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Результаты 321-330 из 4,311
Quantification of the sources of long-range transport of PM2.5 pollution in the Ordos region, Inner Mongolia, China Полный текст
2017
Khuzestani, Reza Bashiri | Schauer, James J. | Wei, Yongjie | Zhang, Lulu | Cai, Tianqi | Zhang, Yang | Zhang, Yuanxun
The Ordos region of Inner Mongolia is rapidly developing and suffers from poor air quality and unhealthy levels of fine particulate matter. PM2.5 concentrations in the Ordos region were found to exceed 75 μg/m3 on average, annually, with peak pollution days in excess of 350 μg/m3, but local air pollution emissions from surrounding sources are not sufficient to drive pollution levels to these concentrations. The current study was designed to quantify sources of PM2.5 and assess the local source contributions and effects of regional transport on local pollution. The results show that the Ordos region is primarily impacted by regional long-range transport of pollutants from anthropogenic sources located outside of the Inner Mongolia in Shanxi province areas but is also largely affected by regional dust transported from the deserts located in western Inner Mongolia. The analysis proved that approximately 77% of PM2.5 mass is transported long-range from the sites exterior to the study area and contributes 59.32 μg/m3 on average, annually, while the local sources contribute 17.41 μg/m3 (23%) on annual average to the PM2.5 mass in the study area. High spatial correlation coefficients (R2 > 0.6) were observed for most of the factors pointing to the transport of external emissions into the area. Spatial correlation analysis, bivariate polar plots and hybrid trajectory models for industrial and secondary inorganic factors provide evidence for the impact of long-range transport from Shanxi province areas. In addition, the deserts in western Inner Mongolia were found to be the source regions for dust. Finally, our analysis shows that the source of oil combustion and mobile factors are impacted by local sources in the Ordos region; however, some regional impacts from other regions were also observed for mobile source in the area.
Показать больше [+] Меньше [-]Embryonic exposures to perfluorooctanesulfonic acid (PFOS) disrupt pancreatic organogenesis in the zebrafish, Danio rerio Полный текст
2017
Sant, Karilyn E. | Jacobs, Haydee M. | Borofski, Katrina A. | Moss, Jennifer B. | Timme-Laragy, Alicia R.
Perfluorooctanesulfonic acid (PFOS) is a ubiquitous environmental contaminant, previously utilized as a non-stick application for consumer products and firefighting foam. It can cross the placenta, and has been repeatedly associated with increased risk for diabetes in epidemiological studies. Here, we sought to establish the hazard posed by embryonic PFOS exposures on the developing pancreas in a model vertebrate embryo, and develop criteria for an adverse outcome pathway (AOP) framework to study the developmental origins of metabolic dysfunction. Zebrafish (Danio rerio) embryos were exposed to 16, 32, or 64 μM PFOS beginning at the mid-blastula transition. We assessed embryo health, size, and islet morphology in Tg(insulin-GFP) embryos at 48, 96 and 168 hpf, and pancreas length in Tg(ptf1a-GFP) embryos at 96 and 168 hpf. QPCR was used to measure gene expression of endocrine and exocrine hormones, digestive peptides, and transcription factors to determine whether these could be used as a predictive measure in an AOP. Embryos exposed to PFOS showed anomalous islet morphology and decreased islet size and pancreas length in a U-shaped dose-response curve, which resemble congenital defects associated with increased risk for diabetes in humans. Expression of genes encoding islet hormones and exocrine digestive peptides followed a similar pattern, as did total larval growth. Our results demonstrate that embryonic PFOS exposures can disrupt pancreatic organogenesis in ways that mimic human congenital defects known to predispose individuals to diabetes; however, future study of the association between these defects and metabolic dysfunction are needed to establish an improved AOP framework.
Показать больше [+] Меньше [-]Effects of terrestrial and marine organic matters on deposition of dechlorane plus (DP) in marine sediments from the Southern Yellow Sea, China: Evidence from multiple biomarkers Полный текст
2017
Wang, Guoguang | Peng, Jialin | Hao, Ting | Feng, Lijuan | Liu, Qiaoling | Li, Xianguo
As an emerging halogenated organic contaminant, Dechlorane Plus (DP) was scarcely reported in marine environments, especially in China. In this work, 35 surface sediments and a sediment core were collected across the Southern Yellow Sea (SYS) to comprehensively explore the spatio-temporal distribution and possible migration pathway of DP. DP concentrations ranged from 14.3 to 245.5 pg/g dry weight in the surface sediments, displaying a seaward increasing trend with the high levels in the central mud zone. This spatial distribution pattern was ascribed to that fine particles with the elevated DP levels were preferentially transported to the central mud zone under hydrodynamic forcing and/or via long-range atmospheric transportation and deposition. DP concentrations in sediment core gradually increased from the mid-1950s to present, which corresponded well with the historical production and usage of DP, as well as the economic development in China. Significantly positive correlation between DP and total organic carbon (TOC) in both surface sediments and sediment core indicated TOC-dependent natural deposition of DP in the SYS. We used multiple biomarkers, for the first time, to explore the potential effects of terrestrial and marine organic matters (TOM and MOM) on DP deposition. The results showed that competition may occur between TOM and MOM for DP adsorption, and MOM was the predominant contributor in controlling DP deposition in the marine sediments from the SYS.
Показать больше [+] Меньше [-]Database-driven screening of South African surface water and the targeted detection of pharmaceuticals using liquid chromatography - High resolution mass spectrometry Полный текст
2017
Wood, Timothy Paul | Du Preez, Christiaan | Steenkamp, Adriaan | Duvenage, Cornelia | Rohwer, Egmont R.
Pharmaceuticals and personal care products are released into aquatic environments, largely as a result of ineffectual removal during wastewater treatment. Here we present a screening strategy based on the use of three commercially available mass spectral databases, combined into a single searchable entity and parallelized by cluster computing. In addition to this, a targeted solid phase extraction method with Ultra High Pressure Liquid Chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC-QTOF) was used to quantify 99 pharmaceuticals in South African surface water on a national level. Limits of quantification were in the low ng/L range for the majority of the compounds and it was found that nationally both Lamotrigine and Nevirapine occurred most often. Prednisolone and Ritonavir were present at the highest average concentration; 623 and 489 ng/L respectively. It is however shown that more than 50% of the targets chosen for analysis are not detectable in any of the samples, which highlights the utility of untargeted, database driven screening; prior to the use of costly analytical standards. Untargeted screening detected 45% of the compounds detected in targeted mode, and furthermore tentatively identified a total of 4273 unique compounds across the samples. Automatically triggered MS/MS analyses yielded 92 unique hits with greater than 95% confidence. It is therefore suggested that untargeted screening should precede the targeted approach as a matter of economy and to guide the selection of targets for quantification. There is however great room for improvement in current commercial database search methodologies as a large bottleneck exists due to processing time.
Показать больше [+] Меньше [-]A pilot study on the association between rare earth elements in maternal hair and the risk of neural tube defects in North China Полный текст
2017
Huo, Wenhua | Zhu, Yibing | Li, Zhenjiang | Pang, Yiming | Wang, Bin | Li, Zhiwen
Rare earth elements (REEs) have many applications in industry, agriculture, and medicine, resulting in occupational and environmental exposure and concerns regarding REE-associated health effects. However, few epidemiological studies have examined the adverse effects of REEs on pregnancy outcomes. Therefore, this study examined the relationship between the REE concentrations in maternal hair growing during early pregnancy and the risk of neural tube defects (NTDs) in offspring. We included 191 women with NTD-affected pregnancies (cases) and 261 women delivering healthy infants (controls). The cases were divided into three subtypes: anencephaly, spina bifida, and encephalocele. Four REEs in maternal hair were analyzed by inductively coupled plasma-mass spectrometry: lanthanum (La), cerium (Ce), praseodymium (Pr), and neodymium (Nd). A questionnaire was used to collect information about maternal sociodemographic characteristics and dietary habits. The median concentrations of Ce and Pr in the NTD group were higher than those in the control group, whereas there were no significant differences for La and Nd. The adjusted odds ratios (ORs) for the four REE concentrations above the median in the case groups were not significantly > 1. An increasing frequency of the consumption of beans or bean products and fresh fruit was negatively correlated with the four REE concentrations. Our results did not suggest that the concentrations of REEs in maternal hair were associated with the risk of NTDs or any subtype of NTDs in the general population.
Показать больше [+] Меньше [-]Comparative adsorption of Pb2+ and Cd2+ by cow manure and its vermicompost Полный текст
2017
Zhu, Weiqin | Du, Wenhui | Shen, Xuyang | Zhang, Hangjun | Ding, Ying
Organic waste has great potential for use as an amendment to immobilize heavy metals in the environment. Therefore, this study investigates various properties of cow manure (CM) and its derived vermicompost (CV), including the pH, cationic exchangeable capacity (CEC), elemental composition and surface structure, to determine the potential of these waste products to remove Pb2+ and Cd2+ from solution. The results demonstrate that CV has a much higher pH, CEC and more irregular pores than CM and is enriched with minerals and ash content but has a lower C, H, O and N content. Adsorption isotherms studies shows that the adsorption of Pb2+ and Cd2+ onto either CM or CV follows a Langmuir model and presents maximum Pb2+ and Cd2+ adsorption capacities of 102.77 mg g−1 and 38.11 mg g−1 onto CM and 170.65 and 43.01 mg g−1 onto CV, respectively. Kinetic studies show that the adsorption of Pb2+ onto CM and CV fits an Elovich model, whereas the adsorption of Cd2+ onto CM and CV fits a pseudo-second-order model. Desorption studies indicate that CV is more effective than CM in removing Pb2+ and Cd2+. FTIR analysis demonstrates that the adsorption of Pb2+ and Cd2+ onto CM mainly depends on existed aliphatic alcohol, aromatic acid as well as new produced carbonates, whereas that onto CV may be contributed by the existed aliphatic alcohol, aromatic acids as well as some carbonates and phosphates. Thus, vermicomposting disposal of cow manure with destination mineral addition may broaden the way of its recycle and environmental usage.
Показать больше [+] Меньше [-]Source apportionment of urban air pollutants using constrained receptor models with a priori profile information Полный текст
2017
Liao, Ho-Tang | Yau, Yu-Chen | Huang, Chun-Sheng | Chen, Nathan | Chow, Judith C. | Watson, John G. | Tsai, Shih-Wei | Chou, Charles C.-K. | Wu, Chang-Fu
Exposure to air pollutants such as volatile organic compounds (VOCs) and fine particulate matter (PM2.5) are associated with adverse health effects. This study applied multiple time resolution data of hourly VOCs and 24-h PM2.5 to a constrained Positive Matrix Factorization (PMF) model for source apportionment in Taipei, Taiwan. Ninety-two daily PM2.5 samples and 2208 hourly VOC measurements were collected during four seasons in 2014 and 2015. With some a priori information, we used different procedures to constrain retrieved factors toward realistic sources. A total of nine source factors were identified as: natural gas/liquefied petroleum gas (LPG) leakage, solvent use/industrial process, contaminated marine aerosol, secondary aerosol/long-range transport, oil combustion, traffic related, evaporative gasoline emission, gasoline exhaust, and soil dust. Results showed that solvent use/industrial process was the largest contributor (19%) to VOCs while the largest contributor to PM2.5 mass was secondary aerosol/long-range transport (57%). A robust regression analysis showed that secondary aerosol was mostly contributed by regional transport related factor (25%).
Показать больше [+] Меньше [-]In vitro effect of 4-nonylphenol on human chorionic gonadotropin (hCG) stimulated hormone secretion, cell viability and reactive oxygen species generation in mice Leydig cells Полный текст
2017
Jambor, Tomáš | Tvrdá, Eva | Tušimová, Eva | Kováčik, Anton | Bistáková, Jana | Forgács, Zsolt | Lukáč, Norbert
Nonylphenol is considered an endocrine disruptor and has been reported to affect male reproductive functions. In our in vitro study, we evaluated the effects of 4-nonylphenol (4-NP) on cholesterol levels, hormone formation and viability in cultured Leydig cells from adult ICR male mice. We also determined the potential impact of 4-NP on generation of reactive oxygen species (ROS) after 44 h of cultivation. The cells were cultured with addition of 0.04; 0.2; 1.0; 2.5 and 5.0 μg/mL of 4-NP in the present of 1 IU/mL human chorionic gonadotropin (hCG) and compared to the control. The quantity of cholesterol was determined from culture medium using photometry. Determination of hormone production was performed by enzyme-linked immunosorbent assay. Metabolic activity assay was used for quantification of cell viability. The chemiluminescence technique, which uses a luminometer to measure reactive oxygen species, was employed. Applied doses of 4-NP (0.04–5.0 μg/mL) slight increase cholesterol levels and decrease production of dehydroepiandrosterone after 44 h of cultivation, but not significantly. Incubation of 4-NP treated cells with hCG significantly (P < 0.001) inhibited androstenedione, but not testosterone, formation at the highest concentration (5.0 μg/mL). The viability was significantly (P < 0.05); (P < 0.001) increased at 1.0; 2.5 and 5.0 μg/mL of 4-NP after 44 h treatment. Furthermore, 44 h treatment of 4-NP (0.04–5.0 μg/mL) caused significant (P < 0.001) intracellular accumulation of ROS in exposed cells. Taken together, the results of our in vitro study reported herein is consistent with the conclusion that 4-nonylphenol is able to influence hormonal profile, cell viability and generate ROS.
Показать больше [+] Меньше [-]Mild acid and alkali treated clay minerals enhance bioremediation of polycyclic aromatic hydrocarbons in long-term contaminated soil: A 14C-tracer study Полный текст
2017
Biswas, Bhabananda | Sarkar, Binoy | Rusmin, Ruhaida | Naidu, R.
Bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils requires a higher microbial viability and an increased PAH bioavailability. The clay/modified clay-modulated bacterial degradation could deliver a more efficient removal of PAHs in soils depending on the bioavailability of the compounds. In this study, we modified clay minerals (smectite and palygorskite) with mild acid (HCl) and alkali (NaOH) treatments (0.5–3 M), which increased the surface area and pore volume of the products, and removed the impurities without collapsing the crystalline structure of clay minerals. In soil incubation studies, supplements with the clay products increased bacterial growth in the order: 0.5 M HCl ≥ unmodified ≥0.5 M NaOH ≥3 M NaOH ≥3 M HCl for smectite, and 0.5 M HCl ≥3 M NaOH ≥0.5 M NaOH ≥3 M HCl ≥ unmodified for palygorskite. A14C-tracing study showed that the mild acid/alkali-treated clay products increased the PAH biodegradation (5–8%) in the order of 0.5 M HCl ≥ unmodified > 3 M NaOH ≥ 0.5 M NaOH for smectite, and 0.5 M HCl > 0.5 M NaOH ≥ unmodified ≥ 3 M NaOH for palygorskite. The biodegradation was correlated (r = 0.81) with the bioavailable fraction of PAHs and microbial growth as affected particularly by the 0.5 M HCl and 0.5 M NaOH-treated clay minerals. These results could be pivotal in developing a clay-modulated bioremediation technology for cleaning up PAH-contaminated soils and sediments in the field.
Показать больше [+] Меньше [-]Reducement of cadmium adsorption on clay minerals by the presence of dissolved organic matter from animal manure Полный текст
2017
Zhou, Wenjun | Ren, Lingwei | Zhu, Lizhong
Clay minerals are the most popular adsorbents/amendments for immobilizing heavy metals in contaminated soils, but the dissolved organic matter (DOM) in soil environment would potentially affect the adsorption/immobilization capacity of clay minerals for heavy metals. In this study, the effects of DOM derived from chicken manure (CM) on the adsorption of cadmium (Cd2+) on two clay minerals, bentonite and zeolite, were investigated. The equilibrium data for Cd2+ sorption in the absence or presence of CM-DOM could be well-fitted to the Langmuir equation (R2 > 0.97). The presence of CM-DOM in the aqueous solution was found to greatly reduce the adsorption capacity of both minerals for Cd2+, in particular zeolite, and the percentage decreases for Cd2+ sorption increased with increasing concentrations of Cd2+ as well as CM-DOM in aqueous solutions. The adsorption of CM-DOM on zeolite was greater than that on bentonite in the absence of Cd2+, however, a sharp increase was observed for CM-DOM sorption on bentonite with increasing Cd2+ concentrations but little change for that on zeolite, which can be attributed to the different ternary structures on mineral surface. The CM-DOM modified clay minerals were utilized to investigate the effect of mineral-adsorbed CM-DOM on Cd2+ sorption. The adsorbed form was found to inhibit Cd2+ sorption, and further calculation suggested it primarily responsible for the overall decrease in Cd2+ sorption on clay minerals in the presence of CM-DOM in aqueous solutions. An investigation for the mineral surface morphology suggested that the mineral-adsorbed CM-DOM decreased Cd2+ sorption on bentonite mainly through barrier effect, while in the case of zeolite, it was the combination of active sites occupation and barrier effect. These results can serve as a guide for evaluating the performance of clay minerals in immobilizing heavy metals when animal manure is present in contaminated soils.
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