Polychlorinated Biphenyls Concentrations Research Articles

Polychlorinated biphenyl and polybrominated diphenyl ether profiles vary with feeding ecology and marine rearing distribution among 10 Chinook salmon (Oncorhynchus tshawytscha) stocks in the North Pacific Ocean

Chinook salmon (Oncorhynchus tshawytscha) along the west coast of North America have experienced significant declines in abundance and body size over recent decades due to several anthropogenic stressors. Understanding the reasons underlying the relatively high levels of persistent organic pollutants (POPs) in Chinook stocks is an important need, as it informs recovery planning for this foundation species, as well for the Chinook-dependent Resident killer whales (Orcinus orca, RKW) of British Columbia (Canada) and Washington State (USA). We evaluated the influence of stock-related differences in feeding ecology, using stable isotopes, and marine rearing ground on the concentrations and patterns of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Chinook salmon. A principal components analysis (PCA) revealed a clear divergence of PCB and PBDE congener patterns between Chinook with a nearshore rearing distribution (‘shelf resident’) versus a more offshore distribution. Shelf resident Chinook had 12-fold higher PCB concentrations and 46-fold higher PBDE concentrations relative to offshore stocks. Shelf resident Chinook had PCB and PBDE profiles that were heavier and dominated by more bioaccumulative congeners, respectively. The higher δ13C and δ15N in shelf resident Chinook compared to the offshore rearing stocks, and their different marine distributions explain the large divergence in contaminant levels and profiles, with shelf resident stocks being heavily influenced by land-based sources of industrial contamination. Results provide compelling new insight into the drivers of contaminant accumulation in Chinook salmon, raise important questions about the consequences for their health, and explain a major pathway to the heavily POP-contaminated Resident killer whales that consume them.

SAT425 Effects Of Endocrine-disrupting Polychlorinated Biphenyls On Adolescent Microglial Cytokine Expression And Responses To Secondary Inflammatory Challenge

Abstract Disclosure: S.L. Kissinger: None. A.J. Fitzgibbon: None. R.A. Mejia: None. M.R. Bell: None. Polychlorinated biphenyls (PCBs) are a group of ubiquitous environmental endocrine-disrupting chemicals (EDCs), and exposure is associated with endocrine, neuronal, and immune dysfunction in various tissue types. Innate immune cells of the nervous system called microglia are critical in responding to infection and injury, and disruption of these functions is associated with neurodegenerative disease and mental health disorders. In addition, microglia are known to regulate developmental processes during neonatal and adolescent periods, in hormone-sensitive and age- and sex-differentiated ways. Work in our lab has shown that early life PCBs can affect microglia function in ways that depend on the age and sex of the individual rat in vivo. Ongoing work uses in vitro approaches to demonstrate direct effects on microglia. In primary culture, preliminary data suggest that acute PCB exposure causes neonatal microglia to become hyperresponsive to a secondary challenge; however, effects in adolescent microglia are unknown. To test the hypothesis that PCB exposure directly alters microglia activity in an age- and sex-specific manner, we determined the effects of PCBs on cytokine gene expression in acutely isolated microglia, with or without a secondary lipopolysaccharide (LPS) challenge. Adolescent Sprague-Dawley rats underwent transcardial saline perfusion, brains were removed and homogenized into a single cell suspension with collagenase and mechanical disruption, and debris was removed. Microglia, identified as CD11b+ cells, were collected by magnetic bead isolation and plated in enriched media for 24 hours prior to experimentation. Cells were exposed to one of three concentrations of PCB 153 (0.1 µM, 1 µM, 10 µM), DMSO vehicle, or DMEM/F12 media control for 18 hours, followed by a 4-hour LPS challenge (0.5 µg/mL) or PBS vehicle control. RNA was isolated and converted to cDNA for qPCR analysis of Tnf and Il1b gene expression, analyzed by two-way (exposure x challenge) ANOVAs within both male and female cells. Results indicate that 1.0 µM PCB 153 exposure caused an increase in expression of both cytokines, more so in females than males. Preliminary results (n = 3) indicate that the 10 µM dose may also blunt the later LPS response. These results confirm that microglia are directly sensitive to PCBs, however they illustrate that cells may show differential responses depending on the stage of development. Continued work will explore acute cell toxicity and confirm release of cytokines. Adolescent microglia dysfunction from PCB exposure may be a mechanism of adolescent-onset disorders, or increased risk of neurodegenerative conditions triggered by additional challenges later in life. Presentation: Saturday, June 17, 2023

Evaluation of Polychlorinated Biphenyls in Sediments from Surface Waters of Igodan, Okunmo, Lebi, Idepe and OAUSTECH in Okitipupa, Ondo State Nigeria

The presence of PCBs in water bodies is an emerging issue for water quality. This is because, once PCBs reach a lake or river, they concentrate in the sediments by attaching to the organic matter. Therefore, the objective of this paper is to evaluate the level of polychlorinated biphenyls (PCBs) in sediment from surface waters of Igodan, Okunmo, Lebi, Idepe and Oaustech in Okitipupa, Ondo State Nigeria using appropriate standard methods. Data obtained reveals that in Igodan the concentration of PCBs in sediment w.as PCB 44 (5.42±0.00), PCB 18 (3.04±0.00), PCB 28 (3.27±0.07) and PCB 170 (6.60±0.00). Okunmo PCBs concentration in sediment was PCB 44 (0.67±0.00), PCB 18 (0.03±0.00), PCB 28 (0.32±0.00) and PCB 170 (0.18±0.00). Lebi PCBs concentration in Sediment was PCB 44 (0.82±0.00), PCB 18 (3.96±0.00), PCB 28 (1.12±0.00) and PCB 170 (1.08±0.00). Except for PCB 170 (0.33±0.02), the PCB concentration in sediment from the Idepe and the OAUSTECH were both below the detection limit (BDL). Correlation between Physicochemical Parameters and PCBs homologs shows a negative correlation for the relationship of EC (Electrical Conductivity), TOC (Total Organic Carbon) and pH at ( -0.283), (-0.262) and ( -0.246) respectively. According to multivariate investigation, releases from nearby factories, deterioration of electrical cables and transformers, waste from university laboratories and facilities, as well as diesel residues from lister engines could be associated with the elevated levels of PCBs in sediments collected from the five sampled sites in Ondo State. TriPCBs > tetraPCBs were in this order in which the median concentrations of PCB homologues were found in sediments from the surface water.

Ecological and Health Risk Assessment of Polychlorinated Biphenyls in Water and Sediments in Bodo Riverine Area, River State, Nigeria

Concentrations of nine polychlorinated biphenyls (PCBs) were assessed in sediments and water in the Bodo River area, Gokana Local Government of River state Nigeria to assess the risk associated within the region due to the effect of oil spillage and marine pollution. The analytical procedure involved the application of Gas Chromatography coupled with mass spectrometric detection (GC/MS) for identification and quantification of and polychlorinated biphenyls respectively with high degree of accuracy and precision after triplicate analysis. All the selected PCB congeners analyzed were detected in the analyzed samples at different frequencies. The total concentrations of PCBs ranged from nd (not detected) to 4.15 mg/kg in sample A with an average concentration of 1.66 mg/kg, nd to 8.4 mg/kg in sample B with an average concentration of 3.25 mg/kg and nd to 7.30 mg/kg in sample C with an average concentration of 3.64 mg/kg in sediments. While the total concentrations of PCBs in the water sample ranged from nd (not detected) to 1.25 mg/kg in sample A with an average concentration of 0.56 mg/kg, nd to 4.50 mg/kg in sample B with an average concentration of 1.20 mg/kg and nd to 2.2 mg/kg in sample C with an average concentration of 0.88 mg/kg. Health risk assessment employed in this study includes the chronic daily intake and the carcinogenic risk via ingestion, inhalation and dermal contact using established guidelines. The total concentrations of PCBs were used to assess the cancer risk probabilities in humans via ingestion, dermal contact and inhalation of sediments particles. Very low cancer risk was found in all water samples compared to sediments samples caused by ƩPCBs. The results of the ecological risk assessment of PCBs in the Bodo River demonstrated the presence of PCBs in all sampling sites showing that the sites were highly contaminated with largely negative biological effects and a high potential risk to the environment.

Identification of the Contamination Sources by PCBs Using Multivariate Analyses: The Case Study of the Annaba Bay (Algeria) Basin.

Persistent Organic Pollutants (POPs), particularly the indicator polychlorinated biphenyls (PCBs), were first quantified in water and sediments of two wadis, Boujemaâ and Seybouse, as well as in the effluents from a fertilizer and phytosanitary production industrial plant (Fertial). Since these contaminated discharges end in Annaba Bay (Algeria) in the Mediterranean Sea, with a significant level of contamination, all the potential sources should be identified. In this work, this task is conducted by a multivariate analysis. Liquid-liquid extraction and gas chromatography/mass spectrometry (GC-MS) methods were applied to quantify seven PCB congeners, usually taken as indicators of contamination. The sum of the PCB concentrations in the sediments ranged from 1 to 6.4 μg/kg dw (dry weight) and up to 0.027 μg/L in waters. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used for the multivariate analysis, indicating that the main sources of PCB emissions in the bay are urban/domestic and agricultural/industrial. The outfalls that mostly contribute to the pollution of the gulf are the Boujemaâ wadi, followed by the Seybouse wadi, and finally by the Fertial cluster and more precisely the annex basin of the plant. Although referring to a specific site of local importance, the work aims to present a procedure and a methodological analysis that can be potentially applicable to further case studies all over the world.

Remedial effectiveness of a pond biomanipulation: Habitat value and concentrations of polychlorinated biphenyls in fish

The fish and plant communities in a pond contaminated with polychlorinated biphenyls (PCBs) in East Tennessee, USA, were manipulated to reduce ecological and human-health risk associated with exposure to the chemical contaminants. We evaluated the success of the remedial action using a habitat valuation approach, as well as measuring PCB concentrations in fish. Risk reduction objectives included: alter the fish community to favor fish that do not resuspend, bioaccumulate, or biomagnify PCBs; stabilize contaminated sediments to improve water quality; and stabilize shoreline soils and enhance riparian habitat. Fish targeted for removal included gizzard shad, largemouth bass, and nonnative carp. Reduced PCB concentrations in fish have characterized the new bluegill-dominated community, although a weir-overtopping event led to the need for additional removals of gizzard shad and largemouth bass. Sunfish abundance is high, as was intended. Moreover, amphibian and waterbird diversities have increased in the years following biomanipulation, possibly owing to improvements in the riparian zone and increased structural (vegetation) complexity in both the aquatic and terrestrial environment. Thus, the remedial action has improved aspects of habitat value, and PCB concentrations in sunfish have dropped below the remediation level (risk-based target value) for this pond (1 µg/g in fish fillets or 2.3 µg/g in whole body fish).

Polychlorinated biphenyls (PCBs) in intertidal sediment and water from Lagos lagoon: Baseline report on occurrence, distribution and ecotoxicological risk assessment

To assess the occurrence and potential ecological risk associated with organic micropollutants in Lagos lagoon, 27 polychlorinated biphenyls (PCBs) were analysed in sediments and surface water. Sediment samples were obtained from 18 designated sites (SD1 – SD18) using a Van Veen grab sampler and extracted following standard procedures. Cleaned extracts were analysed using gas chromatography with electron capture detector (ECD). The concentration of ∑PCBs in sediment samples ranged between 6757.61 and 273.46 µg/kg. The PCB homologues distribution patterns in sediments indicated that the low-chlorinated (∑di-PCB - ∑penta-PCB) PCBs were more dominant with 61.1 % occurrence than the high-chlorinated ((∑hexa-PCB - ∑nona-PCB) PCBs with 38.9 % relative abundance. The following is the decreasing order of the average homologue composition of PCBs in sediment samples: ∑tetra-PCB (24.6%) > ∑octa-PCB (21 %) > ∑hexa-PCB (13.8 %) > ∑penta-PCB (12.8) > ∑tri-PCB (11.4 %) > ∑hepta-PCB (7.8 %) > ∑nona-PCB (4.9 %) > ∑di-PCB (2.9 %). More so, the ∑PCBs in surface water samples ranged from 69.28 to 440.90 ng/L, with the mean ranging between 7.21 and 16.33 ng/L. The class distribution of PCB homologue profiles in water samples indicated that highly-chlorinated (∑hexa-PCB to ∑nona-PCB) PCBs were the dominant homologues, with 94.4 % occurrence, compared to the very low occurrence rate (5.6 %) of the low-chlorinated (∑di-PCB to ∑penta-PCB) PCBs. Hexa-PCBs (PCB-138 and PCB-153) were the dominant congeners in most water samples. The concentrations of ∑PCBs in sediments and surface water were unprecedentedly high at almost all locations. The total toxicity equivalent concentrations (TTECs) of dioxin-like PCBs for the sediment samples ranged from 0.001 to 2.43 µg/kg, with an average of 0.34 µg/kg. These findings suggest that PCB congeners are pervasive from anthropogenic point sources of pollution. Intensive site-specific monitoring and remediation are recommended.

Effect of typhoons on spatiotemporal patterns of multi-group persistent organic pollutants in sediment of Chinese southeastern coastal estuaries

Estuaries are susceptible to both anthropogenic disturbances and global climate changes. Impacts may be discriminated by pollution patterns of widely quantified persistent organic pollutants (POPs), though data are scarce for extreme climate events. This study quantified four groups of POPs, i.e., polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), and hexachlorocyclohexanes (HCHs), in sediments from seven Chinese coastal estuaries across a gradient of socioeconomic development in their watersheds with comparisons among the pre-typhoon, typhoon, and post-typhoon periods during 2016–2019. The maximal average concentrations, up to 1561 μg PAHs kg−1, 235 μg DDTs kg−1, and 38.9 μg HCHs kg−1, were quantified in the Jiulong River estuary and 7.61 μg PCBs kg−1 in the Jiao River estuary. Anthropogenic activities contributed to the distinctive spatial distributions of four groups of POPs in estuaries with non-agricultural gross domestic product (NAGDP) per capita significantly relating to sedimentary concentrations of PAHs and PCBs and agricultural gross domestic product (AGDP) per capita relating to DDTs and HCHs. Seasonality and typhoons led to less temporal variations in sedimentary POPs concentrations, whose spatial heterogeneity was remarkably reduced in the post-typhoon period rather than in the pre-typhoon and typhoon periods. The results of this study suggested that fingerprinting legacy POPs in spatial and temporal distributions contributed to identifying the effects of anthropogenic disturbances and climate changes on estuarine sediment quality.

Polyurethane Foam Emission Samplers to Identify Sources of Airborne Polychlorinated Biphenyls from Glass-Block Windows and Other Room Surfaces in a Vermont School.

We hypothesized that emissions of polychlorinated biphenyls (PCBs) from Aroclor mixtures present in building materials explain their concentrations in school air. Here, we report a study of airborne concentrations and gas-phase emissions in three elementary school rooms constructed in 1958. We collected airborne PCBs using polyurethane foam passive air samplers (PUF-PAS, n = 6) and PCB emissions from building materials using polyurethane foam passive emission samplers (PUF-PES, n = 17) placed over flat surfaces in school rooms, including vinyl tile floors, carpets, painted bricks, painted drywall, and glass-block windows. We analyzed all 209 congeners represented in 173 chromatographic separations and found that the congener distribution in PUF-PES strongly resembled the predicted diffusive release of gas-phase PCBs from a solid material containing Aroclor 1254. Concentrations of airborne total PCBs ranged from 38 to 180 ng m-3, a range confirmed by an independent laboratory in the same school. These levels exceed action levels for all aged children set by the State of Vermont and exceed guidance levels set by the U.S. EPA for children under age 3. Emissions of PCBs from the glass-block windows (30,000 ng m-2 d-1) greatly exceeded those of all other surfaces, which ranged from 35 to 2700 ng m-2 d-1. This study illustrates the benefit of the direct measurement of PCB emissions to identify the most important building remediation needed to reduce airborne PCB concentrations in schools.

Bedload sediment transport model for revealing the multi-year trend of polychlorinated biphenyl contamination in the river sediment (Kupa, Croatia).

This article investigated the multi-year polychlorinated biphenyl (PCB) burden of the sediment collected along the Kupa River flow in Croatia using the bedload sediment transport model. Kupa, as the natural border between Croatia and Slovenia, belongs to the water system Krupa (Slovenia) → Lahinja (Slovenia) → Kupa (Croatia) → Sava → Danube → Black Sea. From 1962 to 1985, the total quantity of waste calculated for pure PCBs, released by a capacitor manufacturer into the environment within various locations of the Krupa River in Slovenia, was 70 tons. Krupa River (Slovenia) has become one of the most PCB-polluted rivers in Europe, and consequently, PCBs have been detected in the Kupa River (Croatia). Model application revealed that contamination of the Kupa River (Croatia) started significantly earlier than 1983, when a high concentration of PCB was detected for the first time in the Krupa River (Slovenia), with probably significantly higher sediment concentrations at the upstream boundary of the Kupa. A slow concentration changes and PCB accumulation in the sediment should be expected downstream compared to the upstream boundary, governed mainly by high flow events. The PCBs in sediments from 2020/2021 are markedly different after the Lahinja confluence with Kupa (0.2-0.6μgkg-1 vs. 1.4-34.3μgkg-1). Measurements of PCBs in Kupa sediment suggest that the intake of PCB has not yet been completely stopped, which should be confirmed by detailed monitoring in the future. The contamination situation observed in the Kupa River represents an excellent example of the persistency of PCBs in the environment.

Congener-Specific Emissions from Floors and Walls Characterize Indoor Airborne Polychlorinated Biphenyls.

To reconcile the federal regulation of material polychlorinated biphenyl (PCB) concentrations with recently implemented state regulations of airborne PCBs, there is a need to characterize the relationship between PCB emissions from surfaces and air concentrations. We hypothesized that the magnitude and congener distribution of emissions from floors and walls fully account for the airborne PCBs measured in rooms constructed during the height of PCB production and sales. We measured emissions of PCB congeners from various wall and floor materials using polyurethane foam passive emission samplers before and after hexane wiping. Our results revealed that PCB emissions from flooring adequately predicted the magnitude and congener distribution of PCBs observed in the room air. Emissions varied by material within a single building (5 × 103 ng m-2 day-1 from wood panel walls to 3 × 104 ng m-2 day-1 from vinyl tile) and within the same room. Yet congener distributions between material emission PCB profiles and room air PCB profiles were statistically similar. Hexane wiping significantly reduced PCB emissions (>60%), indicating the importance of surface films as an ongoing source of airborne PCBs. The magnitude and congener distribution of material bulk concentrations did not explain that of material emissions or air concentrations. Passive measurements of polychlorinated biphenyl emissions from floors in a university building predict the concentrations of PCBs in room air.

Effects of mixtures of polychlorinated biphenyls (PCBs) and three organochlorine pesticides on cognitive function differ between older Mohawks at Akwesasne and older adults in NHANES

BackgroundAkwesasne Mohawks has been exposed to high concentrations of polychlorinated biphenyls (PCBs) and background levels of organochlorine pesticides, hexachlorobenzene (HCB), dichlorodiphenyl dichloroethylene (DDE), and mirex. We have previously reported relative contributions to the mixture of low- and high-chlorinated PCBs, HCB, and DDE on cognitive decrements in Mohawks of various ages. ObjectiveThis study examines differences in the mixture effects of PCB congener groups, HCB, DDE, and mirex on cognitive function in older Mohawks and less PCB-exposed older adults from the National Health and Nutrition Examination Survey (NHANES) 1999–2002 cycles. MethodsWe used Bayesian kernel machine regression (BKMR) to evaluate the mixture effects of different PCB congener groups, HCB, DDE, and mirex on cognitive function in both populations. Models were adjusted for age, sex, education levels, and race/ethnicity focusing on individuals 60 years and older. ResultsOlder Mohawks had 3-fold higher mean total PCB concentrations and 1.8-fold higher mirex, but slightly lower mean DDE and HCB levels than NHANES older adults. Higher mixture concentrations were significantly associated with greater cognitive decline. In older Mohawks, low- and high-chlorinated PCBs, HCB, and DDE contributed to the cognitive score decline. In contrast, score decline in older NHANES adults were primarily from high-chlorinated PCBs and DDE with a threshold dose of approximately 2.08–2.27 ng/g and 2.02–2.40 ng/g, respectively. ConclusionMixtures of PCBs and organochlorine pesticides increase the risk of cognitive decline in both older Mohawks and NHANES older adults. However, contributions to these mixture effects show significant differences. In older Mohawks, high- and low-chlorinated PCBs, DDE, and HCB are the primary contributors, while high-chlorinated PCBs and DDE are important contributors in NHANES older adults. Due to chronic heavy exposures to PCBs, older Mohawks had a significantly increased risk of cognitive decline compared to general older adults from NHANES.

Serum levels of polychlorinated biphenyls and polybrominated diphenyl ethers in early pregnancy and their associations with gestational diabetes mellitus

Polychlorinated Biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) are extensively present in humans and may disturb glucose metabolism during pregnancy. However, previous reports on the associations between PCBs/PBDEs levels and gestational diabetes mellitus (GDM) have been inconsistent. We performed a nested case-control study to measure the serum levels of 6 PCB and 7 PBDE congeners in early pregnancy, and to assess their associations with GDM risk and blood glucose levels. Totally, 208 serum samples (104 GDM cases and 104 controls) were included based on a prospective cohort which was carried out in Jiangsu province, China, from 2020 to 2022. The results showed that PCB-153 was the major PCB congener, whereas PBDE-47 was the predominant PBDE congener. The continuous concentrations of PCB-153, PBDE-28, and total PCB were significantly related to an increased risk of GDM, with adjusted ORs (95%CI) of 1.25 (1.04–1.50), 1.19 (1.02–1.39), and 1.37 (1.05–1.79), respectively. Potential dose-response relationships were also observed between serum levels of PCB-153 (P = 0.011), PBDE-28 (P = 0.028), total PCB (P = 0.048), and total PCB/PBDE (P = 0.010) and GDM risk. Moreover, PCB-153, PBDE-28 and total PCB levels were positively related to 1-h OGTT blood glucose (adjusted βPCB-153: 0.14, 95%CI: 0.00–0.28; adjusted βPBDE-28: 0.20, 95%CI: 0.08–0.32; adjusted βtotal PCB: 0.30, 95%CI: 0.09–0.50), whereas none of the PCBs/PBDEs were statistically related to fasting blood glucose and 2-h OGTT blood glucose (all P > 0.05). Further meta-analysis also supported the association of PCBs exposure with GDM risk. Our study provides further evidence that PCBs/PBDEs exposure may increase GDM risk during pregnancy.

Two Age Groups of Adult Pikeperch (Sander lucioperca) as Bioindicators of Aquatic Pollution

Pikeperch of age classes 3+ and 4+ were collected from the Garaši reservoir (Serbia) to analyze their bioindicator potential and compare their possible differences. Concentrations of 26 elements were determined in gills, muscles, and liver by inductively-coupled plasma optical emission spectrometry (ICP-OES) and of 17 organochlorine pesticides (OCPs), and six polychlorinated biphenyls (PCBs) in muscle by gas chromatography with mass spectrometric detection (GC-MS). Histopathological changes in the liver and gills were analyzed as biomarkers of general fish health. Only the concentrations of Cd, Na, and P in the muscles differed significantly. The OCPs and PCBs concentrations were below the detection limits, so fish meat consumption does not pose a risk concerning these substances. Hg and Cd exceeded the maximum allowed concentrations in some 4+ individuals, probably due to biomagnification. Gills were the most affected by metal exposure in both age classes. Histopathological changes and indices were minor and did not differ significantly between age classes, suggesting that pollution did not affect the morphology and structure of gills and liver. There were no significant correlations between elemental accumulation and fish condition or between histopathological scores. Therefore, both age classes can be used as bioindicators of pollution.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in adipose tissue of women from Grand Tunis and their association with demographic factors and dietary habits

Dichlorodiphenyl trichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB) and polychloronated biphenyls (PCBs) were measured in 25 woman adipose tissues collected in 2016 from Grand Tunis, Tunisia. p,p’-DDE, p,p’-DDT, HCB and β-HCH were the dominant organochlorine pesticides (OCPs) in decreasing order in all samples. The total OCP levels varied from 79 to 343 ng g−1 lipid with a median value of 189 ng g−1 lipid and DDTs contributed approximately 88% to sum OCP. The ratio of p,p’-DDT/p,p’-DDE across all samples is below one, which suggests mainly historic exposure but may indicate some recent exposure to the banned pesticide. The median concentration of PCBs was 109 ng g−1 lipid and ranged between 27 and 204 ng g−1 lipid. PCB-153, PCB-180, PCB-138 and PCB-170 were the most abundant congeners, which contributed about 78% of the total PCBs. Spearman analysis showed that dominant organochlorine compounds (OCs) are highly positive correlated except for PCB-28/31, indicating that women from Tunis are exposed via similar routes. Inhalation exposure could be a possible pathway for the uptake of the less chlorinated congeners. We found positive and statistically significant association with subjects age for HCB (r = 0.517; p = 0.009) and PCBs (r = 0.65; p = 0.001) levels and a weak age-dependent accumulation was found for HCHs (r = 0.375; p = 0.065) and DDTs (r = 0.388; p = 0.056). The concentrations of OC subgroups were not associated with BMI, parity and residence. No association was observed between fish, red/white meat, milk and dairy products consumption and levels of HCB, HCHs and PCBs. DDTs levels were significantly correlated only with milk (p = 0.048) and milk products (p = 0.047) intake.

Unlocking the potential of resuscitation-promoting factor for enhancing anaerobic microbial dechlorination of polychlorinated biphenyls

Microbial dechlorination of polychlorinated biphenyls (PCBs) is limited by the slow growth rate and low activity of dechlorinators. Resuscitation promoting factor (Rpf) of Micrococcus luteus, has been demonstrated to accelerate the enrichment of highly active PCB-dechlorinating cultures. However, it remains unclear whether the addition of Rpf can further improve the dechlorination performance of anaerobic dechlorination cultures. In this study, the effect of Rpf on the performance of TG4, an enriched PCB-dechlorinating culture obtained by Rpf amendment, for reductive dechlorination of four typical PCB congeners (PCBs 101, 118, 138, 180) was evaluated. The results indicated that Rpf significantly enhanced the dechlorination of the four PCB congeners, with residual mole percentages of PCBs 101, 118, 138 and 180 in Rpf-amended cultures being 16.2–29.31 %, 13.3–20.1 %, 11.9–14.4 % and 9.4–17.3 % lower than those in the corresponding cultures without Rpf amendment after 18 days of incubation. Different models were identified as appropriate for elucidating the dechlorination kinetics of distinct PCB congeners, and it was observed that the dechlorination rate constant is significantly influenced by the PCB concentration. The supplementing Rpf did not obviously change dechlorination metabolites, and the removal of chlorines occurred mainly at para- and meta- positions. Analysis of microbial community and functional gene abundance suggested that Rpf-amended cultures exhibited a significant enrichment of Dehalococcoides, Dehalogenimonas and Desulfitobacterium, as well as non-dechlorinators belonging to Desulfobacterota and Bacteroidetes. These findings highlight the potential of Rpf as an effective additive for enhancing PCB dechlorination, providing new insights into the survival of functional microorganisms involved in anaerobic reductive dechlorination.

Polychlorinated biphenyls residues in bivalve shellfish from Niger Delta: distribution pattern, tissue burden and food safety assessment

ABSTRACT This study investigated the distribution pattern, tissue burden, and safety of bivalve shellfish for human consumption. Edible species of bivalve shellfish harvested from Niger delta were screened for polychlorinated biphenyl (PCB) contaminants. Instrumental analysis and quantification of PCB congeners were performed using gas chromatography fitted with electron capture detector (GC-ECD). Results indicated an accumulation of PCB concentration of 0.36 ng/g, 0.89 ng/g, 0.98 ng/g, and 1.73 ng/g at Andoni, Iko Town, Ibeno, and Bonny, respectively. The PCB burden showed bloody cockle at Bonny location recorded the highest concentration of PCB congeners (2.37 ng/g), closely followed by mangrove oyster (2.13 ng/g) at Iko Town location, while Donax clam at Ibeno (0.09 ng/g) has the least PCB burden. The results obtained were lower in relation to food regulatory threshold. However, PCB tissue burden of bivalve shellfish harvested at the study locations indicated an environment impacted by anthropogenic activities that could negatively affect human health which depends on these shellfish for food.

PCB decomposition promoted by sugarcane bagasse organic waste

This work aimed to explore the changes in the bacterial community composition of soil contaminated with high concentration of polychlorinated biphenyls (PCBs) treated by biostimulation with sugarcane bagasse. Non-sterilized soil samples were spiked with transformer oil contaminated with PCB 18, 52, 66, 87,101, 110, 153, 180, and 187. The biostimulation experiment was performed by mixing non-sterilized PCB-contaminated soil with sterilized sugarcane bagasse and incubating the mixture 90 d in darkness at 25 ± 1 °C. The results showed that percentage removal of 88 % was similar for all PCB congeners in biostimulated soil, independently of their degree of chlorination, and it was accompanied by a significant change in bacterial community composition. Relative abundance of the bacterial communities at the phylum level in biostimulation treatment showed they were conquered by Proteobacteria and Firmicutes, followed by Acidobacteria and Actinobacteria.Bacteriall diversity increased in the biostimulation system due to the enrichment in genera possessing PCB remediation capacity which demonstrated the boosting potential of sugarcane bagasse in soil with high concentration of PCBs.

Assessment of exposure of benthic organisms to selected organochlorine pollutants in the west Spitsbergen fjords

Climate-related changes in environmental conditions, such as reduction of sea ice, intensive glacier retreat, and increasing summer precipitation, directly influence the arctic marine environment and, therefore, the organisms living there. Benthic organisms, being an important food source for organisms from higher trophic levels, constitute an important part of the Arctic trophic network. Moreover, the long lifespan and limited mobility of some benthic species make them suitable for the study of the spatial and temporal variability of contaminants. In this study, organochlorine pollutants (polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB)) were measured in benthic organisms collected in three fjords of western Spitsbergen. Two of these were recommended by the Marine Biodiversity and Ecosystem Functioning (MARBEF) Network of Excellence as European flagship sites, namely Hornsund as the Biodiversity Inventory and Kongsfjorden as the Long-Term Biodiversity Observatory. Adventfjorden, with notable human activity, was also studied. Ʃ7 PCB and HCB concentrations in sediments were up to 2.4 and 0.18 ng/g d.w. respectively. Concentrations of Ʃ7 PCBs and HCB measured in collected benthic organisms were up to 9.1 and 13 ng/g w.w., respectively. In several samples (41 of 169) the concentrations of ∑7 PCBs were below the detection limit values, yet nevertheless the results of the research show effective accumulation of target organochlorine contaminants by many Arctic benthic organisms. Important interspecies differences were observed. Free-living, mobile taxa, such as shrimp Eualus gaimardii, have accumulated a large quantity of contaminants, most probably due to their predatory lifestyle. ∑7 PCB and HCB concentrations were both significantly higher in Hornsund than in Kongsfjorden. Biomagnification occurred in 0 to 100 % of the predator-prey pairs, depending on the congener analyzed. Although the sampled organisms were proved to have accumulated organochlorine contaminants, the measured levels can be considered low, and not posing a substantial threat to the biota.

A robust and ultra-high-surface hydrogen-bonded organic framework promoting high-efficiency solid phase microextraction of multiple persistent organic pollutants from beverage and tea.

Persistent organic pollutants (POPs) are widely distributed in the environment and are toxic, even at low concentrations. In this study, we first used hydrogen-bonded organic framework (HOF) to enrich POPs, based on solid phase microextraction (SPME). The HOF called PFC-1 (self-assembled by 1,3,6,8-tetra(4-carboxylphenyl)pyrene) has an ultra-high specific surface area, excellent thermochemical stability, and abundant functional groups, making it potential to be an excellent coating in SPME. And the as-prepared PFC-1 fiber have demonstrated outstanding enrichment abilities for nitroaromatic compounds (NACs) and POPs. Furthermore, the PFC-1 fiber was coupled with gas chromatography-mass spectrometry (GC-MS) to develop an ultrasensitive and practical analytical method with wide linearity (0.2-200ng·L-1), low detection limits for organochlorine pesticides (OCPs) (0.070-0.082ng·L-1) and polychlorinated biphenyls (PCBs) (0.030-0.084ng·L-1), good repeatability (6.7-9.9%), and satisfactory reproducibility (4.1-8.2%). Trace concentrations of OCPs and PCBs in drinking water, tea beverage, and tea were also determined precisely with the proposed analytical method.