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Результаты 2831-2840 из 3,208
Effects of added polyacrylamide on changes in water states during the composting of kitchen waste Полный текст
2015
Yang, Yu-Qiang | Chen, Zhuo-Xian | Zhang, Xue-Qing | Hu, Li-Fang | Shen, Dong-Sheng | Long, Yu-Yang
The effects of adding polyacrylamide (PAM), to attempt to delay the loss of capillary water and achieve a better level of organic matter humification, in the composting of kitchen waste were evaluated. Four treatments, with initial moisture content of 60 % were used: 0.1 % PAM added before the start of composting (R1), 0.1 % PAM added when the thermophilic phase of composting became stable (at >50 °C) (R2), 0.1 % PAM added when the moisture content significantly decreased (R3), and no PAM added (R4). The introduction of PAM in R1 and R2 significantly increased the capillary force and delayed the loss of moisture content and capillary water. The introduction of PAM in R2 and R3 improved the composting process, in terms of the degradation of biochemical fractions and the humification degree. These results show that the optimal time for adding PAM was the initial stage of the thermophilic phase.
Показать больше [+] Меньше [-]Determination of selected pharmaceuticals in tap water and drinking water treatment plant by high-performance liquid chromatography-triple quadrupole mass spectrometer in Beijing, China Полный текст
2015
Cai, Mei-Quan | Wang, Rong | Feng, Li | Zhang, Li-Qiu
A simultaneous determination method of 14 multi-class pharmaceuticals using solid-phase extraction (SPE) followed by high-performance liquid chromatography-tandem mass spectrometer (HPLC-MS/MS) was established to measure the occurrence and distribution of these pharmaceuticals in tap water and a drinking water treatment plant (DWTP) in Beijing, China. Target compounds included seven anti-inflammatory drugs, two antibacterial drugs, two lipid regulation drugs, one antiepileptic drug, and one hormone. Limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.01 to 1.80 ng/L and 0.05 to 3.00 ng/L, respectively. Intraday and inter-day precisions, recoveries of different matrices, and matrix effects were also investigated. Of the 14 pharmaceutical compounds selected, nine were identified in tap water of Beijing downtown with the concentration up to 38.24 ng/L (carbamazepine), and the concentration levels of detected pharmaceuticals in tap water (<5 ng/L for most pharmaceuticals) were lower than previous studies in other countries. In addition, ten and six pharmaceuticals were measured in raw water and finished water at the concentration ranged from 0.10 to 16.23 and 0.13 to 17.17 ng/L, respectively. Five compounds were detected most frequently in DWTP, namely antipyrine, carbamazepine, isopropylantipyrine, aminopyrine, and bezafibrate. Ibuprofen was found to be the highest concentration pharmaceutical during DWTP, up to 53.30 ng/L. DWTP shows a positive effect on the removal of most pharmaceuticals with 81.2–99.5 % removal efficiencies, followed by carbamazepine with 55.4 % removal efficiency, but it has no effect for removing ibuprofen and bezafibrate.
Показать больше [+] Меньше [-]The international environmental specimen banks—let’s get visible Полный текст
2015
Küster, Anette | Becker, Paul R. | Kucklick, John R. | Pugh, Rebecca S. | Koschorreck, Jan
Environmental specimen banks (ESBs) are facilities that archive samples from the environment for future research and monitoring purposes. In addition, the long-term preservation of representative specimens is an important complement to environmental research and monitoring. Today, environmental specimen banking is experiencing a renaissance due to an increase in regulatory interest in ESB biota standards and trend data. The International Environmental Specimen Bank Group (IESB) promotes the worldwide development of techniques and strategies of environmental specimen banking and the international cooperation and collaboration among national ESBs. In order to provide a current and comprehensive overview on international environmental specimen banking activities, a questionnaire was sent to the national ESBs and asked for detailed information on the respective ESBs. The results show the rich diversity of national sampling programs, including more detailed information on archived samples, sampling strategies, and studies that have already been performed in the respective countries. All ESBs completing the survey expressed a strong interest in cooperating with other ESBs on a collaborative project. The collected information of national ESBs is intended to be made publicly available.
Показать больше [+] Меньше [-]Toxicity bioassays for water from black-odor rivers in Wenzhou, China Полный текст
2015
DeFu, He | RuiRui, Chen | EnHui, Zhu | Na, Chen | Boyang, | HuaHong, Shi | MinSheng, Huang
Following urbanization, a large number of urban rivers were contaminated and turned to black-odor rivers. The traditional approach for detecting water quality is based on chemical or physical analysis. However, biological toxicity of black-odor water has been less addressed. As two typical black-odor rivers, Jiushanwai River (JS) and Shanxia River (SX) are tributaries of Wen-Rui Tang River in Wenzhou (south of China). The eco-safety of the urban rivers was evaluated by bioassay for water toxicity in this study. Ten and 5 sampling sites were respectively set along JS and SX. Water samples were collected monthly from October 2010 to October 2011. The general physical and chemical parameters of river water were monitored. In order to investigate the ecotoxicological effects of black-odor water, the following bioassays were used: (1) Fish acute toxicity test (Danio rerio, comprehensive toxicity), (2) luminescent bacteria bioassay (Qinghaiensis vibrio, toxicity to bacteria), and (3) tropical claw embryo assay (Xenopus tropicalis, embryo toxicity). Biotoxicity of black-odor rivers water was demonstrated by D. rerio, Q. vibrio, and X. tropicalis embryos. Toxicological effects of black-odor water were respectively shown by mortality of zebrafish, and by the relative inhibitory light rate of luminescent bacteria. However, luminescent bacteria were more sensitive to inspect biotoxicity than zebrafish. In X. tropicalis embryos test, toxicological effects of black-odor water were mostly shown by embryos’ survival rate and teratogenic rate. Bioassay results showed that toxicity of SX water was higher than that of JS water, especially in summer. Statistical analysis of luminescent bacteria toxicity test showed that biotoxicity of SX and JS was high in summer, but low in winter and spring. The seasonal changes of water toxicity of the black-odor river were positively correlative with changes of water temperature (p < 0.05), and related to pH and ammonium nitrogen of water. Typical black-odor river water displays different degrees of biotoxicity to D. rerio, luminescent bacteria, and X. tropicalis embryos. The ecotoxicological risk of black-odor rivers was demonstrated in urban area, which suggests bioassay is necessary for evaluation of water quality. In the present study, spatial and seasonal bioassay for toxicity of JS and SX provides a complete example for evaluation of urban rivers.
Показать больше [+] Меньше [-]Investigation of the interaction between As and Sb species and dissolved organic matter in the Yangtze Estuary, China, using excitation–emission matrices with parallel factor analysis Полный текст
2015
Wang, Ying | Zhang, Di | Shen, Zhen-yao | Feng, Cheng-hong | Zhang, Xiao
The interactions between trivalent or pentavalent As/Sb and dissolved organic matter (DOM) in four regions (the river channel, the adjacent coastal area, and the northern and southern nearshore areas) of the Yangtze Estuary, China, were studied using fluorescence quenching titration combined with excitation–emission matrix spectroscopy and parallel factor analysis (PARAFAC). The As/Sb–DOM complexation characteristics were investigated using FTIR and UV absorbance spectroscopy and zeta potential analysis. Four protein-like components and one humic-like component were identified in the DOM from the Yangtze Estuary, China, by PARAFAC analysis. The tryptophan-like substance represented by component 2 was the dominant component and played an important role in the complexation between DOM and As/Sb. The results of complexation modeling demonstrated that the binding capacity of trivalent As/Sb with DOM was higher than that of pentavalent As/Sb with DOM. The DOM from the north nearshore area with the most acidic functional groups and greatest aromaticity possessed the highest binding capacity for trivalent and pentavalent As/Sb. The increase in the UV absorbance and the charge neutralization further indicated the interaction between As/Sb and DOM. The higher binding capacity of Sb(III) with DOM was mainly due to the hydroxyl and carboxyl groups. Our study demonstrates that the use of the advanced EEM–PARAFAC method in fluorescence quenching studies is very useful for evaluating the properties of DOM–pollutant interactions.
Показать больше [+] Меньше [-]Three decades of environmental specimen banking at the National Institute for Environmental Studies, Japan Полный текст
2015
Karube, Zin-ichi | Tanaka, Atsushi | Takeuchi, Akinori | Takazawa, Yoshikatsu | Takagi, Mai | Kinoshita, Ayako | Seyama, Haruhiko | Shibata, Yasuyuki
After two decades operation of the initial environmental specimen banking, a new program, Environmental Time Capsule Program, started in 2002 as a government-supported long-term program to construct a firm scientific basis for various environmental research studies. The program consists of long-term environmental specimen banking activity and specimen collection of endangered wildlife and is based on cryogenic sample preservation facility called Environmental Time Capsule building, which completed construction in 2004. After 9 years of extensive research, research focuses have been selected and the program was reorganized to the environmental sample collection part and endangered wildlife collection part in 2011. Due to huge environmental disaster caused by the Great East Japan earthquake and the tsunami as well as subsequent nuclear power plant accident at Fukushima, a new sampling and monitoring program started at affected areas in collaboration with the reorganized environmental sample collection and archiving program. Outlines of the quality assurance and quality control (QA/QC) activities in the program and future perspective under related international activities, particularly Stockholm Convention, are reported.
Показать больше [+] Меньше [-]Antifungal efficiency of a lipopeptide biosurfactant derived from Bacillus subtilis SPB1 versus the phytopathogenic fungus, Fusarium solani Полный текст
2015
Mnif, Ines | Hammami, Ines | Triki, Mohamed Ali | Azabou, Manel Cheffi | Ellouze-Chaabouni, Semia | Ghribi, Dhouha
Bacillus subtilis SPB1 lipopeptides were evaluated as a natural antifungal agent against Fusarium solani infestation. In vitro antifungal assay showed a minimal inhibitory concentration of about 3 mg/ml with a fungicidal mode of action. In fact, treatment of F. solani by SPB1 lipopeptides generated excessive lyses of the mycelium and caused polynucleation and destruction of the related spores together with a total inhibition of spore production. Furthermore, an inhibition of germination potency accompanied with a high spore blowing was observed. Moreover, in order to be applied in agricultural field, in vivo antifungal activity was proved against the dry rot potato tubers caused by F. solani. Preventive treatment appeared as the most promising as after 20 days of fungi inoculation, rot invasion was reduced by almost 78 %, in comparison to that of non-treated one. When treating infected tomato plants, disease symptoms were reduced by almost 100 % when applying the curative method. Results of this study are very promising as it enables the use of the crude lipopeptide preparation of B. subtilis SPB1 as a potent natural fungicide that could effectively control the infection of F. solani in tomato and potato tubers at a concentration similar to the commercial fungicide hymexazol and therefore prevent the damage of olive tree.
Показать больше [+] Меньше [-]Effect of confertifolin from Polygonum hydropiper L. against dengue vector mosquitoes Aedes aegypti L Полный текст
2015
Maheswaran, Rajan | Ignacimuthu, Savarimuthu
The essential oil from the leaves of Polygonum hydropiper L. (Polygonaceae) was tested against Aedes aegypti L. The LC₅₀ values were 190.72 and 234.37 ppm against second and fourth instar larvae of A. aegypti, respectively. Confertifolin (6,6,9a-trimethy l-4,5,5a,6,7,8,9,9a-octahydronaphtho [1,2-c] furan-3 (1H)-one) was isolated from the essential oil of P. hydropiper leaves using silica gel column chromatography. The LC₅₀ values were 2.90 and 2.96 ppm for second and fourth instar larvae of A. aegypti, respectively. At 10 ppm, the concentration of confertifolin showed ovicidal activity of 100, 100, and 77.6 % on 0–6, 6–12, and 12–18 h old eggs; the repellent activity was 323.2 min; and oviposition deterrent activity was 97.52 % and adulticidal activity was 100 % against A. aegypti. The results were statistically significant at P < 0.05 level. The results suggested that confertifolin as an effective major constituent against A. aegypti and might be considered as a potent source for the production of superior natural mosquitocides.
Показать больше [+] Меньше [-]Geochemical background and ecological risk of heavy metals in surface sediments from the west Zhoushan Fishing Ground of East China Sea Полный текст
2015
Xu, Gang | Liu, Jian | Pei, Shaofeng | Hu, Gang | Kong, Xianghuai
Surface sediment grain size as well as the spatial distribution, pollution status, and source identification of heavy metals in the west Zhoushan Fishing Ground (ZFG) of the East China Sea were analyzed to study the geochemical background concentrations of heavy metals and to assess their potential ecological risk. Our results show that surface sediments in the eastern part of study area were mainly composed of sand-sized components. Spatial distributions of heavy metals were mainly controlled by grain size and terrigenous materials, and their concentrations in the coarsest grain sediments formed primarily during the Holocene transgressive period could represent the element background values of our study area. Contamination factor suggests that there was no pollution of Pb, Zn, and Cr generally in our study area and slight pollution of Cu, Cd, and As (especially Cu) at some stations. In addition, ecological harm coefficient indicates that the ecological risk of each heavy metal, except for Cd, at two stations was low as well. These results are consistent with the pollution load index and ecological risk index, which suggest both the overall level of pollution and the overall ecological risk of six studied metals in sediment were relatively low in our study area. Enrichment factor indicates that the heavy metals came mostly from the natural source. Summarily, the quality level of sediment in our study area was relatively good, and heavy metals in sediments could not exert threat to aquatic lives in the ZFG until now.
Показать больше [+] Меньше [-]Stabilization of As-, Pb-, and Cu-contaminated soil using calcined oyster shells and steel slag Полный текст
2015
Moon, Deok Hyun | Wazne, Mahmoud | Cheong, Kyung Hoon | Chang, Yoon-Young | Baek, Kitae | Ok, Yong Sik | Park, Jeong-Hun
In this study, As-, Pb-, and Cu-contaminated soil was stabilized using calcined oyster shells (COS) and steel slag (SS). The As-contaminated soil was obtained from a timber mill site where chromate copper arsenate (CCA) was used as a preservative. On the other hand, Pb- and Cu-contaminated soil was obtained from a firing range. These two soils were thoroughly mixed to represent As-, Pb-, and Cu-contaminated soil. Calcined oyster shells were obtained by treating waste oyster shells at a high temperature using the calcination process. The effectiveness of stabilization was evaluated by 1-N HCl extraction for As and 0.1-N HCl extraction for Pb and Cu. The treatment results showed that As, Pb, and Cu leachability were significantly reduced upon the combination treatment of COS and SS. The sole treatment of SS (10 wt%) did not show effective stabilization. However, the combination treatment of COS and SS showed a significant reduction in As, Pb, and Cu leachability. The best stabilization results were obtained from the combination treatment of 15 wt% COS and 10 wt% SS. The SEM-EDX results suggested that the effective stabilization of As was most probably achieved by the formation of Ca-As and Fe-As precipitates. In the case of Pb and Cu, stabilization was most probably associated with the formation of pozzolanic reaction products such as CSHs and CAHs.
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