Class Of Persistent Organic Pollutants Research Articles

Metabolomic interference induced by short-chain chlorinated paraffins in human normal hepatic cells

Short-chain chlorinated paraffins (SCCPs) are an emerging class of persistent organic pollutants (POPs) that are widely detected in environmental matrices and human samples. Because of their environmental persistence, long-range transport potential, bioaccumulation potential, and biotoxicity, SCCPs pose a significant threat to human health. In this study, metabolomics technology was applied to reveal the metabolomic interference in human normal hepatic (L02) cells after exposure to low (1 μg/L), moderate (10 μg/L), and high (100 μg/L) doses of SCCPs. Principal component analysis (PCA) and metabolic effect level index (MELI) values showed that all three SCCP doses caused notable metabolic perturbations in L02 cells. A total of 72 metabolites that were annotated by MS/MS and matched with the experimental spectra in the Human Metabolome Database (HMDB) or validated by commercially available standards were selected as differential metabolites (DMs) across all groups. The low-dose exposure group shared 33 and 36 DMs with the moderate- and high-dose exposure groups, respectively. The moderate-dose exposure group shared 46 DMs with the high-dose exposure group. In addition, 33 DMs were shared among the three exposure groups. Among the 72 DMs, 9, 9, and 45 metabolites participated in the amino acid, nucleotide, and lipid metabolism pathways, respectively. The results of pathway enrichment analysis showed that the most relevant metabolic pathways affected by SCCPs were the lipid metabolism, fatty acid β-oxidation, and nucleotide metabolism pathways, and that compared with low-dose exposure, moderate- and high-dose SCCP exposures caused more notable perturbations of these metabolic pathways in L02 cells. Exposure to SCCPs perturbed glycerophospholipid and sphingolipid metabolism. Significant alterations in the levels of phosphatidylcholines, phosphatidylethanolamines, and sphingomyelins indicated SCCP-induced biomembrane damage. SCCPs inhibited fatty acid β-oxidation by decreasing the levels of short- and medium-chain acylcarnitines in L02 cells, indicating that the energy supplied by fatty acid oxidation was reduced in these cells. Furthermore, compared with low- and moderate-dose SCCPs, high-dose SCCPs produced a significantly stronger inhibition of fatty acid β-oxidation. In addition, SCCPs perturbed nucleotide metabolism. The higher hypoxanthine levels observed in L02 cells after SCCP exposures indicate that SCCPs may induce several adverse effects, including hypoxia, reactive oxygen species production, and mutagenesis in L02 cells.

Research Progress on Distribution, Transportation, and Control of Per- and Polyfluoroalkyl Substances in Chinese Soils

Per- and polyfluoroalkyl substances (PFAS) are a class of persistent organic pollutants that have attracted much attention in recent years, which has the characteristics of diverse species, refractory degradation, long-distance transportation, easy bioaccumulation, etc. The distribution, accumulation, and potential toxicity of PFAS in water and organisms have received extensive attention worldwide. However, studies on PFAS distribution and transportation in soil are still hovering at a preliminary stage. The PFAS pollution surveys in Chinese soils are mainly concentrated in the economically developed eastern regions. The types and concentrations of PFAS in soils are directly related to the industrial types, atmospheric deposition, and human activities in these surveyed areas, which are similar to foreign soil surveys. Traditional perfluoro carboxylic acid (PFCAs) and perfluoro octane sulfonate (PFSAs) are the most important types of PFAS in Chinese soils. This study reviewed the distribution characteristics, transportation pathways, and influencing factors of PFAS in Chinese soils, as well as domestic and foreign control policies on PFAS pollution. Meanwhile, this study further pointed out the shortcomings of the current research on the distribution and control of PFAS in soil in order to provide a reference for the investigation, research, and control of PFAS pollution in Chinese soils.

Mechanisms and targeted reversion/prevention of hepatic fibrosis caused by the non-hereditary toxicity of benzo(a)pyrene

The effect of long term exposure to low concentrations of environmental pollutants on hepatic disorders is a major public health concern worldwide. Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants. In recent years, an increasing number of studies have focused on the deleterious effects of low concentrations of PAHs in the initiation or exacerbation of the progression of chronic liver disease. However, the underlying molecular mechanisms and effective intervention methods remain unclear. Here, we found that in hepatocytes, a low concentration of benzo(a)pyrene (B[a]P, an indicator of PAHs) chronic exposure continuously activated 14-3-3η via an epigenetic accumulation of DNA demethylation. As a “switch like” factor, 14-3-3η activated its downstream PI3K/Akt signal, which in turn promoted vascular endothelial growth factor (VEGF) production and secretion. As the characteristic fibrogenic paracrine factor regulated by B[a]P/14-3-3η, VEGF significantly induced the neovascularization and activation of hepatic stellate cells, leading to the development of hepatic fibrosis. Importantly, targeted 14-3-3η by using its specific inhibitor invented by our lab could prevent B[a]P-induced hepatic fibrosis, and could even reverse existent hepatic fibrosis caused by B[a]P. The present study not only revealed novel mechanisms, but also proposed an innovative approach for the targeted reversion/prevention of the harmful effects of exposure to PAHs on chronic liver disease.

Occurrence and Sources of Persistent Organic Pollutants in Upper Urban Soil of Cluj-Napoca, Romania

"Most persistent organic pollutants (POPs) were made for specific purposes due to certain characteristic and properties. They can cause various diseases and are problematic for the environment due to their high persistence and toxicity. This study attests the presence of three classes of POPs namely polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the upper urban soils of Cluj-Napoca, Romania. Soil samples were collected from 10 sampling points areas with heavy traffic. For determination of the compounds, gas chromatography coupled with mass spectrometry and with electron capture detector was used. The obtained results indicate a low level of pollution, the concentrations ranging between 8.83–184.92 ng/g for PAHs, 5.36–112.35 ng/g for PCBs, and 25.96–334.83 ng/g for OCPs. To identify the pollution emission sources, different PAHs and OCPs diagnostic ratios have been applied. Keywords: persistent organic pollutants, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides, upper urban soil"

Spatiotemporal distribution, source analysis and ecological risk assessment of polychlorinated biphenyls (PCBs) in the Bohai Bay, China

As a class of persistent organic pollutants (POPs), the spatial and temporal distribution of polychlorinated biphenyls (PCBs) in seawater is important for environmental assessment. Surface water samples were collected from 35 stations during summer and 36 stations during autumn of 2020 in the Bohai Bay. The concentration, composition, distribution and sources of PCBs were analyzed to assess the ecological impact of PCBs. The average concentration of ∑18PCBs was 124.6 ng/L (range of 28.1–445.5 ng/L) in summer and 122.8 ng/L (range of 21.0–581.4 ng/L) in autumn. PCBs in surface seawater of the Bohai Bay showed high near-shore and low far-shore characteristics, indicating the serious influence of land-based sources such as port activities and river inputs. Proportion analysis showed that Tetra-PCBs and Penta-PCBs were the major constituents in most stations. It was assessed as moderate and high risk (MRQ > 0.1) by mixture risk quotient (MRQ) and concentration addition (CA) model in surface seawater of the Bohai Bay. Principal component analysis (PCA) was used to explain the sources of PCBs in the Bohai Bay. PCBs in the Bohai Bay may come from commercial PCBs and their incineration products, municipal landfills, wood and coal combustion, and industrial activities, etc.

A novel exfoliated graphite-based device for passive sampling and detection of polycyclic aromatic hydrocarbons in air

Water scarcity is a major problem in the Sub-Saharan Africa, as such rainwater harvesting is considered as an alternative source of water. However, air pollution may affect the quality of taken rainwater. Specifically, particle-bound polycyclic aromatic hydrocarbons (PAHs) a class of persistent organic pollutants (POPs) known to have toxic effects on human beings and environmental sectors. In this study, a novel electrode material called exfoliated graphite (EG) was synthesized and used as sorbent material in fabrication of passive sampler and electrode device for the monitoring of polycyclic aromatic hydrocarbons (PAHs) in air. The surface morphology, structure, surface functionality of the materials were investigated using, Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR) techniques. A sorption kinetic’s evaluation of EG was conducted. It was found that EG has shown an outstanding affinity towards detection of PAHs with maximum partition coefficients. Moreover, EG electrode-based device was developed and utilized for detection of PAHs in air through electrochemical technique. This was conducted by exposing the sampler to PAHs gases for 12 days, thereafter it was transferred to a blank supporting electrolyte and analyzed using differential pulse voltammetry (DPV). The EG-based tubular sampler was calibrated in a laboratory flow-through exposure experiment. Furthermore, the effects of time and pollutants concentration were examined under controlled experimental conditions. Most importantly, extraction of the sampler was performed, followed by determination of PAHs using gas chromatography-mass spectrometer (GC–MS). As the result, uptake of PAHs onto the EG tubular based sampler was observed with linear uptake throughout the exposure time. Interestingly, an increasing of uptake by PAHs was indicated when the concentration of the pollutant was increased. These results imply that EG showed a great potential and preferable candidate for monitoring of PAHs in air.

SAT427 Effects Of Polychlorinated Biphenyls (PCBs) On Transcription Factor NFκB Activation In Neonatal Rat Microglia Primary Culture

Abstract Disclosure: C.E. Dressel: None. G.M. Valdez: None. M.R. Bell: None. Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that are lipophilic and accumulate in the food chain. Despite bans on PCB production, human exposure continues and can cause disruptions in endocrine, nervous, and immune system functions. As such, PCBs may interfere with the actions of microglia, the innate immune cells of the central nervous system. Healthy microglia are critical for neural development, maintenance of neural functions, and responses to stress, injury, or infection. Initial studies of primary neonatal rat microglial cultures indicate that PCBs alter gene expression of proinflammatory cytokine TNF-α and IL-1β in response to a secondary inflammatory lipopolysaccharide (LPS) challenge. Production of these cytokines is, in part, regulated by transcription factor NFκB. This experiment tests the hypothesis that PCBs alter NFκB activation in neonatal microglia. The forebrains of male and female neonatal Sprague-Dawley rats were dissected to remove meninges, homogenized with collagenase and gentle trituration, and plated on coverslips in DMEM FBS+ media to establish a primary mixed glial culture. After one week, microglia were subcultured using mild trypsin treatment and maintained in conditioned media for 24 hours. The microglia were then exposed to either PCB 153 (0.1 µM) or DMSO vehicle control (0.036%) for 18 hours. After 18 hours, the cells were treated with either LPS (0.5 µg/mL) or PBS vehicle control for 4 hours and then fixed. Immunocytochemistry was used to visualize NFκB and identify microglia, with anti-p65 and Ox42 antibodies, respectively. Coverslips were mounted with DAPI-containing media and the cells were imaged via confocal microscopy. In response to immune activation, NFκB typically translocates from the cytosol to the nucleus. Therefore, we assessed NFκB activation by quantifying p65 fluorescent pixel intensity and percentage of area covered in nuclear or cytoplasmic regions according to DAPI and Ox42 channel masks using ImageJ. A two-way ANOVA was used to identify the effects of PCB vs. DMSO exposure and LPS vs. PBS challenge. Preliminary data indicated that LPS increased the ratio of nuclear to cytosolic NFκB, as expected. PCB exposed cells tended to have lower NFκB presence in the nucleus and cell as a whole, but a greater proportion of NFκB staining localized within the nucleus relative to the rest of the cell. With the current sample (n=4-6 per group, 2-3 males and females each), no interactions between PCBs and LPS were observed. Continued work will increase sample size to explore sex differences and the time course of NFκB response to PCBs, which may help broaden our understanding of the mechanisms by which PCBs affect normal brain activity and disrupt healthy endocrine, immune, and neural development. Presentation: Saturday, June 17, 2023

Comparative genomics reveals evidence of polycyclic aromatic hydrocarbon degradation in the moderately halophilic genus Pontibacillus

Polycyclic aromatic hydrocarbons (PAHs) are a common class of persistent organic pollutants (POPs) that are widely distributed in various environments and pose significant threats to both environmental and human health. The genus Pontibacillus, a type of moderately halophilic bacteria, has demonstrated potential for biodegrading aromatic compounds in high-salinity environments. However, no previous study has comprehensively investigated the PAH degradation mechanisms and environmental adaptability in the genus Pontibacillus. In this study, we sequenced the whole genome of the PAH-degrading strain Pontibacillus chungwhensis HN14 and conducted a comparative genomics analysis of genes associated with PAH degradation, as well as salt and arsenic tolerance using ten other Pontibacillus sp. strains. Here, we elucidated potential degradation pathways for benzo[a]pyrene and phenanthrene, which were initiated by cytochrome P450 monooxygenases, in most Pontibacillus strains. Moreover, four Pontibacillus strains were selected to investigate the biodegradation of benzo[a]pyrene and phenanthrene under high-salt (5% NaCl) stress, and all four strains exhibited exceptional degradation abilities. The results of comparative genomics and phenotypic analyses demonstrate that the genus Pontibacillus have the potential to degrade polycyclic aromatic hydrocarbons in high-salinity environments, thus providing valuable insights for biodegradation in extreme environments.

Pollution Characteristics and Risk Evaluation of PAHs in Subsidence Water Bodies in Huainan Coal Mining Area, China

As a class of persistent organic pollutants (POPs), polycyclic aromatic hydrocarbons (PAHs) have mutagenic, teratogenic, and carcinogenic effects, so they can pose a greater threat to the natural environment and human health. Most of the PAHs in coal mining areas originate from the mining and utilization process of coal resources, which has a variety of carriers in the environment: atmosphere, water bodies, soil, sediments, etc. To study their pollution status in the subsidence waters of the Huainan coal mining area, sixteen priority control PAHs of sixteen surface water samples from seven subsidence water bodies were tested using gas chromatography–mass spectrometry (GC–MS), and their pollution characteristics were analyzed. Overall, the concentration of PAHs ranged from 212 to 283 ng·L−1, and benzo[b]fluoranthene (BbF) had the highest average concentration. In addition, the concentration of PAHs above four rings was relatively high. After statistical analysis, the Pearson correlation coefficient calculation showed a highly significant positive correlation between PAHs with the same number of rings. Three principal factors were selected using factor analysis, which could explain 88.37% of the total variance, to conduct the source identification. Coal combustion was found to be the main source of PAH pollution in the area. Then, ecological risk using the risk quotient (RQ) method was carried out. The results showed that PAH contamination was medium risk, among which, benzo[a]anthracene (BaA) and BbF had a high ecological risk. In addition, the results of biological toxicity evaluation using the species sensitivity distribution model (SSD) showed that benzo[a]pyrene (BaP) had a high proportion of potential effects on aquatic organisms. By using the response addition model, the evaluation results showed that the ecological risk of the subsidence water bodies in the Panyi mine was the highest. Finally, human health risks were evaluated from two pathways: dermal contact and ingestion. The carcinogenic health risks from the dermal contact exceeded the permissible limits, while the hazard entropy of non-carcinogenic risks from the above two pathways were less than 1.

Fluorescence Turn-On/Off Responses of In (III)-MOF to Short-Chain Perfluorocarboxylic Acids

AbstractShort-chain perfluorocarboxylic acids (PFCAs) are a class of persistent organic pollutants that are widely used as substitutes for long-chain PFCAs. However, they also pose a non-negligible risk to ecosystems. In this study, we demonstrated that a fluorescent metal–organic framework (MOF) (named V-101) constructed from In3+ and an aromatic-rich tetratopic carboxylate ligand 5-[2,6-bis (4-carboxyphenyl) pyridin-4-yl] isophthalic acid (H4BCPIA) exhibited highly efficient turn-off and turn-on fluorescence responses toward five short-chain PFCAs in water and methanol, respectively. The limits of detection of V-101 toward five short-chain PFCAs are down to μg/L level, and it showed good anti-interference abilities toward short-chain PFCAs in the presence of common metal ions. The major mechanisms associated with fluorescence responses were molecular collisions and interactions between V-101 and short-chain PFCAs. This work demonstrates that the structure variety of MOFs imparts them with the potential of MOFs in the detection of short-chain PFCAs for pollution control.

Environmental profile, potential sources, and ecological risk of polycyclic aromatic hydrocarbons in a typical coastal bay and outer bay area.

As a class of persistent organic pollutants, polycyclic aromatic hydrocarbons (PAHs) are widely present and accumulate in multimedia environments. The pollution characteristics, spatiotemporal distribution, potential sources, influencing factors, and ecological risks of 16 PAHs were investigated in the water-sediment system of the Hangzhou Bay and outer bay area (HZB and OBA, respectively). The total concentrations of 16 PAHs (∑PAHs) were 220 ± 97.0 and 130 ± 36.0ng/L in the seawater and 343 ± 179 and 505 ± 415μg/kg (dry weight) in the sediments of the HZB and OBA, respectively. The pollution level of PAHs in the HZB seawater was higher than that in the OBA seawater, but the opposite result was found in the sediments. Moreover, ∑PAHs exhibited high temporal variability in the HZB seawater (rainy season > dry season), whereas ∑PAHs in the sediments showed no significant difference between seasons. The molecular diagnostic ratio method was used to identify pollution sources and showed that the PAHs in seawater came from different pollution sources (fuel combustion and petroleum), whereas the PAHs in the sediments originated from coincident sources (mixed combustion). Correlation analysis revealed that temperature was positively related to ∑PAHs, whereas salinity was negatively related to seawater ∑PAHs values. Ecological risk assessment demonstrated that the potential for adverse ecological effects was low to moderate in seawater but moderate to high in the sediments.

Polybrominated diphenyl ethers in type 2 diabetes mellitus cases and controls: Repeated measurements prior to and after diagnosis.

Previous studies have reported associations between certain persistent organic pollutants (POPs) and type 2 diabetes mellitus (T2DM). Polybrominated diphenyl ethers (PBDEs) are a class of POPs that are found in increasing concentrations in humans. Although obesity is a known risk factor for T2DM and PBDEs are fat-soluble, very few studies have investigated associations between PBDEs and T2DM. No longitudinal studies have assessed associations between repeated measurements of PBDE and T2DM in the same individuals and compared time trends of PBDEs in T2DM cases and controls. To investigate associations between pre- and post-diagnostic measurements of PBDEs and T2DM and to compare time trends of PBDEs in T2DM cases and controls. Questionnaire data and serum samples from participants in the Tromsø Study were used to conduct a longitudinal nested case-control study among 116 T2DM cases and 139 controls. All included study participants had three pre-diagnostic blood samples (collected before T2DM diagnosis in cases), and up to two post-diagnostic samples after T2DM diagnosis. We used logistic regression models to investigate pre- and post-diagnostic associations between PBDEs and T2DM, and linear mixed-effect models to assess time trends of PBDEs in T2DM cases and controls. We observed no substantial pre- or post-diagnostic associations between any of the PBDEs and T2DM, except for BDE-154 at one of the post-diagnostic time-points (OR=1.65, 95% CI: 1.00, 2.71). The overall time trends of PBDE concentrations were similar for cases and controls. The study did not support PBDEs increasing the odds of T2DM, prior to or after T2DM diagnosis. T2DM status did not influence the time trends of PBDE concentrations.

Brominated flame retardants and legacy organochlorines in archived human placenta samples: Sex differences, temporal analysis and associations with infant birth weight.

Perinatal exposure to persistent organic pollutants (POPs) has been suggested to play a role in the etiology of adverse pregnancy outcomes. This study evaluated temporal changes in the accumulation of several classes of POPs, including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and several organochlorine pesticides in human placenta and examined their associations with birth outcomes at delivery. Placental tissues (n = 99) previously collected and archived at the Duke University Medical Center from 2009 to 2015 were analyzed for 22 POPs using gas chromatography mass spectrometry. The mean age of mothers was 30.6 years; 8% of newborns were characterized as low birthweight (<2500 g). Of the 22 POPs targeted in the analysis, only p,p’-DDE, BDE-47 and BDE-100 were detected in more than 50% of the samples, with median concentrations of 0.110, 0.310, and 0.033 ng/g wet weight, respectively. Placental PBDE concentrations generally decreased over time, particularly BDE-47. Placental tissues associated with female infants had significantly higher levels of BDE-100 than placental tissues associated with male infants (p = 0.02) and a similar, but not statistically significant trend was observed for BDE-47 (p = 0.07). Multivariate regression models revealed that placental BDE-47 concentrations were associated with a significantly lower birthweight among male, but not female infants. A similar, although non-statistically significant, trend was observed for other POPs, further suggesting sex-specific associations between gestational exposure to POPs and birthweight.

Ethylene vinyl acetate copolymer is an efficient and alternative passive sampler of hydrophobic organic contaminants. A comparison with silicone rubber

There is a growing demand for assessing the concentrations of Hydrophobic Organic Contaminants (HOCs) in aquatic environments, including Persistent Organic Pollutants (POPs). The hydrophobicity of POPs challenges their quantification in waters due to the sub-trace concentrations, especially when using conventional spot sampling. The results from the conventional samples are only a “snapshot” of the concentrations (if detected) at the specific sampling moment. Contrary, passive sampling provides average concentration levels over weeks or months from the quantification of accumulated pollutants during the deployment period. The present work compared ethylene vinyl acetate (EVA) and silicon rubber (SR) as monophasic passive samplers to measure dissolved concentrations of HOCs. Four classes of POPs were studied: (i) polychlorinated dibenzo-p-dioxins (PCDDs), (ii) polychlorinated dibenzofurans (PCDFs), (iii) polychlorinated biphenyls (PCBs), including the dioxin-like congeners, and (iv) the polybrominated diphenyl ethers (PBDEs). The polymer-water partition coefficients (Kpw), determined by the cosolvent and crossed calibrations, were, on average, one logarithmic unit larger in EVA than in the SR. The diffusion coefficients (Dp) estimated by the “film-stacking” method were, on average, two orders of magnitude smaller in the EVA than in the SR. For both polymers, the theoretical model of mass transfer resistance confirmed that the water boundary layer controlled the absorption, thus allowing the use of Performance Reference Compounds (PRCs) to estimate the in-situ sampling rates.Larger Kpw's in EVA may be an advantage because they imply longer time scales to reach equilibrium, higher absorption capacities and hence a higher absorbed contaminant mass, especially for compounds that reach equilibrium relatively faster (log Kow < 5). In addition, the longer times to attain equilibrium for EVA maintain this sampler longer in the linear phase of absorption, and the time-weighted average concentration may only be assessed in this phase when the compounds have not yet reached equilibrium.

Comparative evaluation and prioritization of key influences on biodegradation of 2,2′,4,4′-tetrabrominated diphenyl ether by bacterial isolate B. xenovorans LB400

Polybrominated diphenyl ethers (PBDEs) are a class of persistent organic pollutants being widely distributed and harmful to human health and wildlife, and the development of sustainable rehabilitation strategies including microbial degradation is of great concern. Although the increasing number of bacteria, especially the broad-spectrum and potent aerobes have been isolated for the efficient removal of PBDEs, the external influences and the corresponding influential mechanism on biodegradation are not fully understood yet. Given the wide-spectrum biodegradability of aerobic bacterial isolate, B. xenovorans LB400 for PBDEs, the dual impacts of many pivotal factors including pH, temperature, presence of dissolved organic matter (DOM) and cadmium ion etc. were comprehensively revealed on biodegradation of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47). Due to the structural resemblance and stimulation of specific enzyme activity in bacteria, the biphenyl as substrates showed the greater capacity than non-aromatic compounds in improving biodegradation. The individual adaptation to neutrality and cultivation at about 30 °C was beneficial for biodegradation since the bacterial cellular viability and enzyme activity was mostly preserved. Although it was possibly good for the induction of hormesis and favorable to enhance the permeability or bioavailability of pollutant, the exceeding increase of Cd2+ or DOM may not give the profitable increase of biodegradation yet for the detrimental effect. For biodegradation, the mechanistic relationship that took account of the integrative correlation with the influential factors was artfully developed using partial least square (PLS) regression technique. Relative to the most significant influence of culture time and initial concentration of BDE-47, the larger relevance of other factors primarily marked as pH and DOM was consecutively shown after the quantitative prioritization. This may not only help understand the influential mechanism but provide a prioritizing regulation strategy for biodegradation of BDE-47. The PLS-derived relationship was validated with the certain predictability in biodegradation, and could be used as an alternative to accelerate a priori evaluation of suitability or improve the feasibility of such bacteria in remediation of PBDEs in the environment.

ASSESSMENT OF POLYCHLORINATED BIPHENYLS LOAD LEVEL IN SOILS COLLECTED FROM RESIDENTIAL AREAS

Polychlorinated biphenyls (PCBs) are listed as a class of Persistent Organic Pollutants (POPs) under the Stockholm Convention. PCBs represent a threat to human health and environment because of their toxicity, persistence, and tendency to bio-accumulate at the top of the food chain. Additionally, some PCBs are suspected carcinogens. Because of their chemical stability and their excellent electrical insulation and thermal conductive properties, PCBs have been used in widespread industrial, commercial and domestic applications. The aim of this study is to establish the load level of these compounds in soils from residential areas. The soil samples were collected from gardens, parks and households located in Bucharest. The interest compounds (PCB with IUPAC number 28, 52, 101, 118, 138, 153, 180) were extracted from soil with organic solvents (hexane: acetone = 1:1) and analysed by gas chromatography with electron capture detector. The analytical results show that the most abundant compounds were those with a high degree of chlorination. The total content of PCBs ranged between 0.0004 mg/kg and 0.028 mg/kg, so values of concentration that are not exceed the alert threshold (0.25 mg/kg).

Sublethal Exposure of Per- and Polyfluoroalkyl Substances of Varying Chain Length and Polar Functionality Results in Distinct Metabolic Responses in Daphnia magna.

Per- and polyfluoroalkyl substances (PFAS) are a class of persistent organic pollutants used in industrial applications because of their physicochemical properties, which results in their ubiquitous presence across environmental matrices. To date, legacy PFAS have been well studied; however, the concentration of alternative PFAS may exceed the concentration of legacy pollutants, and more information is needed regarding the sublethal toxicity at the molecular level of aquatic model organisms, such as Daphnia magna. Perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorohexanesulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) are four widely detected PFAS alternatives of varying chain length and polar functionality that are quantified in aquatic environments. The present study examines the metabolic perturbations of PFAS with varying chemistries to D. magna using targeted mass spectrometry-based metabolomics. Daphnia were acutely exposed to sublethal concentrations of PFBA, PFHxA, PFHxS, and PFNA before the polar metabolite profile was extracted from single organisms. Multivariate analysis demonstrated significant separation between the sublethal concentrations of PFHxA, PFHxS, and PFNA relative to the controls; in sum, longer chain lengths demonstrated greater overall perturbations to the extracted metabolic profiles. Univariate statistics revealed significant perturbations in the concentrations of several amino acids, nucleotides/nucleosides, and neurotransmitters with exposure to PFAS. These metabolic perturbations are consistent with disruptions in energy metabolism (pantothenate and coenzyme A metabolism, histidine metabolism) and protein synthesis (aminoacyl-transfer RNA biosynthesis and amino acid metabolism), which were identified through biochemical pathway analysis. These results provide evidence that although PFAS chemistry (chain length and polar functional group) invokes unique metabolic responses, there is also an underlying toxic mode of action that is common with select PFAS exposure. Overall, the present study highlights the capabilities of environmental metabolomics to elucidate the molecular-level perturbations of pollutants within the same chemical class to model aquatic organisms, which can be used to prioritize risk assessment of substituted PFAS alternatives. Environ Toxicol Chem 2023;42:242-256. © 2022 SETAC.

Simultaneous Dispersive Liquid–Liquid Microextraction and Determination of Different Polycyclic Aromatic Hydrocarbons in Surface Water

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants of water, and their determination at trace levels in the aquatic ecosystems is essential. In this work, an ultrasound-assisted dispersive liquid-liquid microextraction (DLLME) procedure was suggested utilizing a binary dispersive agent for recovery of different molecular weight polycyclic aromatic hydrocarbons (PAHs) from waters. The detection was carried out by gas chromatography-mass spectrometry (GC-MS) as well as high-performance liquid chromatography with fluorescence and diode-array detection (HPLC-FD/PDA). The method was optimized for the extraction of analytes with respect to the mixture composition, ratios of components, ultrasonication time and centrifugation parameters. The analytical schemes for PAHs extraction from water samples using different ratios of extraction and dispersive solvents are reported. The mixture consisting of chloroform and methanol was applied for the extraction of PAHs containing two or three fused aromatic rings; the mixture of chloroform and acetonitrile is suitable for PAHs containing more than four aromatic rings. The mixture of chloroform:acetone + acetonitrile was applied in the universal scheme and allowed for the simultaneous extraction of 20 PAHs with different structures. The developed sample preparation schemes were combined with GC-MS and HPLC-FD/PDA, which allowed us to determine the analytes at low concentrations (from 0.0002 µg/L) with the recoveries exceeding 80% and relative standard deviations of about 8%. The developed methods for the determination of 20 PAHs were applied to the analysis of water samples from the Karasun Lake (Krasnodar), Azov Sea (Temryuk) and Black Sea (Sochi).

Exposure To Perfluoroalkyl Substances And Risk Of Hepatocellular Carcinoma In The Multiethnic Cohort

BACKGROUND AND AIM: Exposure to per- and polyfluoroalkyl substances (PFAS), a class of persistent organic pollutants, is ubiquitous. Animal studies suggest that PFAS may increase risk of fatty liver and hepatocellular carcinoma (HCC) via impacts on hepatic lipid, amino acid, and glucose metabolism, but human data are lacking. We examined associations of PFAS exposure, altered metabolic pathways, and risk of non-viral HCC. METHODS: In this nested case-control study, prediagnostic plasma PFAS and metabolomics were measured in 50 incident HCC cases and 50 individually matched controls from the Multiethnic Cohort Study (MEC). Cases and controls were matched by age, sex, race, and study area. PFAS exposure and risk of HCC were examined using conditional logistic regression. A metabolome wide association study and pathway enrichment analysis was performed for PFAS exposure and HCC risk, and key metabolites/metabolic pathways were identified using a meet in the middle approach. RESULTS: High perfluorooctane sulfonic acid (PFOS) levels (90th percentile from NHANES&amp;#x3e;55 &amp;#x3bc;g/L) were associated with more than 4 fold increased risk of HCC (OR=4.5; 95% CI: 1.2-16.0). The pathway enrichment analysis showed that PFOS exposure was associated with alterations in amino acid and glycan biosynthesis pathways, which were in turn associated with HCC risk. We identified four metabolites linking PFOS exposure with HCC, including glucose, butyric acid (a short chain fatty acid), α-Ketoisovaleric acid (a branched-chain α-keto acid), and 7alpha-Hydroxy-3-oxo-4-cholestenoate (a bile acid), each of which was positively associated with PFOS exposure and risk of HCC. CONCLUSTIONS: Exposure to high levels of PFOS was associated with increased risk of HCC, and the likely mechanisms were via alterations in glucose, amino acid, and bile acid metabolism. Larger studies are warranted to confirm these findings. Key Words: Chemical exposure, exposome, perfluorinated alkyl substance, hepatocellular carcinoma, metabolome, bile acid, metabolic pathway

Detection of Toxic Polychlorinated Biphenyls by Nanoporous Metal–Organic Frameworks

As a class of persistent organic pollutants (POPs), polychlorinated biphenyls (PCBs) are highly hazardous to the ecosystem, and their effective and facile detection is of high importance. Herein, we present two nanoporous metal–organic frameworks (MOFs), (Me2NH2)[In(CPTTA)]·(DMF)1.5(H2O)3.5 (BUT-174) and (Et2NH2)[In(CPTTA)]·(DEF)(H2O)3 (BUT-175), constructed by In3+ ions and the aromatic-rich tetratopic carboxylate ligands, 5′-(4-carboxylatophenyl)-[1,1′:3′,1″-terphenyl]-3,4′′,5-tricarboxylate (CPTTA4–), which exhibit highly efficient turn-down fluorescence response toward 12 PCBs, especially for three highly toxic non-ortho-substituted PCBs (PCB-77, -126, and -169) with the so-called “coplanar” molecular configuration in various solvents with the limits of detection (LODs) down to the ppb level owing to the inner filter effect between MOFs and PCBs. In addition, the MOFs show high sensing selectivity toward PCBs over many relevant interferents, including hexabromocyclododecane (HBCD), decabromodiphenyl oxide (DBDPO), perfluorobutanoic acid (PFBA), and perfluorooctanoic acid (PFOA), as well as good recyclability and stability. It is demonstrated by this work that structurally well-defined MOFs could be promising sensory materials for the detection of highly toxic PCBs in a facile way.