Polychlorinated Biphenyls Research Articles

Establishing the Mechanisms Involved in the Environmental Exposure to Polychlorinated Biphenyls (PCBs) in the Risk of Male Infertility.

Exposure to toxic chemicals, such as plasticizers, alkylphenol compounds, and polychlorinated biphenyls (PCBs), has increased due to environmental contamination. PCBs, categorized as persistent organic pollutants (POPs), are lipophilic chemicals commonly used in lubricants, cutting oils, and electrical insulators. PCBs may have detrimental effects on hormone-producing glands, potentially contributing to male infertility. Thus, the objective of this study was to provide a comprehensive overview of the adverse effects of PCBs on the male reproductive system. Searches of three electronic databases were performed using MESH terms and 32 studies were included. Although the exact mechanism of action for PCBs remains unclear, several PCBs are regarded as potential endocrine disruptors due to their ability to interact with hormone signaling pathways. PCBs have been found to disrupt physiological functions by mimicking endogenous hormones as agonists or antagonists, altering patterns of hormone synthesis, hormone receptor affinities or numbers, and modulating enzymes involved in hormone secretion. These reports highlight the pleiotropic nature of PCB function and the susceptibility of the reproductive system. Endocrine-disrupting PCBs can mimic, alter, or block hormonal responses, inhibiting natural signaling to the testes and epididymis via various mechanisms such as binding to sex hormone-binding globulin and androgen-binding protein or blocking cell surface receptors. Furthermore, PCBs can alter the hormonal environment in the prostate or seminal vesicles by changing the affinity of androgens for their receptors. The testicles and genital organs may be susceptible to various estrogenic effects, leading to changes in the quality or quantity of their secretions and the volume of semen.

Persistent organic pollutants and endogenous sex-related hormones in Hispanic/Latino adults: The Hispanic Community health study/study of Latinos (HCHS/SOL).

Previous studies have demonstrated associations of persistent organic pollutants (POPs) with sex-related hormones; however, findings were inconsistent. Sex-specific impacts and pathways through which adiposity influences associations are not completely understood. We sought to evaluate sex-specific associations of POPs serum concentration with sex-related hormones and to explore pathways through which adiposity may modify associations. We studied 1073 men and 716 postmenopausal women participating in the "Persistent Organic Pollutants, Endogenous Hormones, and Diabetes in Latinos" ancillary study which is a subcohort of the "Hispanic Community Health Study/Study of Latinos." We use baseline examination data collected from 2008 to 2011 to investigate associations between eight organochlorine pesticides (OCPs), five polychlorinated biphenyls (PCB) groups, sum of polybrominated diphenyl ethers and polybrominated biphenyl 153 on sex hormone binding globulin (SHBG) and various sex-related hormone levels. We examined associations cross-sectionally using linear and logistic regression models adjusted for complex survey design and confounders. PCBs and select OCPs were associated with increased SHBG in women and decreased estradiol (E2) and/or bioavailable E2 in men. For instance, per quartile increase in serum concentrations of ∑PCBs and oxychlordane were associated with decreased levels of E2 (β=-6.36pmol/L; 95% CI: 10.7,-2.02 and β=-5.08pmol/L; 95% CI: 8.11,-2.05) and bioavailable E2 (β=-4.48pmol/L; 95% CI: 7.22,-1.73 and β=-4.23pmol/L; 95% CI: 6.17,-2.28), respectively, in men, and increased levels of SHBG (β=7.25nmol/L; 95% CI:2.02,12.8 and β=9.42nmol/L; 95% CI:4.08,15.0), respectively, in women. p,p'-DDT and β-HCCH, and o,p'-DDT were also associated with decreased testosterone (T) and bioavailable T (ng/dL) levels in men. Adiposity modified associations in men, revealing stronger inverse associations of PCBs, PBDEs, and several OCPs with LH, SHBG, E2, bioavailable E2, T, and the ratios of LH to FSH and E2 to T in those with below median body mass index and waist-to-hip ratio. Distinct patterns of hormone dysregulation with increasing POPs serum concentration were identified in men and post-menopausal women. In men but less so in postmenopausal women, adiposity modified associations of POPs serum concentration with sex-related hormones.

Environmental contaminants assessment for frequently harvested migratory waterfowl in the Northeast Atlantic flyway.

Waterfowl serve as indicators of ecosystem health and represent a pathway of contaminant exposure for hunters who consume them. In the northeast Atlantic Flyway, data on baseline contaminant loads in waterfowl are lacking. We assessed five species of commonly harvested (and consumed) waterfowl for mercury, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and per- and polyfluoroalkyl substances (PFAS). We found that Canada geese (Branta canadensis) and wood ducks (Aix sponsa) had lower contaminant burdens than mallards (Anas platyrhynchos), American green-winged teal (Anas carolinensis), and American black ducks (Anas rubripes). Regardless of species, all samples contained detectable levels of PCBs and at least one OCP and PFAS. Mercury and OCPs posed limited non-cancer risks to human consumers who follow current waterfowl consumption advisories. Based on a probabilistic risk assessment, lower consumption rates were required to reduce risks from PCBs compared to other contaminants. Protective human consumption advisories depend in part on the level of allowable cancer risk and whether contaminants were considered toxicologically to act individually or collectively. Accordingly, revisions to consumption advisories to protect public hunter health given these new data hinge upon risk management decisions. These data can be used to update waterfowl consumption advisories in the northeast Atlantic Flyway and inform future research into the health effects of legacy and contemporary contaminants on the sustainability of waterfowl populations.

The screening of priority pollutants in the Bohai Sea based on ecological risk assessment.

The Bohai Sea (BS) is a semi-enclosed inland sea and China's most polluted coastal sea. With the rapid economic development of the circum-Bohai Sea region, large amounts of pollutants have been discharged into the BS, posing a significant threat to human health and the ecosystem. Great efforts have been made on investigating the levels of various pollutants in the BS; however, the priority pollutants which are required for the implementation of suitable environmental management and remediation measures in this system remain unclear. By using the risk quotient method, this study evaluated the ecological risks of various pollutants (including antibiotics, heavy metals, total petroleum hydrocarbons (TPHs), endocrine disruptors, pesticides, and persistent organic pollutants) in BS water and sediments over the past twelve years to identify the priority pollutants in this system. The results showed that 8 and 10 pollutants were at risk in BS water and sediments, respectively. Overall, 13 pollutants (arsenic (As), copper (Cu), mercury (Hg), nickel (Ni), chromium (Cr), lead (Pb), zinc (Zn), cadmium (Cd), TPHs, bisphenol A (BPA), erythromycin, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs)) in the BS were identified to have potential risks and should be included in the list of priority pollutants. The monitoring of the changes in the contents of these pollutants in BS water and sediments needs to be strengthened in the future.

Persistent organic pollutants (POPs) in marine sediments of the Arctic fjord Kongsfjorden, Svalbard Islands.

New data on the occurrence of POPs, including polychlorinated biphenyls (PCBs) and legacy pesticides (LPs), along with current-use pesticides (CUPs) in the surface marine sediments of Kongsfjorden over five years (2018-2022) are presented. LPs examined were p,p'-dichlorodiphenyltrichloroethane (DDT), p,p'-l,l-dichloro-2,2-bis(chlorophenyl)ethylene (DDE), and hexachlorocyclohexane (HCH), while CUPs included chlorpyrifos (CPF), dacthal (DAC), and endosulfan (ENDO). LPs (0.12-0.59ng/g) were in higher amounts than CUPs (0.01-0.15ng/g). The first data on CPF (0.003-0.07ng/g) and DAC (0.001-0.06ng/g) in Arctic marine sediments were obtained. Σ34PCBs (0.25-0.62ng/g) were found with a dominance of lower molecular weight congeners, probably transported via atmospheric currents. A general increasing trend in concentrations of target compounds was observed over the study period. Overall, higher concentrations of these compounds were found near the tidal glaciers, suggesting that glacier meltwater plays a role in releasing contaminants. However, the potential influence of oceanic currents on their transport cannot be ruled out.

Optimizing biodegradation of polychlorinated biphenyls (PCBs) using bacteria isolated from common effluent treatment plant (CETP) sludge: Integration of machine learning, kinetic studies, and metabolomic analysis

Optimizing biodegradation of polychlorinated biphenyls (PCBs) using bacteria isolated from common effluent treatment plant (CETP) sludge: Integration of machine learning, kinetic studies, and metabolomic analysis

Contaminant-Associated Disruption of the Skin Transcriptome in the Endangered St. Lawrence Estuary Beluga.

The St. Lawrence Estuary (SLE) beluga (Delphinapterus leucas) population in Canada is Endangered, and endocrine disrupting contaminants, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and other halogenated flame retardants, have been identified as a threat to the recovery of this population. Here, potential impacts of these contaminants on SLE beluga were evaluated by comparing skin transcriptome profiles and biological pathways between this population and a population less exposed to contaminants (Eastern Beaufort Sea) used as a reference. Differential gene expression analysis indicated potential seasonal or geography-related (Arctic vs temperate regions) effects on the skin transcriptome. Among the gene transcripts that were associated with Σ31PCB (123 genes), Σ29PBDE (198 genes), HBB (347 genes), and PBEB (126 genes) blubber concentrations, several were related to immune response pathways. In addition, 18 toxicology-related gene transcripts selected from the literature were correlated with organohalogen concentrations and were used to derive new threshold values in beluga skin for potential biological effects of ΣPCB (1,500 ng/g lw), ΣPBDE (52 ng/g lw), and two other flame retardants, i.e., HBB (1.2 ng/g lw) and PBEB (0.04 ng/g lw). Results suggest that exposure to these organohalogens pose a risk to the immune system of SLE beluga.

Effect of Combustion Material on the Level of Persistent Organic Pollutants in Smoked Pork

Background: Although smoking has historically been one of the most prevalent methods for food preservation, it was considered a source of carcinogenic and mutagenic persistent organic pollutants (POPs), such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) due to incompletely combustion process. In this study, POPs in pork samples smoked with different materials: sawdust only (NP group), sawdust and polyethylene (PE group), sawdust and polystyrene (PS group), and mixed sawdust (M group) were detected and quantified. Method: The GC-MS method was applied to quantify several POPs in pork samples smoked by various materials. After that, multivariate statistics were used to elucidate differences among groups and chemical markers associated with each smoking material, underscoring the need to evaluate the implications of smoking materials on food safety and public health. Results: The total PAH and PCB contents were lowest in the NP samples (smoked with sawdust only), with PAH levels ranging from 500 to 2000 μg/kg lipid and PCB levels from 0.5 to 1.3 μg/kg lipid. In contrast, the PE, PS, and M groups, which were smoked with sawdust combined with different polymers and contaminants, showed higher levels. The PAH content in these groups exceeded 3000 μg/kg lipid, while PCB levels in PE and PS ranged from 1.5 to over 3.0 μg/kg lipid, and M samples had the widest variation, spanning from 0.6 to 3.2 μg/kg lipid. Regarding PCDD/Fs, none were detected in the NP samples, while the PE and PS groups contained between 1.2 and 1.5 pg/g lipid, with specific compounds identified (e.g., 234678-HxCDF in PE and 12378-PeCDF and 123478-HxCDF in PS). The M samples exhibited the highest PCDD/Fs content, ranging from 5.0 to 14.0 pg/g lipid, with up to six compounds formed, including one PCDD and five PCDFs. Conclusion: The analysis also revealed that the presence of polyethylene and polystyrene significantly elevated POP levels in the respective groups. Meanwhile, samples in the M group possessed various chemical compositions with multiple concentrations, presented by the large area on the PCA biplot and usually intermingled with samples of other groups. Especially, OCDD was the only PCDD that was detected only in M group simples.

Polychlorinated biphenyls induced toxicities upon cell lines and stem cells: a review.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants emitted during e-waste activities. Upon release into the environment, PCBs can pose harmful effects to the humans and environment. The present review focused on the effects of PCBs on cell proliferation, apoptosis, functional and developmental toxicity and potential possible molecular mechanisms upon cells and stem cells. The review also highlights the effects of low- and high-chlorinated, and dioxin and non-dioxin PCBs. The review suggested that high chlorinated and dioxin like PCBs at higher concentrations posed more toxic effects to cells and stem cells. PCBs at higher levels induced hepatotoxicity, carcinogenicity, reproductive toxicity, neurotoxicity and lung cell toxicity. PCBs triggered reactive oxygen species which actives mitogen activated pathways, nuclear factor and cytochrome pathway for cell proliferation and apoptosis. Further, review highlights PCBs induced toxicity in stem cells with the focus on developmental and functional toxicity. The review could be useful to understand the PCBs toxicities and mechanisms and will guide to policy makers to design policies for e-waste pollutant.

Treatment of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in stormwater using polishing columns with biochar and granular activated carbon.

Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) are recalcitrant organic pollutants often detected in stormwater. Various stormwater control measures (SCMs) can remove PAHs and PCBs by filtration, adsorption, and biodegradation. However, dissolved PAHs and PCBs remain present in the treated outflow of SCMs. To provide further treatment, two types of biochar (biochar A and biochar B), a granular activated carbon (GAC), and a regenerated GAC (RAC) were tested in a column study with synthetic stormwater containing PAHs and PCBs in low concentrations. Results showed that PAH concentrations were reduced by 98.2-99.8% (range: <limit of quantification (LOQ) - 1.89μg/L), while PCB concentrations were reduced by 86.0-97.9% (range: <LOQ - 0.7μg/L). The extraction of PCBs from the media showed that >62% of the PCBs accumulated at the first third of the column due to adsorption onto the black carbon material thus providing information for management. The difference in treatment performances of different PAHs and PCBs may be caused by the molecular structure of the contaminants. Lifetime calculations indicated that biochar had lifetimes >36-51 years, while GAC and RAC showed lifetimes longer than 147 and 206 years, respectively, based on predicted precipitation for scaled up designs. The results showed that biochar and activated carbons can be efficient adsorbents for stormwater polishing treatment. With consideration of efficiency, sustainability and cost, RAC is recommended for polishing treatment of dissolved PAHs and PCBs.

Tissue bioaccumulation and distribution of organic contaminants in Brazilian guitarfish Pseudobatos horkelii reveal a concerning impact of contraceptive hormones and fecal sterols.

The critically endangered Brazilian guitarfish faces significant threats from environmental contamination. Assessing the impacts of such stressor is paramount from a conservational perspective. This study investigated the concentrations, distribution and accumulation patterns of organic contaminants in pregnant Brazilian guitarfish Pseudobatos horkelii. Blood, gill, gonad, liver, and muscle concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers, fecal sterols, and synthetic hormones used as human contraceptives were assessed. Synthetic hormones, especially D-norgestrel, showed the highest concentrations, mainly in the liver. Together with the results of fecal sterols, this finding suggests that guitarfish are exposed to sewage discharge. OCPs, especially hexachlorobenzene, mirex, endosulfans, and drins, showed considerably high concentrations, indicating the relevance of agricultural inputs. PCBs presented significant concentrations in the muscle, indicating long-term exposure, in contrast with other analytes that were primarily concentrated in the liver. These results have conservational implications, since contaminants analyzed herein have endocrine disruptive effects.

Uncovering the Potential Link Between Polychlorinated Biphenyls and Cardiovascular Diseases: A Comprehensive Analysis

Background: A family of persistent organic pollutants, known as polychlorinated biphenyls (PCBs), are extensively found in the environment and may be harmful to the cardiovascular system. Systematic reviews and meta-analyses are required to thoroughly evaluate the association between PCB exposure and cardiovascular disease (CVDs), despite the fact that studies on the subject have produced inconsistent results. Objective: The purpose of this study was to investigate the relationship between PCBs exposure and cardiovascular disease risk in order to provide more conclusive data to promote public health actions. Methods: The studies that met the inclusion criteria were screened out using the databases PubMed, Web of Science, ScienceDirect, and Cochrane Library. The comprehensive effect size (OR) was calculated using the random-effects model; the study’s heterogeneity was analyzed using I2 statistics; the major reasons of heterogeneity were identified using subgroup analysis; and publication bias graphically was measured using the Egger’s test. Results: A meta-analysis of 11 studies revealed that total PCBs (OR = 1.56, 95% CI: 1.20–1.75), non-dioxin-like PCBs (NDL-PCBs) (OR = 1.33, 95% CI: 1.15–1.53), and dioxin-like PCBs (DL-PCBs) (OR = 1.31, 95% CI: 1.10–1.57) were all found to be positively associated with the risk of cardiovascular disease. Subgroup analysis revealed that study type, biomaterials, and literature quality were the most significant drivers of variation. Furthermore, certain PCB homologues, such as non-dioxin-like (NDL)-PCB153 and dioxin-like (DL)-PCB118, are highly related with cardiovascular disease. Conclusions: According to this meta-analysis, exposure to PCBs may increase the risk of cardiovascular disease. Notwithstanding major drawbacks, our results emphasize the significance of lowering exposure to PCBs and offering a solid theoretical basis for public health initiatives.

The pollution fast-track to the arctic: how Southern wintering areas contribute to organochlorine loads in a migrant seabird breeding in the arctic.

This study examines how southern wintering areas may contribute to organochlorine (OCs) loads in arctic seabirds during breeding. Light-sensitive geolocators (GLS loggers) were deployed on Arctic skuas (Stercorarius parasiticus) in one high arctic and two subarctic colonies. Hexcahlorobenzene (HCB), Chlordanes, Mirex, p, p'-dichlorodiphenyldichloro- ethylene (p, p'-DDE), and Polychlorinated biphenyls (PCBs) were measured in the blood of breeding adults at the nest (58 individuals, a total of 128 samples) in northern Norway and Svalbard between 2009 and 2015. We compared OC concentrations and OC profiles among nesting skuas wintering in five Atlantic regions, determined by the GLS loggers: the coast of Argentina, the Caribbean, the coast of western Africa, the coast of Southern Africa, and the Mediterranean Sea. As predicted, HCB, which is semi-volatile and has high long-range transport potential, showed high prevalence in birds wintering in all regions except the Mediterranean. Mirex showed the highest prevalence in birds wintering off the coasts of Argentina and southern Africa, in accordance with high background levels previously documented in the Southern Ocean. Chlordanes were particularly prevalent in skuas wintering off southern Africa, whereas p, p'-DDE seemed relatively evenly distributed among wintering areas. As predicted, the prevalence of PCBs was much higher in birds wintering in the Mediterranean Sea than in birds from other regions. This study thus suggests that the Mediterranean Sea, the mid- and southern Atlantic are essential sources of different OCs in the blood of Arctic skuas breeding in the European Arctic.

Polychlorinated Biphenyls Induce Cytotoxicity and Inflammation in an In Vitro Model of an Ocular Barrier

Polychlorinated biphenyls (PCBs) are heterogeneous, synthetic, and widespread organochlorine compounds, and are one of the persistent organic pollutants present in improperly dumped waste and electronic equipment (e-waste), with a high bioaccumulation potential. In this study, the toxicity of Aroclor 1254 (a mixture of commercial PCBs) in human corneal epithelial cells (HCEpiCs), in an in vitro model of an ocular barrier, was evaluated. Aroclor 1254 (0.1–10 μg/mL) reduced cell viability, trans-endothelial electric resistance (TEER) and cell migration. Moreover, it induced an inflammatory response, as indicated by the increase in cPLA2 activity, PGE2 production, phosphorylation of ERK 1/2 and p-38, and release of inflammatory cytokines. Aroclor 1254 can damage corneal cells, compromising the integrity of the eye’s outermost barrier. This damage may facilitate the occurrence of infectious processes that are physiologically prevented by the corneal barrier.

Polychlorinated naphthalenes (PCNs) and polychlorinated biphenyls (PCBs) in surface soils and street dusts in Detroit, Michigan.

Polychlorinated naphthalenes (PCNs) and polychlorinated biphenyls (PCBs) are toxic contaminants that were produced and used in large quantities for their stability, inertness, and other desirable electrical, cooling, and lubricating properties. Due to their environmental persistence and improper disposal, these contaminants have become broadly distributed in the environment. This study examines the levels, composition, distribution, and potential sources of these compounds in surface soils and street dusts collected at 19 residential and industrial areas in Detroit, Michigan. Each sample was analyzed for 32 PCN and 37 PCB congeners using gas chromatography/mass spectrometry. The geometric mean concentrations of total PCNs and total PCBs were 61 (range:11-1933) and 432 (range: 32-18,637) ng/g, respectively. The most common PCNs were tetra- to hexacongeners and PCN-59 was most prevalent individual congener. For PCBs, hexaPCBs were most common and PCB-158 was dominant. PCN and PCB levels in soils at most sites exceeded health-based guideline levels. Given the short half-lives of PCNs and restrictions on PCN and PCB production, our results imply ongoing or recent releases. Emission sources identified by principal components and other analyses include industrial thermal processes included fuel combustion and electrical waste handling at a scrap metal processor for PCNs and PCBs, respectively. The presence of sources and "hotspots" of these toxic "legacy" contaminants in urban settings like Detroit highlight the potential for human exposure and the need to identify and control sources to prevent further environmental dispersal, exposure and risk.

Distribution and bioconcentration of semivolatile organic compounds (SVOCs) in soils and vascular plant Colobanthus quitensis from Sub-Antarctic and Antarctic regions.

Semi-volatile organic compounds (SVOCs) are widely distributed across the globe, including polar regions. This study investigates the distribution and bioconcentration of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) in soils and Colobanthus quitensis, while also estimating potential emission sources. Results indicated high concentrations of PAHs in soils and plants from the Sub-Antarctic region, while OCPs and PCBs were more prevalent in the Antarctic region, with higher contaminant concentrations found in soils than in plant tissues. Hexachlorobenzene (HCB) and dichlorodiphenyldichloroethylene (p,p'-DDE) were significantly higher in the Antarctic region, suggesting historical dichlorodiphenyltrichloroethane (DDT) use, while PCB 153 and 180 were the most representative PCBs in the Antarctic region. Phenanthrene (Phe) was the dominant PAH in both regions. The bioconcentration factor analysis from soils (BCFSoils) revealed potential anthropogenic influences for certain contaminants, including γ-hexachlorocyclohexane (γ-HCH) and PCB 9 in the Sub-Antarctic region, and HCB, p,p'-DDE, PCB 9, and benzo-naphtho-thiophene in the Antarctic region. However, compounds with higher hydrophobicity showed lower Bioconcentration factor (BCFSoils) values, indicating a tendency to accumulate in soil rather than plant tissues. This was consistent with the inverse relationship found between BCFSoils and the octanol-water partition coefficient (Log KOW). Diagnostic ratios of PAHs revealed a predominantly pyrogenic source in the Sub-Antarctic region, while a mixture of sources was observed in the Antarctic region.

Effect of polystyrene micro/nanoplastics on PCBs removal in constructed wetlands planted with Myriophyllum aquaticum.

The co-occurrence of microplastics (MPs) and nanoplastics (NPs) with polychlorinated biphenyls (PCBs) is an emerging environmental concern. Wetland plants, with their unique anaerobic-aerobic environments, offer a promising approach for PCBs removal. However, the impact of MPs and NPs on PCBs dynamics in constructed wetlands is not well understood. This study examined the influence of polystyrene MPs and NPs of two different sizes on PCBs fate in constructed wetlands featuring Myriophyllum aquaticum. Results showed that although there was no significant difference in overall PCBs removal rates, the presence of MPs increased residues of highly chlorinated PCBs from 331μg/kg to 379μg/kg, while the presence of NPs increased residues of lightly chlorinated PCBs from 125μg/kg to 153μg/kg. Additionally, MPs and NPs increased plant uptake of PCBs from 0.08% to 0.10-0.14%, despite potential inhibition of plant growth. While MPs/NPs elevated microorganism counts, they did not affect microbial diversity or community structure. Importantly, MPs significantly inhibited the main PCB-dechlorinating bacteria (Dehalococcoidia) and had a greater impact on PCB-degrading enzymes (dioxygenase, K03381) compared to NPs. This study highlights the complex interactions between MPs/NPs and PCBs in wetland environments and their implications for bioremediation strategies.

The Association between Serum Polychlorinated Biphenyls and Incident Cardiovascular Disease among Type 2 Diabetes.

Polychlorinated biphenyls (PCBs) were associated with cardiovascular disease (CVD) in the general population. However, it is unclear whether PCBs exposure increases the additional risk of CVD among type 2 diabetes (T2D) cases. This study aims to investigate the associations between serum concentrations of PCBs and incident CVD among T2D cases. The study population was derived from Dongfeng-Tongji cohort in 2008 and followed up until December 31, 2018, with a total of 2,806 participants with type 2 diabetes included and 1180 of them developed CVD during the follow-up. Cox proportional hazard regression models and quantile g-computation method were conducted for the associations of serum PCB levels with incident CVD risk. Compared with the first quartile, the risk of incident CVD was increased by 25%, 30%, and 28% in the fourth quartile of serum concentrations of PCB28, PCB52, and PCB101, respectively. Similar results were obtained for lower-chlorinated PCBs (PCB28 + PCB52 + PCB101) with HR (95% CI) of 1.257 (1.063, 1.486), and 1.346 (1.139, 1.589) in the third and fourth quartiles, respectively (P trend = 0.001). Quantile g-computation indicated that mixed exposure to PCBs increased the risk of CVD and the top three weights of PCB congeners were PCB101, PCB52, and PCB28. Serum PCB independently increased the risk of incident CVD among T2D cases, in which lower-chlorinated PCBs played a dominant role.

Transcriptomic analysis of effects of developmental PCB exposure in the hypothalamus of female rats.

This study investigated the consequences of perinatal exposure to Aroclor 1221 (A1221), a weakly estrogenic polychlorinated biphenyl (PCB) mixture and known endocrine-disrupting chemical (EDC), in female rats. Previous work has shown behavioral and physiological effects of A1221, and the current study extended this work to comprehensive transcriptomic profiling of two hypothalamic regions involved in the control of reproduction: the arcuate nucleus (ARC) and anteroventral periventricular nucleus (AVPV). Female Sprague-Dawley rats were fed a cookie treated with a small volume of A1221 (1mg/kg) or vehicle (3% DMSO in sesame oil) during pregnancy from gestational days 8-18 and after birth from postnatal (P) days 1-21, exposing the offspring via placental and lactational transfer. In female offspring, developmental, physiological, and hormonal effects of A1221 were relatively modest. However, because prior work has implicated this exposure in neurobehavioral disruptions, we sought to determine whether developmental programming of the brain transcriptome could underlie these latter phenotypes. We used 3' targeted RNA sequencing in the hypothalamus (arcuate nucleus, anteroventral periventricular nucleus) of experimental females at P8, 30, and 60 and identified significant alterations in gene expression and gene ontology (GO) terms in an age- and tissue-specific manner. Most notably, terms related to synaptic signaling, neurotransmitter regulation, immune response, and cellular structure were identified. Changes in pathways associated with synaptic functions and cellular metabolism were further identified, indicating that A1221 exposure can impact neurodevelopmental and neuroendocrine processes at a molecular level, even in the absence of overt developmental changes. These findings of molecular reprogramming may explain the behavioral effects of A1221 and highlight novel molecular targets and pathways that warrant further investigation to understand the effects of EDCs on the developing brain.

Halogenated organic compounds in mangrove sediments from Bintan Island, Indonesia: Occurrence, profiles, sources, and potential ecological risk.

The first comprehensive analysis of halogenated organic compounds (HOCs), including 209 full congeners of polychlorinated biphenyls (PCBs), 26 organochlorinated pesticides (OCPs), 41 polybrominated diphenyl ethers (PBDEs), and four other brominated flame retardants (BFRs), was performed on surface mangrove sediments from Bintan Island, Province of the Riau Archipelago, Indonesia. Among the measured HOC contaminants, the mean concentration of ∑209PCBs (2.3±0.96 ng g-1 dw) was higher than that of p,p'-DDE (1.8±0.70 ng g-1 dw), ∑41PBDEs (1.8±1.1 ng g-1 dw), trans-nonachlor (0.42±0.13 ng g-1 dw), and other BFRs (0.20±0.29 ng g-1 dw), while other OCP related compounds less than 0.2 ng g-1 dw. In addition, concentrations of unintentionally produced PCBs such as PCB-11 and PCB-47/48/75 ranged from 0.57-1.5 ng g-1 dw. Variations in HOCs accumulation and profiles among mangrove habitats and species indicate different anthropogenic stressors and species-specific accumulations. The ecological risk estimation from HOCs exposure on dwelling sediment biota in mangrove sediments varied from no risk to potentially causing adverse effects in several locations. Overall, this study provides fundamental information on the function of mangrove ecosystems as an accumulation zone for HOCs in tropical regions.