Refine search
Results 3021-3030 of 4,308
Qualitative and quantitative studies of chemical composition of sandarac resin by GC-MS Full text
2017
Kononenko, I. | de Viguerie, L. | Rochut, S. | Walter, Ph
The chemical composition of sandarac resin was investigated qualitatively and quantitatively by gas chromatography-mass spectrometry (GC-MS). Six compounds with labdane and pimarane skeletons were identified in the resin. The obtained mass spectra were interpreted and the mass spectrometric behaviour of these diterpenoids under EI conditions was described. Quantitative analysis by the method of internal standard revealed that identified diterpenoids represent only 10–30% of the analysed sample. The sandarac resin from different suppliers was analysed (from Kremer, Okhra, Color Rare, La Marchande de Couleurs, L'Atelier Montessori, Hevea). The analysis of different lumps of resins showed that the chemical composition differs from one lump to another, varying mainly in the relative distributions of the components.
Show more [+] Less [-]Risk assessment and interpretation of heavy metal contaminated soils on an urban brownfield site in New York metropolitan area Full text
2017
Qian, Yu | Gallagher, Frank | Deng, Yang | Wu, Meiyin | Feng, Huan
In this study, soil samples were collected at 22 sites in Liberty State Park, New Jersey, in 2005, for metal enrichment and potential ecological risk assessment. The geoaccumulation index (I gₑₒ) showed that enrichment levels of trace metals followed an order of Cu > Pb > Zn > As > Cr > Hg while the potential ecological risk factor ([Formula: see text]) indicated that the potential ecological risk of the metals was in the order of Cu > Pb > As > Hg > Zn > Cr. Among these 22 sites, this investigation identified 9 sites at moderate ecological risk, 3 sites at considerable ecological risk, and 4 sites at high ecological risk according to the potential ecological risk index (RI). Hierarchical cluster analysis (CA) of soil metal concentrations separated the study sites into four groups, which are supported by the significant difference in RI values. Geographically, three regions in the Liberty State Park brownfield site were determined based on the CA results and RI values. Subarea 1 had low ecological risk while subareas 2 and 3 had a greater potential for ecological risk. Significant correlations of Pb with Cr and Zn were observed in subareas 2 and 3, respectively. This study shows that statistical approaches coupled with a risk assessment index provide a more comprehensive interpretation of land contamination than a single approach in support of planning land redevelopment.
Show more [+] Less [-]Cu(II) adsorption from copper mine water by chitosan films and the matrix effects Full text
2017
Frantz, Tuanny S. | Silveira, Nauro, Jr | Quadro, Maurízio S. | Andreazza, Robson | Barcelos, Amauri A. | Cadaval, Tito R. S., Jr | Pinto, Luiz A. A.
Adsorption of copper ions onto chitosan films was studied, and the matrix effect was evaluated using a synthetic solution and a real effluent from closed copper mine. Chitosan films were prepared by casting technique and characterized. The adsorption study was carried out by equilibrium isotherms, thermodynamics, and kinetics. The thermodynamic parameters indicated that the copper adsorption onto chitosan film was favorable, spontaneous, and exothermic, suggesting an increased randomness at the solid/solution interface. The matrix effect was evaluated in kinetic assays, where a synthetic solution and a real system were carried out at different stirring rates. The highest values of adsorption capacity reached in all stirring rates were about 20% lower in the real effluent, and this reduction in the competitiveness was due to the presence of other ions in the matrix of the real effluent. The maximum adsorption capacity of copper ions onto chitosan films for the synthetic solution was of 450 mg g⁻¹, and the removal percentage was in the range from 78 to 96%, and these values for the real effluent were of 360 mg g⁻¹ and removal ranging from 62 to 76%. The mapping done of ions present in the water adsorbed of the mine in the films showed that the same was homogeneously distributed in the films’ surfaces.
Show more [+] Less [-]Construction of the Syngonium podophyllum-Pseudomonas sp. XNN8 Symbiotic Purification System and Investigation of Its Capability of Remediating Uranium Wastewater Full text
2017
Deng, Qin-wen | Wang, Yong-dong | Ding, De-xin | Hu, Nan | Sun, Jing | He, Jia-dong | Xu, Fei
The endophyte Pseudomonas sp. XNN8 was separated from Typha orientalis which can secrete indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate deaminase and siderophores and has strong resistance to uranium it was then colonized in the Syngonium podophyllum; and the S. podophyllum-Pseudomonas sp. XNN8 symbiotic purification system (SPPSPS) for uranium-containing wastewater was constructed. Afterwards, the hydroponic experiments to remove uranium from uranium-containing wastewater by the SPPSPS were conducted. After 24 days of treatment, the uranium concentrations of the wastewater samples with uranium concentrations between 0.5 and 5.0 mg/L were lowered to below 0.05 mg/L. Furthermore, the uranium in the plants was assayed using Fourier transform infrared spectroscopy (FTIR) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The Pseudomonas sp. XNN8 was found to generate substantial organic groups in the roots of the Syngonium podophyllum, which could improve the complexing capability of S. podophyllum for uranium. The uranium in the roots of S. podophyllum was found to be the uranyl phosphate (47.4 %) and uranyl acetate (52.6 %).
Show more [+] Less [-]Loss of crop yields in India due to surface ozone: an estimation based on a network of observations Full text
2017
Shyam Lal, | Venkataramani, Sethuraman | Naja, Manish | Kuniyal, JagdishChandra | Mandal, TuhinKumar | Bhuyan, PradipKumar | Kumari, KandikondaMaharaj | Tripathi, Sachchidanand | Sarkar, Ujjaini | Das, Trupti | Swamy, YerramsettiVenkata | Gopal, KotaloRama | Gadhavi, Harish | Kumar, ModathiKottungal Satheesh
Surface ozone is mainly produced by photochemical reactions involving various anthropogenic pollutants, whose emissions are increasing rapidly in India due to fast-growing anthropogenic activities. This study estimates the losses of wheat and rice crop yields using surface ozone observations from a group of 17 sites, for the first time, covering different parts of India. We used the mean ozone for 7 h during the day (M7) and accumulated ozone over a threshold of 40 ppbv (AOT40) metrics for the calculation of crop losses for the northern, eastern, western and southern regions of India. Our estimates show the highest annual loss of wheat (about 9 million ton) in the northern India, one of the most polluted regions in India, and that of rice (about 2.6 million ton) in the eastern region. The total all India annual loss of 4.0–14.2 million ton (4.2–15.0%) for wheat and 0.3–6.7 million ton (0.3–6.3%) for rice are estimated. The results show lower crop loss for rice than that of wheat mainly due to lower surface ozone levels during the cropping season after the Indian summer monsoon. These estimates based on a network of observation sites show lower losses than earlier estimates based on limited observations and much lower losses compared to global model estimates. However, these losses are slightly higher compared to a regional model estimate. Further, the results show large differences in the loss rates of both the two crops using the M7 and AOT40 metrics. This study also confirms that AOT40 cannot be fit with a linear relation over the Indian region and suggests for the need of new metrics that are based on factors suitable for this region.
Show more [+] Less [-]Comprehensive study on parameter sensitivity for flow and nutrient modeling in the Hydrological Simulation Program Fortran model Full text
2017
Luo, Chuan | Li, Zhaofu | Wu, Min | Jiang, Kaixia | Chen, Xiaomin | Li, Hengpeng
Numerous parameters are used to construct the HSPF (Hydrological Simulation Program Fortran) model, which results in significant difficulty in calibrating the model. Parameter sensitivity analysis is an efficient method to identify important model parameters. Through this method, a model’s calibration process can be simplified on the basis of understanding the model’s structure. This study investigated the sensitivity of the flow and nutrient parameters of HSPF using the DSA (differential sensitivity analysis) method in the Xitiaoxi watershed, China. The results showed that flow was mostly affected by parameters related to groundwater and evapotranspiration, including DEEPFR (fraction of groundwater inflow to deep recharge), LZETP (lower-zone evapotranspiration parameter), and AGWRC (base groundwater recession), and most of the sensitive parameters had negative and nonlinear effects on flow. Additionally, nutrient components were commonly affected by parameters from land processes, including MON-SQOLIM (monthly values limiting storage of water quality in overland flow), MON-ACCUM (monthly values of accumulation), MON-IFLW-CONC (monthly concentration of water quality in interflow), and MON-GRND-CONC (monthly concentration of water quality in active groundwater). Besides, parameters from river systems, KATM20 (unit oxidation rate of total ammonia at 20 °C) had a negative and almost linear effect on ammonia concentration and MALGR (maximal unit algal growth rate for phytoplankton) had a negative and nonlinear effect on ammonia and orthophosphate concentrations. After calibrating these sensitive parameters, our model performed well for simulating flow and nutrient outputs, with R ² and ENS (Nash–Sutcliffe efficiency) both greater than 0.75 for flow and greater than 0.5 for nutrient components. This study is expected to serve as a valuable complement to the documentation of the HSPF model to help users identify key parameters and provide a reference for performing sensitivity analyses on other models.
Show more [+] Less [-]Complex organic pollutant mixtures originating from industrial and municipal emissions in surface waters of the megacity Jakarta—an example of a water pollution problem in emerging economies Full text
2017
Dsikowitzky, Larissa | Hagemann, Lukas | Dwiyitno, | Ariyani, Farida | Irianto, Hari Eko | Schwarzbauer, Jan
During the last decades, the global industrial production partly shifted from industrialized nations to emerging and developing countries. In these upcoming economies, the newly developed industrial centers are generally located in densely populated areas, resulting in the discharge of often only partially treated industrial and municipal wastewaters into the surface waters. There is a huge gap of knowledge about the composition of the complex organic pollutant mixtures occurring in such heavily impacted areas. Therefore, we applied a non-target screening to comprehensively assess river pollution in a large industrial area located in the megacity Jakarta. More than 100 structurally diverse organic contaminants were identified, some of which were reported here for the first time as environmental contaminants. The concentrations of paper manufacturing chemicals in river water—for example, of the endocrine-disrupting compound bisphenol A (50–8000 ng L⁻¹)—were as high as in pure untreated paper industry wastewaters. The non-target screening approach is the adequate tool for the identification of water contaminants in the new global centers of industrial manufacturing—as the first crucial step towards the evaluation of as yet unrecognized environmental risks.
Show more [+] Less [-]Characterization of semen quality, testicular marker enzyme activities and gene expression changes in the blood testis barrier of Kunming mice following acute exposure to zearalenone Full text
2017
Long, Miao | Yang, Shuhua | Dong, Shuang | Chen, Xinliang | Zhang, Yi | He, Jianbin
A total of 95 8-week-old male Kunming mice were randomly assigned into five groups and exposed to zearalenone (ZEA) at doses of 25, 50, and 75 mg/kg delivered by intra-peritoneal (i.p.) injection for 5 days. The testis and epididymis indices involving sperm quality and morphology, testis enzyme activities, serum concentrations of testosterone and estrogen, and the expression levels of the three gene and protein of N-cadherin, vimentin, and claudin 11 related to the blood testis barrier (BTB) were analyzed. Results showed that ZEA significantly decreased body weight and semen quality compared to the control group along with increased activity of alkaline phosphatase (ALP), acid phosphatase (ACP), lactate dehydrogenase (LDH), and reduced serum concentrations of testosterone and estrogen. At the mRNA and protein levels, expression of N-cadherin, vimentin, and claudin 11 significantly increased; however, the mRNA and protein of N-cad expression decreased. These data suggest acute exposure to ZEA reduces sperm quality and significantly decreases the concentration of serum testosterone and estradiol. In addition, the activities of the testis marker enzymes and associated mRNA and protein expressions of the BTB were also significantly affected. Our results demonstrated that ZEA has a significant impact on the reproductive parameters of male mice which showed compensatory response to strengthen the barrier function of the BTB following ZEA exposure.
Show more [+] Less [-]Disinfection by-product formation during chlor(am)ination of algal organic matters (AOM) extracted from Microcystis aeruginosa: effect of growth phases, AOM and bromide concentration Full text
2017
Chen, Juxiang | Gao, Naiyun | Li, Lei | Zhu, Mingqiu | Yang, Jing | Lu, Xian | Zhang, Yansen
Algae organic matter (AOM), including extracellular organic matter (EOM) and intracellular organic matter (IOM), has caused a series of problems to the water quality, among which formation of disinfection by-products (DBPs) during subsequent chlor(am)ination process was especially serious and concerned. This study characterized physicochemical properties of the EOM and IOM solution extracted from different growth phases of Microcystis aeruginosa and investigated the corresponding formation potential of DBPs during chlor(am)ination process. Besides, the effects of initial concentration of xEOM, IOM, and Br⁻ on the yields of disinfection by-product formation potential were studied. The results indicated that the specific UV absorbance (SUVA₂₅₄) values of IOM and EOM (1.09 and 2.66 L/mg m) were considerably lower than that of natural organic matter (NOM) (4.79 L/mg m). Fluorescence dates showed the soluble microbial by-product was dominant in both EOM and IOM, and the tryptophan was the main component of AOM. From the excitation–emission matrix figure of EOM and IOM, we found that the content of the high molecular weight protein substance in IOM was higher than EOM. During chlorination of EOM and IOM, the yields of four kinds of DBPs followed the order trichloroethene (TCM) > 1,1-DCP > dichloride acetonitrile (DCAN) > trichloronitromethane (TCNM), while the order was TCM > DCAN > TCNM > 1,1-DCP during chloramination process. The bromine substitution factor (BSF) value increased with the increasing of the concentration of Br⁻. When the concentration of Br⁻ was 500 μg/L, the BSF values of chlorination EOM and IOM were 51.1 and 68.4%, respectively. As the concentration of Br⁻ increased, the formation of Cl–DBPs was inhibited and the formation of Br–DBPs was promoted. Graphical abstract ᅟ
Show more [+] Less [-]Assessment of alternatives to environmental toxic formalin for DNA conservation in biological specimens Full text
2017
Sarot, Emeline | Carillo-Baraglioli, Marie-Françoise | Duranthon, F. (Francis) | Péquignot, Amandine | Pyronnet, Stéphane
One essential step of museum and clinical specimen preservation is immersion in a fixative fluid to prevent degradation. Formalin is the most largely used fixative, but its benefit is balanced with its toxic and carcinogenic status. Moreover, because formalin-fixation impairs nucleic acids recovery and quality, current museum wet collections and formalin-fixed, paraffin-embedded clinical samples do not represent optimal tanks of molecular information. Our study has been developed to compare formalin to two alternative fixatives (RCL2® and ethanol) in a context of molecular exploitation. Based on a unique protocol, we created mammalian fixed collections, simulated the impact of time on preservation using an artificial ageing treatment and followed the evolution of specimens’ DNA quality. DNA extraction yield, purity, visual integrity and qualitative and quantitative ability to amplify the Cox1 gene were assessed. Our results show that both RCL2 and ethanol exhibit better performances than formalin. They do not impair DNA extraction yield, and more importantly, DNA alteration is delayed over the preservation step. The use of RCL2 or ethanol as fixative in biological collections may insure a better exploitation of the genetic resources they propose.
Show more [+] Less [-]