A high-throughput method for the determination of 14 UV-filters in human plasma by LC-MS/MS: Minimize interferences from proteins and phospholipids in the matrix.

Accurate monitoring of UV-filters exposure levels in human plasma is a challenge because of the significant differences in the physicochemical properties of UV-filters, as well as the matrix effect caused by abundant proteins and phospholipids in plasma. Therefore, an effective and rapid method for simultaneous determination of 14 UV-filters in human plasma using protein precipitation-solid phase extraction (SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Acetonitrile with 0.1 % formic acid and 10 % isopropanol (v/v) were used as mobile phases. A gradient elution on an ACQUITY UPLC BEH-C18 column at 30 °C and 0.3 mL/min flow rate was applied for separation. The electrospray ionization positive or negative modes were selected to determine the corresponding analyte to increase selectivity and sensitivity. Results showed that acetonitrile-tetrahydrofuran (v/v, 8:2) as the extraction solvent can effectively precipitate protein in plasma and improve the solubility of UV-filters. The HybridSPE cartridge improved the removal efficiency of phospholipids, while 1 mL of methanol elution increased the extraction recoveries of targets. Fourteen UV-filters achieved good linearities, low detection limits (0.050 to 0.10 µg/L) and quantification limits (0.10 to 1.0 µg/L). Method accuracy and precision, extraction recoveries, and storage stabilities of all analytes met the criterion of 80-120 %. Moreover, this method was successfully applied for the determination of UV-filters in plasma randomly collected from adults. Nine of 14 UV-filters were determined and their concentrations were distributed widely, suggesting a big variation of individual UV-filters exposure.

Revealing chemical release from plastic debris in animals' digestive systems using nontarget and suspect screening and simulating digestive fluids.

Plastic debris in the environment are not only pollutants but may also be important sources of a variety of contaminants. This work simulated kinetics and potential of chemical leaching from plastic debris in animals' digestive systems by incubating polyvinyl chloride (PVC) cord particles in artificial digestive fluids combined with nontarget and suspect screening based on UHPLC-Orbitrap HRMS. Impacts of particle size, aging, and digestive fluid were investigated to elucidate mechanisms of chemical leaching. Thousands of chemical features were screened in the leachates of PVC cord particles in the artificial digestive fluids, among which >60% were unknown. Bisphenol A (BPA) and bis(2-ethylhexyl) phthalate (DEHP) were the dominant identified CL1 compounds. Finer size and aging of the PVC particles and prolonged incubation time enhanced chemical release, resulting in greater numbers, higher levels, and more complexity in components of the released chemicals. The gastrointestinal fluid was more favorable for chemical leaching than the gastric fluid, with greater numbers and higher levels. Hundreds to thousands of chemical features were screened and filtered in the leachates of consumer plastic products, including food contact products (FCPs) in the artificial bird gastrointestinal fluid. In addition to BPA and DEHP, several novel bisphenol analogues were identified in the leachate of at least one FCP. The results revealed that once plastic debris are ingested by animals, hundreds to thousands of chemicals may be released into animals' digestive tracts in hours, posing potential synergistic risks of plastic debris and chemicals to plastic-ingesting animals. Future research should pay more attentions to identification, ecotoxicities, and environmental fate of vast amounts of unknown chemicals potentially released from plastics in order to gain full pictures of plastic pollution in the environment.

Asiatic acid and madecassic acid cause cardiotoxicity via inflammation and production of excessive reactive oxygen species in zebrafish.

Centella asiatica (L.) Urban is a famous Chinese traditional medicine, which is widely used for treating various chronic inflammatory diseases. Although there are reports that Centella total glycosides exhibit heart-protective properties, our previous experiment showed that it has cardiac toxic effects in zebrafish. The components of Centella total glycosides are complex, so we recommend further research to determine their key components and mechanisms. In this study, sample quantification was done using liquid chromatography-tandem mass spectrometry. The cardiotoxicity of Centella total glycosides, asiaticoside, madecassoside, asiatic acid, and madecassic acid was evaluated using zebrafish and cell models. The zebrafish oxidative stress model and myocarditis model were used to explore further the mechanisms through which cardiotoxicity is achieved. Asiatic acid and madecassic acid caused zebrafish cardiotoxicity and H9C2 cell death. However, no toxicity effects were observed for asiaticoside and madecassoside in zebrafish, until the solution was saturated. The results from the cell model study showed that asiatic acid and madecassic acid changed the expression of apoptosis-related genes in myocardial cells. In the zebrafish model, high concentrations of these components raised the levels of induced systemic inflammation, neutrophils gathered in the heart, and oxidative stress injury. Asiatic acid and madecassic acid are the main components causing cardiotoxicity in zebrafish. This may be due to enhanced inflammation and reactive oxygen species injury, which causes myocardial cell apoptosis, which further leads to cardiac toxicity.

Determination of polyfluoroalkyl substances in cosmetic products using dispersed liquid-liquid extraction coupled with UHPLC-MS/MS.

Human exposure to polyfluoroalkyl substances (PFASs) via cosmetics has been of increasing concern due to the tremendous detrimental health impacts of PFASs. Developing an effective method for extracting and determining PFASs in cosmetics is crucial in accurately assessing their corresponding human exposure risk. Herein, this study developed a new sample pre-treatment method to address the challenges posed by the variety and complexity of cosmetic matrices. Seventeen PFASs in cosmetic products, including 9 perfluoro carboxylic acids and 8 perfluorosulfonic acids, were simultaneously determined using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The whole pre-treatment process can be divided into three steps. In step 1, cosmetics with diverse matrix types can be effectively dispersed during extraction by using saturated sodium chloride-acetonitrile and saturated sodium chloride-tetrahydrofuran as extraction solvents. In step 2, the pre-purification step employs a potassium ferrocyanide-zinc acetate co-precipitant to remove high molecular weight interferents from the extraction solution, thereby enhancing the efficiency of solid-phase extraction (SPE). In step 3, WAX-SPE is utilized to further eliminate interferents from the extraction solution while concentrating the analytes, meeting the trace analysis requirements for PFASs in cosmetics. The method detection limits were 0.09-0.26 ng g-1. The recoveries ranged from 70.1% to 114.7%, with relative standard deviations in the range of 2.0-19.1%. The method was applied to cosmetic samples in the Guangzhou market, and the total concentration of PFASs ranged from 0 to 10.8 ng g-1. This method has strong anti-interference ability, good applicability, high sensitivity, and good reproducibility, making it suitable for the analysis and detection of perfluorinated acids in cosmetic samples. It provides technical support for cosmetics safety regulation.

Exposure of Reproductive-Aged Women to Multiple Metals and Its Associations with Unexplained Recurrent Miscarriage.

Exposure to heavy metals exerts toxic effects on female reproduction and embryo development. This study examined the exposure of patients with unexplained recurrent miscarriage (uRM) to multiple metals and the correlations among exposures to different metals. A total of 275 participants were enrolled, including 43 healthy women without previous miscarriage (the control group) and 232 uRM women (the case group); among these uRM women, 159 had two miscarriages (2M), 42 had three miscarriages (3M) and 31 had four or more miscarriages (≥4M). A total of 22 elements were measured in serum samples via inductively coupled plasma-mass spectrometry. The levels of calcium (104.37 mg/L vs. 92.65/93.02/92.61/92.47 mg/L) and selenium (131.85 µg/L vs. 117.80/118.04/115.88/124.35 µg/L) were higher in the controls than in the total uRM group and the 2M, 3M and ≥4M subgroups. The level of vanadium was significantly lower in the controls than in the total uRM group (0.15 µg/L vs. 0.23 µg/L), and the level of lead was lower in the controls than that in the total uRM group and the 2M, 3M and ≥4M subgroups (0.01 µg/L vs. 0.28/0.18/0.63/0.34 µg/L). After adjusting for age, body mass index and education level, calcium and selenium exposure were consistently negatively associated with miscarriage, while lead exposure was positively associated with miscarriage. In addition, the correlations among exposures to different metals slightly differed between the control and uRM groups. Therefore, changes in some metal elements in the blood might be related to the risk of uRM.

Correlation analysis between sleep quality and the mental health status of female sex workers during the COVID-19 pandemic in Hubei Province.

Objective: Female sex workers (FSWs) in entertainment venues are subject to condemnation and rejection by their families and the outside world. As a result, they are prone to psychological problems, including anxiety and even suicidal tendencies. The aim of the current study was to understand the sleep and mental health status of local FSWs and to identify associated risk factors, so as to provide a scientific basis for improving the social recognition of FSWs and establishing effective psychological interventions. Methods: A stratified cluster random sampling method was used to select women engaged in commercial sex in bathing, sauna, karaoke halls and other entertainment venues. A self-designed questionnaire assessing mental health-related factors was administered face-to-face with the respondents. 90 participants were randomly selected for blood tests to analyze the relationship between biological indicators and sleep quality. Results: The rates of depression, anxiety and somnipathy among FSWs were 32.7%, 43.1% and 8.6%, respectively. The correlation coefficients (r) between sleep quality and depression, anxiety and social support were 0.07, 0.09 and -0.09, respectively. Divorce or widowhood, technical secondary school education, alcohol consumption and exercise were independent risk factors for depression in FSWs (p< 0.05) while living in urban areas and counties and having a sense of social support were protective factors (P< 0.05). Quarantining due to the pandemic and exercise were independent risk factors for anxiety in FSWs (P< 0.05) while living in counties and having a sense of social support were protective factors (P< 0.05). Quarantining due to the pandemic was an independent risk factor for somnipathy in FSWs (P< 0.05) while being married was a protective factor (P< 0.05). NE/NA was a protective factor for sleep disorders (OR=0.042, P=0.05), with an AUC of 0.87. Conclusion: FSWs should appropriately adjust their work form during the pandemic period, maintain a positive and optimistic attitude, establish long-term stable social relationships, and seek a greater sense of social support. The government should provide comprehensive bio-psycho-social interventions to address the mental and physical health status of this population.

Physicochemical characterization and cosmetic application of kelp blanching water polysaccharides.

Seaweeds account for half of global mariculture and have become a key player in bio-based industries. Seaweed process typically starts with hot water blanching that helps reduce postharvest quality deterioration but also generates large amounts of hydrothermal waste. This study aims to explore the feasibility of isolating water-soluble biopolymers from seaweed hydrothermal waste and their potential applications. Using Saccharina japonica (formerly Laminaria japonica) blanching water as example, 2.9 g/L of polymeric substances were efficiently isolated by ultrafiltration, implying biopolymer coproduction potential of ~5.8 kt from blanching wastewater of current kelp industry. Physicochemical characterizations revealed polysaccharidic nature of the biopolymers, with high contents of fucose, uronic acids and sulfate, showing distinct but also overlapping structural features with hot water-extracted kelp polysaccharides. The main fraction of the blanching water polymers after anion exchange chromatography was acidic polysaccharide, the major backbone residues of which were (1-4) linked mannopyranose, (1-4) linked gulopyranose and (1-2) linked fucopyranose while the branched residues were primarily 1,3,4-, 1,2,4- and 1,4,6-linked hexoses but also 1,3,4-fucopyranose. Furthermore, the polysaccharides were found to have a good compatibility in cosmetic creams with added cohesiveness and freshness, demonstrating the application potential of such natural biopolymers from currently underexplored seaweed blanching water.

Profile, Tissue Distribution, and Time Trend of Bisphenol Plastic Additives in Freshwater Wildlife of the Pearl River Ecosystem, China.

Plastic-related contaminants in the environment have attracted increasing attention, with plastic pollution becoming a serious issue globally. The present study investigated the potential bioaccumulation and biotransfer of bisphenol (BP) compounds that are widely added in various products such as plastics and other products in a freshwater ecosystem, China. Among commonly applied 14 BP analogues, bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS) were predominant, representing 64%-100% of the total concentrations of BPs (ΣBPs) in freshwater wildlife. Both the concentrations and analogue profiles in the fish showed seasonal differences and species dependence. Higher BP concentrations were observed in fish collected during the dry season than the wet season. Higher percentages of non-BPA analogues (e.g., BPS and BPF) were observed in fish collected during the wet season. Pelagic species accumulated notably higher levels of BPs than midwater and bottom species. The liver generally contained the highest ΣBPs, followed successively by the swim bladder, belly fat, and dorsal muscle. The analogue profile also showed some differences among tissues, varying by species and season. Lower ΣBPs but higher percentages of non-BPA analogues were observed in female than male common carp. Time trends of the BPA concentration in fish varied by species, probably related to habitats and diets of the fish. Habitats, feeding behaviors, and trophic transfer may have significant impacts on exposure of wildlife to BPs in natural ecosystems. The BPs did not demonstrate strong potential for bioaccumulation. More research is warranted about metabolism and transgenerational transfer of BPs in wildlife to fully reveal the bioaccumulation and consequently ecological risks of these chemicals in the environment. Environ Toxicol Chem 2023;42:2130-2142. © 2023 SETAC.

Multi-residue determination of bisphenol analogues in organism tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

A reliable and sensitive analyzing method was developed and validated for determination of 13 novel bisphenol analogues (BPs) along with bisphenol A (BPA) in organism tissues. The complex organism tissues were treated by ultrasonic-assisted extraction using acetonitrile/formic acid (99:1, v/v), followed by successive purification using enhanced matrix removal-lipid sorbents and primary secondary amine sorbents. The BPs were finally determined by ultra-high performance liquid chromatography-tandem mass spectrometry after derivatization using pyridine-3-sulfonyl chloride. Satisfactory recoveries of 75 - 118% were obtained for the BPs, with good repeatability (RSD < 20%). Matrix interferences were efficiently diminished. The method quantification limits (MQLs) reached 0.003 - 0.1 ng g-1 dry weight (dw). The validated method was successfully applied to a preliminary investigation of the BPs in wild marine organisms collected from the nearshore waters along the coast of Guangdong, China. Besides BPA, novel BPs such as bisphenol F, bisphenol AF, and tetrabromobisphenol A were also detected at < MDL - 15.5 ng g-1 dw. This work laid a strong basis for further in-depth research on bioaccumulation of the novel BPs in the environment.

Relationship of polycyclic aromatic hydrocarbons exposure with vascular damages among sanitation workers.

Chronic exposure to polycyclic aromatic hydrocarbons (PAHs) leads to a high incidence of cardiovascular diseases. To assess the effects of PAHs exposure on vascular damages in occupationally exposed populations, 196 sanitation workers were recruited. According to the differences of occupation or operation, they were divided into exposure group (n = 115) and control group (n = 81). Sixteen serum PAHs were determined by gas chromatography-tandem mass spectrometery. Tumor necrosis factor ɑ (TNF-ɑ) and angiotensin II (ANG-II) in serum, blood lipids and blood pressure were also measured. Results showed that, except for indeno(1,2,3-cd)pyrene, dibenzo(a,h)anthracene and benzo(g,h,i)perylene, the detection frequencies of other PAHs were above 85%, showing that subjects are generally exposed to PAHs. The top three compounds in serum concentrations of PAHs were phenanthrene, acenaphthylene and anthracene. Moreover, the concentrations of total serum PAHs in the exposure group were significantly higher than those in the control (p < 0.05), suggesting a higher PAHs exposure in the former. Though there was no significant difference in blood lipids and blood pressure between groups (p > 0.05), TNF-ɑ and ANG-II levels in the exposure group were significantly higher than those in the control group (p < 0.05), suggesting that PAHs exposure may be related to pro-inflammatory effects and vascular endothelial damages.

High-performance nontarget analysis of halogenated organic compounds in tap water, fly ash, soil and sediment using ultrahigh resolution mass spectrometry and scripting approaches based on Cl/Br-specific search algorithms.

Halogenated organic compounds (HOCs) are a huge group of pollutants, which have caused severe environmental pollution worldwide. This study developed a nontarget analysis method for characterization of known and unknown HOCs in tap water, fly ash, soil and sediment using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) with aid of scripting data-processing approaches. The FT-ICR-MS was equipped with an electrospray ionization source operated in negative ion mode, and full scan at a mass resolution around 200,000 was applied. Data screening scripts were developed based on exact mass differences and abundance ratios between neighboring chlorine/bromine isotopologues. Cosine similarity analysis was applied to evaluating similarity between measured and simulated isotopologue distributions which were constituted by abundance ratios between neighboring isotopologues for identification of polychlorinated and polybrominated compounds. From huge amount of peaks in raw mass spectra, thousands of MS features of HOCs were screened out. In total 824 HOC formulae were finally identified, including 702 organochlorines, 108 organobromines, and 14 mix-chlorine/bromine-containing organic compounds (OClBrs), mainly being monochlorinated/monobrominated compounds (∼90%) whose abundances were also the most prominent. Dozens of HOCs were tentatively structurally elucidated, including halogenated phenols, carboxylic acids, benzenesulfonic acids, etc. Three novel OClBrs were structurally identified, i.e., bromochlorobenzoic acid, bromodichlorophenol and bromotrichlorophenol. The data-processing scripts and strategies can facilitate accurate and high-throughput nontarget analysis of both common and novel/emerging halogenated organic pollutants in complex matrices. The research results provide informative insights into pollution profiles of HOCs in the environment, suggesting that halogenated organic pollutants remain to be seriously concerned.

Volatile organic compounds from second-hand smoke may increase susceptibility of children through oxidative stress damage.

Although humans are generally exposed to second-hand smoke (SHS), volatile organic compounds (VOCs) exposure derived from SHS and its health hazard to non-smokers are rarely investigated. Thus, we examined the effects of SHS on VOCs exposure and oxidative stress damage via a passive smoking simulation experiment in 6 children and 7 adults. To further validate the studied urinary VOC metabolites as biomarkers for passive smoking, 259 children were recruited. The levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), malonaldehyde (MDA), trans-3'-hydroxycotinine (OH-Cot) and 31 VOC metabolites in urine were determined. The results showed that the geomean concentrations of 17 VOC metabolites in urine of children were 26.5%-138% higher than those of adults after passive smoking. The levels of urinary 8-OHdG, MDA and OH-Cot increased by 24.6%, 18.8% and 600% in children, but only 1.25%, 10.3% and 116% in adults, respectively. Therefore, children are more vulnerable to SHS than adults. After exposure to SHS, the levels of 8 urinary VOC metabolites of benzene, acrylonitrile, 1-bromopropane, propylene oxide, toluene, methyl methacrylate and cyanide increased by 60.9%-538% within 23 h. These 8 VOC metabolites were also significantly associated with 8-OHdG or MDA in urine (p < 0.01). Therefore, exposure to VOCs caused by SHS increases body oxidative stress damage. OH-Cot level higher than 2.00 µg/g Cr can be used as a threshold of passive smoking. The levels of urinary s-benzylmercapturic acid (BMA) and s-phenylmercapturic acid (PMA) in children increased by 494% and 728% within 6 h after passive smoking, respectively. Population validation study indicated that BMA and PMA levels were significantly elevated in children exposed to SHS. Therefore, in addition to OH-Cot, urinary BMA and PMA are potentially useful short-term biomarkers of passive smoking. Future studies should focus on the differences in VOC metabolism and detoxification mechanisms between children and adults.

Glabrol impurity exacerbates glabridin toxicity in zebrafish embryos by increasing myofibril disorganization.

ETHNOPHARMACOLOGICAL RELEVANCE: Glabridin, extracted from Glycyrrhiza glabra L., is widely used for the treatment of hyperpigmentation because of its anti-inflammatory and antioxidant activities and its ability to inhibit melanin synthesis. This led to the strict regulation of its quality and safety. However, traditional quality control methods used for plant extracts cannot reflect the product quality owing to multiple unknown impurities, which necessitates the further analysis of impurities. AIM OF THE STUDY: The study identified the toxic impurities of glabridin and their toxicological mechanism. MATERIALS AND METHODS: In total, 10 glabridin samples from different sources were quantified using high-performance liquid chromatography. Sample toxicities were evaluated using zebrafish and cell models. To identify impurities, samples with different toxicity were analyzed by ultra-high-performance liquid chromatography coupled with quadrupole-Orbitrap mass spectrometry. The toxicity of related impurities was verified in the zebrafish model. Phalloidin stain was used to evaluate subtle changes in myofibril alignment. RESULTS: Although glabridin content in the samples was similar, there were significant differences in toxicity. The results were verified using four different mammalian cell lines. Higher contents of glabrone and glabrol were identified in the sample with the highest toxicity. In the zebrafish model, the addition of glabrol reduced the LC50 of glabridin to 9.224, 6.229, and 5.370 µM at 48, 72, and 96 h post-fertilization, respectively, whereas glabrone did not have any toxic effect. Phalloidin staining indicated that a glabrol impurity exacerbates the myotoxicity of glabridin in zebrafish embryos. CONCLUSION: Glabrol, but not glabrone, was identified as a key impurity that increased glabridin toxicity. This finding indicates that controlling glabrol content is necessary during glabridin product production.

A description of the current status of chronic fatigue syndrome and associated factors among university students in Wuhan, China.

Introduction: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a group of chronic conscious fatigue that is not easily relieved by rest and is accompanied by corresponding physiological dysfunction and psychological symptoms. However, due to the insufficient understanding of the pathogenesis of ME/CFS, there is currently a lack of effective treatment methods. In addition, there are few surveys on the current status of ME/CFS in the central region of China, and the data on ME/CFS among university students in the central region are lacking. This group conducted a survey on university students in Wuhan, Hubei Province in 2022 to collect and analyze the current status of ME/CFS among university students in central China for the first time, aiming to understand the current development of ME/CFS among university students, investigate the influencing factors of its prevalence, fill the data gaps, and provide a reliable basis for developing interventions for chronic fatigue syndrome among university students. Methods: A cross-sectional study was conducted among university students in a university in Hubei province. Data were collected via online questionnaire surveys. The contents included demographic characteristics, lifestyles, disease history, depression, anxiety, sleep, ME/CFS and other associated factors. SAS 9.4 statistical software was used to analyze and estimate the effect of associated factors on ME/CFS. Results: A total of 1826 subjects were included in the final analysis. The results showed that the prevalence of ME/CFS in university students was 6.25%. Univariate analysis showed that exercise, alcohol consumption, study, overnights, diet, anxiety, depression, and sleep quality were associated with ME/CFS (P < 0.05). Multivariate analysis showed that overnights, overeating, anxiety, and sleep quality were independent risk factors, while learning was a protective factor. Conclusion: College students should pay enough attention to ME/CFS, improve their understanding of ME/CFS, and improve people's ability to understand ME/CFS.

Characterization of Compound-Specific Chlorine Isotopologue Distributions of Polychlorinated Organic Compounds by GC-HRMS for Source Identification.

Distributions of chlorine isotopologues are potentially a fingerprint feature of organochlorines. However, the exact distributions remain little known. This study measured compound-specific chlorine isotopologue distributions of six polychlorinated organic compounds (POCs) for source identification. Complete chlorine isotopologues of POCs were detected by gas chromatography coupled to high-resolution mass spectrometry. The measured relative abundances (Ameas), theoretical relative abundances (Atheo), and relative variations between Ameas and Atheo (ΔA) of chlorine isotopologues were determined. These ΔA values were applied to characterize differences in isotopologue distribution patterns, and the ΔA patterns directly illustrated the distribution characteristics. Perchloroethylene (PCE) and trichloroethylene (TCE) from two manufacturers were chosen as model analytes to develop and validate the analytical method, including precision, concentration dependency, and temporal drift. The ΔA values of isotopologues of the PCE and TCE chemicals were from -82.5 to 19.9‰ with standard deviations (SDs) of 0.3-16.9‰. In addition, the ΔA values of the first three isotopologues (with 0-2 37Cl atoms) were from -15.5 to 19.9‰ with SDs of 0.3-1.6‰, showing sufficient precisions. No concentration dependency and temporal drift of ΔA were observed. The method has been successfully applied to source identification for PCE and TCE in commercial chemicals and plastic materials, and four polychlorinated biphenyls in chemicals and sediments, demonstrating that the ΔA values and ΔA patterns were discernable for POCs from different sources. This study demonstrates that compound-specific chlorine isotopologue distributions of POCs are differentiable and measurable, proposing a novel approach to perform fingerprinting analysis for the distributions, which is anticipated to facilitate source identification for organochlorine pollutants.

Chlorine isotope analysis of polychlorinated organic pollutants using gas chromatography-high resolution mass spectrometry and evaluation of isotope ratio calculation schemes by experiment and numerical simulation.

Compound-specific isotope analysis of chlorine (CSIA-Cl) is a practicable and high-performance approach for revelation of transformation processes and source identification of chlorinated organic pollutants. This study conducted CSIA-Cl for typical polychlorinated organic pollutants using gas chromatography-high resolution mass spectrometry (GCHRMS) with an alternate injection mode using perchloroethylene (PCE) and trichloroethylene (TCE) as model analytes. PCE and TCE standards from two manufacturers were employed for method development, and chlorine isotope ratio calculation schemes were evaluated by experiment and numerical simulation. The achieved precision (standard deviation of isotope ratios) was up to 0.21‰ for PCE and 0.43‰ for TCE. The limits of detection for CSIA-Cl of were 0.05 µg/mL (0.05 ng on column), and the linearities were 0.05-1 µg/mL. Two isotope ratio calculation schemes, i.e., one using complete molecular isotopologues and another using the first pair of neighboring chlorine isotopologues of each analyte, were evaluated in terms of accuracy and precision. The complete-isotopologue scheme showed evidently higher precision and was more competent to reflect trueness than the isotopologue-pair scheme and the two schemes could present completely different outcomes. The method has been successfully applied to PCE and TCE reagents from different suppliers, a trichloromethane reagent, and a plastic material. The relative isotope ratio variations (Δ37Cl) of PCE and TCE in the reagents and plastic material were from -1.84±0.7‰ to 15.12±0.85‰. The analytes from different sources could mostly be discerned from each other by chlorine isotope ratios. This study will be conducive to transformation process elucidation and source identification of for PCE and TCE, and facilitate CSIA-Cl using GC-MS for more polychlorinated organic pollutants, particularly in selection and optimization of isotope ratio calculation schemes.

Are chlorine isotopologues of polychlorinated organic pollutants binomially distributed? Theoretical evaluation, numerical simulation, experimental evidences and implications for chlorine isotope analysis and source identification.

Relative abundances of chlorine isotopologues of polychlorinated organic compounds (POCs) are commonly recognized to comply with binomial distribution. This study investigated whether chlorine isotopologue distributions of polychlorinated organic pollutants are binomial and evaluated implications of the distributions to relevant analytical and environmental research by theoretical derivation, numerical simulation and experiment. Chlorine kinetic isotope effects and equilibrium isotope effects vary in stepwise chlorination reactions, leading to inconsistent chlorine isotope ratios on different reaction positions of products, which results in non-binomial chlorine isotopologue distributions of the products. After physical changes and dechlorination, chlorine isotopologues of POCs are unlikely binomially distributed. The experimental results demonstrated that the chlorine isotopologue distributions of perchloroethylene, trichloroethylene, methyl-triclosan, and 2,3,7,8-tetrachlorodibenzofuran in standards and four polychlorinated biphenyls in both standard solutions and sediments were non-binomial. The patterns of chlorine isotope ratios derived from pairs of neighboring chlorine isotopologues of POCs from different sources were different, implying different isotopologue distributions, which might cause biases in compound-specific isotope analysis of chlorine (CSIA-Cl) and source identification. A complete-isotopologue scheme for isotope ratio calculation is recommended to CSIA-Cl for obtaining accurate data. Gas chromatography-double focusing magnetic-sector high resolution mass spectrometry is a promising instrument for CSIA-Cl that uses the complete-isotopologue scheme due to its excellent sensitivity, selectivity and ruggedness. This study yields new insights into chlorine isotopologue distributions of polychlorinated organic pollutants and proposes practicable solutions to improve CSIA-Cl that uses gas chromatography-mass spectrometry and facilitate source identification of polychlorinated organic pollutants.

Human exposure and health risk assessment of an increasingly used antibacterial alternative in personal care products: Chloroxylenol.

The ban of some antibacterial ingredients, such as triclosan (TCS) and triclocarban (TCC), in personal care products (PCPs) in some countries (but not in China) has resulted in the increasing use of antibacterial alternatives, such as chloroxylenol (PCMX). However, the underlying human health risks and environmental impacts of PCMX exposure are largely unknown. Thus, the distribution characteristics of PCMX in PCPs and susceptible populations and the major routes and health risks of human exposure to PCMX were investigated. The PCMX, TCS, and TCC concentrations in PCPs, urine, drinking water, and surface water were determined using high-performance liquid chromatograph system equipped with diode array detector or triple quadrupole mass spectrometer. Results showed that PCMX is widely used in antibacterial hand sanitizers and household disinfectants in China. The addition of PCMX as an antibacterial ingredient in PCPs showed an increasing trend. The geomean concentrations of urinary PCMX in children and pregnant women were 21.6 and 31.9 µg·L-1, respectively, which were much higher than TCS and TCC. A considerable concentration of PCMX ranging from 1.62 to 9.57 µg·L-1 was observed in the aquatic environment, suggesting a potential massive-use of PCMX by humans. Human PCMX exposure via drinking was negligible because the PCMX concentrations in drinking water were less than 2.00 ng·L-1. During human simulation experiment, we found that dermal contact was the dominant route of human PCMX exposure, accounting for 92.1% of the urinary PCMX concentration. The estimated daily intake of PCMX in 9.68% of children and 5.66% of pregnant women was higher than the reference dose. However, the urinary 8-hydroxy-2'-deoxyguanosine concentrations remained stable despite the elevated PCMX concentrations, thereby suggesting that daily PCMX exposure may not cause oxidative DNA damage in humans. Nevertheless, the potential ecotoxicity and health risks induced by chronic PCMX exposure cannot be ignored because of its increasing use.

Lifetime bioaccumulation, gender difference, tissue distribution, and parental transfer of organophosphorus plastic additives in freshwater fish.

Plastic pollution has been a growing global issue. Various plastic additives may enter the environment with plastic debris, which could also become contaminants. Lifetime bioaccumulation, gender difference, tissue distribution, and parental transfer potential of commonly applied organophosphorus plastic additives (OPPAs) were investigated in wildlife fish of the Pearl River system, China. The OPPAs were widely detected in 7 consumable fish species. Tris (2-chloropropyl) phosphate was the predominant compound, with a median concentration of 18.8 ng/g lipid weight. The total OPPA concentrations (ΣOPPAs) were higher in the livers and swimming bladders, suggesting important roles of lipophilicity on the OPPAs accumulation in the fish. Besides, the livers were more abundant in the non-chlorinated OPPAs relative to the other tissues, indicating potentially stronger metabolism of the chlorinated OPPAs in the livers. Redbelly tilapia contained obviously lower ΣOPPAs than the other species. On the other hand, proportions of the chlorinated OPPAs were obviously lower in barbel chub and Guangdong black bream. For an individual species, higher ΣOPPAs were usually detected in the female than in the male fish. Furthermore, the females contained higher proportions of the non-chlorinated OPPAs. These results suggested potentially more accumulation of the OPPAs, particularly the non-chlorinated OPPAs in the female than in the male fish. Body weight dependence of the OPPAs accumulation showed varied patterns depending on species, tissue, and compound. Species-specific characteristics affected by both ecology and organisms' physiology should be considered in combination in assessing bioaccumulation of the OPPAs. The OPPAs were slightly bioaccumulative with LogBAFs of 1.2-3.3. The OPPAs did not show obvious inclination to be partitioned to biota from sediment. Omnipresence of the OPPAs in both egg/ovary and testis of the fish suggested potential transgenerational transfer of these chemicals, which can be a serious ecological issue and warrants further research.

Exposure to volatile organic compounds may be associated with oxidative DNA damage-mediated childhood asthma.

Volatile organic compounds (VOCs) are important and ubiquitous air pollutants, which may lead to a significant increase in the prevalence of respiratory diseases. To investigate the relationships between VOCs exposure and childhood asthma, 252 asthmatic children and 69 healthy children were recruited. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG, a biomarker of oxidative DNA damage), trans-3'-hydroxycotinine (OH-Cot, a biomarker of passive smoking) and 27 VOC metabolites were simultaneously determined by an ultra-high-performance liquid chromatography-tandem mass spectrometer. Results showed that levels of 8-OHdG and most VOC metabolites in asthmatic children were significantly higher than those in healthy children. More than half of the VOC metabolites were significantly and positively associated with OH-Cot with maximal ß coefficient of 0.169, suggesting that second-hand smoking is one important source of VOCs exposure for children in Guangzhou. Significant dose-response relationships between most VOC metabolites and 8-OHdG were observed. Each unit increase in ln-transformed VOC metabolite levels was significantly associated with 5.5-32% increase in ln-transformed 8-OHdG level. Moreover, each unit increase in ln-transformed 8-OHdG level was associated with an 896% increased odd ratios (OR) of asthma in children (OR = 9.96, 95% confidence intervals (CI): 4.75, 20.9), indicating that oxidative stress induced by VOCs exposure may have a significant impact on childhood asthma. Urinary 3-&4-Methylhippuric acid (3-&4-MHA, OR: 5.78, 95% CI: 3.50, 9.54), rac 2-Aminothiazoline-4-carboxylic acid (ATCA, OR: 2.90, 95% CI: 1.69, 4.99) and N-Acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA, OR: 2.76, 95% CI: 1.73, 4.43) which may derive from m/p-xylene, cyanide and 1,3-butadiene exposure, respectively, could significantly and maximally increase the odds of asthma. Interestingly, they also had the strongest associations with 8-OHdG among all investigated VOC metabolites. Moreover, DHBMA strongly correlated with most VOC metabolites. Hence, DHBMA is a suitable biomarker to indicate not only VOCs exposure profile, but also the DNA damage-mediated asthma induced by VOCs.