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Результаты 1151-1160 из 1,506
Geographical distribution of non-PBDE-brominated flame retardants in mussels from Asian coastal waters
2012
Isobe, Tomohiko | Ogawa, Shohei P. | Ramu, Karri | Sudaryanto, Agus | Tanabe, Shinsuke
Hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and decabromodiphenyl ethane (DBDPE) used as alternatives for polybrominated diphenyl ethers (PBDEs) are also persistent in the environment as PBDEs. Limited information on these non-PBDE brominated flame retardants (BFRs) is available; in particular, there are only few publications on environmental pollution by these contaminants in the coastal waters of Asia. In this regard, we investigated the contamination status of HBCDs, BTBPE, and DBDPE in the coastal waters of Asia using mussels as a bioindicator. Concentrations of HBCDs, BTBPE, and DBDPE were determined in green (Perna viridis) and blue mussels (Mytilus edulis) collected from the coastal areas in Cambodia, China (mainland), SAR China (Hong Kong), India, Indonesia, Japan, Malaysia, the Philippines, and Vietnam on 2003–2008. BTBPE and DBDPE were analyzed using GC-MS, whereas HBCDs were determined by LC-MS/MS. HBCDs, BTBPE, and DBDPE were found in mussels at levels ranging from <0.01 to 1,400, <0.1 to 13, and <0.3 to 22 ng/g lipid wt, respectively. Among the three HBCD diastereoisomers, α-HBCD was the dominant isomer followed by γ- and β-HBCDs. Concentrations of HBCDs and DBDPE in mussels from Japan and Korea were higher compared to those from the other Asian countries, indicating extensive usage of these non-PBDE BFRs in Japan and Korea. Higher levels of HBCDs and DBDPE than PBDEs were detected in some mussel samples from Japan. The results suggest that environmental pollution by non-PBDE BFRs, especially HBCDs in Japan, is ubiquitous. This study provides baseline information on the contamination status of these non-PBDE BFRs in the coastal waters of Asia.
Показать больше [+] Меньше [-]Influence of sampling sufficiency on biodiversity analysis of microperiphyton communities for marine bioassessment
2012
Xu, Henglong | Zhang, Wei | Jiang, Yong | Zhu, Mingzhuang | Al-Rasheid, Khaled A. S.
INTRODUCTION: With quick responses to environmental changes, easy sampling, relative immobility, increasing availability of easily used taxonomic references, and allowing standardization for temporal and spatial comparisons, the biodiversity measures of microperiphyton communities have widely been accepted as useful indicators to evaluate environmental stress and anthropogenic impact. MATERIALS AND METHODS: The influence of sampling sufficiency for biodiversity analysis of microperiphyton communities was studied using a range of statistical methods in coastal waters of the Yellow Sea, northern China, from May to June 2010. Samples were collected from two depths using an artificial substrate. RESULTS: Sampling sizes represented a significant influence on biodiversity analysis of microperiphyton communities, e.g., 20 slide replicates (350 cm2) were sufficient for the microperiphyton communities at both depths, while 10 slide replicates (175 cm2) could meet the sampling strategy only for the samples with colonization times of 10 days or more at a depth of 1 m for recovering 90% species during the study period. Otherwise, more slide replicates were required with the increase of water depths and shortening colonization times for recovering microperiphyton species, e.g., for recovering 90% species of a “mature” microperiphyton community (>10 days), ∼10 slide replicates (∼175 cm2) were sufficient at a depth of 1 m, while for the “young” samples (>10 days) much more (15–30) slide replicates were required at both depths in this study. Furthermore, to achieve <10% standard errors, six (105 cm2) and nine (∼160 cm2) slide replicates were required for biodiversity analysis of the microperiphyton communities with various colonization times at depths of 1 and 3 m during the summer season, respectively. CONCLUSION: These results suggest that sampling sizes represented a significant influence on biodiversity analysis of microperiphyton communities for monitoring programs and ecological conservation researches in marine ecosystems.
Показать больше [+] Меньше [-]Degradation of 1,4-dioxane using advanced oxidation processes
2012
Chitra, Sengadir | Paramasivan, Kanapathy | Cheralathan, Mayilsamy | Sinha, Pradeep Kumar
INTRODUCTION: In the nuclear industry 1,4-dioxane is used as a solvent in liquid scintillation technique for measuring low-energy beta-emitters such as 3H or C14 in aqueous media. Improper disposal of 1,4-dioxane can contaminate the ground and surface waters. Conventional wastewater treatment processes like chemical treatment, air stripping, carbon adsorption, and biological treatment are ineffective for the degradation of 1,4-dioxane. METHODS: In the present study, the kinetics of degradation of 1,4-dioxane using advanced oxidation processes viz., H2O2 alone, Fe(II) + H2O2, UV (15 W) + H2O2, UV (15 W) + Fe(II) + H2O2, US (130 KHz) + Fe(II) + H2O2, and sunlight + Fe(II) + H2O2 at pH 3.0 was investigated. The optimization of Fe (II) for the processes using Fe (II) + H2O2 was carried out. CONCLUSIONS: The kinetics of degradation using sunlight + Fe (II) + H2O2 was found to be fastest when compared to the other processes. The degradation was found to follow first-order kinetics. Formation of acidic intermediates was suspected from the observed pH changes during the degradation processes.
Показать больше [+] Меньше [-]Assessing the effects of tertiary treated wastewater reuse on a Mediterranean river (Llobregat, NE Spain), part III: pathogens and indicators
2012
Rubiano, María-Eugenia | Agulló-Barceló, Míriam | Casas-Mangas, Raquel | Jofre, Juan | Lucena, Francisco
PURPOSE: Need, coupled with advances in water treatment technology, is motivating a growing interest in augmenting drinking water supplies with reclaimed water. Using reclaimed water to increase the flow of the Llobregat River upstream the water catchment site of the complex multi-step drinking water treatment plant of Sant Joan Despí has been considered. The impact of reclaimed water discharges on the load of E. coli, spores of sulphite-reducing clostridia, somatic coliphages, cytopathogenic enteroviruses, and total and infectious Cryptosporidium oocysts in the Llobregat River water was assessed to gain information for funded decisions in potential future emergencies. METHODS: Enterovirus and Cryptosporidium oocysts were concentrated from great water volumes prior to enumeration, whereas indicators were enumerated directly from the samples. Both indicators and pathogens were enumerated by cultural techniques that determine infectious microbes. RESULTS AND DISCUSSION: Densities of both indicators and pathogens in reclaimed water, despite that it was disinfected by UV irradiation alone or by UV irradiation plus chlorination, were significantly lower than their densities in the river water, both upstream and downstream the reclaimed water release site in the river. CONCLUSION: Results gathered indicate that discharging reclaimed water into the river does not increment the load of indicators and pathogens of the river water. Then, in emergency situations due to severe water shortages after prolonged droughts, at least from the infectious diseases point of view, the risks of augmenting drinking water supplies with reclaimed water can be satisfactorily and safely managed.
Показать больше [+] Меньше [-]Evaluation of the potential impact of polluted sediments using Manila clam Ruditapes philippinarum: bioaccumulation and biomarker responses
2012
Won, Eun-Ji | Hong, Seongjin | Ra, Kongtae | Kim, Kyung-Tae | Shin, Kyung-Hoon
An assessment was made to monitor the short-term impact of heavily polluted sediments that may move out from the brackish man-made Lake Shihwa outside of the sea dike due to operations of a tidal power plant. Here, we exposed the Manila clam Ruditapes philippinarum collected from the western coast of Korea to natural sediment under lab condition for 96 h. Sediments were collected from Lake Shihwa and outside of the sea dike representing polluted and reference conditions, respectively. The results of chemical analysis revealed that the concentrations of nonylphenol and heavy metals in water and sediment from the inner region of Lake Shihwa were significantly higher than those of reference sediments. After 48 and 96 h of exposure, 30 specimens of clams were sampled from each experimental condition, and concentrations of nonylphenol and metals were measured in clams, water, and sediments. Several biomarkers, including concentrations of metallothionein-like proteins, and activities of the antioxidant enzymes glutathione S-transferase and catalase were determined in clams to characterize the effects of polluted sediments to clams. After 96 h of exposure, R. philippinarum assimilated nonylphenol up to 71 times compared to initial concentrations. However, there was no apparent uptake of heavy metals into the clams. Additionally, antioxidant enzymes exhibited higher activities in clams exposed to the polluted sediment. The results of the present study with physiological responses in R. philippinarum suggest that sediment transportation caused by the operation of a tidal power plant in Lake Shihwa will have striking effects on benthic organisms in the adjacent coastal area.
Показать больше [+] Меньше [-]Levels and seasonal variations of organochlorine pesticides in urban and rural background air of southern Ghana
2012
Adu-Kumi, Sam | Kareš, Radovan | Literák, Jaromír | Borůvková, Jana | Yeboah, Philip O. | Carboo, Derick | Akoto, Osei | Darko, Godfred | Osae, Shiloh | Klánová, Jana
Urban, suburban and rural background air samples were collected in southern Ghana in 2008 employing polyurethane foam disc passive air samplers (PAS). PAS were analysed for organochlorine pesticides (OCPs), namely hexachlorocyclohexanes (α-, β-, γ- and δ-hexachlorocyclohexane), dichlorodiphenyltrichloroethane including metabolites (o,p′- and p,p′-DDT, DDE and DDD), hexachlorobenzene, pentachlorobenzene, aldrin, dieldrin, endrins (endrin, endrin aldehyde and endrin ketone), isodrin, heptachlors (heptachlor, heptachlor epoxide A and heptachlor epoxide B), chlordanes (α-, β-chlordane, oxychlordane and trans-nonachlor), endosulfans (α- and β-endosulfan and endosulfan sulphate), methoxychlor and mirex using a gas chromatograph coupled to a mass spectrometer. The levels of OCPs ranged for the individual pesticides from below limit of quantification to 750 pg m−3 (for α-endosulfan), and current agricultural application seemed to be the main primary source of most abundant pesticides. Re-volatilization of previously used pesticides from contaminated soils could not be ruled out either as potential secondary source of contamination, especially in warm and dry seasons and periods of intensive agricultural activities. Higher atmospheric concentrations were observed in November and December during the dry season compared to lower concentrations observed in June, July and August when the country experiences heavy rains. The highest seasonal variation was observed for currently used pesticides as α-endosulfan. A p,p′-DDT/p,p′-DDE ratio suggested recent inputs of fresh technical DDT.
Показать больше [+] Меньше [-]Biosorption of strontium from aqueous solution by fungus Aspergillus terreus
2012
Khani, M. H. | Pahlavanzadeh, H. | Alizadeh, K.
INTRODUCTION: The biosorption characteristics of strontium ions using fungus Aspergillus terreus were investigated. Experimental parameters affecting the biosorption process such as pH, contact time, initial metal concentration, and temperature were studied. MATHEMATICAL DESCRIPTION: Fungus A. terreus exhibited the highest strontium uptake capacity at 15°C at an initial strontium ion concentration of 876 mg L−1 and an initial pH of 9. Biosorption capacity increased from 219 to 308 mg g−1 with a decrease in temperature from 45°C to 15°C at this initial strontium concentration. The equilibrium data fitted very well to the Langmuir adsorption model in the concentration range of strontium ions and at all the temperatures studied. CONCLUSION: Evaluation of the experimental data in terms of biosorption dynamics showed that the biosorption of strontium onto fungus followed the pseudo-second-order dynamics well (R2 > 0.985). The calculated thermodynamics parameters (−1.64 < ∆G° < −1.93 kJ mol−1 at temperatures of 45–15°C, ∆H° = −4.83 kJ mol−1 and ∆S° = −0.01 kJ mol−1 K−1) showed that the biosorption of strontium ions were feasible, spontaneous, and exothermic at the temperature ranges of 15–45°C.
Показать больше [+] Меньше [-]Molecular properties of a fermented manure preparation used as field spray in biodynamic agriculture
2012
Spaccini, R. | Mazzei, P. | Squartini, A. | Giannattasio, M. | Piccolo, A.
Manure products fermented underground in cow horns and commonly used as field spray (preparation 500) in the biodynamic farming system, were characterized for molecular composition by solid-state nuclear magnetic resonance [13 C cross-polarization magic-angle-spinning NMR (13 C-CPMAS-NMR)] spectroscopy and offline tetramethylammonium hydroxide thermochemolysis gas chromatography-mass spectrometry. Both thermochemolysis and NMR spectroscopy revealed a complex molecular structure, with lignin aromatic derivatives, polysaccharides, and alkyl compounds as the predominant components. CPMAS-NMR spectra of biodynamic preparations showed a carbon distribution with an overall low hydrophobic character and significant contribution of lignocellulosic derivatives. The results of thermochemolysis confirmed the characteristic highlighted by NMR spectroscopy, revealing a molecular composition based on alkyl components of plant and microbial origin and the stable incorporation of lignin derivatives. The presence of biolabile components and of undecomposed lignin compounds in the preparation 500 should be accounted to its particularly slow maturation process, as compared to common composting procedures. Our results provide, for the first time, a scientific characterization of an essential product in biodynamic agriculture, and show that biodynamic products appear to be enriched of biolabile components and, therefore, potentially conducive to plant growth stimulation.
Показать больше [+] Меньше [-]Removal of faecal indicator pathogens from waters and wastewaters by photoelectrocatalytic oxidation on TiO2/Ti films under simulated solar radiation
2012
Venieri, Danae | Chatzisymeon, Efthalia | Sofianos, Spiridon S. | Politi, Eleonora | Xekoukoulotakis, Nikolaos P. | Katsaounis, Alexandros | Mantzavinos, Dionissios
PURPOSE: The disinfection efficiency of water and secondary treated wastewater by means of photoelectrocatalytic oxidation (PEC) using reference strains of Enterococcus faecalis and Escherichia coli as faecal indicators was evaluated. Operating parameters such as applied potential (2–10 V), initial bacterial concentration (103–107 CFU/mL), treatment time (up to 90 min) and aqueous matrix (pure water and treated effluent) were assessed concerning their impact on disinfection. METHODS: PEC experiments were carried out using a TiO2/Ti film anode and a zirconium cathode in the presence of simulated solar radiation. Bacterial inactivation was monitored by the culture method and real-time SYBR green PCR. RESULTS: A 6.2 log reduction in E. faecalis population was achieved after 15 min of PEC treatment in water at 10 V of applied potential and an initial concentration of 107 CFU/mL; pure photocatalysis (PC) led to only about 4.3 log reduction, whilst negligible inactivation was recorded when the respective electrochemical oxidation process was applied (i.e. without radiation). PEC efficiency was generally improved increasing the applied potential and decreasing initial bacterial concentration. Regarding real wastewater, E. coli was more susceptible than E. faecalis during treatment at a potential of 5 V. Wastewater disinfection was affected by its complex composition and the contained mixed bacterial populations, yielding lower inactivation rates compared to water treatment. Screening the results obtained from both applied techniques (culture method and real-time PCR), there was a discrepancy regarding the recorded time periods of total bacterial inactivation, with qPCR revealing longer periods for complete bacterial reduction. CONCLUSIONS: PEC is superior to PC in terms of E. faecalis inactivation presumably due to a more efficient separation and utilization of the photogenerated charge carriers, and it is mainly affected by the applied potential, initial bacterial concentration and the aqueous matrix.
Показать больше [+] Меньше [-]Volatile organic compounds and bioaerosols in the vicinity of a municipal waste organic fraction treatment plant. Human health risks
2012
Vilavert, Lolita | Nadal, Martí | Figueras, María J. | Domingo, José L.
PURPOSE: The aim of this study was to analyze air concentrations of chemical and microbiological pollutants in the vicinity of an organic waste treatment plant, Ecoparc-2, located in Montcada i Reixac (Catalonia, Spain), as well as to determine the seasonal trends. The human health risks due to the presence of those agents were also assessed. METHODS: Air samples were collected at different distances and wind directions from the Ecoparc-2 in two campaigns (winter and summer of 2010). The levels of 19 volatile organic compounds (VOCs) were analyzed by GC-MS or HPLC-UV. In turn, the airborne amount of total bacteria, gram-negative bacteria, and fungi (including Aspergillus fumigatus) was also determined. RESULTS: Mean VOC concentrations were found to be 32.4 and 15.7 μg/m3 in winter and summer, respectively. Fungi at 25°C presented the highest geometric mean (1,126 and 863 cfu/m3 in winter and summer, respectively), while the concentrations of fungi at 37°C and total bacteria were also important in the hot season (332 and 250 cfu/m3, respectively). These results are in agreement with data obtained from the scientific literature. Anyhow, no significant differences were observed between both campaigns including those related to distances and wind directions. The current pollutant levels in the surrounding environment were also various orders of magnitude lower than those recently observed inside the facility. CONCLUSIONS: The human exposure to VOCs near the Ecoparc-2 was estimated to be low. Furthermore, the current environmental concentrations of those chemical and microbiological agents were clearly below threshold values recommended by regulatory organizations.
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