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1.
Environ Monit Assess ; 193(2): 94, 2021 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-33507416

RESUMEN

Nowadays, workers in petrochemical industry might be exposed to organic volatile compounds, including benzene, toluene, ethylbenzene, and xylene (BTEX). The aim of this study was to investigate the concentration of BTEX contaminations and the biological index in employees of petrochemical sites in the west of Iran. The study was conducted as a cross-sectional study on 30 stations and 60 inhalation and biological samples collected in winter and summer. The NIOSH 2549 and 1501 methods were used for sampling and analyzing the inhaled samples. Gas chromatography-mass spectrometry (GC-MS) equipped with flame ionization detector and high-performance liquid chromatography (HPLC) was used to measure the volatile contaminations. The results showed that the mean concentrations of benzene, toluene, and xylene were significantly different in summer and winter. Significant and strong correlations were observed between the concentrations of benzene, toluene, and xylene and the biological values (r > 0.7). Moreover, the concentration of benzene (ß = 0.836), toluene (ß = 0.718), and xylene (ß = 0.786) predicted the changes in their biological values. Given the hazardous concentrations of benzene and toluene in industrial plants and the correlation of the concentration levels and biological values, management and control strategies should be implemented to eliminate and reduce the pollutants and the effects.


Asunto(s)
Compuestos Orgánicos Volátiles , Xilenos , Benceno/análisis , Derivados del Benceno/análisis , Estudios Transversales , Monitoreo del Ambiente , Humanos , Irán , Tolueno/análisis , Xilenos/análisis
2.
Food Chem ; 338: 127988, 2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-32950866

RESUMEN

The potential for tristyrylphenol ethoxylates (TSPEOs) residues to contaminate crops or be released into the environment is of increasing concern, as they are toxic to living organisms. This study determined the dissipation of TSPEO homologues in cucumber under field conditions. TSPEOn (n = 6-29) dissipated more rapidly in cucumber than in soil samples, with half-lives of 1.80-4.30 d and 3.73-6.52 d, respectively. Short-chain TSPEOn (n = 6-11) persisted for longer than other oligomers in soil. Concentrations of the final residues (∑TSPEOs) in cucumber and soil were 24.3-1349 µg/kg and 47.3-1337 µg/kg, respectively. TSP15EO or TSP16EO was the dominant oligomer, with concentrations of 2.30-150 µg/kg. The risk assessment showed that the acute and chronic dietary exposure risks of ∑TSPEOs in cucumber were 0.03-0.57% and 0.05-0.39%, respectively, suggesting little or no health risk to Chinese consumers.


Asunto(s)
Derivados del Benceno/análisis , Derivados del Benceno/química , Cucumis sativus/química , Dieta , Suelo/química , Estirenos/análisis , Estirenos/química , Residuos de Plaguicidas/análisis , Residuos de Plaguicidas/química , Medición de Riesgo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/química
3.
Environ Pollut ; 267: 115464, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32866878

RESUMEN

Benzene, toluene, ethylbenzene, and xylene isomers (BTEX) are known to affect environmental air and health quality. In this study, the levels of BTEX compounds were determined in indoor air environments during the winter generated by several different heaters: diesel pot-bellied heater with chimney (DH); electric heater (EH); unfluted gas heater (GH); kerosene heater (KH); and wood pot-bellied heater with chimney (WH). The samples were collected using a diffusion passive adsorbent (activated charcoal) and then analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the heaters differ in the quantity of BTEX released during operation. The KH was the most polluted heater based on BTEX measurement, followed by DH. The ∑BTEX for heaters were observed as follows: KH (290 µg m-3); DH (120 µg m-3); GH (84 µg m-3); WH (31 µg m-3); EH (16 µg m-3). Toluene was the predominant compound in all air samples. In KH and DH, the toluene to benzene ratios (T/B) were higher than 4 due to fuel evaporation, while GH had a T/B ratio of 3.9, indicating that the combustion of liquefied petroleum gas (LPG) was the main source. Moreover, a risk assessment was performed to evaluate where the cancer risks (CR) for benzene and ethylbenzene exceeded the critical values (10-6). KH was found to be the most harmful heater for residents, followed by DH and GH. For non-carcinogenic compounds, hazard quotients (HQ) were found to be less than one and thus unlikely to cause health problems.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Benceno/análisis , Derivados del Benceno/análisis , Monitoreo del Ambiente , Jordania , Medición de Riesgo , Estaciones del Año , Tolueno/análisis , Xilenos/análisis
4.
Ecotoxicol Environ Saf ; 203: 111026, 2020 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-32888594

RESUMEN

The detection of phenolic compounds, i.e. resorcinol (RC) catechol (CC) and hydroquinone (HQ) are important due to their extremely hazardous impact and poor environmental degradation. In this work, a novel and sensitive composite of electrochemically reduced graphene oxide-poly(Procion Red MX-5B)/gold nanoparticles modified glassy carbon electrode (GCE/ERGO-poly(PR)/AuNPs) was assembled for voltammetric detection of benzenediol isomers (RC, CC, and HQ). The nanocomposite displayed high peak currents towards the oxidation of RC, HQ, and CC compared to non-modified GCE. The peak-to-peak separations were 0.44 and 0.10 V for RC-CC and CC-HQ, respectively. The limit of detections were 53, 53, and 79 nM for HQ, CC, and RC with sensitivities of 4.61, 4.38, and 0.56 µA/µM (S/N = 3), respectively. The nanocomposite displayed adequate reproducibility, besides good stability and acceptable recoveries for wastewater and cosmetic samples analyses.


Asunto(s)
Compuestos Azo/química , Derivados del Benceno/análisis , Técnicas Electroquímicas/métodos , Oro/química , Grafito/química , Nanocompuestos/química , Contaminantes Químicos del Agua/análisis , Cosméticos/química , Electrodos , Nanopartículas del Metal/química , Oxidación-Reducción , Reproducibilidad de los Resultados , Aguas Residuales/química
5.
Ecotoxicol Environ Saf ; 203: 111027, 2020 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-32888595

RESUMEN

The available evidence on the indoor air quality of operating rooms (ORs) in the Low- and Middle-income Countries (LMICs) is very scarce. Moreover, there is no study on the comparing the concentration of indoor air pollutants in different ORs. Therefore, this study aimed to measure and compare the benzene, toluene, ethylbenzene and xylene (BTEX) concentrations in the air of different ORs in hospitals of Sabzevar, Iran. Moreover, carcinogenic and non-carcinogenic risk of exposure to these pollutants were assessed using Monte Carlo simulations technique. This cross-sectional study was based on volatile organic compounds (VOCs) passive sampling of eight ORs including General surgery, Curettage, Eye surgery, Neurosurgery, Orthopedic, Laparoscopic, Cesarean and Ear, nose, throat (ENT) in two monthly campaigns from November 2019 to February 2020. One-way ANOVA and Post-hoc analyses were used to compare the concentration of BTEX compounds in different ORs. The overall mean (standard deviation (SD)) of benzene, toluene, ethylbenzene, xylene and total BTEX concentrations were 10.0 (1.8), 7.2 (1.9), 1.8 (0.6), 0.4 (0.2) and 19.4 (4.1) µg/m3. The Curettage OR had the highest (12.93 µg/m3) and ENT OR had the lowest (7.42 µg/m3) benzene concentrations. The highest concentrations of toluene, ethylbenzene and total BTEX were observed in General surgery OR. The cancer risks of exposure to benzene in all ORs were higher than the acceptable range recommended by Unite State Environmental Protection Agency (USEPA, 1 × 106). However, the hazard quotient (HQ) values for all ORs were at safe level (HQ < 1). Overall, our study suggested that the concentrations of BTEX compounds were significantly difference in different ORs and benzene had a carcinogenic risk for personnel and surgical staff in different ORs.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/análisis , Quirófanos/normas , Humo/análisis , Compuestos Orgánicos Volátiles/análisis , Benceno/análisis , Derivados del Benceno/análisis , Carcinógenos/análisis , Estudios Transversales , Monitoreo del Ambiente/métodos , Humanos , Irán , Tolueno/análisis , Xilenos/análisis
6.
Environ Sci Pollut Res Int ; 27(35): 44519-44527, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32770338

RESUMEN

Urinary benzene, toluene, ethylbenzene, and xylenes (BTEX) can be used as a reliable biomarker of exposure to these pollutants. This cross-sectional study aimed to employ biomonitoring to assess BTEX exposure among South Pars Gas Field (SPGF) workers in Assaluyeh, Iran. Forty employees who were working on the site were recruited as the case group. Besides, 31 administrative employees were recruited as the control group. Pre-shift and post-shift spot urine samples were collected from the subjects in the case group, while the subjects in the control group provided mid-morning urine samples. Overall, 111 urine samples, including 80 samples from the case group and 31 samples from the controls, were collected. Gas chromatography-mass spectrometry (GC/MS) was used to determine the urinary levels of BTEX compounds. The median urinary levels of benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene in the post-shift samples of the exposed group were 1.24, 2.28, 0.5, 1.32, and 1.5 µg/l, respectively. Significant differences were observed in urinary BTEX levels among smokers and non-smokers in both studied groups (p < 0.05). Accordingly, the median urinary BTEX concentrations in smokers were 2 to 6.5 times higher than the corresponding values in non-smoker subjects. Smoking status was the only predictor of the urinary BTEX concentration. Our findings revealed that refinery workers are exposed to significant levels of BTEX compounds. Considering the health risks associated with BTEX exposure for refinery workers, implementation of suitable control strategies, such as using appropriate personal protective equipment and improving on-site ventilation systems, are recommended reducing their exposure to BTEX via the inhalation.


Asunto(s)
Contaminantes Atmosféricos , Exposición Profesional , Contaminantes Atmosféricos/análisis , Benceno/análisis , Derivados del Benceno/análisis , Monitoreo Biológico , Estudios Transversales , Monitoreo del Ambiente , Humanos , Irán , Gas Natural , Exposición Profesional/análisis , Tolueno/análisis , Xilenos/análisis
7.
J Environ Sci (China) ; 95: 225-239, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32653184

RESUMEN

Benzene homologues are important chemical precursors to the formation of ground-level ozone and secondary organic aerosol (SOA) in the atmosphere, in addition, some toxic species are harmful to human health. Strict countermeasures have been taken to fight air pollution since 2013, and total amount control of volatile organic compounds is being promoted in China at present. Therefore, it is important to understand the pollution situation and the control status of ambient benzene homologues in China. This paper reviews research progress from published papers on pollution characteristics, atmospheric photochemical reactivity, health risk assessment and source identification of ambient benzene homologues in recent years in China, and also summarizes policies and countermeasures for the control of ambient benzene homologues and the relevant achievements. The total ambient levels of benzene, toluene, ethylbenzene and xylenes (BTEX) shows a declining tendency from 2001 to 2016 in China. The mass concentrations of BTEX are generally higher in southern regions than in northern regions, and they present vertical decreasing variation characteristics with increasing altitude within the height range of about 5500 m. Toluene has the highest ozone formation potential and SOA formation potential both in urban areas and background areas, while benzene poses an obvious carcinogenic risk to the exposed adult populations in urban areas. Source identification of ambient benzene homologues suggested that local governments should adopt differentiated control strategies for ambient benzene homologues. Several recommendations are put forward for future research and policy-making on the control of ambient benzene homologues in China.


Asunto(s)
Contaminantes Atmosféricos/análisis , Benceno , Adulto , Derivados del Benceno/análisis , China , Monitoreo del Ambiente , Humanos , Medición de Riesgo , Tolueno/análisis , Xilenos
8.
Sud Med Ekspert ; 63(4): 39-45, 2020.
Artículo en Ruso | MEDLINE | ID: mdl-32686390

RESUMEN

The aim of the study was to develop a method for the determination of 2-methoxyhydroxybenzene in biological material. TLC, UV spectrophotometry, HPLC and GC-MS were used in the experiments. The use of a mixture of ethyl acetate-acetone (7:3 by volume) for the isolation of 2-methoxyhydroxybenzene from biological material is justified. Optimal isolation conditions are established. Purification of the substance was carried out by extraction and chromatography in sorbent column (KCC-3) 80/120 µm. For preliminary identification, TLC was used on Sorbfil PTSX-AF-A-UV plates. Confirmation of identification was carried out by the UV spectrum in ethanol by HPLC with the retention time in a 250×4.6 mm column «SunFire C18¼ (mobile phase acetonitrile-0.025 M potassium dihydrogen phosphate solution 6: 4). Confirmation identification and quantification was performed by GC-MS using a fixed phase capillary column of 5% phenyl-95% methyl polysiloxane after derivatization of the analyte with N-trimethylsilyl-N-methyl trifluoroacetamide (heating for 30 min at a temperature of 60 °C). Ions 45, 58, 73, 91, 107, 136, 151, 166, 181, 196 m/z are present in the mass spectrum of the derivative. The validation of the methodology for the determination of 2-methoxyhydroxybenzene in biomaterial based on the application of the GC-MS method was carried out. The compliance of the methodology with the criteria of linearity, selectivity, correctness, precision and stability is established. The detection limit and the limit of quantification are 8 and 15 µg per 100 g of biomaterial, respectively.


Asunto(s)
Acetona , Derivados del Benceno , Derivados del Benceno/análisis , Cromatografía Líquida de Alta Presión , Cromatografía de Gases y Espectrometría de Masas
9.
J Oleo Sci ; 69(7): 767-770, 2020 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-32522942

RESUMEN

The volatile components produced by Leptolejeunea elliptica (Lejeuneaceae), which is a liverwort grown on the leaves of tea (Camellia sinensis), were collected and analyzed using headspace solid-phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS). 1-Ethyl-4-methoxybenzene (1), 1-ethyl-4-hydroxybenzene (2), and 1-acetoxy-4-ethylbenzene (3) were identified as the major components together with several other phenolic compounds, including 1,2-dimethoxy-4-ethylbenzene, and 4-ethylguaiacol in addition to sesquiterpene hydrocarbons, such as α-selinene, ß-selinene, ß-elemene, and ß-caryophyllene. GC/Olfactometry showed the presence of linalool, acetic acid, isovaleric acid, trans-methyl cinnamate, and trans-4,5-epoxy-(2E)-decenal, as the volatile components produced by L. elliptica.


Asunto(s)
Hepatophyta/metabolismo , Compuestos Orgánicos Volátiles/análisis , Compuestos Orgánicos Volátiles/aislamiento & purificación , Ácido Acético/análisis , Ácido Acético/aislamiento & purificación , Anisoles/análisis , Anisoles/aislamiento & purificación , Derivados del Benceno/análisis , Derivados del Benceno/aislamiento & purificación , Camellia sinensis , Cromatografía de Gases y Espectrometría de Masas/métodos , Japón , Olfatometría , Fenol/análisis , Fenol/aislamiento & purificación , Fenoles/análisis , Fenoles/aislamiento & purificación , Sesquiterpenos Policíclicos/análisis , Sesquiterpenos Policíclicos/aislamiento & purificación , Sesquiterpenos/análisis , Sesquiterpenos/aislamiento & purificación , Microextracción en Fase Sólida/métodos
10.
Environ Sci Pollut Res Int ; 27(29): 36306-36315, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32556985

RESUMEN

Release of analytes from their native matrix and diffusion into the gas phase is the rate-limiting step for the sampling of volatiles in complex solid samples. This limitation is more serious in the solvent-less and solvent-free microextraction sampling strategies. In this research, a three-stage reinforced sampling strategy including high-pressure/sonication/low-pressure was introduced for fast and efficient release of analytes in soil samples. For this purpose, a novel ultrasound-assisted pressure-regulated solid-phase microextraction (UA-PR-SPME) device was developed. It was coupled with gas chromatography-flame ionization detection (GC-FID) and carried out for the determination of benzene, toluene, ethylbenzene, and xylenes (BTEX, as the model analytes) in complex solid samples. Graphene oxide/3-aminopropyltriethoxysilane (GO-APTES) nanocomposite was synthesized and used as the SPME fiber coating. Under optimal conditions, the limits of detection (LODs) were obtained 0.1-0.4 ng/g. The calibration curves were linear over the range of 2.4-5000 ng/g. Relative standard deviations (RSDs%) were calculated 5.1-7.0% (n = 6). The developed technique was employed for the analysis of BTEX in contaminated soil samples.


Asunto(s)
Contaminantes Ambientales , Benceno/análisis , Derivados del Benceno/análisis , Suelo , Microextracción en Fase Sólida , Tolueno/análisis , Xilenos/análisis
11.
Environ Monit Assess ; 192(5): 321, 2020 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-32358693

RESUMEN

Environmental friendly building materials (BMs) get more attention due to their potential to reduce carbon and air pollutant emissions. However, recycled building materials (RBMs) have no required standard of volatile organic compounds (VOCs) emissions. This study was mainly about the assessment of benzene, toluene, ethylbenzene, and xylene (BTEX), as well as carbonyls emissions from recycled building materials, including gypsum board (GB), calcium silicate board (CSB), fiber cement board (FCB), class I built wall tile (WT), and waterproof gypsum board (WGB). The highest initial and final levels of BTEX were observed on CSB, followed by GB and FCB, and no detectable BTEX were observed on WT and WGB. Benzene was with the highest level among all identified BTEX. Emissions of carbonyls were observed on all materials. The highest initial and final levels of carbonyls were observed on GB, followed by FCB and CSB, while the lowest ones were detected on WT and WGB. The final (96-h) steady-state emissions of BTEX from GB and CSB were 9 and 37 times those from conventional pairs and 27 and 41 times those from low-VOC pairs. Similarly, the final steady-state emissions of carbonyls from GB and CSB were 4.8 and 1.3 times those from conventional pairs and 16 and 2.5 times those from low-VOC pairs. The requirement of evaluation standard for VOC emissions from RBMs is highly recommended to protect consumers. Graphical abstract.


Asunto(s)
Contaminantes Atmosféricos , Materiales de Construcción , Monitoreo del Ambiente , Contaminantes Atmosféricos/análisis , Benceno/análisis , Derivados del Benceno/análisis , Materiales de Construcción/análisis , Reciclaje , Tolueno/análisis , Xilenos/análisis
12.
Bull Environ Contam Toxicol ; 104(6): 786-791, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32333044

RESUMEN

This study aims to determine BTEX concentrations in the Metropolitan Region of Rio de Janeiro (MRRJ, Brazil) and evaluate potential health risks of benzene and ethylbenzene exposure based on the collected data, in 2015, the year before the Rio 2016 Olympic Games. Samples were collected and analyzed following method TO-15 (U.S.EPA). Toluene was the most abundant compound in all samples (mean concentration 16.72 ± 15.70 µg m-3). The average benzene concentration in ambient air (3.44 ± 3.14 µg m-3) was slightly lower than the yearly average "upper assessment threshold", 3.5 µg m-3, established by EU Directive 2008/50/EC. The calculated cancer risk values were > 1 × 10-6 for all samples, clearly indicating a potential cancer risk and the importance of fixed measurements by the monitoring stations to assess ambient air quality in the urban areas of the MRRJ. Calculated ratios for the BTEX species indicate that these compounds are predominantly emitted from vehicular sources with a contribution from industrial sources.


Asunto(s)
Contaminantes Atmosféricos/análisis , Derivados del Benceno/análisis , Benceno/análisis , Monitoreo del Ambiente/métodos , Exposición por Inhalación/análisis , Tolueno/análisis , Xilenos/análisis , Brasil , Ciudades , Humanos , Medición de Riesgo
13.
Food Chem ; 321: 126727, 2020 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-32283503

RESUMEN

Alkenylbenzenes are natural toxins with genotoxic and carcinogenic effects in rodents, which are highly present in condiments frequently consumed. The aim of this study was the development of the first multi-analyte method for the determination of eight alkenylbenzenes (eugenol, methyl eugenol, acetyl eugenol, trans-isoeugenol, safrole, estragole, myristicin and trans-anethole) in different pepper varieties by gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS-Q-Orbitrap) in combination with a simple ultrasound-assisted extraction method (UAE). The method was successfully validated, and it was applied for studying the presence of these analytes in peppers as well as to elucidate the effects of the berries' maturity and the geographical origin on alkenylbenzene contents. The analysis of the pepper samples showed that eugenol (10.5-120 mg/kg), trans-anethole (10.7-42.7 mg/kg) and estragole (2.2-45.7 mg/kg) tended to be the most detected alkenylbenzenes at high levels, whereas trans-isoeugenol (0.69-3.6 mg/kg) and safrole (0.20-3.0 mg/kg) were minor components. Estragole (PubChem CID: 8815); trans-anethole (PubChem CID: 637563); Myristicin (PubChem CID: 4276); Safrole (PubChem CID: 5144); Eugenol (PubChem CID: 3314); Methyl eugenol (PubChem CID: 7127); Acetyl eugenol (PubChem CID: 7136); trans-Isoeugenol (PubChem CID: 853433); Caffeine (PubChem CID: 2519); Dicyclohexylmethanol (PubChem CID: 78197).


Asunto(s)
Derivados del Benceno/análisis , Análisis de los Alimentos/métodos , Cromatografía de Gases y Espectrometría de Masas/métodos , Piper nigrum/química , Anisoles/análisis , Compuestos de Bencilo/análisis , Fraccionamiento Químico/métodos , Dioxolanos/análisis , Eugenol/análogos & derivados , Eugenol/análisis , Piper nigrum/fisiología , Pirogalol/análogos & derivados , Pirogalol/análisis , Safrol/análisis , Ultrasonido
14.
J Chromatogr A ; 1621: 461035, 2020 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-32188564

RESUMEN

The present work described two triacontyl-bonded silica adsorbents containing different polar embedded groups (i.e. amide- and carbamate-type) for high performance liquid chromatography, which were prepared by covalent surface modification of silica gel with respective pre-synthesized polar-embedded triacontyl (C30) silane. The acylimidazole-mediated method was used for the first time for the synthesis of amide-type alkyl silane, while the carbamate-type silane was obtained via an improved solvent-free procedure. A conventional C30 stationary phase was also developed on the same silica substrate in the similar manner, which was used as a reference column for comparison of the unique mechanisms facilitated and/or furnished by the polar groups. The successful immobilization of the designed C30 species was confirmed by infrared spectroscopy and elemental analysis. In further comparison with an amide-embedded octadecyl (C18) two other conventional C18 stationary phases of different surface chemistry, detailed chromatographic characterization of the C30 series stationary phases was performed in terms of surface density, hydrophobicity, aromatic selectivity, shape selectivity and water tolerance using a diversified range of analytes, including homologous alkylbenzenes, isomeric polycyclic aromatic hydrocarbons, carotenes, congeners of polychlorobiphenyls, aromatic amines, phenolic compounds, estrogens and nucleosides. A high resemblance between the chromatographic behaviors of the two polar-modified C30 stationary phases was observed, meanwhile they demonstrated noticeable differences from non-polar C30 stationary phase. The polar-embedded C30 phases showed satisfactory performance towards the solutes of interest in the studied conditions. The beneficial synergy of the polar groups and the triacontyl chains enabled these polar-enhanced C30 stationary phases to address challenging separation tasks with high selectivity.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Dióxido de Silicio/química , Amidas/química , Aminas/análisis , Derivados del Benceno/análisis , Carbamatos/química , Carotenoides/análisis , Estrógenos/análisis , Interacciones Hidrofóbicas e Hidrofílicas , Nucleósidos/análisis , Fenoles/análisis , Bifenilos Policlorados/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Silanos/química , Gel de Sílice/química
15.
Anal Bioanal Chem ; 412(8): 1769-1784, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32043201

RESUMEN

Simultaneous speciation of benzenediol isomers (BDIs), 1,2-benzenediol (catechol, CC), 1,3-benzenediol (resorcinol, RS), and 1,4-benzenediol (hydroquinone, HQ), was investigated by differential pulse voltammetry (DPV) using a graphite paste electrode (GPE) modified with Prussian blue-polyaniline nanocomposite. The modified GPE showed good stability, sensitivity, and selectivity properties for all the three BDIs. Prussian blue-doped nanosized polyaniline (PBNS-PANI) was synthesized first by using mechanochemical reactions between aniline and ferric chloride hexahydrate as the oxidants and then followed by the addition of potassium hexacyanoferrate(II) in a solid-state and template-free technique. The material was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The DPV measurements are performed in phosphate electrolyte solution with pH 4.0 at a potential range of - 0.1 to 1.0 V. The proposed modified electrode displayed a strong, stable, and continuous three well-separated oxidation peaks towards electrooxidation at potentials 0.20, 0.31, and 0.76 V for HQ, CC, and RS, respectively. The calibration curves were linear from 1 to 350.5 µM for both HQ and CC, while for RS, it was from 2 to 350.5 µM. The limit of detection was determined to be 0.18, 0.01, and 0.02 µM for HQ, CC, and RS, respectively. The analytical performance of the PBNS-PANI/GPE has been evaluated for simultaneous determination of HQ, CC, and RS in creek water, commercial hair dye, and skin whitening cream samples with satisfactory recoveries between 90 and 106%. Overall, we demonstrated that the presence of NS-PANI and PB resulted in a large redox-active surface area that enabled a promising analytical platform for simultaneous detection of BDIs. Graphical abstract.


Asunto(s)
Compuestos de Anilina/química , Derivados del Benceno/análisis , Ferrocianuros/química , Nanoestructuras/química , Derivados del Benceno/química , Calibración , Electrodos , Humanos , Concentración de Iones de Hidrógeno , Isomerismo , Cinética , Límite de Detección , Espectroscopía Infrarroja por Transformada de Fourier
16.
Mil Med ; 185(Suppl 1): 390-395, 2020 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-32074307

RESUMEN

BACKGROUND: Military aircrews' health status is critical to their mission readiness, as they perform physically and cognitively demanding tasks in nontraditional work environments. Research Objectives: Our objective is to develop a broad operational risk assessment framework and demonstrate its applicability to health risks to aircrews because of airborne chemical exposure, considering stressors such as heat and exertion. METHODS: Extrapolation of generic exposure standards to military aviation-specific conditions can include computation of risk-relevant internal dosimetry estimates by incorporating changes in breathing patterns and blood flow distribution because of aspects of the in-flight environment. We provide an example of the effects of exertion on peak blood concentrations of 1,2,4-trimethylbenzene computed using a physiologically based pharmacokinetic model. RESULTS: Existing published collections on the effects of flight-related stressors on breathing patterns and blood flow address only a limited number of stressors. Although data exist that can be used to develop operational exposure limits specific to military aircrew activities, efforts to integrate this information in specific chemical assessments have been limited. CONCLUSIONS: Efforts to develop operational exposure limits would benefit from guidance on how to make use of existing assessments and expanded databases of the impact of environmental stressors on adult human physiology.


Asunto(s)
Aeronaves/instrumentación , Sustancias Peligrosas/análisis , Exposición Profesional/análisis , Medicina Aeroespacial/métodos , Medicina Aeroespacial/estadística & datos numéricos , Aeronaves/estadística & datos numéricos , Derivados del Benceno/análisis , Derivados del Benceno/sangre , Sustancias Peligrosas/sangre , Humanos , Exposición Profesional/estadística & datos numéricos , Medición de Riesgo/métodos , Estados Unidos , United States Environmental Protection Agency/organización & administración , United States Environmental Protection Agency/estadística & datos numéricos
17.
Chemosphere ; 246: 125769, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31918090

RESUMEN

Land Use Regression models (LUR) are the most common tools to estimate intra-urban air pollutant exposure in epidemiological studies. However, number of available and published models in developing and middle up income countries is still scarce. Here, we developed seasonal and overall LUR models for the spatial distribution of benzene, toluene, ethylbenzene and xylene (BTEX) based on 20 monitoring stations and 166 potentially predictive variables (PPVs) in Urmia, Iran. Carcinogenic and non-carcinogenic risks of exposure to BTEX and its sensitivity analysis were assessed using a probabilistic approach. The mean and standard deviation (in brackets) of overall benzene, toluene, ethylbenzene and xylene were 12.83 (16.19), 27.03 (32.00), 4.72 (4.15) and 27.35 (29.36) µg/m3, respectively. In all models the R2 value of LUR models of benzene, toluene, ethylbenzene, xylene and total BTEX ranged from 0.66 to 0.85, 0.61, 0.88, 0.72 to 0.94, 0.75 to 0.84 and 0.67 to 0.93. The root mean square error (RMSE) for leave-one-out cross-validations (LOOCV) for benzene, toluene, ethylbenzene and xylene ranged from 7.48 to 10.31, 23.0 to 30.0, 3.40 to 6.90, 16.27 to 24.49, 36.10-50.0 µg/m3, respectively. The estimated lifetime carcinogenic risk (LTCR) indicated that ambient concentration of benzene is at a risk level for Urmia inhabitants (LTCR >10-6). Sensitivity analysis for LTCR model indicated that concentration of benzene (C) was the most effective variable in increasing the carcinogenic risk (correlation coefficient ranged from 0.97 to 0.98 for all models).


Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente , Benceno/análisis , Derivados del Benceno/análisis , Carcinógenos/análisis , Humanos , Irán , Medición de Riesgo , Análisis Espacial , Tolueno/análisis , Xilenos/análisis
18.
J Chromatogr A ; 1617: 460840, 2020 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-31948724

RESUMEN

Sensitive methods are required for in situ monitoring of volatile organic compounds (VOCs). Herein, carbon nanotube (CNT) sponges were investigated as a new type of adsorbent for enriching trace aromatic VOCs. A square pillar configuration (3 mm × 3 mm × 45 mm, 5 mg) of a CNT sponge was enclosed in a glass tube (4 mm i.d.). After accumulating the sample vapor, a direct current pulse (26 V, 0.5-3.0 s) through the CNT sponge allowed narrow desorption bandwidths of 0.48-0.84 s (with a photoionization detector) and 1.2 s (with a flame ionization detector) and high desorption efficiency (>96.5%). Gas chromatographic analysis of a nine-component VOC mixture (100 mL adsorption volume) gave enrichment factors of 88 (benzene) to 323 (toluene and m-xylene) with detection limits in the range of 0.9-2.6 ppb (v/v). These results demonstrate that CNT sponges are a promising preconcentrator material for trace detection of VOCs. The adsorption breakthrough experiments exhibited good correlation with the kinetic adsorption and Langmuir isotherm models. The maximum adsorption capacities of the CNT sponge increased in the order benzene (0.13 mg/g) < toluene (2.45 mg/g) < ethylbenzene (13.90 mg/g) < o-xylene (14.31 mg/g), with R2 values of >0.95. The rollup phenomena observed during multicomponent adsorption were explained by the competitive displacement or adsorption affinities of aromatic VOCs. The feasibility of the CNT sponge preconcentrator in a real environment was tested for interfering species (NO2 and NH3), laboratory air, and a human breath sample and demonstrated similar performance as in the controlled nine-component tests.


Asunto(s)
Nanotubos de Carbono/química , Compuestos Orgánicos Volátiles/análisis , Adsorción , Benceno/análisis , Derivados del Benceno/análisis , Cromatografía de Gases , Cinética , Tolueno/análisis , Xilenos/análisis
19.
Environ Sci Pollut Res Int ; 27(10): 11093-11104, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31955332

RESUMEN

The present study was carried out to observe the variation of volatile organic compounds (VOCs) namely benzene, toluene, ethylbenzene, and xylene isomers (BTEX) at three different sites of Delhi, during 2016-2017. Four hourly sampling was carried out day and night separately. Results showed that BTEX concentration was highest in post-monsoon and lowest in monsoon season. Again, daily variation shows that benzene (47%) and toluene (35%) were more during night than day when it was 44% and 33% respectively. Mean concentration of BTEX was observed in following order: ethylbenzene ~ o-xylene < m,p-xylene < toluene < benzene, while overall seasonal variation was observed as follows: post-monsoon > summer > winter > monsoon. Possible emission sources of BTEX were also established through corresponding ratios of individual compounds. Xylene isomers together accounted highest ozone formation potential. The risk assessments of BTEX were carried out in terms of non-cancer (the hazard quotient, HQ) and cancer (the incremental lifetime cancer risk, ILCR) regarding the inhalation exposure only. It was observed that benzene and xylene isomers possessed higher HQs than ethylbenzene and toluene at all sites throughout the study. Again, benzene was found with higher mean ILCR (3.58 × 10-5) than ethylbenzene (1.47 × 10-5).


Asunto(s)
Contaminantes Atmosféricos/análisis , Ozono/análisis , Benceno/análisis , Derivados del Benceno/análisis , Monitoreo del Ambiente , India , Medición de Riesgo , Tolueno/análisis , Xilenos/análisis
20.
Chemosphere ; 242: 125281, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31896191

RESUMEN

In this study, the potential of pulverized waste tires (PWTs), either on their own or mixed with soil (well graded sand), to act as adsorptive fill materials was evaluated by conducting laboratory tests for accessing their adsorption and geotechnical properties. PWT (0, 5, 10, 15, 25, and 100 wt%) was mixed with soil to evaluate the removal of benzene, toluene, ethylbenzene, and xylene (BTEX) components and two heavy metal ions (Pb2+ and Cu2+). Adsorption batch tests were performed to determine the equilibrium sorption capacity of each mixture. Subsequently, compaction, direct shear, and consolidation tests were performed to establish their geotechnical properties. The results showed that BTEX had the strongest affinity based on the uptake capacity by the soil-PWT mixtures. The adsorption of BTEX increased for greater PWT content, with pure PWT having the highest adsorption capacity toward BTEX removal: uptake capacities for xylene, ethylbenzene, toluene, and benzene were 526, 377, 207 and 127 µg/g sorbent, respectively. Heavy metal removal was increased by increasing the amount of PWT up to 10 wt%, and then decreased beyond this ratio. Compacted soil-PWT mixtures comprising 5-25 wt% PWT have relatively low dry unit weight, low compressibility, adequate shear capacity for many load-bearing field applications, and satisfactory adsorption of organic/inorganic contaminants, such that they could also be used as adsorptive fill materials.


Asunto(s)
Derivados del Benceno/análisis , Metales Pesados/análisis , Contaminantes del Suelo/análisis , Residuos Sólidos/análisis , Adsorción , Benceno/análisis , Modelos Teóricos , Eliminación de Residuos , República de Corea , Suelo/química , Tolueno/análisis , Xilenos/análisis
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