) levels in fish and sediment from River Niger (Onitsha axis) was investigated. Fish and sediment samples were collected during dry and rainy seasons from upstream and downstream of the river. Extraction was carried out using n-hexane: acetone mixture (50:50) and PCBs were determined using gas chromatography-electron captor detection. Average recovery of 97.67% was obtained for fish and 95.88% for sediment. PCBs concentration and biota-sediment accumulation factor (BSAF) were higher downstream for both seasons. There was no significant difference (P < 0.05) in PCBs concentration between dry and rainy seasons. Concentrations of PCBs in fish were below the Food and Drug Association (FDA, 2018) tolerance level of 2 ppm. Also, noncarcinogenic hazard quotient (HQ) for PCBs congeners in fish samples were ˂1, which indicates no noncarcinogenic health risks from consumption of fish from Niger River. However, carcinogenic HQ for normal fish consumption in children was above 1 in some sample locations but below 1 for adults. Also, carcinogenic HQ for habitual fish consumption was above 1 in some sample locations for both children and adults. There is presence of PCBs in River Niger as a result of anthropogenic activities and industrial discharges, with human risks especially for children.

The protein expression disorders of connexins (Cx26, Cx32 and Cx43)and keratin 8 in bovine placenta under the influence of DDT, DDE and PCBs.

Polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its metabo- lite, dichlorodiphenyldichloroethylene (DDE) can disturb the secretory function of the ovary and both contractions and secretory function of the uterus during the estrus cycle and pregnancy. Additionally, PCBs can pass through the placental barrier into allantoic and amniotic fluid. The presence of PCBs in these fluids is associated with higher frequency of spontaneous abortions and premature births in humans and animals. Therefore, the effect of PCBs, DDT and DDE on the connexins (Cx26, Cx32 and Cx43) and keratin 8 (KRT8) expression in bovine placentomes was investigated. The placentome slices from the second trimester of pregnancy were incubated with PCB153, 126, 77, DDT and DDE (each at doses of 1, 10 or 100 ng/ml) for 48 h. Then, the slices were stained using immunohistochemistry. The density of Cxs staining was measured with Axio- Vision Rel. 4.8 software in fetal-maternal connections and binuclear cells (BNC). None of the tested xenobiotics (XBs) affected the localization of Cxs and KRT8 in the fetal-maternal connec- tion area, but the XBs affected the density of Cxs in fetal-maternal connections and binuclear cells (BNCs). Depend on the doses, in fetal-maternal connections all used PCBs changed the protein expression of different Cxs, while in BNCs, all tested XBs except DDT increased the ex- pression of Cxs. None of investigated XBs affected on KRT8 expression. In summary, used XBs affect the expression of Cxs and change the quantitative relationships between them. Therefore, XBs can unfavorably influence function of the utero-placental barrier in cows.

Distribution of polychlorinated biphenyls in effluent from a large municipal wastewater treatment plant: Potential for bioremediation?

This study involved an evaluation of the potential for bioremediation of polychlorinated biphenyls (PCBs) in the effluent from a large municipal wastewater treatment plant. It was focused on the presence of PCBs in two types of effluents: the continuous effluent present during dry weather conditions and the intermittently present effluent that was present during wet weather due to incoming stormwater. The annual discharge of PCBs for both types of effluent was calculated based on a five-year dataset (2011–2015). In addition, the toxicity and bioremediation potential of the PCBs in the effluent were also assessed. It was found that the continuous effluent was responsible for the majority of the discharged PCB into the receiving river (1821 g for five years), while the intermittent effluent contributed 260 g over the five years. The average number of chlorine per biphenyl for the detected PCB congeners showed a 19% difference between the two types of effluent, which indicated a potential for organohalide respiration of PCBs during the continuous treatment. This was further supported by a high level of tri-, tetra- and penta-chlorinated congeners accounting for 75% of the anaerobically respired PCBs. Potential for aerobic degradation and thus biomineralization of PCBs was identified for both effluents. Furthermore, toxicity of 12 dioxin-like PCBs showed that normal operation of the wastewater reduced the toxicity throughout the wastewater treatment plant.

Assessing the ability of white-rot fungi to tolerate polychlorinated biphenyls using predictive mycology

ABSTRACTThe aim of the present study was to assess the ability of different white-rot fungi to tolerate polychlorinated biphenyls (PCBs) using predictive mycology, by relating fungal growth inhibition to ligninolityc enzyme secretion. Fungal strains were grown in the presence of PCBs in solid media and their radial growth values were modelled through the Dantigny-logistic like function in order to estimate the time required by the fungal colonies to attain half their maximum diameter. The principal component analysis (PCA) revealed an inverse correlation between strain tolerance to PCBs and the laccase secretion over time, being laccase production closely associated with fungal growth capacity. Finally, a PCA was run to regroup and split between resistant and sensitive fungi. Simultaneously, a function associated with a model predicting the tolerance to PCBs was developed. Some of the assayed isolates showed a promising capacity to be applied in PCB bioremediation.Abbreviations: Polychlorinated biphenyls (PCBs), white-rot fungi (WRF)

Microbial Characterization of Methanogenic and Iron-reducing Consortium in Reactors with Polychlorinated Biphenyls

Recent papers have confirmed current environmental pollution and the continuous release of polychlorinated biphenyls (PCBs) despite the prohibition of its manufacture worldwide. As the dehalogenating microorganisms are able to remove halogens from various analogous compounds, the characterization of PCB metabolisms can improve the degradation of similar compounds. Thus, this study extensively evaluated the microbial community developed in methanogenic and iron-reducing reactors. The horizontal-flow anaerobic reactor (HAIB) with real waste of Aroclor (1mL L-1) was fed with mineral medium, ethanol, and sodium formate. Bacteria belonging to Thermotogaceae (Thermotogae), Geobacteraceae, Chloroflexi, Proteobacteria, and Firmicutes (Clostridium) were identified in the HAIB reactor. Bacteria belonging to the Chloroflexi, Firmicutes, and Geobacteraceae are associated with the degradation of hydrocarbons and could be related to the Aroclor waste in this paper. Furthermore, 5.26 × 1012 cells gTVS-1 of iron-reducing bacteria were quantified by the most probable number method in the HAIB reactor, suggesting that this group has an important role in aromatic degradation. Moreover, the evaluation of methanogenic and iron-reducing microorganisms in batch reactors with Aroclor 1260 was performed and the biomass growth was not affected by the addition of PCB. The methane production reached 0.38 µmol CH4 gTVS-1 and the iron reduction attained 90% in batch reactors. Through microbial analyses from HAIB and batch reactors, lower diversity was evidenced in the presence of PCB. This paper indicates the relevant role of iron-reducing organisms and Chloroflexi, Geobacteraceae, and Firmicutes group in PCB metabolism.

Assessment of persistent organic pollutants and their relationship with immunoglobulins in blood of penguin colonies from Antarctica

ABSTRACT: Persistent organic pollutants (POPs) may affect the immune system of seabirds, and some field studies have examined this effect. There are evidences that POPs cause negative effects on the immune system, but in Antarctic penguins data are scarce. In order to assess the risks that POPs may have on wild animals, some immunological studies constitute a good alternative. Determining the levels of immunoglobulins can deliver relevant information about the potential impact of POPs in seabirds from different environments. However, there are very few records in penguins so far. The aim of the present work was to quantify the concentrations of polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (LDDT), endosulfans, and immunoglobulin IgY in blood samples of colonies of chinstrap penguins (Pygoscelis antarctica) that inhabit in the Antarctic Peninsula area. Analysis of POPs in blood samples was carried out through extraction with QuEChERS method, followed by gas chromatography. Detection of IgY concentrations was achieved by ELISA test, using anti-chicken antibodies. There was some significant correlation between immunoglobulin and the presence of PCBs and endosulfans. Even though the levels of these pollutants are low to cause any biological effect on the birds, the results are indicating some influence on the IgY concentrations in penguin blood.

Evolutionary toxicology: Meta-analysis of evolutionary events in response to chemical stressors.

The regulatory decision-making process regarding chemical safety is most often informed by evidence based on ecotoxicity tests that consider growth, reproduction and survival as end-points, which can be quantitatively linked to short-term population outcomes. Changes in these end-points resulting from chemical exposure can cause alterations in micro-evolutionary forces (mutation, drift, selection and gene flow) that control the genetic composition of populations. With multi-generation exposures, anthropogenic contamination can lead to a population with an altered genetic composition, which may respond differently to future stressors. These evolutionary changes are rarely discussed in regulatory or risk assessment frameworks, but the growing body of literature that documents their existence suggests that these important population-level impacts should be considered. In this meta-analysis we have compared existing contamination levels of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) that have been documented to be associated with evolutionary changes in resident aquatic organisms to regulatory benchmarks for these contaminants. The original intent of this project was to perform a meta-analysis on evolutionary events associated with PCB and PAH contamination. However, this effort was hindered by a lack of consistency in congener selection for "total" PCB or PAH measurements. We expanded this manuscript to include a discussion of methods used to determine PCB and PAH total contamination in addition to comparing regulatory guidelines and contamination that has caused evolutionary effects. Micro-evolutionary responses often lead populations onto unique and unpredictable trajectories. Therefore, to better understand the risk of population-wide alterations occurring, we need to improve comparisons of chemical contamination between affected locations. In this manuscript we offer several possibilities to unify chemical comparisons for PCBs and PAHs that would improve comparability among evolutionary toxicology investigations, and with regulatory guidelines. In addition, we identify studies documenting evolutionary change in the presence of PCB and PAH contamination levels below applicable regulatory benchmarks.

Potential Impacts of PCBs on Sediment Microbiomes in a Tropical Marine Environment

Within the tropical marine study site of Guánica Bay, Puerto Rico, polychlorinated biphenyls (PCBs) are subjected to coastal and oceanic currents coupled with marine microbial and geochemical processes. To evaluate these processes a hydrodynamic model was developed to simulate the transport of PCBs within nearshore and offshore marine areas of Guánica Bay. Material transport and circulation information from the model were matched with measurements from samples collected from within the bay. These samples, consisting of both intertidal and submerged sediments, were analyzed for physical characteristics (organic carbon, grain size, and mineralogy), microbial characteristics (target bacteria levels and microbial community analyses), presence of PCBs, and PCB-degrading enzymes. Results show that the bay geometry and bathymetry limit the mixing of the extremely high levels of PCBs observed in the eastern portion of the bay. Bay bottom sediments showed the highest levels of PCBs and these sediments were characterized by high organic carbon content and finer grain size. Detectable levels of PCBs were also observed within sediments found along the shore. Microbes from the bay bottom sediments showed a greater relative abundance of microbes from the Chloroflexi, phylum with close phylogenetic associations with known anaerobic PCB-degrading organisms. Based on quantitative PCR measurement of the biphenyl dioxygenase gene, the intertidal sediments showed the greatest potential for aerobic PCB degradation. These results elucidate particular mechanisms of PCB’s fate and transport in coastal, tropical marine environments.

Polychlorinated biphenyls (PCBs) in fish from the Sana River (Bosnia and Herzegovina): A preliminary study on the health risk in sport fishermen

Fish is the main single source of polychlorinated biphenyls (PCBs) exposure in men. Anecdotal reports suggest high wild fish consumption rates among sport fishermen in Sanski Most area, Bosnia and Herzegovina (BiH). Presence of PCBs in the environment in BiH was previously documented. The main objective of this work was to estimate the magnitude of PCBs exposure and assess the potential health risk in sport fishermen in Sanski Most. The fishing pattern and magnitude of fish consumption were estimated in the questionnaire survey conducted during April 2012 among members (n = 60) of the local sport fishermen association in Sanski Most. Calculated median and high-end (90th percentile) fish consumption rates were 31 g d−1 and 126 g d−1, respectively. The PCB concentrations (as Aroclor 1254 equivalents), determined by ELISA immunoassay in 28 fish fillets ranged from undetectable to 208 μg kg−1. Two different exposure scenarios were used: (a) median exposure, calculated from the median fish consumption rate and median PCB concentrations, and (b) “worst case” scenario, calculated from the high-end fish consumption rate and mean PCB concentrations. The results suggest negligible lifelong cancer and non-cancer risks in case of low to moderate fish consumption rate, but possibly unacceptable risk levels in high-end consumers.

Contaminants reduce male contribution to reproduction at the population scale

In many populations, males compete for mates and contribute to genetic diversity, but are assumed to have little impact on population growth rates and density, because one father is all that is necessary to fertilize a large number of eggs and sire a potential cohort. A factor affecting male reproductive output is exposure to contaminants that either disrupt endocrine function or mimic hormones. Polychlorinated biphenyls (PCBs) persist in aquatic ecosystems and may interfere with the reproductive contribution of male fish to populations. We quantified 28 PCB congeners in adult male bluegills across eight Illinois lakes. In spring 2011 and 2012, mature male bluegills from lakes with conspecifics with PCB whole‐body residues ranging from undetectable to high (2,000 ng/g dry mass total PCBs) were placed in experimental ponds with mature females containing no detectable PCB body residues and allowed to reproduce in spring under natural conditions. The presence of PCBs in fish had no effect on the presence of intersex or other gonadal deformities in adult males nor was gonad size, lipid concentration, and survival affected. Males with high PCBs were heavier than those from lakes with low PCB concentrations. The relative density of juvenile bluegills produced in ponds by fall, a fitness endpoint in this species, was negatively related to contaminant concentration in fathers. Contaminant exposure and other factors that affect male reproduction may not only suppress the relative contribution of males to genetic diversity, but also the overall density of cohorts within populations.

Analysis of a microbial community associated with polychlorinated biphenyl degradation in anaerobic batch reactors.

The degradation of polychlorinated biphenyls (PCBs) was investigated under fermentative-methanogenic conditions for up to 60 days in the presence of anaerobic biomass from a full-scale UASB reactor. The low methane yields in the PCBs-spiked batch reactors suggested that the biomass had an inhibitory effect on the methanogenic community. Reactors containing PCBs and co-substrates (ethanol/sodium formate) exhibited substantial PCB reductions from 0.7 to 0.2 mg mL(-1). For the Bacteria domain, the PCBs-spiked reactors were grouped with the PCB-free reactors with a similarity of 55 %, which suggested the selection of a specific population in the presence of PCBs. Three genera of bacteria were found exclusively in the PCB-spiked reactors and were identified using pyrosequencing analysis, Sedimentibacter, Tissierela and Fusibacter. Interestingly, the Sedimentibacter, which was previously correlated with the reductive dechlorination of PCBs, had the highest relative abundance in the RCS-PCB (7.4 %) and RCS-PCB-PF (12.4 %) reactors. Thus, the anaerobic sludge from the UASB reactor contains bacteria from the Firmicutes phylum that are capable of degrading PCBs.