خيارات البحث
النتائج 1 - 10 من 380
Biodegradation of Jet Fuel by Three Gram Negative Bacilli Isolated from Kerosene Contaminated Soil النص الكامل
2018
Adetitun, David | Akinmayowa, Victoria | Atolani, Olubunmi | Olayemi, Albert
Petroleum hydrocarbon contamination is a major global prevalent issue in the petroleum sector. This research focuses on evaluating biodegradation of three Gram-negative bacilli, isolated from cowpea planted soil, contaminated with kerosene. The Gram negative bacilli strains have been characterized and identified, using MicrobactTM ID24E systems for the identification of Enterobacteriaceae and common Miscellaneous Gram-Negative Bacilli (MGNB). The identified organisms include Aeromonas hydrophila, Vibrio parahaemolyticus, and Actinobacillus sp. with the biodegradation indices, monitored for the evaluation of their degrading abilities, being Optical density at 600 nm (OD600nm), pH, and emulsification stability. The chemical profile of single cultures and mixed cultures (consortia) on the jet fuel hydrocarbon has been determined by means of Gas Chromatography Mass Spectrometry (GC-MS), the results of which indicate that all the isolates have undergone above 70% reduction of the hydrocarbon substrates in terms of residual compounds. There has been 48 hydrocarbon compounds in the undegraded jet fuel which, following degradation process, decrease to 5, 13, 7, 10, 6, 9, and 10 compounds for Aeromonas hydrophila, Vibrio parahaemolyticus, Actinobacillus sp., Aeromonas hydrophila and Vibrio parahaemolyticus, Aeromonas hydrophila and Actinobacillus sp., Vibrio parahaemolyticus and Actinobacillus sp., Aeromonas hydrophila, Vibrio parahaemolyticus,and Actinobacillus sp., respectively. The degradation efficiency of the isolates have been relatively high and comparable to the control. Results from this study indicate that all the strains, especially the consortia, are potential candidates for remediating the problem of hydrocarbon contamination in the environment.
اظهر المزيد [+] اقل [-]N-nitrosodimethylamine in drinking water - Using a rapid, solid-phase extraction method.
1995
Jenkins S.W.D. | Koester C.J. | Taguchi V.Y. | Wang D.T. | Palmentier J.F.P. | Hong K.P.
Determination of the residues of organochlorine insecticides and polychlorinated biphenyls in heterogeneous system water-sediment
1997
Buzarov, D. (Univerzitet u Novom Sadu, Novi Sad (Yugoslavia). Prirodno-matematicki fakultet, Institut za hemiju) | Vojinovic-Miloradov, M. | Pavkov, S. | Macvanin, N.
The monitoring the content of organochlorine insecticides and polychlorinated biphenyls in heterogeneous system of water-sediment is of a primary interest for the researching of contamination of the aquatic ecosystem because of high bioconcentration factors of these compounds and their bioaccumulation in flora and fauna of the aquatic basin. The sampling of water and sediment were done in the Boka Kotorska Bay (south Adriatic Montenegro Seaside), and estuary Bojana - Ulcinj, Montenegro (Yugoslavia), in AuTumn of 1995. The residues of organochlorine insecticides and polychlorinated biphenyls were determined by gas chromatography, Varian 3400 with capillary columns OV-101, length 25 m, with ECD. The residues of isomers of HCH (hexachlorocyclohexane), DDT and PCB (polychlorinated biphenyls) were identified in all investigated samples.
اظهر المزيد [+] اقل [-]An intriguing case of detection of PCB [polychrorinated biphenyls] residues
1997
Babic, S. (Beocinska fabrika cementa - BFC, Beocin (Yugoslavia)) | Vojinovic-Miloradov, M. | Sudji, J. | Buzarov, D.
The results of the determination of PCB (polychlorinated biphenyls) residues by gas chromatography, in the samples of underground water of one alluvial well of the river Danube (Serbia, Yugoslavia) have been presented. The residues of PCB (polychlorinated biphenyls) in examined samples (February-March period, 1997) were detected.
اظهر المزيد [+] اقل [-]Application of gas chromatographic retention times to determine physicochemical properties of nitrated, oxygenated, and parent polycyclic aromatic hydrocarbons النص الكامل
2022
Vuong, Quang Tran | Son, Ji-Min | Thang, Phan Quang | Ohura, Takeshi | Choi, Sung-Deuk
Nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) are receiving attention because of their high toxicity compared with parent PAHs. However, the experimental data of their physicochemical properties has been limited. This study proposed the gas chromatographic retention time (GC-RT) technique as an effective alternative one to determine octanol-air partition coefficients (KOA) and sub-cooled liquid vapor pressures (PL) for 11 NPAHs, 10 OPAHs, and 19 parent PAHs. The slopes and intercepts of the linear regressions between temperature versus KOA and PL were provided and can be used to estimate KOA and PL for the 40 targeted compounds at any temperature. The internal energies of phase transfer (ΔUOA) and enthalpies of vaporization (ΔHL) for all targeted compounds were also calculated using the GC-RT technique. High-molecular-weight compounds may release or absorb higher heat energy to transform between different phases. NPAHs and OPAHs had a non-ideal solution behavior with activity in octanol (γₒcₜ) in the range of 19–53 and 18–1,078, respectively, which is larger than the unity threshold. A comparison among four groups of PAH derivatives showed that a functional group (nitro-, oxygen-, chloro-, and bromo-) in PAH derivatives increased γₒcₜ for corresponding parent PAHs by tens (mono-group) to hundreds of times (di-group). This study suggests that the GC-RT method is applicable for indirectly measuring the physicochemical properties of various groups of organic compounds.
اظهر المزيد [+] اقل [-]Tissue distribution of phthalates in celery under different cultivation patterns and associated dietary exposure النص الكامل
2022
Zhao, Fang | Ma, Zhihong | Ping, Hua | He, Zhaoying | Li, Bingru | Gao, Yuan | Li, Cheng
To investigate tissue distribution, spatial difference, temperature variation, and potential health risks of PAEs in vegetables, celery was used as a model plant. Celery samples were collected from open fields and greenhouses from two provinces in China over four seasons. Celery tissues were analyzed for 16 PAE compounds by gas chromatography–tandem mass spectrometry. The total content of PAEs was 89.0–1130.3 μg kg⁻¹ dry weight (dw) in stems and 155.0–2730.8 μg kg⁻¹ dw in leaves. Concentrations of PAEs in celeries showed notable spatial differences (P < 0.05), and the levels in samples from open fields were lower than those in samples from plastic greenhouses. In celeries from greenhouses, higher PAE concentrations were observed for plants grown at high temperatures than in plants grown at low temperatures. Discrepancies in tissue distribution indicated different uptake pathways of PAE contaminants. Risk assessments to humans found that both carcinogenic risks and non-carcinogenic risks of PAEs via celery consumption were at an acceptable level. Further research should consider other exposure pathways of PAEs and pay special attention to reducing PAE contents in vegetables.
اظهر المزيد [+] اقل [-]The association of co-exposure to polycyclic aromatic hydrocarbon and phthalates with blood cell-based inflammatory biomarkers in children: A panel study النص الكامل
2022
Zhao, Lei | Liu, Miao | Liu, Linlin | Guo, Wenting | Yang, Huihua | Chen, Shuang | Yu, Jie | Li, Meng | Fang, Qin | Lai, Xuefeng | Yang, Liangle | Zhang, Xiaomin
The association of co-exposure to polycyclic aromatic hydrocarbons (PAHs) and phthalates (PAEs) with blood cell-based inflammatory biomarkers is largely unknown. We conducted a panel study of 144 children aged 4–12 years, with up to 3 repeated visits across 3 seasons. For each visit, we collected the first-morning urine for 4 consecutive days and fasting blood on the day of physical examination. We developed a gas chromatography/tandem mass spectrometry method to detect the metabolites of 10 PAHs (OH-PAHs) and 10 PAEs (mPAEs) in urine samples. We employed linear mixed-effects models to evaluate the individual associations of each OH-PAH and mPAE with blood cell-based inflammatory biomarkers over different lag times. Bayesian kernel machine regression (BKMR) and quantile g-computation were used to evaluate the overall associations of OH-PAHs and mPAEs mixtures with blood cell-based inflammatory biomarkers. After multiple adjustments, we found positive associations of summed hydroxylphenanthrene (∑OHPHE), summed OH-PAHs, and mono-n-butyl phthalate with inflammatory biomarkers such as neutrophil count, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and the systemic immune-inflammation index (SII) at lag 0 (the day of physical examination). Each 1% increase in ∑OHPHE was related to a 0.18% (95% confidence interval: 0.10%, 0.25%) increase in SII, which was the strongest among the above associations. The results of BKMR and quantile g-computation suggested that co-exposure to PAHs and PAEs mixture was associated with an elevated white blood cell count, neutrophil count, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and SII, to which ∑OHPHE and 1-hydroxypyrene (1-OHPYR) might be the major contributors. In addition, gender and age modified the associations of ∑OHPHE and 1-OHPYR with inflammatory biomarkers, where girls and younger children were more susceptible. In conclusion, co-exposure to PAHs and PAEs was associated with elevated inflammation in children, in which ∑OHPHE and 1-OHPYR might play important roles.
اظهر المزيد [+] اقل [-]Health risk assessment of polychlorinated biphenyls (PCBs) in baby clothes. A preliminary study النص الكامل
2022
Herrero, Marta | González, Neus | Rovira, Joaquim | Marquès, Montse | Domingo, José L. | Abalos, Manuela | Abad, Esteban | Nadal, Martí
Health risk assessment of polychlorinated biphenyls (PCBs) in baby clothes. A preliminary study النص الكامل
2022
Herrero, Marta | González, Neus | Rovira, Joaquim | Marquès, Montse | Domingo, José L. | Abalos, Manuela | Abad, Esteban | Nadal, Martí
Clothes may contain a large range of chemical additives and other toxic substances, which may eventually pose a significant risk to human health. Since they are associated with pigments, polychlorinated biphenyls (PCBs) may be especially relevant. On the other hand, infants are very sensitive to chemical exposure and they may wear some contact and colored textiles for a prolonged time. Consequently, a specific human health risk assessment is required. This preliminary study was aimed at analyzing the concentrations of PCBs in ten bodysuits purchased in on-line stores and local retailers. The concentrations of 12 dioxin-like and 8 non-dioxin-like PCB congeners were determined by gas chromatography coupled to high resolution mass spectrometry, with detection limits ranging between 0.01 and 0.13 pg/g. The dermal absorption to PCBs of children at different ages (6 months, 1 year and 3 years old) was estimated, and the non-cancer and cancer risks were evaluated. Total levels of PCBs ranged from 74.2 to 412 pg/g, with a mean TEQ concentration of 13.4 pg WHO-TEQ/kg. Bodysuits made of organic cotton presented a total mean PCB concentration substantially lower than clothes made of regular cotton (11.0 vs. 15.8 pg WHO-TEQ/kg). The dermal absorption to PCBs for infants was calculated in around 3·10⁻⁵ pg WHO-TEQ/kg·day, regardless the age. This value is > 10,000-fold lower than the dietary intake of PCBs, either through breastfeeding or food consumption. Furthermore, this exposure value would not pose any health risks for the infants wearing those bodysuits. Anyhow, as it is a very preliminary study, this should be confirmed by analyzing larger sets of textile samples. Further investigations should be also focused on the co-occurrence of PCBs and other toxic chemicals (i.e., formaldehyde, bisphenols and aromatic amines) in infant clothes.
اظهر المزيد [+] اقل [-]Health risk assessment of polychlorinated biphenyls (PCBs) in baby clothes. A preliminary study النص الكامل
2022
Herrero, Marta | González, Neus | Rovira, Joaquim | Marquès, Montse | Domingo, José L | Abalos, Manuela | Abad Holgado, Esteban | Nadal, Martí | 0000-0003-4399-6138 | Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
Clothes may contain a large range of chemical additives and other toxic substances, which may eventually pose a significant risk to human health. Since they are associated with pigments, polychlorinated biphenyls (PCBs) may be especially relevant. On the other hand, infants are very sensitive to chemical exposure and they may wear some contact and colored textiles for a prolonged time. Consequently, a specific human health risk assessment is required. This preliminary study was aimed at analyzing the concentrations of PCBs in ten bodysuits purchased in on-line stores and local retailers. The concentrations of 12 dioxin-like and 8 non-dioxin-like PCB congeners were determined by gas chromatography coupled to high resolution mass spectrometry, with detection limits ranging between 0.01 and 0.13 pg/g. The dermal absorption to PCBs of children at different ages (6 months, 1 year and 3 years old) was estimated, and the non-cancer and cancer risks were evaluated. Total levels of PCBs ranged from 74.2 to 412 pg/g, with a mean TEQ concentration of 13.4 pg WHO-TEQ/kg. Bodysuits made of organic cotton presented a total mean PCB concentration substantially lower than clothes made of regular cotton (11.0 vs. 15.8 pg WHO-TEQ/kg). The dermal absorption to PCBs for infants was calculated in around 3·10-5 pg WHO-TEQ/kg·day, regardless the age. This value is > 10,000-fold lower than the dietary intake of PCBs, either through breastfeeding or food consumption. Furthermore, this exposure value would not pose any health risks for the infants wearing those bodysuits. Anyhow, as it is a very preliminary study, this should be confirmed by analyzing larger sets of textile samples. Further investigations should be also focused on the co-occurrence of PCBs and other toxic chemicals (i.e., formaldehyde, bisphenols and aromatic amines) in infant clothes. | This study is part of the EarlyCLOTHES study, which was financially supported by the Spanish Ministry of Science and Innovation through grant PID 2019-104443 GB-I00. Additional support was provided by the Agency for Management of University and Research grants (AGAUR, Generalitat de Catalunya, Spain) through SGR 2017-SGR-245. M. Herrero was recipient of a grant within the Martí Franquès Research Fellowship Programme, while J. Rovira received a postdoctoral fellowship from “Juan de la Cierva-incorporación” program of the Ministry of Science, Innovation and Universities (IJC 2018-035126-I). | Peer reviewed
اظهر المزيد [+] اقل [-]Associations between polybrominated diphenyl ethers (PBDEs) levels in adipose tissues and female menstrual cycle and menstrual bleeding duration in Shantou, China النص الكامل
2022
Shi, Xiaoling | Wang, Xin | Peng, Lin | Chen, Yebin | Liu, Caixia | Yang, Qingtao | Wu, Kusheng
The endocrine-disrupting effects of human exposure to polybrominated diphenyl ethers (PBDEs) have been studied, but their associations with menstrual status were not clearly clarified. This study was to evaluate the associations between PBDE levels in adipose tissues and the menstrual cycle and menstrual bleeding duration alteration. A total of 298 female cases undergoing surgery were recruited from two hospitals in Shantou, China. Demographic, clinical, and pathological information were collected, and adipose tissues were obtained during mammary or abdominal surgery. Gas chromatography with mass spectrometry was used to analyze 14 PBDE congeners in the adipose samples. The associations between PBDE levels and menstrual cycle (MC) and menstrual duration (MD) were analyzed by logistic regression models, estimating odds ratios (ORs) and 95% confidence intervals (CIs). BDE-153 had the highest level in the adipose samples, followed by BDE-209, BDE-183 and BDE-47. Compared with referents, median levels of BDE-47, -71, −153, −183 were higher in women with MC > 30 days (all P < 0.05); BDE-47, -153, −183, −209 were also higher in women with MD > 5.5 days (all P < 0.05). After adjusted for age and parity, BDE-47, -71, −153, −183 were associated with prolonged MC (OR = 1.20, 1.15, 1.12, 1.11, respectively, all P < 0.05) in the logistic regression models; and BDE-47, -153, −183, −209 were associated with the prolonged MD (OR = 1.13, 1.09, 1.10, 1.11, respectively, all P < 0.05). Several individual PBDE congeners in female adipose were found associated with prolonged menstrual cycle and menstrual duration. PBDEs may influence reproductive health of women by altering menstrual status.
اظهر المزيد [+] اقل [-]Occurrence of chlorinated and brominated polycyclic aromatic hydrocarbons from electric arc furnace for steelmaking النص الكامل
2022
Yang, Lili | Shen, Jia | Zheng, Minghui | Yang, Qiuting | Li, Da | Liu, Guorui
Chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are persistent organic pollutants with potential carcinogenic toxicities that are even higher than those of their parent PAH congeners. Current knowledge of Cl/Br-PAH sources and emission characteristics is lacking. Electric arc furnace (EAF) steelmaking is a potential source for Cl/Br-PAHs, considering that preheating of raw materials before they enter the EAF could produce suitable conditions for Cl/Br-PAHs formation. In this field study, we identified EAFs as an important source of Cl/Br-PAHs and clarified their emission concentrations, fingerprints by gas chromatography coupled with high-resolution magnetic mass spectrometry. Potential formation mechanisms of Cl/Br-PAHs were also proposed. The mass concentration ranges for Σ₁₈Cl-PAHs and Σ₁₈Br-PAHs in stack gas were 25.85–4191 ng Nm⁻³ and 1.02–341 ng Nm⁻³, respectively. The variation of concentration indicated that the steel scrap composition greatly affected the production of Cl/Br-PAHs. The congener ratios including 6-chlorobenzo [a]pyrene/3-chlorofluoranthene and 1-chloroanthracene/1-chloropyrene could be used to estimate the influence of industrial sources on Cl-PAH occurrences in the air. Ring structure growth was the dominant formation pathway for Cl/Br-PAHs, distinctly different from dioxin formation mechanisms dominated by precursor dimerization and chlorination.
اظهر المزيد [+] اقل [-]