خيارات البحث
النتائج 1241 - 1250 من 6,473
Linking aerosol characteristics of size distributions, core potential pathogens and toxic metal(loid)s to wastewater treatment process
2020
Yang, Dang | Jiang, Lu | Han, Yunping | Liu, Jianwei | Wang, Xiaodong | Yan, Xu | Liu, Junxin
Wastewater treatment plants (WWTPs) play important roles in water purification but are also important source of aerosols. However, the relationship between aerosol characteristics and wastewater treatment process remains poorly understood. In this study, aerosols were collected over a 24-month period from a WWTP using a modified anaerobic-anoxic-oxic process. The aerated tank (AerT) was characterized by the highest respiratory fraction (RF) concentrations (861–1525 CFU/m³) and proportions (50.76%–65.96%) of aerosol particles. Fourteen core potential pathogens and 15 toxic metal(loid)s were identified in aerosols. Mycobacterium was the genus that aerosolized most easily in fine grid, pre-anoxic tank, and AerT. High wastewater treatment efficiency may increase the emission of RF and core potential pathogens. The median size of activated sludge, richness of core potential pathogens in wastewater, and total suspended particulates were the most influential factors directly related to the RF proportions, core community of potential pathogens, and composition of toxic metal(loid)s in WWTP aerosols, respectively. Relative humidity, temperature, input and removal of biochemical oxygen demand, dissolved oxygen, and mixed liquor suspended solids could also directly or indirectly affect the aerosol characteristics. This study enhances the mechanistic understanding of linking aerosol characteristics to treatment processes and has important implications for targeted manipulation.
اظهر المزيد [+] اقل [-]Combined toxic effects of fludioxonil and triadimefon on embryonic development of zebrafish (Danio rerio)
2020
Wang, Yanhua | Xu, Chao | Wang, Dou | Weng, Hongbiao | Yang, Guiling | Guo, Dongmei | Yu, Ruixian | Wang, Xinquan | Wang, Qiang
Pesticides scarcely exist as individual compounds in the water ecosystem, but rather as mixtures of multiple chemicals at relatively low concentrations. In this study, we aimed to explore the mixture toxic effects of fludioxonil (FLU) and triadimefon (TRI) on zebrafish (Danio rerio) by employing different toxicological endpoints. Results revealed that the 96-h LC₅₀ values of FLU to D. rerio at multiple developmental stages ranged from 0.055 (0.039–0.086) to 0.61 (0.33–0.83) mg L⁻¹, which were less than those of TRI ranging from 3.08 (1.84–5.96) to 9.75 (5.99–14.78) mg L⁻¹. Mixtures of FLU and TRI exerted synergistic effects on embryonic zebrafish. Activities of total superoxide dismutase (T-SOD) and catalase (CAT) were markedly altered in most of the individual and pesticide mixture treatments compared with the control. The expressions of 16 genes involved in oxidative stress, cellular apoptosis, immune system and endocrine system displayed that embryonic zebrafish were affected by the individual pesticides and their mixtures, and greater variations of four genes (ERɑ, Tnf, IL and bax) were found when exposed to pesticide mixtures compared with their individual compounds. Therefore, more studies on mixture toxicities among different pesticides should be taken as a priority when evaluating their ecological risk.
اظهر المزيد [+] اقل [-]Maternal preconception phthalate metabolite concentrations in follicular fluid and neonatal birth weight conceived by women undergoing in vitro fertilization
2020
Wu, Lin-Jing | Teng, Xue-Mei | Yao, Yang-Cheng | Liu, Chong | Du, Yao-Yao | Deng, Tao-Ran | Yuan, Xiao-Qiong | Zeng, Qiang | Li, Yu-Feng | Guo, Na
Exposure to phthalates during gestation has been associated with decreased birth weight among offspring. However, the associations between preconception phthalate metabolites in follicular fluid (FF) and offspring birth weight among women undergoing in vitro fertilization (IVF) remain largely unknown. Here, we explored the associations between preconception phthalate metabolite concentrations in FF and the birth weights of singletons and twins among women undergoing IVF. We recruited 147 female participants who gave birth to 90 singletons and 57 twin infants at the Reproductive Medicine Center, Tongji Hospital, Wuhan, between November and December 2016. Each participant was asked to complete a questionnaire at the time of recruitment and provide a FF sample on the day of oocyte retrieval. The FF concentrations of eight phthalate metabolites were determined using high-performance liquid chromatography and tandem mass spectrometry. Birth outcomes were abstracted from medical records. The associations between phthalate metabolites in FF and birth weights of the singleton and twin groups were evaluated using generalized linear models (GLMs). We found that birth weight in the twin group had negative dose-response associations with maternal preconception monobenzyl phthalate (MBzP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) in FF (both P for trends < 0.05) and that birth weight in the singleton group had positive dose-response associations with monoethyl phthalate (MEP) and mono(2-ethyl-5 hydroxyhexyl) phthalate (MEHHP) in FF (both P for trends < 0.05). These associations persisted when we modeled as continuous variables. In addition, we observed male-specific association between decreased twin birth weight and MEOHP and MBzP and a female-specific associations between increased singleton birth weight and MEP, MEHHP and the sum of di(2-ethylhexyl) phthalate (∑DEHP) (all P for interactions < 0.05). Preconception phthalate metabolites in maternal FF may affect the birth weights of both singleton and twin newborns.
اظهر المزيد [+] اقل [-]Industrial development as a key factor explaining variances in soil and grass phyllosphere microbiomes in urban green spaces
2020
Yan, Zhen-Zhen | Chen, Qing-Lin | Zhang, Yu-Jing | He, Ji-Zheng | Hu, Hang-Wei
Microbiota in urban green spaces underpin ecosystem services that are essential to environmental health and human wellbeing. However, the factors shaping the microbial communities in urban green spaces, especially those associated with turf grass phyllosphere, remain poorly understood. The lack of this knowledge greatly limits our ability to assess ecological, social and recreational benefits of urban green spaces in the context of global urbanization. In this study, we used amplicon sequencing to characterize soil and grass phyllosphere bacterial communities in 40 urban green spaces and three minimally disturbed national parks in Victoria, Australia. The results indicated that urbanization might have shown different impacts on soil and grass phyllosphere microbial communities. The bacterial diversity in soil but not in grass phyllosphere was significantly higher in urban green spaces than in national parks. Principal coordinate analysis revealed significant differences in the overall patterns of bacterial community composition between urban green spaces and national parks for both soil and grass phyllosphere. Industrial development, as represented by the number of industries in the region, was identified as a key driver shaping the bacterial community profiles in urban green spaces. Variation partitioning analysis suggested that industrial factors together with their interaction with other factors explained 20% and 28% of the variances in soil and grass phyllosphere bacterial communities, respectively. The findings highlight the importance of industrial development in driving the spatial patterns of urban microbiomes, and have important implication for the management of microbiomes in urban green spaces.
اظهر المزيد [+] اقل [-]Di-(2-ethylhexyl) phthalate induced nephrotoxicity in quail (Coturnix japonica) by triggering nuclear xenobiotic receptors and modulating the cytochrome P450 system
2020
Wang, Hui | Guan, Tian-Qi | Sun, Jin-Xu | Talukder, Milton | Huang, Yue-Qiang | Li, Yan-Hua | Li, Jin-Long
Di-(2-ethylhexyl) phthalate (DEHP), a plasticizer that is mainly used in the production of polyvinyl alcohol-containing chloride products, has attracted attention due to potential threats to human health and the environment. Nevertheless, knowledge of DEHP-induced nephrotoxicity is still limited. To explore the mechanism of DEHP-induced nephrotoxicity, quail were treated with 0, 250, 500 and 1000 mg/kg DEHP by oral gavage for 45 days. Based on the results of histopathological analysis, DEHP exposure induced a disorganized renal structure, a partially dilated glomerulus and an atrophied Bowman’s space. Renal tubular epithelial cells were unclear, and swelling of columnar epithelial cells was observed, suggesting that DEHP exposure caused renal disease and renal injury. Notably, DEHP interfered with the homeostasis of cytochrome P450 systems (CYP450s) by increasing the activities or contents of CYP450s (total CYP450, Cyt b5, ERND, APND, AH and NCR). The expression levels of certain CYP450 isoforms (CYP1A, CYP1B, CYP2C, CYP2D, CYP2J and CYP3A) were significantly downregulated in the kidney in DEHP-treated quail. Furthermore, DEHP induced the expression of nuclear receptors (AHR, CAR and PXR) in a dose-dependent manner. The results of this study suggested that DEHP-induced nephrotoxicity in quail was associated with the induction of nuclear xenobiotic receptor (NXR) responses and interference with CYP450 homeostasis. In conclusion, all data indicated that DEHP induced nephrotoxicity by triggering NXRs and modulating the cytochrome P450 system. The results of this study provide a new basis for understanding the nephrotoxicity of DEHP.
اظهر المزيد [+] اقل [-]REMOVED: Perfluoroalkyl, fluorotelomer sulfonate, and perfluorooctane sulfonamide contamination in biosolids: Composition, co-contamination and re-use implications
2020
Sleep, Julie A. | Juhasz, Albert L.
This article has been removed: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).This article has been removed at the request of the Authors.This article has been retracted because the authors did not seek or receive appropriate approvals to use these materials for the purposes of this publication. The authors apologise for any inconvenience caused.
اظهر المزيد [+] اقل [-]Humpback whales (Megaptera novaeangliae) breeding off Mozambique and Ecuador show geographic variation of persistent organic pollutants and isotopic niches
2020
Remili, Anaïs | Gallego, Pierre | Pinzone, Marianna | Castro, Cristina | Jauniaux, Thierry | Garigliany, Mutien-Marie | Malarvannan, Govindan | Covaci, Adrian | Dāsa, Kr̥shṇā
Humpback whales (Megaptera novaeangliae) from the Southern Hemisphere carry information on persistent organic pollutants (POPs) from their feeding zones in Antarctica to their breeding grounds, making this species a sentinel of contaminants accumulation in the Southern Ocean. This study aimed to evaluate driving factors, namely feeding areas, trophic level, and sex, affecting POP concentrations in the blubber of humpback whales breeding off Mozambique and off Ecuador. Biopsies of free-ranging humpback whales including blubber and skin were collected in 2014 and 2015 from Ecuador (n = 59) and in 2017 from Mozambique (n = 89). In both populations, HCB was the major contaminant followed by DDTs > CHLs > PCBs > HCHs > PBDEs. POP concentrations were significantly higher in males compared to females. HCB, DDTs, HCHs and PBDEs were significantly different between whales from the Mozambique population and the Ecuador population. Sex and feeding habits were important driving factors accounting for POP concentrations in Ecuador whales. The whales from our study had some of the lowest POP concentrations measured for humpback whales in the world. These whales fed predominantly on krill as reflected from the low δ¹³C and δ¹⁵N values measured in the skin. However, the isotopic niches of whales from Mozambique and Ecuador did not overlap indicating that the two populations are feeding in different areas of the Southern Ocean.
اظهر المزيد [+] اقل [-]The mechanism of root growth inhibition by the endocrine disruptor bisphenol A (BPA)
2020
Bahmani, Ramin | Kim, DongGwan | Modareszadeh, Mahsa | Thompson, Drew | Park, Jeong Hoon | Yoo, Hye Hyun | Hwang, Seongbin
Bisphenol A (BPA) is a harmful environmental contaminant acting as an endocrine disruptor in animals, but it also affects growth and development in plants. Here, we have elucidated the functional mechanism of root growth inhibition by BPA in Arabidopsis thaliana using mutants, reporter lines and a pharmacological approach. In response to 10 ppm BPA, fresh weight and main root length were reduced, while auxin levels increased. BPA inhibited root growth by reducing root cell length in the elongation zone by suppressing expansin expression and by decreasing the length of the meristem zone by repressing cell division. The inhibition of cell elongation and cell division was attributed to the enhanced accumulation/redistribution of auxin in the elongation zone and meristem zone in response to BPA. Correspondingly, the expressions of most auxin biosynthesis and transporter genes were enhanced in roots by BPA. Taken together, it is assumed that the endocrine disruptor BPA inhibits primary root growth by inhibiting cell elongation and division through auxin accumulation/redistribution in Arabidopsis. This study will contribute to understanding how BPA affects growth and development in plants.
اظهر المزيد [+] اقل [-]PM2.5 exposure of various microenvironments in a community: Characteristics and applications
2020
Hsu, Wei-Ting | Chen, Jyh-Larng | Candice Lung, Shih-Chun | Chen, Yu-Cheng
While the measurement of particulate matter (PM) with a diameter of less than 2.5 μm (PM₂.₅) has been conducted for personal exposure assessment, it remains unclear how models that integrate microenvironmental levels with resolved activity and location information predict personal exposure to PM. We comprehensively investigated PM₂.₅ concentrations in various microenvironments and estimated personal exposure stratified by the microenvironment. A variety of microenvironments (>200 places and locations, divided into 23 components according to indoor, outdoor, and transit modes) in a community were selected to characterize PM₂.₅ concentrations. Infiltration factors calculated from microenvironmental/central-site station (M/S) monitoring campaigns with time-activity patterns were used to estimate time-weighted exposure to PM₂.₅ for university students. We evaluated exposures using a four-stage modeling approach and quantified the performance of each component. It was found that the SidePak monitor overestimated the concentration by 3.5 times as compared with the filter-based measurements. Higher mean concentrations of PM₂.₅ were observed in the Taoist temple and night market microenvironments; in contrast, lower concentrations were observed in air-conditioned offices and car microenvironments. While the exposure model incorporating detailed time-location information and infiltration factors achieved the highest prediction (R² = 0.49) of personal exposure to PM₂.₅, the use of indoor, outdoor, and transit components for modeling also generated a consistent result (R² = 0.44).
اظهر المزيد [+] اقل [-]Spatial distribution and seasonal variations of atmospheric organophosphate esters (OPEs) in Tianjin, China based on gridded field observations
2020
Liang, Yuanyuan | Wang, Huan | Yang, Qiaoyun | Cao, Shengyu | Yan, Caiqing | Zhang, Liwen | Tang, Naijun
The atmospheric concentrations of 14 organophosphate esters (OPEs) were monitored by passive air sampling at 33 sites to determine their spatial distributions, and seasonal variations (summer and winter) in Tianjin, North China. The total concentrations of the OPEs (∑₉OPEs) in the summer ranged from 0.08 to 1113 ng/sample with a median of 98.4 ng/sample, which was non-statistically different from the concentrations obtained in the winter (which ranged from 1.93 to 548 ng/sample with a median of 46.2 ng/sample). Among the observed OPEs, the concentrations of TnBP and TCiPP were statistically higher in the summer compared with the winter (p < 0.05). For grouped OPEs, only a significantly higher level of chlorinated OPEs was found in summer than that in winter. In the winter, spatial differences were found to be significantly different between the concentrations of TnBP, TiBP, TCEP, and TEHP in the suburban and rural areas (p < 0.05). Considering the possible point-sources, in the summer, the concentrations of TDCPP, TCiPP, DPEHP, TEHP, and the total concentration of TCPs (denoted as ∑₃TCP, comprised of the concentrations of TCP, TmCP, and ToCP) in an electronic-waste (e-waste) dismantling area were higher than those obtained at the other sampling sites. ∑₉OPEs at the e-waste site and another site located near a manufacturing plant of organophosphate flame retardants (OFRs) were both higher than the median concentrations obtained at the other sampling sites, and TCiPP was the most abundant pollutant. In the winter, the concentrations of ∑₉OPEs at the e-waste site were still higher than their median concentrations at the other sites. Because OPEs are used in aircraft lubricating oils and hydraulic fluids, an airport was thought to be another important source of TiBP and TPhP in the present study. Therefore, the e-waste site, airport, and OFR manufacturing plant may be the major sources of OPEs in the environment.
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