Families Of Persistent Organic Pollutants Research Articles

Drinking water quality impacts oocyte viability and embryo development.

Normal reproductive function and fertility is considered a "sixth vital sign" because disruptions to this sensitive physiological system can forewarn other health issues, including exposure to environmental toxicants. We found that female mice exhibited profound loss of embryos during pre-implantation and fetal development coincident with a change to the source of their drinking water. When female mice were provided with tap water from the building in which they were housed (Water 2), instead of tap water from a neighboring building which was their previous supply (Water 1), ovulated oocytes were degenerated or had impaired meiotic maturation, and failed to form embryos. The harmful effects of Water 2 exposure were not reversible even following a recovery period; however, carbon-filtration of Water 2 removed the toxic contaminant. Water composition analysis to identify the responsible toxicant(s) found that trace elements were present at expected levels and phthalates were undetectable. Per- and Poly-fluoroalkyl Substances (PFAS), a family of persistent organic pollutants were detected at ∼4 ng/L. To investigate further, female mice were given drinking water categorized by level of PFAS contamination (0.6 ng/L, 2.8 ng/L, or 4.4 ng/L) for 9 weeks. Compared to mice consuming purified MilliQ water, mice consuming PFAS-contaminated water had decreased oocyte quality, impaired embryogenesis and reduced cell numbers in blastocysts. PFAS concentration in the drinking water was negatively correlated with oocyte viability. Importantly, the levels of PFAS detected in the tap water are within current "safe level" guidelines, and further research is needed to determine whether PFAS are responsible for the observed reproductive toxicity. However, this research demonstrating that water deemed suitable for human consumption has detrimental effects on mammalian embryo development has important implications for public health and water quality policies.

Toxicity of persistent organic pollutants: a theoretical study

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

IDENTIFICATION OF TARGET GENES INVOLVED IN RESPONSES OF Populus TO POLYCHLORINATED BIPHENYLS BASED ON RNA-SEQ

Steel slag and rice husk bokashi are the ameliorant that expected can decrease P-retention Phytoremediation represents an effective, low-cost, environmentally friendly alternative that improves soil properties, although there have been significant developments in the last decade. From the scientific point of life, the main challenge is to decipher the metabolic pathways involved in response to contaminants and to understand their regulation. This information is essential if we aspire to improve the natural capacities of some plant species to remediate contaminated soils. A comprehensive study of the molecular response to polychlorinated biphenyls (PCBs), a family of persistent organic pollutants of particular relevance on a global scale, was obtained. A transcriptomic approach based on RNA-seq technology has been used to identify the genes involved in the metabolism of in-plant compounds and to quantify their activation levels in different controlled situations. It is surprising that this response is virtually unknown at the molecular level, despite its great potential applied in the context of phytoremediation technology. We apply to hybrid poplar (Populus tremula x alba) crops with Aroclor 1221. And we took samples of RNA, thus generating a matrix of four elements with their corresponding controls. On the other hand, we perform functional analyzes with bioinformatic tools based on sequence comparisons and gene co-expression networks. The response of genes of particular interest was validated using qRT-PCR technology. This is the first comprehensive study of the response of a plant organism to the presence of PCBs. A considerable number of structural and regulatory genes have been found, defining new transcription factors whose expression is proportional to the concentration of pollutant in the medium or the time of exposure to it. Correlation analyzes allow us to state that the metabolic response to PCBs, including possible degrading pathways, is involved in at least fifteen transcription factors and approximately forty proteins or enzymes that are particularly induced.

Associations between human internal chemical exposure to Persistent Organic Pollutants (POPs) and In Vitro Fertilization (IVF) outcomes: Systematic review and evidence map of human epidemiological evidence

The impact of environmental chemicals like persistent organic pollutants (POPs) on reproductive health is still poorly understood, despite the high societal and economical costs. The aim of the present study was to systematically review and evaluate the human evidence on the associations between internal levels of POPs and in vitro Fertilization (IVF) outcomes among women. We applied a protocol based on the National Toxicology Program Office of Health Assessment and Translation's guidelines for the study search, selection and quality assessment. Fifteen studies were finally retained in the present work. The results showed that main families of POPs are still pervasive in follicular fluid and serum of women undergoing IVF treatments. Globally, we found inconsistent findings across studies for specific exposure-outcome dyads, suggesting that adverse effects of POPs on IVF outcomes cannot be ruled out. Specifically, there is evidence that POPs, notably some polychlorinated biphenyls and organochlorine pesticides, may impair embryo quality and pregnancy rates. Most studies have been performed in small cohorts (n<50) and focused on PCBs and OCPs, whereas major research gaps remain for emerging compounds (e.g. perfluoroalkylated substances) and the most clinically relevant outcome, live birth rate. The overall evidence presented ‘serious’ or ‘very serious’ risk of bias, mainly due to the lack of consideration of relevant confounding variables, low sample size or underreporting of methods. Globally, we judged the level of evidence being “low”. Given the high economical and societal costs associated to infertility and IVF, further well-designed research is urged to fill the highlighted gaps.

Spatial distribution, patterns and source contributions of POPs in the atmosphere of Great Mendoza using the WRF/CALMET/CALPUFF modelling system

Abstract Global monitoring of Persistent Organic Pollutants (POPs) has allowed the knowledge of levels and distribution around the world as well as the understanding of its transport through the atmosphere. However, there are still some gaps in this regard, especially in some locations, as the case of Great Mendoza, a medium-sized urban area located in the center-west of Argentina. In this work, the WRF/CALMET/CALPUFF modeling system was used to estimate airborne levels of four families of POPs (PCBs, PBDEs, DDTs and HCB) in the study area. The model was validated from measured data obtained from eleven sites using passive air samplers with polyurethane foam disks (PUFs), subsequently analyzed by GC-ECNI/MS. Considering both sets of data, measured and simulated airborne concentrations, five statistical performance metrics were calculated for each family of POP [Mean bias error, (MBE), Fractional Bias (FB), Normalized Mean Square Error (NMSE), Factor of two (Fa2) and Pearson correlation coefficient (r)]. Results exhibited a good agreement between modeled and measured data, showing that WRF/CALMET/CALPUFF modeling system predicts POPs airborne concentrations with reasonable accuracy at a local scale. Model output was used to examine the relative source contribution to ground-level concentrations and to assess the spatial variability of the studied POPs in the study area. Source apportionment showed the prevalence of emissions from open burning of municipal solid waste (ranging from 9% to 90%) on the simulated atmospheric concentrations. HCB presented the lowest mean contribution from this activity (37%) but the highest variability (SD = 20%), followed by PCBs (69 ± 9%), and PBDEs (84 ± 4%). The spatial pattern obtained from simulations exhibited that both, lowest and highest levels predicted by the model, occurred in areas where no samples were taken, suggesting that the real gradient in the POPs air concentrations would be much greater than those reflected by measured data. This work highlights the usefulness of the implementation of an atmospheric dispersion model, not only in the study of air quality and exposure levels but also as a tool for the proper design of monitoring networks, taking into account the time and cost that sampling campaigns take, and the conclusions that are intended to be made from the analysis of the obtained data.

Snow Amplification of Persistent Organic Pollutants at Coastal Antarctica.

Many legacy and emerging persistent organic pollutants (POPs) have been reported in polar regions, and act as sentinels of global pollution. Maritime Antarctica is recipient of abundant snow precipitation. Snow scavenges air pollutants, and after snow melting, it can induce an unquantified and poorly understood amplification of concentrations of POPs. Air, snow, the fugacity in soils and snow, seawater and plankton were sampled concurrently from late spring to late summer at Livingston Island (Antarctica). Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) concentrations in snow and air were close to equilibrium. POPs in soils showed concentrations close to soil-air equilibrium or net volatilization depending on chemical volatility. Seawater-air fugacity ratios were highly correlated with the product of the snow-air partition coefficient and the Henry's law constant (KSA H'), a measure of snow amplification of fugacity. Therefore, coastal seawater mirrored the PCB congener profile and increased concentrations in snowmelt due to snowpack releasing POPs to seawater. The influence of snowpack and glacier inputs was further evidenced by the correlation between net volatilization fluxes of PCBs and seawater salinity. A meta-analysis of KSA, estimated as the ratio of POP concentrations in snow and air from previously reported simultaneous field measurements, showed that snow amplification is relevant for diverse families of POPs, independent of their volatility. We claim that the potential impact of atmospheric pollution on aquatic ecosystems has been under-predicted by only considering air-water partitioning, as snow amplification influences, and may even control, the POP occurrence in cold environments.

Determination of Descriptors Which Influence the Toxicity of Organochlorine Compounds Using Qsar Method

Organochlorine Pesticides (OCP) are organic compounds obtained by the chlorination of various unsaturated hydrocarbons. They are very toxic and therefore belong to the family of persistent organic pollutants. If formerly these pesticides were used to fight against certain vectors of diseases and thus improve the productivity of the host, today they are considered as "enemy" of the environment. To understand the origin of the toxicity of organochlorine compounds, we used 73 molecules (test set: 50 and validation: 23) containing at least one chlorine atom and for which the toxicity (LogLC50) against Poecilia reticulata is known to establish QSAR models. Firstly, we used principal component analysis (PCA) to identify the best descriptors. Then, the different models were established using the method of multiple linear regression (MLR). Models established with quantum and physicochemical descriptors only showed satisfactory results. But the best model was determined with the combination of both quantum and physicochemical descriptors. The criteria of this model are as follows:&#x0D; R2 = 0.939 ; R2ajusted = 0.932 ; Pvalue &lt; 0.0001; α = 0.05&#x0D; R2CV = 0.935 ; R2 - R2CV = 0.004 ; MCE = 0.073; F = 134.701&#x0D; These criteria show that the toxicity of organochlorine compounds is well described by the combination of quantum and physicochemical descriptors namely lipophilia (LogP), polarizability (pol), entropy (S), zero-point energy (ZPE) and the number of chlorine atoms (NCl).

Leaching of polycyclic aromatic hydrocarbons (PAHs) from sewage sludge-derived biochar

Polycyclic aromatic hydrocarbons (PAHs), a family of persistent organic pollutants with various negative health effects, are inherently formed during biochar pyrolysis. However, the knowledge regarding the leaching potentials and mechanisms of PAHs remains limited for biochar implementation to soil. In this study we evaluated the leaching behaviors of PAHs from sewage sludge-derived biochar pyrolyzed at different temperatures (300–700 °C) using the protocol of Synthetic Precipitation Leaching Procedure (SPLP) with deionized water. Leachate concentrations of sixteen U.S. Environmental Protection Agency PAHs increased with the increasing pyrolysis temperature, exhibiting an opposite pyrolytic temperature dependence with their concentrations in biochar. The total leachate PAH concentration peaked at 700 °C with 11.75 μg/L, corresponding to 15.9% of total PAHs present in biochar. PAH leaching was associated with the release of hydrophobic organic compounds (HOCs) that created a mobile phase to facilitate the mobilization of PAHs into water. The enhanced release of calcium, aluminum, and barium from the biochars with pyrolysis temperature could also favor the leaching of biochar PAHs, due to the destruction of HOCs-(metal ions)-mineral linkages, which improved the release of HOCs and HOCs-bound PAHs; and because the extent of metal cross-linking in biochar is reduced, enabling better diffusion of PAHs through the inner matrix and thus accelerating their desorption.

Development of an on–site detection approach for rapid and highly sensitive determination of persistent organic pollutants in real aquatic environment

Analysis of organic pollutants is usually accomplished in centralized laboratories. However, the time-delayed and time-consuming process is insufficient and risky for precisely detection due to the contamination of vials, the losses of analytes during transportation and storage. Herein, a rapid and highly sensitive on-site detection approach was developed without using any vials by coupling an on-site pre-equilibrium solid phase microextraction (SPME) sampling method with a portable gas chromatography mass spectrometer (portable GC-MS), for the determination of three families of persistent organic pollutants (polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons). Based on sampling-rate (SR) calibration method, the concentrations of target analytes in aquatic systems could be easily determined. Limits of detection (LODs) in the low parts-per-tillion levels (≤5.25 ng·L−1) were obtained for most of the investigated analytes with a total analysis time only ∼30 min. The proposed on-site detection approach was then successfully applied in the determination of persistent organic pollutants in real aquatic environment. A comparable result obtained by liquid extraction (LE) equipped with laboratorial GC-MS demonstrated the accuracy of the on-site detection method. In general, this study demonstrated a rapid and highly sensitive on-site approach, avoiding any risks of contamination during sampling and analysis, for determination of POPs as well as the potential applications for other organic pollutants in aquatic phase.

Henry's Constants of Persistent Organic Pollutants by a Group-Contribution Method Based on Scaled-Particle Theory.

A group-contribution method based on scaled-particle theory was developed to predict Henry's constants for six families of persistent organic pollutants: polychlorinated benzenes, polychlorinated biphenyls, polychlorinated dibenzodioxins, polychlorinated dibenzofurans, polychlorinated naphthalenes, and polybrominated diphenyl ethers. The group-contribution model uses limited experimental data to obtain group-interaction parameters for an easy-to-use method to predict Henry's constants for systems where reliable experimental data are scarce. By using group-interaction parameters obtained from data reduction, scaled-particle theory gives the partial molar Gibbs energy of dissolution, Δg̅2, allowing calculation of Henry's constant, H2, for more than 700 organic pollutants. The average deviation between predicted values of log H2 and experiment is 4%. Application of an approximate van't Hoff equation gives the temperature dependence of Henry's constants for polychlorinated biphenyls, polychlorinated naphthalenes, and polybrominated diphenyl ethers in the environmentally relevant range 0-40 °C.

Polychlorinated biphenyls (PCBs) inhibit hepcidin expression through an estrogen-like effect associated with disordered systemic iron homeostasis.

Polychlorinated biphenyls (PCBs), with 209 congeners, are a large family of persistent organic pollutants. PCBs elicit a wide range of toxicities, such as neurotoxicity, hepatoxicity, oncogenicity, and endocrine-disrupting effects. However, an understanding of the potential disruption of systematic iron metabolism by PCBs is still limited. To maintain iron homeostasis, the hepcidin-ferroportin (FPN) axis is critically important, and hepcidin is the central governor in guiding dietary iron absorption and iron egress from macrophages. Hepcidin is secreted by hepatocytes and binds to FPN to promote its degradation. Dysregulation of hepcidin gives rise to disordered iron homeostasis, associated with diverse diseases including anemia and β-thalassemia. Our previous study demonstrated that there is an estrogen response element (ERE) within the promoter of hepcidin gene and that its expression is regulated by estrogen. In the current study, we demonstrated that both PCB153 and PCB126 greatly suppress hepcidin expression in HepG2 cells, with a greater repression occurring in cells upon PCB126 treatment. Further studies uncovered that both PCB153 and PCB126 harbor estrogenic activity and that the estrogenic activity of PCB126 was stronger than that of PCB153 in HepG2 cells. Mechanistic investigation revealed that PCBs suppress hepcidin transcription through a functional ERE within the hepcidin promoter, analogous to the action of 17β-estradiol. Moreover, hepatic hepcidin was downregulated in wild-type mice upon PCB126 administration, coupled with elevated serum iron content as well as reduced hepatic and splenic iron mass. These changes were not replicated in hepcidin-deficient mice upon PCB administration. Additionally, hepatocytes were observed with severe accumulation of lipid droplets in the livers of mice challenged with PCB126, irrespective of the presence of hepcidin. To summarize, our results have deciphered a suppressive role of PCBs in restraining the expression of hepcidin through mimicking estrogenic activity and revealed a novel property of PCBs in disrupting systemic iron metabolism. This study also unearthed a PCB-mediated connection linking estrogen-like activity, iron effects, and lipid homeostasis.

Levels of PCDDs, PCDFs, and dioxin-like PCBs in human milk among Hong Kong mothers

Dioxins are a family of persistent organic pollutants (POPs) listed under the Stockholm Convention, and include PCDDs, PCDFs, and dioxin-like PCBs. These toxic chemicals are carcinogenic, widely dispersed, and have long half-lives. They have contaminated the food web and, being fat-soluble, accumulate in adipose tissues and milk in the human body. To assess human exposure, we collected breast milk samples from 137 first-time mothers recruited from around Hong Kong. Samples were analysed by HRGC–HRMS in four pools, according to the subject's age and length of residency. Exposure was related to age, duration of stay, and possibly diet. Generally, older mothers, and mothers with a longer stay in Hong Kong, had higher levels of dioxins in their milk. This pattern was clearest for the PCBs, although deviations were observed for some of the PCDD/Fs. Mean concentrations, measured per gram of lipid weight in terms of WHO toxic equivalents (WHO-TEQs), were 7.48pg/g for PCDD/Fs and 3.79pg/g for PCBs, giving a total of 11.27pg/g for PCDD/Fs and PCBs combined. Compared to an earlier Hong Kong study we conducted in 2002, the mean WHO-TEQ values in our latest findings were about 9% lower overall for PCDD/Fs and 19% lower for PCBs, with the mean total WHO-TEQ for PCDD/Fs and PCBs being around 13% lower in this study. This indicates a general declining trend in the levels of POPs in Hong Kong. However, our levels were still high when compared to those in some other Asian-Pacific countries. More stringent policies on reducing and eliminating POPs should help to lower these. Continued surveillance for POPs in human milk, as well as in common foodstuffs, will provide us with important information on human exposures that will be necessary for tracking our progress, and making future health risk assessments.

Which persistent organic pollutants can we map in soil using a large spacing systematic soil monitoring design? A case study in Northern France

Persistent organic pollutants (POPs) impact upon human and animal health and the wider environment. It is important to determine where POPs are found and the spatial pattern of POP variation. The concentrations of 90 molecules which are members of four families of POPs and two families of herbicides were measured within a region of Northern France as part of the French National Soil Monitoring Network (RMQS: Réseau de Mesures de la Qualité des Sols). We also gather information on five covariates (elevation, soil organic carbon content, road density, land cover and population density) which might influence POP concentrations. The study region contains 105 RMQS observation sites arranged on a regular square grid with spacing of 16 km. The observations include hot-spots at sites of POP application, smaller concentrations where POPs have been dispersed and observations less than the limit of quantification (LOQ) where the soil has not been impacted by POPs. Fifty nine of the molecules were detected at less than 50 sites and hence the data were unsuitable for spatial analyses. We represent the variation of the remaining 31 molecules by various linear mixed models which can include fixed effects (i.e. linear relationships between the molecule concentrations and covariates) and spatially correlated random effects. The best model for each molecule is selected by the Akaike Information Criterion. For nine of the molecules, spatial correlation is evident and hence they can potentially be mapped. For four of these molecules, the spatial correlation cannot be wholly explained by fixed effects. It appears that these molecules have been transported away from their application sites and are now dispersed across the study region with the largest concentrations found in a heavily populated depression. More complicated statistical models and sampling designs are required to explain the distribution of the less dispersed molecules.

Thermodynamic Stability of Neutral and Anionic PFOS: A Gas-Phase, n-Octanol, and Water Theoretical Study

The thermodynamic stability of the 89 isomers of the eight-carbon-atom compound perfluorooctane sulfonate (PFOS) in their neutral and anionic forms has been studied in the gas phase, n-octanol, and water using density functional theory (B3LYP/6-311+G(d,p)). The gas-phase calculations are compared with previous semiempirical and partial ab initio studies; the calculations in water and n-octanol are reported for the first time. The results obtained indicate that the thermodynamic stability assessment of this family of persistent organic pollutants is independent of the environment and type of species (neutral or anionic) considered and that it is important to consider other PFOSs outside of the 83-89 set, which is the most frequently studied.