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Aerobic denitrification and biomineralization by a novel heterotrophic bacterium, Acinetobacter sp. H36 Полный текст
2017
Su, Jun feng | Shi, Jing xin | Ma, Fang
A novel aerobic denitrification and biomineralization strain H36 was isolated from the Qu Jiang artificial lake. Based on phylogenetic characteristics, the isolated strain was identified as Acinetobacter species. Strain H36 was confirmed to have the ability to perform simultaneous denitrification and biomineralization. Results showed the strain H36 had the capability to completely reduce 96.29% of NO3−–N and 78.59% of Ca2+ over 112h under aerobic condition. Response surface methodology (RSM) analysis demonstrated the highest removal ratio of Ca2+ was 74.24% with hardness concentration of 350mg/L, pH of 8.5, organic concentration of 0.75g/L and inoculum size of 15%. The highest removal ratio of nitrate was 77.00% with hardness concentration of 350mg/L, pH of 7.5, organic concentration of 0.75g/L and inoculum size of 10%. Besides, X-ray diffraction (XRD) analysis showed calcium carbonate could be formed in the process of biomineralization.
Показать больше [+] Меньше [-]Compositional shifts in bacterial communities associated with the coral Palythoa caribaeorum due to anthropogenic effects Полный текст
2017
Paulino, Gustavo Vasconcelos Bastos | Broetto, Leonardo | Pylro, Victor Satler | Landell, Melissa Fontes
Corals harbor abundant and diverse prokaryotic communities that may be strongly influenced by human activities, which in turn compromise the normal functioning of coral species and predispose them to opportunistic infections. In this study, we investigated the effect of sewage dumping on the bacterial communities associated with the soft coral Palythoa caribaeorum at two sites in the Brazilian coast. We observed a dominance of bacterial species classified as human pathogens at sites exposed to untreated sewage discharge. The microbial diversity of undisturbed sites was more homogeneous and diverse and showed greater abundance. In addition, bacterial communities differed substantially between the exposed and undisturbed areas. The microbial community associated with the samples collected from the exposed sites revealed the anthropogenic effect caused by organic matter from untreated sewage dumping, with an abundance of pathogenic bacterial species.
Показать больше [+] Меньше [-]Characteristics of mass concentration, chemical composition, source apportionment of PM2.5 and PM10 and health risk assessment in the emerging megacity in China Полный текст
2017
Jiang, Nan | Yin, Shasha | Guo, Yue | Li, Jingyi | Kang, Panru | Zhang, Ruiqin | Tang, Xiaoyan
In this study, 228 daily Particulate matter (PM) filters (57 Quartz and 57 Teflon samples for both PM2.5 and PM10, respectively) were collected from an urban site in Zhengzhou in typical months from 2014 autumn to 2015 summer representing the four seasons. PM concentrations, water-soluble inorganic ions, organic carbon, elemental carbon, and elements were determined, and positive matrix factorization was used for source apportionments. Health risks of toxic elements in PM2.5 and PM10 were also evaluated. The annual mean values of PM2.5 and PM10 were higher than the standards in China, and the highest seasonal concentrations of PM2.5 and PM10 were in winter. Secondary inorganic aerosols (SIAs) were the major component, with the ratio of SIAs/PM highest in summer. The seasonal concentrations of SO42− were high in winter and summer. Crustal elements mainly existed in PM2.5–10; however, elements from anthropogenic sources (i.e., Zn, Pb, Cu, As, Cd, and Mo) were more abundant in fine particles than in the coarse fraction. The main pollution sources were dust, SIAs, coal combustion, vehicle and road dust, and industry, accounting for 10%, 26%, 25%, 20% and 15% in PM2.5 and 32%, 14%, 24%, 18% and 8% in PM10, respectively. Dust source has the highest contribution in PM10; however, SIAs source has the highest content in fine particles. The carcinogenic risks of As to children through the daily intake pathway in PM2.5 and PM10 exceeded the acceptable level. Noncarcinogenic risks of As and Cd in PM2.5 and PM10 to children via the daily intake pathway were significant. Moreover, the sum of noncarcinogenic risks in PM10 via inhalation exposure for local residents and that via dermal absorption for children were significant. The details of the pollution characteristics and the results of source apportionments and health risks assessment of PM2.5 and PM10 in this study can play an important role for the government to formulate reasonable and effective policy to mitigate the atmospheric pollution of PM. To our knowledge, this systematic study is the first to investigate the chemical characterizations, source apportionments, and health effects of PM2.5 and PM10 in Zhengzhou.
Показать больше [+] Меньше [-]Assessment of trace element accumulation in surface sediments off Chennai coast after a major flood event Полный текст
2017
Gopal, V. | Krishnakumar, S. | Simon Peter, T. | Nethaji, S. | Suresh Kumar, K. | Jayaprakash, M. | Magesh, N.S.
The present study was conducted to assess the trace element concentration in marine surface sediments after major flood event of Chennai metropolis, India. Thirty surface samples were collected from off Chennai coast. Trace elements, organic matter, CaCO3, sand-silt-clay and C/N ratios were studied to understand the accumulation dynamics on sediments. The elemental concentration, calcium carbonate and OM distribution suggest that they are derived from urban runoff and transported through Adyar and Cooum Rivers. The enrichment factor reveals that the sediments are enriched by Pb, Cu, Zn, Cr, Co, Ni followed by Fe. The observed Igeo value shows that the samples are contaminated by Pb, Cu and Zn. The elemental concentration of the surface sediments is low when compared to other coastal region except Pb. The elevated level of Pb in the surface sediments is probably due to migration of contaminated urban soil from industrial and transportation sectors into marine environment.
Показать больше [+] Меньше [-]Bio-monitoring of metal impact on metallothioneins levels in the gastropod Phorcus turbinatus (Born, 1778) in the northeastern and the eastern coasts of Tunisia Полный текст
2017
Boulajfene, Wafa | Strogyloudi, Evangelia | Catsiki, Vassiliki-Angelique | El Mlayah, Ammar | Tlig-Zouari, Sabiha
This work is an evaluation of metal contamination degree in Phorcus turbinatus and a monitoring of metals impact on metallothioneins functioning. The gastropod was sampled from six stations along the northeastern and eastern coasts of Tunisia during four seasons (2014–2015). Our results suggested that sedimentological metallic contents (Copper, Zinc and Cadmium) vary significantly depending on stations and not significantly according to seasons except for copper. Nevertheless, differences were no significant between stations and significant between seasons as for ambient factors, metallic intrinsic contents and metallothioneins rates. The monodonta tissue seems to be enriched in the four analyzed metals (Cu, Zn, Cd and Hg) and this species seems to have an ability to accumulate metals. Metal effect on the protein induction may be linked to physicochemical factors (temperature, O2 and Cu contents in sediment). In fact, metallothioneins levels were positively correlated to the dissolved oxygen rates and negatively linked to temperature.
Показать больше [+] Меньше [-]Assessment of 226Ra, 238U, 232Th, 137Cs and 40K activities from the northern coastline of Oman Sea (water and sediments) Полный текст
2017
Darabi-Golestan, F. | Hezarkhani, A. | Zare, M.R.
Water and sediment samples were collected from northern coast of Oman Sea covering from Goatr to Hormoz canyon seaport. Water and sediment quality assessment for naturally or anthropogenic radionuclides at Oman Sea as a main strategic golf for trade and transit, is an important issue. Correspondence analysis (CA) by R-mode analysis represents that sigma(T)-temperature-conductivity-O2 parameters are well-correlated with 226Ra, 232Th and 40K. Accordingly Q-mode analysis revealed an indicator samples of ST13W for different radionuclides, ST03W for O2, and simultaneously ST34W-ST21W-ST08W-ST04W for sigma(T) parameters. The CA results overlapped with factor and cluster analysis results that explained 85.8% of total variance of water samples. Descriptive analysis of sediments indicates more significant variation than water samples. The 232Th and 226Ra generally showing that ST13D to ST25D sediments that restricted to Pi Bashk coastline are concentrated from 137Cs and 40K. By comparison with reference-values from Iran and other parts of the world, they are acceptable with respect to environmental and radioisotope hazards.
Показать больше [+] Меньше [-]Presence of trace elements in the silverside Odontesthes argentinensis Полный текст
2017
Thompson, Gustavo A. | Volpedo, Alejandra V.
The silverside Odontesthes argentinensis is an economically significant resource for commercial fisheries in South America. We evaluated the presence of trace elements in the stomach content and fish tissues (muscle and otoliths) of O. argentinensis. In addition, we assessed the presence of trace elements in its prey (zooplankton) and in seawater in a coastal temperate area. The most abundant trace elements found in the water, zooplankton, stomach content, and fish tissues (muscle and otoliths) constituted of Ba, Mn, Sr and Zn, while Cd, Cu and Pb were observed in lower concentrations. We concluded that O. argentinensis specimens captured from the environment, within the length range analyzed for muscle samples (total length: <21cm), are deemed fit for human consumption because the concentrations of trace elements mostly meet the standards established in the Argentine Food Code. The information obtained in this study is vital for O. argentinensis farming in closed systems.
Показать больше [+] Меньше [-]Evaluation of indoor/outdoor urban air pollution by magnetic, chemical and microscopic studies Полный текст
2017
Jeleńska, M. | Górka-Kostrubiec, B. | Werner, T. | Kądziałko-Hofmokl, M. | Szczepaniak-Wnuk, I. | Gonet, T. | Szwarczewski, P.
The paper presents comparison of outdoor and indoor air pollution by means of magnetic characteristics of dust settled on the floor indoors (ID) and particulate matter (PM) gathered outdoor on air filters. Samples were collected for one year period in three different locations in Warsaw, Poland. PM was collected in samplers placed at the yard of buildings and ID was collected inside these buildings using a vacuum cleaner. The magnetic methods supplemented by chemical elements analysis and microscope observations were applied to identification of magnetic mineralogy, concentration and grain-size of magnetic fraction and morphology and shape of particles.The results demonstrated differences in magnetic mineralogy and in grain-size distribution between PM and ID. The magnetite was the main magnetic phase in PM and magnetite with metallic iron in ID. The ratios of hysteresis parameters for PM and ID were located in different areas on Day-Dunlop diagram; PM data in the area for PSD magnetite and fine SP grains and ID data around SD + MD mixing curves for magnetite.The difference in magnetic mineralogy, especially the lack of metallic iron in PM, can be explained by the limitation of dust samplers that cannot collect grains larger than roughly 50 μm due to our microscopic observations. PM samplers collect population of dust with smaller grain size than vacuum cleaner or simple sweeping of a floor. The difference in granulometry and outdoor/indoor sources could be one of the reasons for which we did not observed the simple relation between magnetic susceptibility of ID and PM.
Показать больше [+] Меньше [-]Characterization of Enterococcus species isolated from marine recreational waters by MALDI-TOF MS and Rapid ID API® 20 Strep system Полный текст
2017
Christ, Ana Paula Guarnieri | Ramos, Solange Rodrigues | Cayô, Rodrigo | Gales, Ana Cristina | Hachich, Elayse Maria | Sato, Maria Inês Zanoli
MALDI-TOF Mass Spectrometry Biotyping has proven to be a reliable method for identifying bacteria at the species level based on the analysis of the ribosomal proteins mass fingerprint. We evaluate the usefulness of this method to identify Enterococcus species isolated from marine recreational water at Brazilian beaches. A total of 127 Enterococcus spp. isolates were identified to species level by bioMérieux's API® 20 Strep and MALDI-TOF systems. The biochemical test identified 117/127 isolates (92%), whereas MALDI identified 100% of the isolates, with an agreement of 63% between the methods. The 16S rRNA gene sequencing of isolates with discrepant results showed that MALDI-TOF and API® correctly identified 74% and 11% of these isolates, respectively. This discrepancy probably relies on the bias of the API® has to identify clinical isolates. MALDI-TOF proved to be a feasible approach for identifying Enterococcus from environmental matrices increasing the rapidness and accuracy of results.
Показать больше [+] Меньше [-]Life and death of a sewage treatment plant recorded in a coral skeleton δ15N record Полный текст
2017
Duprey, Nicolas N. | Wang, Xingchen T. | Thompson, Philip D. | Pleadwell, Jeffrey E. | Raymundo, Laurie J. | Kim, Kiho | Sigman, Daniel M. | Baker, David M.
We investigated the potential of coral skeleton δ15N (CS-δ15N) records for tracking anthropogenic-N sources in coral reef ecosystems. We produced a 56yr-long CS-δ15N record (1958–2014) from a reef flat in Guam that has been exposed to varying 1) levels of sewage treatment 2) population density, and 3) land use. Increasing population density (from <30 to 300ind·km−2) and land use changes in the watershed resulted in a ~1‰ enrichment of the CS-δ15N record until a sewage treatment plant (STP) started operation in 1975. Then, CS-δ15N stabilized, despite continued population density and land use changes. Based on population and other considerations, a continued increase in the sewage footprint might have been expected over this time. The stability of CS-δ15N, either contradicts this expectation, or indicates that the impacts on the outer reef at the coring site were buffered by the mixing of reef water with the open ocean.
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