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Evaluation of coarse and fine particles in diverse Indian environments Texte intégral
2017
George, K.V. | Patil, Dinakar D. | Anil, Mulukutla N.V. | Kamal, Neel | Alappat, Babu J. | Kumar, Prashant
The estimates of airborne fine particle (PM₂.₅) concentrations are possible through rigorous empirical correlations based on the monitored PM₁₀ data. However, such correlations change depending on the nature of sources in diverse ambient environments and, therefore, have to be environment specific. Studies presenting such correlations are limited but needed, especially for those areas, where PM₂.₅ is not routinely monitored. Moreover, there are a number of studies focusing on urban environments but very limited for coal mines and coastal areas. The aim of this study is to comprehensively analyze the concentrations of both PM₁₀ and PM₂.₅ and develop empirical correlations between them. Data from 26 different sites spread over three distinct environments, which are a relatively clean coastal area, two coal mining areas, and a highly urbanized area in Delhi were used for the study. Distributions of PM in the 0.43–10-μm size range were measured using eight-stage cascade impactors. Regression analysis was used to estimate the percentage of PM₂.₅ in PM₁₀ across distinct environments for source identification. Relatively low percentage of PM₂.₅ concentrations (21, 28, and 32%) in PM₁₀ were found in clean coastal and two mining areas, respectively. Percentage of PM₂.₅ concentrations in PM₁₀ in the highly urbanized area of Delhi was 51%, indicating a presence of a much higher percentage of fine particles due to vehicular combustion in Delhi. The findings of this work are important in estimating concentrations of much harmful fine particles from coarse particles across distinct environments. The results are also useful in source identification of particulates as differences in the percentage of PM₂.₅ concentrations in PM₁₀ can be attributed to characteristics of sources in the diverse ambient environments.
Afficher plus [+] Moins [-]Genome-wide transcriptional analysis of cardiovascular-related genes and pathways induced by PM2.5 in human myocardial cells Texte intégral
2017
Feng, Lin | Yang, Xiaozhe | Asweto, Collins Otieno | Wu, Jing | Zhang, Yannan | Hu, Hejing | Shi, Yanfeng | Duan, Junchao | Sun, Zhiwei
Air pollution has been a major environment-related health threat. Most of the studies on PM₂.₅ toxicity have verified on the cardiovascular system and endothelial cells. However, researches on PM₂.₅-induced myocardial-related toxicity are limited. This study aims to fully understand the toxic effects of PM₂.₅ on human myocardial cell (AC16) and explore its molecular mechanism based on microarray analysis and bioinformatics analysis. Microarray data analysis manifested that PM₂.₅-induced toxicity affected expression of 472 genes compared with the control group, including 166 upregulated genes and 306 downregulated genes in human myocardial (AC16) cells. GO analysis showed that cellular processes such as immune response, cell maturation, embryonic heart tube morphogenesis, cellular response to electrical stimulus, skeletal muscle tissue regeneration, and negative regulation of signal transduction were upregulated, while regulation of transcription (DNA-dependent), rhythmic process, protein destabilization apoptotic process, and innate immune response were downregulated. The pathway analysis indicates that cell signaling pathways such as cytokine-cytokine receptor interaction, NF-κB signaling pathway, chemokine signaling pathway, endocrine and other factor-regulated calcium reabsorption, HTLV-I infection, and cell adhesion molecules (CAMs) were upregulated, while the TGF-β signaling pathway was downregulated. In addition, Signal-net showed that the TUBA4A, ADRBK2, BRIX1, SMC4, EIF5B, PRMT1, ATG4B, and NDC80 genes were significantly decreased, while the expression of the KRT6B gene was markedly increased compared with the control group. All the genes were verified by qRT-PCR. This study had provided new bioinformatics evidences in PM₂.₅-induced myocardial tissue toxicity which is necessary for further cardiovascular system toxicity studies.
Afficher plus [+] Moins [-]Mitigating biochar phytotoxicity via lanthanum (La) participation in pyrolysis Texte intégral
2017
Li, Yang | Yang, Yanqi | Shen, Fei | Yang, Gang | Zhang, Yanzong | Deng, Shihuai | Zhang, Jing | Zeng, Yongmei | Hu, Yaodong
Biochar (BC) produced from oak sawdust by slow pyrolysis was investigated to check the potential inhibition to early growth of tomato for phytotoxicity assessment. An inverted-U-shaped dose-response relationship between BC dosage and seed germination/seedling growth can be observed. Half maximal effective concentration (EC₅₀), based on the inhibition rate of root and stem length, was 65.7 and 74.0 g kg⁻¹, respectively. At the highest BC dosage of 80.0 g kg⁻¹, germination rate, root, and shoot length were notably inhibited by 34.9, 62.3, and 62.2% compared with their corresponding controls (without BC). Fluorescence intensity, indicating reactive oxygen species (ROS) generation in leaf and root, was 177.7 and 344.5% higher than the control. Similar results on H₂O₂ content in leaf and root were observed as well. Besides, membrane leakage from the leaf and root cells was 2.1- and 1.3-fold higher than the corresponding controls. These results proved that BC exhibited significant phytotoxicity in the early growth stage of tomato. Unlike BC, the inhibitions on seed germination and seedling growth, the ROS accumulation, and the plasma membrane damage were not obvious with increasing La-BC dosage. These results indicated that BC phytotoxicity can be greatly mitigated by La involvement in pyrolysis, which was potentially associated with the reduced organic compounds and free radicals in La-BC. Besides, bio-available La in La-BC was partially involved in mitigating the phytotoxicity.
Afficher plus [+] Moins [-]Traffic represents the main source of pollution in small Mediterranean urban areas as seen by lichen functional groups Texte intégral
2017
Llop, Esteve | Pinho, Pedro | Ribeiro, Manuel C | Pereira, Maria João | Branquinho, Cristina
The land-use type (residential, green areas, and traffic) within relatively small Mediterranean urban areas determines significant changes on lichen diversity, considering species richness and functional groups related to different ecological factors. Those areas with larger volume of traffic hold lower species diversity, in terms of species richness and lichen diversity value (LDV). Traffic areas also affect the composition of the lichen community, which is evidenced by sensitive species. The abundance of species of lichens tolerant to low levels of eutrophication diminishes in traffic areas; oppositely, those areas show a higher abundance of species of lichens tolerating high levels of eutrophication. On the other hand, residential and green areas have an opposite pattern, mainly with species highly tolerant to eutrophication being less abundant than low or moderate ones. The characteristics of tree bark do not seem to affect excessively on lichen composition; however, tree species shows some effect that should be considered in further studies.
Afficher plus [+] Moins [-]Intoxication and biochemical responses of freshwater snail Bellamya aeruginosa to ethylbenzene Texte intégral
2017
Zheng, Shimei | Zhou, Qixing
No acute toxic data of ethylbenzene on gastropod is available in literature. In the present study, the acute toxicity of ethylbenzene was assessed on a freshwater snail Bellamya aeruginosa, which was exposed to ethylbenzene concentration from 1 to 100 mg/L for 96 h. No mortality occurred, but a manifestation of intoxication (distress syndrome) was observed in part of exposed snails, and meanwhile, another part was moved normally. The distress syndrome showed clear dose- and time-dependent effects, and the 96-h EC₅₀ value for distress syndrome was 13.3 mg/L in snail. The biochemical responses induced by ethylbenzene to the snail, including acetylcholinesterase (AChE) in the whole body and superoxide dismutase (SOD), catalase (CAT), glutathione S-transferases (GST), and reduced glutathione (GSH) in the hepatopancreas, were evaluated both for distressed snail and moved snail. The AChE activity of distressed snail was all inhibited more than 45 %, and the inhibition of AChE activity in the moved snail was all less than 30 % and more than 20 %, demonstrating that ethylbenzene exerted nervous toxicity to both distressed snail and moved snail. Meanwhile, the difference for AChE activity between the two different response snails was significant. Among the antioxidant biomarkers (SOD, CAT, GST, and GSH), only GST displayed significant difference between the distressed snail and moved snail. However, the activities of enzymes (SOD, CAT, and GST) in the moved snail were greater than those in the distressed snail, no matter significantly or insignificantly, which indicated that the ability of antioxidant defense in the distressed snail was weaker than that in the moved snail. The findings here reported manifest that ethylbenzene exerted nervous toxicity to snail, and the snail with intoxication response (distress syndrome) presented larger inhibition on AChE activity and weaker antioxidant ability in comparison with the moved snail.
Afficher plus [+] Moins [-]Phytoextraction of rare earth elements in herbaceous plant species growing close to roads Texte intégral
2017
Mikołajczak, Patrycja | Borowiak, Klaudia | Niedzielski, Przemysław
The aim of study was to determine the phytoextraction of rare earth elements (REEs) to roots, stems and leaves of five herbaceous plant species (Achillea millefolium L., Artemisia vulgaris L., Papaver rhoeas L., Taraxacum officinale AND Tripleurospermum inodorum), growing in four areas located in close proximity to a road with varied traffic intensity. Additionally, the relationship between road traffic intensity, REE concentration in soil and the content of these elements in plant organs was estimated. A. vulgaris and P. rhoeas were able to effectively transport REEs in their leaves, independently of area collection. The highest content of REEs was observed in P. rhoeas leaves and T. inodorum roots. Generally, HREEs were accumulated in P. rhoeas roots and leaves and also in the stems of T. inodorum and T. officinale, whereas LREEs were accumulated in T. inodorum roots and T. officinale stems. It is worth underlining that there was a clear relationship between road traffic intensity and REE, HREE and LREE concentration in soil. No positive correlation was found between the concentration of these elements in soil and their content in plants, with the exception of T. officinale. An effective transport of REEs from the root system to leaves was observed, what points to the possible ability of some of the tested plant species to remove REEs from soils near roads.
Afficher plus [+] Moins [-]Trend of childhood blood lead levels in cities of China in recent 10 years Texte intégral
2017
Li, Tao | Zhang, Shuaiming | Tan, Zangwen | Dai, Yaohua
The adverse effects of lead on human especially childhood have been well established. Largely due to the phase out of lead in gasoline, blood lead levels (BLLs) had declined substantially all over the world including China. In 2004, 2007, 2010, and 2013, we conducted a continuous project including 47,346 children aged 0–6 years old from 11 cities all over China to show how the decline happened and to explore what to do next to improve the BLLs of children of China. Our data shown the BLLs of Chinese children decreased from 46.38, 43.58, 38.95 to 37.17 μg/L, but the decline was not enough. These decline was mainly because of the number decrease of children with high BLLs. Integrated strategy should be used to promote the BLLs of Chinese children, like striving to improve the environment, setting new cutoff for high BLLs, and establishing routine blood lead screening.
Afficher plus [+] Moins [-]Plant species diversity reduces N2O but not CH4 emissions from constructed wetlands under high nitrogen levels Texte intégral
2017
Han, Wenjuan | Shi, Mengmeng | Chang, Jie | Ren, Yuan | Xu, Ronghua | Zhang, Chongbang | Ge, Ying
Constructed wetlands (CWs) have been widely used for treating wastewater. CWs also are the sources of greenhouse gas (GHG) due to high pollutant load. It has been reported that plant species diversity can enhance nitrogen (N) removal efficiency in CWs for treating wastewater. However, the influence of plant species diversity on GHG emissions from CWs in habitats with high N levels still lack research. This study established four species richness levels (1, 2, 3, 4) and 15 species compositions by using 75 simulated vertical flow CWs microcosms to investigate the effects of plant species diversity on the GHG emissions and N removal efficiency of CWs with a high N level. Results showed plant species richness reduced nitrous oxide (N₂O) emission and N (NO₃ ⁻-N, NH₄ ⁺-N, and TIN) concentrations in wastewater, but had no effect on methane (CH₄) emission. Especially, among the 15 compositions of plant species, the four-species mixture emitted the lowest N₂O and had under-depletion of N (DₘᵢₙTIN < 0). The presence of Oenanthe javanica had a significantly negative effect on the N₂O emission but had no effect on N removal efficiency. The presence of Rumex japonicus significantly reduced the N (NO₃ ⁻-N and TIN) concentrations in wastewater but had no effect on the N₂O and CH₄ emissions. The N concentrations and GHG emissions in the community of R. japonicus × Phalaris arundinacea were as low as those in the four-species mixture. Assembling plant communities with relatively high species richness (four-species mixture) or particular composition (R. japonicus × P. arundinacea) could enhance the N removal efficiency and reduce the GHG emissions from CWs for treating wastewater with a high N level.
Afficher plus [+] Moins [-]Difference of performance in response to disease admissions between daily time air quality indices and those derived from average and entropy functions Texte intégral
2017
Lai, Li-Wei | Cheng, Wan-Li
Daily time air quality indices, which can reflect air quality in 1 day, are suitable for identifying daily exposure during conditions of poor air quality. The aim of this study is to compare the main effectiveness of four daily time indices in representing variation in the number of disease admissions. These indices include pollution standard index (PSI), air quality index (AQI) and their respective indices derived from mean and entropy functions: MEPSI and MEAQI. The hourly concentrations of fine particulate matter less than 10 μm in diameter (PM₁₀), PM₂.₅, O₃, CO, NO₂ and SO₂ from 1 January 2006 to 31 December 2010 were obtained from 14 air quality monitoring stations owned by the Environmental Protection Administration (EPA) in the Kaoping region, Taiwan.Instead of circulatory system disease admissions, the indices were correlative with the number of respiratory disease admissions with correlative coefficients of 0.49 to 0.56 (P < 0.05). The daily time air quality indices derived from mean and entropy functions improved their performance of reactive range and air pollution identification. The reactive range of MEPSI and MEAQI was 1.4–3 times that of the original indices. The MEPSI and MEAQI increased identification from 40 to 180 in index scale and revealed one to two additional categories of public health effect information. In comparison with other indices, MEAQI is more effective for application to pollution events with multiple air pollutants.
Afficher plus [+] Moins [-]Double genetically modified symbiotic system for improved Cu phytostabilization in legume roots Texte intégral
2017
Pérez-Palacios, Patricia | Romero-Aguilar, Asunción | Delgadillo, Julián | Doukkali, Bouchra | Caviedes, Miguel A. | Rodríguez-Llorente, Ignacio D. | Pajuelo, Eloísa
Excess copper (Cu) in soils has deleterious effects on plant growth and can pose a risk to human health. In the last decade, legume-rhizobium symbioses became attractive biotechnological tools for metal phytostabilization. For this technique being useful, metal-tolerant symbionts are required, which can be generated through genetic manipulation.In this work, a double symbiotic system was engineered for Cu phytostabilization: On the one hand, composite Medicago truncatula plants expressing the metallothionein gene mt4a from Arabidopsis thaliana in roots were obtained to improve plant Cu tolerance. On the other hand, a genetically modified Ensifer medicae strain, expressing copper resistance genes copAB from Pseudomonas fluorescens driven by a nodulation promoter, nifHp, was used for plant inoculation. Our results indicated that expression of mt4a in composite plants ameliorated plant growth and nodulation and enhanced Cu tolerance. Lower levels of ROS-scavenging enzymes and of thiobarbituric acid reactive substances (TBARS), such as malondialdehyde (a marker of lipid peroxidation), suggested reduced oxidative stress. Furthermore, inoculation with the genetically modified Ensifer further improved root Cu accumulation without altering metal loading to shoots, leading to diminished values of metal translocation from roots to shoots. The double modified partnership is proposed as a suitable tool for Cu rhizo-phytostabilization.
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