Unveiling the distribution characteristics of rpf-like genes and indigenous resuscitation promoting factor production in PCB-contaminated soils.

Resuscitation promoting factors (Rpfs), known for their anti-dormancy cytokine properties, have been extensively investigated in the medical field. Although the Rpf from Micrococcus luteus has been successfully utilized to resuscitate and stimulate microbial populations for the degradation of polychlorinated biphenyls (PCBs), the presence of indigenous Rpf homologs in PCB-contaminated soils has not been established. In this study, the distribution characteristics of rpf-like genes and indigenous strain capable of producing Rpf in PCB-contaminated soils were explored. The results revealed the widespread presence of Rpf-like domains and their associated genes, particularly in close association with heavy metals and PCBs. The rpf-like genes were predominantly found in Proteobacteria and displayed a positive correlation with genes involved in PCB degradation and viable but non-culturable (VBNC) formation. Notably, the recombinant Rpf-Ac protein derived from the indigenous strain Achromobacter sp. HR2 exhibited muralytic activity and demonstrated significant efficacy in resuscitating the growth of VBNC cells, while also stimulating the growth of normal cells. These findings shed light on the prevalent presence of Rpf homologs in PCB-contaminated soils and their potential to resuscitate functional populations in the VBNC state, thereby enhancing in situ bioremediation.

Investigation of organic micropollutant pollution in Izmit Bay: a comparative study of passive sampling and instantaneous sampling techniques.

In this study, we used a comprehensive array of sampling techniques to examine the pollution caused by organic micropollutants in Izmit Bay for the first time. Our methodology contains spot seawater sampling, semi-permeable membrane devices (SPMDs) passive samplers for time-weighted average (TWA), and sediment sampling for long-term pollution detection in Izmit Bay, together. Additionally, the analysis results obtained with these three sampling methods were compared in this study. Over the course of two seasons in 2020 and 2021, we deployed SPMDs for 21 days in the first season and for 30 days in the second season. This innovative approach allowed us to gather sea water samples and analyze them for the presence of polycyclic aromatic hydrocarbons (Σ15 PAHs), polychlorinated biphenyls (Σ7 PCBs), and organochlorine pesticides (Σ11 OCPs). Using SPMD-based passive sampling, we measured micropollutant concentrations: PAHs ranged from 1963 to 10342 pg/L in 2020 and 1338 to 6373 pg/L in 2021; PCBs from 17.46 to 61.90 pg/L in 2020 and 8.37 to 78.10 pg/L in 2021; and OCPs from 269.2 to 8868 pg/L in 2020 and 141.7 to 1662 pg/L in 2021. Our findings revealed parallels between the concentrations of PAHs, PCBs, and OCPs in both SPMDs and sediment samples, providing insights into the distribution patterns of these pollutants in the marine ecosystem. However, it is worth noting that due to limited data acquisition, the suitability of spot sampling in comparison to instantaneous sampling remains inconclusive, highlighting the need for further investigation and data collection.

The red listed eagle owl (Bubo bubo) population in Norway is exposed to POP levels exceeding threshold values for adverse health effects.

The eagle owl (Bubo bubo) population in Norway is today classified as critically endangered on the red list of endangered species. Because previous studies have detected high concentrations of Persistent Organic Pollutants (POPs) in birds of prey, concerns have been raised whether POPs exposure are a significant factor to the substantial decline of the eagle owl population. The aims of this study were to measure the levels of POPs in eagle owls and to assess whether POPs may represent a potential health risk. POPs were analysed in liver samples from 100 eagle owls collected between 1994 and 2014. The concentrations of POPs were generally very high and individual birds had levels among the highest measured worldwide. The contaminant groups analysed were highly correlated (p < 0.0001). The concentrations of sum of Polychlorinated Biphenyls (∑PCB) exceeded the threshold value from moderate to severe health risk in 90% of the birds. The birds with cachectic or lean body condition had significantly higher levels of contaminants than those with higher body condition scores. No significant temporal or spatial trends were noted. The lack of temporal trends, suggest that the downward trend of POPs, appear to be levelling off. The lack of differences between inland and coastal regions suggest that the risk of exposure may be comparable between predatory birds feeding in marine or terrestrial food webs. The significantly higher POPs levels detected in individuals with poor body condition may be due to reduced fat stores and thereby higher concentration in the remaining fat and/or the weight loss could be induced by toxic effects. The high proportion of birds exceeding the threshold values for severe and high risk of adverse effects, suggest that the high contamination load may reduce the eagle owl's fitness and survival and, thus, contribute to decline of the eagle owl population.

Variations in thyroid hormone levels in endangered St. Lawrence Estuary belugas: Potential linkage with stress and organohalogen contaminant exposure.

The St. Lawrence Estuary (SLE) beluga (Delphinapterus leucas) population is highly exposed to an array of contaminants that were identified as one of the causes to the non-recovery of this endangered and declining population. In the last decade, an increasing number of parturition-associated complications and calf mortality has been reported in this population. It was suggested that elevated exposure to organohalogens (e.g., the halogenated flame retardants polybrominated diphenyl ethers [PBDEs]) and stress could play a role in this phenomenon by perturbing thyroid hormones. The objective of this study was to investigate the impact of concentrations of organohalogen contaminants and stress (cortisol levels) on thyroid hormone variations in adult male and female SLE belugas. Because plasma could not be collected in SLE belugas for ethical reasons, skin biopsy (n = 40) was used as a less-invasive alternative matrix to determine organohalogens (PBDEs and other halogenated flame retardants, polychlorinated biphenyls, and organochlorine pesticides), cortisol, and thyroid hormones (triiodothyronine [T3] and thyroxine [T4]), and their metabolites reverse T3 and 3,5-diiodothyronine [3,5-T2]). Cortisol and thyroid hormones were analyzed by ultra-performance liquid chromatography-multiple reactions monitoring mass spectrometry (UPLC-MRM/MS). This method was compared using skin and plasma samples obtained from Arctic belugas. Comparisons of linear models showed that cortisol was a weak predictor for T4, rT3 and 3,5-T2. Specifically, there was a weak significant negative association between T4 and cortisol levels. Moreover, in male SLE belugas, a weak significant positive association was found between T3 and Σ34PBDE concentrations in skin. Our findings suggest that stress (i.e., elevated skin cortisol levels) along with organohalogen exposure (mainly PBDEs) may be associated with thyroid hormone level perturbations in skin of cetaceans.

Quantifying 209 Polychlorinated Biphenyl Congeners in Silicone Wristbands to Evaluate Differences in Exposure among Demolition Workers.

A social housing estate in Denmark was designated for demolition due to exceedance of guidance values for polychlorinated biphenyls (PCBs) in indoor air. Here, we deployed precleaned silicone wristbands (n = 46) among demolition workers of these contaminated buildings during single workdays while conducting various work tasks. We established a method to analyze all 209 PCBs in wristbands to identify prominent congeners of exposure and evaluate differences between tasks. Wristbands were extracted using microwave-assisted extraction and then concentrated for gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. Twenty-nine chromatographic peaks representing 37 congeners were detected in every wristband, and tetra-CBs were the dominant homologue group. PCB-66, -44, and -70 were the most abundant congeners measured in worker wristbands, none of which are included within the typical seven indicator or WHO 12 PCBs. Workers who cut PCB-containing sealants had wristbands with the highest PCB concentrations (geometric mean ∑209PCBs = 1963 ng/g wristband), which were followed by those handling concrete elements on the building roof. Additionally, wristbands captured a broader range of PCBs than has been previously measured in air and serum samples. Taken together, our results highlight the importance of total congener analysis in assessing current PCB exposure in demolition work and the utility of wristbands for assessing these exposures.

Polychlorinated biphenyl congeners in water canals and their relationships with water quality parameters: Insights into their risk assessment.

Water pollution with pesticides is one of the most important environmental problems. Polychlorinated biphenyls (PCBs) reach water bodies via agricultural discharge. The aim of this study was to determine the contamination of different water bodies with PCB congeners, and detect the correlation between water quality parameters and seasonal distribution of these PCBs. The results indicated that water canals of AlGharbiah showed the highest ranges of temperature, total dissolved solids (TDS) in spring, and dissolved oxygen (DO) in autumn, while AlQaliobiah water bodies witnessed the highest pH and electrical conductivity (EC) ranges in summer. The highest range of a PCB congener was that of PCB44 (7.96-118.29 µg/g) in sediment samples of Giza, followed by its range (18.01-85.44 µgL-1) in surface water of AlQaliobiah. We found a potential cancer risk from dermal contact with all the investigated PCBs. Principal component analysis (PCA) showed positive correlations between most PCBs and each of EC and TDS, and a negative correlation with DO. While the correlation between PCBs and each of temperature and pH varied according to the geographic location of the governorate. In conclusion, the investigated water canals were contaminated with PCBs, which posed a potential cancer risk and deteriorated water quality.

Multiomics Analysis of PCB126's Effect on a Mouse Chronic-Binge Alcohol Feeding Model.

BACKGROUND: Environmental pollutants, including polychlorinated biphenyls (PCBs) have been implicated in the pathogenesis of liver disease. Our group recently demonstrated that PCB126 promoted steatosis, hepatomegaly, and modulated intermediary metabolism in a rodent model of alcohol-associated liver disease (ALD). OBJECTIVE: To better understand how PCB126 promoted ALD in our previous model, the current study adopts multiple omics approaches to elucidate potential mechanistic hypotheses. METHODS: Briefly, male C57BL/6J mice were exposed to 0.2mg/kg polychlorinated biphenyl (PCB) 126 or corn oil vehicle prior to ethanol (EtOH) or control diet feeding in the chronic-binge alcohol feeding model. Liver tissues were collected and prepared for mRNA sequencing, phosphoproteomics, and inductively coupled plasma mass spectrometry for metals quantification. RESULTS: Principal component analysis showed that PCB126 uniquely modified the transcriptome in EtOH-fed mice. EtOH feeding alone resulted in >4,000 differentially expressed genes (DEGs), and PCB126 exposure resulted in more DEGs in the EtOH-fed group (907 DEGs) in comparison with the pair-fed group (503 DEGs). Top 20 significant gene ontology (GO) biological processes included "peptidyl tyrosine modifications," whereas top 25 significantly decreasing GO molecular functions included "metal/ion/zinc binding." Quantitative, label-free phosphoproteomics and western blot analysis revealed no major significant PCB126 effects on total phosphorylated tyrosine residues in EtOH-fed mice. Quantified hepatic essential metal levels were primarily significantly lower in EtOH-fed mice. PCB126-exposed mice had significantly lower magnesium, cobalt, and zinc levels in EtOH-fed mice. DISCUSSION: Previous work has demonstrated that PCB126 is a modifying factor in metabolic dysfunction-associated steatotic liver disease (MASLD), and our current work suggests that pollutants also modify ALD. PCB126 may, in part, be contributing to the malnutrition aspect of ALD, where metal deficiency is known to contribute and worsen prognosis. https://doi.org/10.1289/EHP14132.

Molecular insights into PCB neurotoxicity: Comparing transcriptomic responses across dopaminergic neurons, population blood cells, and Parkinson's disease pathology.

Parkinson's disease (PD) is a complex neurodegenerative disorder influenced by genetic factors and environmental exposures. Polychlorinated biphenyls (PCBs), a group of synthetic organic compounds, have been identified as potential environmental risk factors for neurodegenerative diseases, including PD. We explored PCB-induced neurotoxicity mechanisms using iPSC-derived dopaminergic neurons and assessed their transcriptomic responses to varying PCB concentrations (0.01 µM, 0.5 µM, and 10 µM). Specifically, we focused on PCB-180, a congener known for its accumulation in human brains. The exposure durations were 24 h and 74 h, allowing us to capture both short-term and more prolonged effects on gene expression patterns. We observed that PCB exposure led to the suppression of oxidative phosphorylation, synaptic function, and neurotransmitter release, implicating these pathways in PCB-induced neurotoxicity. In our comparative analysis, we noted similarities in PCB-induced changes with other PD-related compounds like MPP+ and rotenone. Our findings also aligned with gene expression changes in human blood derived from a population exposed to PCBs, highlighting broader inflammatory responses. Additionally, molecular patterns seen in iPSC-derived neurons were confirmed in postmortem PD brain tissues, validating our in vitro results. In conclusion, our study offers novel insights into the multifaceted impacts of PCB-induced perturbations on various cellular contexts relevant to PD. The use of iPSC-derived dopaminergic neurons allowed us to decipher intricate transcriptomic alterations, bridging the gap between in vitro and in vivo findings. This work underscores the potential role of PCB exposure in neurodegenerative diseases like PD, emphasizing the need to consider both systemic and cell specific effects.

Serum concentration of polychlorinated biphenyls and the risk of type 2 diabetes: a 10-year follow-up historical cohort study.

This study investigated the association between serum concentrations of Polychlorinated Biphenyls (PCBs) and the risk of type 2 diabetes within the general population. A ten-year follow-up historical cohort study was conducted during 2009-2019 as part of the Bushehr MONICA cohort study in Iran. Of 893 non-diabetes participants at base line, 181 individuals were included in the study. The concentration of nine PCB congeners was measured in individuals' serum samples at baseline, and the risk of type 2 diabetes was determined based on fasting blood sugar at the end of follow-up. Multiple logistic regression models were used to assess the study outcomes after adjusting for covariates. This study included 59 diabetes individuals (32.6%; mean [SD] age: 58.64 [8.05]) and 122 non-diabetes individuals (67.4%; mean [SD] age: 52.75 [8.68]). Multivariable analysis revealed that a one-tertile increase (increasing from 33rd centile to 67th centile) in Σ non-dioxin-like-PCBs (OR 2.749, 95% CI 1.066-7.089), Σ dioxin-like-PCBs (OR 4.842, 95% CI 1.911-12.269), and Σ PCBs (OR 2.887, 95% CI 1.120-7.441) significantly associated with an increased risk of type 2 diabetes. The strongest association was obtained for dioxin-like PCBs. The results highlight a significant correlation between PCB exposure and an increased risk of type 2 diabetes. The evidence suggests that additional epidemiological studies are necessary to clarify the link between PCBs and diabetes.

Biological differences of three paclitaxel- and sirolimus-coated balloons on coronary lesions in a rabbit model.

BACKGROUND: Drug-coated balloons (DCBs) are important treatment options for coronary artery disease; however, randomised controlled trials comparing various DCB technologies are sparse, and further investigations are needed. AIMS: This preclinical study aimed to histologically and biologically compare the drug effects and safety of a low-dose paclitaxel-coated DCB (PCB; AGENT), a regular-dose PCB (SeQuent Please NEO) and a sirolimus-coated DCB (SCB; MagicTouch). METHODS: The DCBs were inflated in the healthy iliac arteries of 18 rabbits, which were euthanised after 28 days. The treated iliac arteries and distal skeletal muscles were histopathologically evaluated, and drug concentrations were measured. RESULTS: In the histopathological evaluation, the medial smooth muscle cell loss score regarding depth, an indicator of drug efficacy, was significantly higher with AGENT and SeQuent Please NEO than with MagicTouch (4.0 [3.6-4.0] vs 3.7 [3.7-4.0] vs 2.2 [2.0-2.4]), with significant differences in comparisons between AGENT and MagicTouch (p<0.01) and between SeQuent Please NEO and MagicTouch (p<0.01). AGENT and SeQuent Please NEO showed comparable drug concentrations in the treated artery (p=0.61). In contrast, the drug concentrations in distal skeletal muscles were the highest for MagicTouch, followed by SeQuent Please NEO and AGENT (28.07 [13.19-52.46] ng/mg vs 0.66 [0.22-3.76] ng/mg vs 0.25 [0.04-3.23] ng/mg, respectively). CONCLUSIONS: This study demonstrated that PCBs might have higher efficacy and lower drug concentrations in distal skeletal muscles than the MagicTouch SCB. The efficacy of the AGENT low-dose PCB and the SeQuent Please NEO regular-dose PCB was comparable.

Polychlorinated biphenyls in mussels, small pelagic fish, tuna, turtles, and dolphins from the Croatian Adriatic Sea waters: an overview of the last two decades of monitoring.

This review summarises our two decades of polychlorinated biphenyl (PCB) monitoring in different marine organisms along the eastern Adriatic Sea. The aim was to gain an insight into the trends of PCB distribution in order to evaluate the effectiveness of past and current legislation and suggest further action. Here we mainly focus on PCB levels in wild and farmed Mediterranean mussels, wild and farmed bluefin tuna, loggerhead sea turtles, common bottlenose dolphins, and small pelagic fish. The use of artificial intelligence and advanced statistics enabled an insight into the influence of various variables on the uptake of PCBs in the investigated organisms as well as into their mutual dependence. Our findings suggest that PCBs in small pelagic fish and mussels reflect global pollution and that high levels in dolphins and wild tuna tissues raise particular concern, as they confirm their biomagnification up the food chain. Therefore, the ongoing PCB monitoring should focus on predatory species in particular to help us better understand PCB contamination in marine ecosystems in our efforts to protect the environment and human health.

Is current generation of polychlorinated biphenyls exceeding peak production of the 1970s?

Polychlorinated biphenyls (PCBs) are man-made chemicals that were once widely produced as commercial mixtures for various industrial applications. PCBs were later recognized as environmental pollutants and health hazards, leading to their global phase-out and strict regulations on their production, use, and disposal. Most investigations on PCBs focus on measuring the specific PCBs present in commercial mixtures or marker compounds representing those mixtures. However, there are new sources of PCBs that are gaining more attention. These 'by-product PCBs' are inadvertently produced in certain chemical and product formulations. Our estimates show that U.S. legislation currently permits the generation of more by-product PCBs (~100 million lb. (~45,000 Tonnes) per year) than during peak commercial production of the 1970s (85 million lb. (~39,000 Tonnes) per year). These PCBs are currently going un-detected in most investigations. Therefore, they may be a posing a growing, unmonitored environmental and human health risk. Most people assume PCBs to be legacy pollutants from historically formulated commercial mixtures. However, our research suggests that due to the emergence of by-product PCBs they may need to be reconsidered as an emerging pollutant of concern.

Centurial deposition records of polychlorinated biphenyls and organochlorine pesticides in sediment cores from a plateau deep-water lake of China: Significance of anthropogenic impacts, transformation signals and ecological risks revealed by full congener analysis.

Lake Fuxian, the largest deep freshwater lake in China, has been suffering from increasing ecological and environmental issues along with the rapid urbanization and industrialization in the past 40 years. To better understand the historical pollution of persistent organic pollutants (POPs) in Lake Fuxian, comprehensive analyses of 209 polychlorinated biphenyl (PCB) congeners and 20 organochlorine pesticides (OCPs) were conducted in two intact sediment cores (Core V1 and Core V2). The total mass concentrations of PCBs ranged from 7.60 to 31.47 ng/g (dry weight basis) and 5.55 to 28.90 ng/g during the period of 1908-2019 in Core V1 and 1924-2019 in Core V2, respectively. PCBs exhibited a consecutive increasing trend from 1940s to 2019 in Core V1. The temporal trend of PCBs in Core V2 basically matched to the history of PCB usage and prohibition in China (increasing from 1940s to mid-1960s, a remarkable drop in mid-1970s, and then increasing until 2019). Moreover, low-chlorinated PCBs were dominant among PCB homologues. Mono-CBs, di-CBs, tri-CBs and tetra-CBs accounted for 86.71 %-98.57 % in sediment segments. The PCB sources included unintentional emission and atmospheric deposition, as well as biological transformation. The total mass concentrations of OCPs ranged from 0.74 to 3.82 ng/g in Core V1 and 0.35 to 2.23 ng/g in Core V2, respectively. Similar trend was observed in the two sediment cores with peaks in the early 1990s. The predominant OCPs were γ-hexachlorohexane (γ-HCHs), dieldrin and p,p'-DDD. The ecological risks posed by PCBs and p-p'-DDD in Lake Fuxian were relatively low. In contrast, dieldrin might pose a potential threat to exposed organisms and apparently adverse ecological effects were caused by γ-HCH. This study will provide important baseline information on historical POPs contamination of Lake Fuxian.

Organohalogen compounds in a hotspot for chemical pollution: Assessment in free-ranging Atlantic spotted dolphins (Stenella frontalis).

The assessment of chemical pollution in free-ranging living mammals is viable using remote biopsies and portrays a comprehensive scenario of environmental health. The Southwestern Atlantic Ocean holds incredible biodiversity, but it is under the constant and invisible threat of persistent organic pollutants (POPs) of anthropogenic origin, such as pesticides, brominated flame retardants, and industrial-use compounds (e.g., PCBs). Thus, this study aimed to assess the bioaccumulation of POPs (PCBs, DDTs, HCB, mirex and PBDEs) and natural organobromine compounds (MeO-BDEs) using gas-chromatography coupled to mass spectrometry in biopsy samples of Atlantic spotted dolphins (Stenella frontalis, n = 20) that inhabit and forage both inside and in adjacent areas to degraded (Guanabara Bay) and conserved (Ilha Grande Bay) coastal bays in the Southeastern Brazil. Among the studied compounds, PCBs were predominant in the contamination profile with median concentration of 97.0 µg.g-1 lipid weight (lw), followed by the sum of the p,p' isomers of DDT, DDD, and DDE of 11.0 µg.g-1 lw, the brominated flame retardants PBDEs of 1.6 µg.g-1 lw, and the other organochlorine pesticides mirex of 0.78 µg.g-1 lw, and HCB of 0.049 µg.g-1 lw. The MeO-BDEs were detected with a median concentration of 22.8 µg.g-1 lw. 85 % of the Atlantic spotted dolphins analyzed in this study presented PCB concentration that exceeded even the less conservative threshold limits for adverse health effects (41 µg.g-1 lw). This study shows that despite the conservation status of preserved bays, cetacean species foraging in these locations are still under increased threat. Hence chemical pollution demands local and global efforts to be mitigated.

Level of polychlorinated biphenyls in tumor and blood serum of breast cancer patients and control subjects from Punjab, Pakistan.

The current study examined the level of Polychlorinated biphenyls (PCBs) in tumor and blood serum of female breast cancer patients and control individuals recruited from Punjab, Pakistan. Breast tumor and blood serum from 40 patients and only blood serum from ten control subjects were obtained and concentration of 32 PCB congeners was analyzed through Gas chromatography coupled with Mass spectrophotometry. Sociodemographic variables of the patients along with essential clinical and haematological parameters were taken as covariates. Tumor reflects the highest median (min-max) concentration (ng g-1 lw) of Æ©PCBs at 115.94 (0.05-17.75) followed by 16.53 (0.09-2.94) and 5.24 (0.01-0.59) in blood serum of cancer patients and control group respectively. Median concentrations (ng g-1 lw) of non-dioxine like Æ©PCBs were considerably higher at 83.04, 32.89 and 4.27 compared to 13.03 and 3.50 and 0.97 for dioxin like Æ©PCBs in tumor, serum of breast cancer patients and control subjects respectively. PCB-87 was most dominant congeners in tumor followed by PCB-170 and -82 whereas PCB-28 and -52 reflected greatest contribution in serum of breast cancer patients. Blood haemoglobin, potassium and chloride ions showed significant positive whereas body mass index reflect inverse relationship when regressed with Æ©PCBs in tumor. This pioneer study depicts elevated concentrations of PCBs in patients compared to control, reflecting potential positive association of PCBs with breast cancer which need further confirmation. We concluded that chronic exposure to PCBs might be associated with an increasing number of breast cancer incidences in developing countries like Pakistan, which should be further elucidated through detail in vitro and in vivo studies.

Glucocorticoid hormones in relation to environmental exposure to bisphenols and multiclass pesticides among middle aged-women: Results from hair analysis.

Bisphenols and pesticides have been shown to alter circulating glucocorticoids levels in animals, but there is limited human data. Moreover, measurements from biological fluids may not be able to reflect long-term status of non-persistent pollutants and glucocorticoids due to the high variability in their levels. Using hair analysis, we examined the associations between glucocorticoid hormones and environmental exposure to multi-class organic pollutants among a healthy female population aged 25-45 years old. Concentrations of four glucocorticoids, four polychlorinated biphenyl congeners (PCBs), seven polybrominated diphenyl ether congeners (PBDEs), two bisphenols and 140 pesticides and their metabolites were measured in hair samples collected from 196 Chinese women living in urban areas. Due to the low detection frequency of some pollutants, associations were explored only on 54 pollutants, i.e. PCB 180, bisphenol A, bisphenol S and 51 pesticides and their metabolites. Using stability-based Lasso regression, there were associations of cortisol, tetrahydrocortisol, cortisone, and tetrahydrocortisone with 14, 10, 13 and 17 biomarkers of exposure to pollutants, respectively, with bisphenol S, p,p'-dichlorodiphenyldichloroethylene, diethyl phosphate, 3,5,6-trichloro-2-pyridinol, thiamethoxam, imidacloprid, fipronil, tebuconazole, trifluralin, pyraclostrobin and 1-(3,4-dichlorophenyl)-3-methylurea being associated with at least three of the four hormones. There were also associations between cortisone/cortisol molar ratio and pollutants, namely dimethyl phosphate, 3-methyl-4-nitrophenol, carbofuran, λ-cyhalothrin, permethrin, fipronil, flusilazole, prometryn and fenuron. Some of these relationships were confirmed by single-pollutant linear regression analyses. Overall, our results suggest that background level of exposure to bisphenols and currently used pesticides may interfere with the glucocorticoid homeostasis in healthy women.

Toxicity of persistent organic pollutants: a theoretical study.

CONTEXT: Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are two families of persistent organic pollutants that are dangerous as they remain in the atmosphere for long periods and are toxic for humans and animals. They are found all over the world, including the penguins of Antarctica. One of the mechanisms that explains the toxicity of these compounds is related to oxidative stress. The main idea of this theoretical research is to use conceptual density functional theory as a theory of chemical reactivity to analyze the oxidative stress that PCBs and PBDEs can produce. The electron transfer properties as well as the interaction with DNA nitrogenous bases of nine PCBs and ten PBDEs found in Antarctic penguins are investigated. From this study, it can be concluded that compounds with more chlorine or bromine atoms are more oxidizing and produce more oxidative stress. These molecules also interact directly with the nitrogenous bases of DNA, forming hydrogen bonds, and this may be an explanation for the toxicity. Since quinone-type metabolites of PCBs and PBDEs can cause neurotoxicity, examples of quinones are also investigated. Condensed Fukui functions are included to analyze local reactivity. These results are important as the reactivity of these compounds helps to explain the toxicity of PCBs and PBDEs. METHODS: All DFT computations were performed using Gaussian16 at M06-2x/6-311 + g(2d,p) level of theory without symmetry constraints. Electro-donating (ω-) and electro-accepting (ω +) powers were used as global response functions and condensed Fukui functions as local parameters of reactivity.

Chemical-physical parameters and microbial community changes induced by electrodes polarization inhibit PCB dechlorination in a marine sediment.

Microbial reductive dechlorination of organohalogenated pollutants is often limited by the scarcity of electron donors, that can be overcome with microbial electrochemical technologies (METs). In this study, polarized electrodes buried in marine sediment microcosms were investigated to stimulate PCB reductive dechlorination under potentiostatic (-0.7 V vs Ag/AgCl) and galvanostatic conditions (0.025 mA·cm-2-0.05 mA·cm-2), using graphite rod as cathode and iron plate as sacrificial anode. A single circuit and a novel two antiparallel circuits configuration (2AP) were investigated. Single circuit polarization impacted the sediment pH and redox potential (ORP) proportionally to the intensity of the electrical input and inhibited PCB reductive dechlorination. The effects on the sediment's pH and ORP, along with the inhibition of PCB reductive dechlorination, were mitigated in the 2AP system. Electrodes polarization stimulated sulfate-reduction and promoted the enrichment of bacterial clades potentially involved in sulfate-reduction as well as in sulfur oxidation. This suggested the electrons provided were consumed by competitors of organohalide respiring bacteria and specifically sequestered by sulfur cycling, which may represent the main factor limiting the applicability of METs for stimulating PCB reductive dechlorination in marine sediments.

Global prevalence of organohalide-respiring bacteria dechlorinating polychlorinated biphenyls in sewage sludge.

BACKGROUND: Massive amounts of sewage sludge are generated during biological sewage treatment and are commonly subjected to anaerobic digestion, land application, and landfill disposal. Concurrently, persistent organic pollutants (POPs) are frequently found in sludge treatment and disposal systems, posing significant risks to both human health and wildlife. Metabolically versatile microorganisms originating from sewage sludge are inevitably introduced to sludge treatment and disposal systems, potentially affecting the fate of POPs. However, there is currently a dearth of comprehensive assessments regarding the capability of sewage sludge microbiota from geographically disparate regions to attenuate POPs and the underpinning microbiomes. RESULTS: Here we report the global prevalence of organohalide-respiring bacteria (OHRB) known for their capacity to attenuate POPs in sewage sludge, with an occurrence frequency of ~50% in the investigated samples (605 of 1186). Subsequent laboratory tests revealed microbial reductive dechlorination of polychlorinated biphenyls (PCBs), one of the most notorious categories of POPs, in 80 out of 84 sludge microcosms via various pathways. Most chlorines were removed from the para- and meta-positions of PCBs; nevertheless, ortho-dechlorination of PCBs also occurred widely, although to lower extents. Abundances of several well-characterized OHRB genera (Dehalococcoides, Dehalogenimonas, and Dehalobacter) and uncultivated Dehalococcoidia lineages increased during incubation and were positively correlated with PCB dechlorination, suggesting their involvement in dechlorinating PCBs. The previously identified PCB reductive dehalogenase (RDase) genes pcbA4 and pcbA5 tended to coexist in most sludge microcosms, but the low ratios of these RDase genes to OHRB abundance also indicated the existence of currently undescribed RDases in sewage sludge. Microbial community analyses revealed a positive correlation between biodiversity and PCB dechlorination activity although there was an apparent threshold of community co-occurrence network complexity beyond which dechlorination activity decreased. CONCLUSIONS: Our findings that sludge microbiota exhibited nearly ubiquitous dechlorination of PCBs indicate widespread and nonnegligible impacts of sludge microbiota on the fate of POPs in sludge treatment and disposal systems. The existence of diverse OHRB also suggests sewage sludge as an alternative source to obtain POP-attenuating consortia and calls for further exploration of OHRB populations in sewage sludge. Video Abstract.

Characterization of persistent organic contaminants in the atmosphere of Gadani's ship breaking yards and its surrounding: Implications for sustainable ship recycling practices.

Gadani is internationally renowned for its extensive ship-breaking operations, positioning it as one of the globe's primary ship-breaking hubs. A comprehensive study was conducted to evaluate the presence of organic contaminants in the air within Gadani, encompassing the areas surrounding ship-breaking facilities, proximate residential settlements, and adjacent roadways. Passive air samplers were employed to collect a total of 30 air samples. The analytical results unveiled a notably elevated concentration of specific organic compounds, with a pronounced prevalence of polycyclic aromatic hydrocarbons (PAHs), short-chain chlorinated paraffins (SCCPs), and polychlorinated biphenyls (PCBs) at the ship-breaking yard. Notably, dichlorodiphenyltrichloroethanes (DDTs) and DDE were detected at substantially lower levels. In particular, sites in close proximity to ship-breaking activities exhibited elevated concentrations of PCBs (Σ7PCB 0.065429 to 7.345714 ng/sample), PAHs (Σ8PAH 2.44 to 134.23 ng/sample), and SCCPs (0.18 to 25.6 ng/sample). Conversely, DDTs and DDE demonstrated higher concentrations near residential settlements. The evaluation of Molecular Diagnostic Ratios for PAHs revealed anthracene/anthracene + phenanthrene ratios of 0.88, 0.69, and 0.5 for ship-breaking areas, roadside locations, and community surroundings, respectively. Furthermore, the benz[a]anthracene/benz-[a]anthracene + chrysene molecular ratios were measured at 0.77 (ship-breaking sites), 0.82 (roadside), and 0.83 (community), respectively. The molecular ratio of fluoranthene/fluoranthene + pyrene at ship-breaking sites was 0.23, while roadside and community ratios were 0.36 and 0.89, respectively. These findings underscore the significant contribution of ship-recycling activities to the atmospheric release of SCCPs, PCBs, and PAHs, emphasizing the global imperative for responsible ship recycling practices.