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Resultados 1451-1460 de 2,512
Distribution features of biological hazardous pollutants in residential environments in Korea Texto completo
2014
Lee, Cheol Min | Hong, Soo Jong | Kim, Yoon Shin | Park, Gee Yong | Nam Goung, Sun Ju | Kim, Kyung-Hwan
This research has been conducted continuously since 2009 as part of a cohort of studies examining relationships between asthma and genetic factors, dietary habits, and environmental factors. Based on data from environmental research on house dust mites and endotoxins, which are widely known as pollutants in bedding that cause asthma in pregnant women and children, this work was conducted to obtain basic data that can be used in future cohort studies that analyze links between distribution of biological hazards and physical features of residential environments. The detection rates of house dust mite allergens, Der p1 and Der f1, were 52.7 and 86.5 %, respectively, indicating that Der f1 is a dominant species in domestic indoor environments. According to comparisons between concentrations of house dust mites and endotoxins in bedding of pregnant women and children, Der p1 and endotoxins showed significantly lower concentrations in bedding of pregnant women compared with those in bedding of children, whereas Der f1 showed no significant difference in concentration according to bedding.
Mostrar más [+] Menos [-]Spatial modeling of ecological areas by fitting the limiting factors for As in the vicinity of mine, Serbia Texto completo
2014
Cakmak, Dragan | Perovic, Veljko | Saljnikov, Elmira | Jaramaz, Darko | Sikiric, Biljana
Elevated arsenic (As) concentrations in soil are often found in the vicinity of certain mineral deposits that have been, or are currently, under exploitation, regardless of the target resource. Detailed study of such areas for safe agriculture requires considerable financial costs and long periods of time. Application of an appropriate spatial model that describes the behavior of arsenic in soil and plants can significantly ease the whole investigation process. This paper presents a model of ecological security of an area that, in the past, was an antimony mine and has a naturally high content of arsenic. For simulation and modeling the geographic information science (GIS) technology with the inserted predictors influencing the accessibility of As and its content in plants was used. The results obtained were the following: (1) a categorization of contaminated soils according to soil properties was developed; (2) the proposed methodology allows focusing on particular suspect area saving an energy and human resource input; and (3) new safe areas for growing crops in contaminated area were modeled. The application of the proposed model of As solubility to various crops grown around a former antimony mine near the village of Lisa, southwest Serbia showed that significant expansion of the areas suitable for growing potato, raspberry, and pasture was possible.
Mostrar más [+] Menos [-]Amendment application in a multi-contaminated mine soil: effects on soil enzymatic activities and ecotoxicological characteristics Texto completo
2014
Manzano, Rebeca | Esteban, Elvira | Peñalosa, Jesús M. | Alvarenga, Paula
Several amendments were tested on soils obtained from an arsenopyrite mine, further planted with Arrhenatherum elatius and Festuca curvifolia, in order to assess their ability to improve soil's ecotoxicological characteristics. The properties used to assess the effects were: soil enzymatic activities (dehydrogenase, β-glucosidase, acid phosphatase, urease, protease and cellulase), terrestrial bioassays (Eisenia fetida mortality and avoidance behaviour), and aquatic bioassays using a soil leachate (Daphnia magna immobilisation and Vibrio fischeri bioluminescence inhibition). The treatment with FeSO₄1 % w/w was able to reduce extractable As in soil, but increased the extractable Cu, Mn and Zn concentrations, as a consequence of the decrease in soil pH, in relation to the unamended soil, from 5.0 to 3.4, respectively. As a consequence, this treatment had a detrimental effect in some of the soil enzymatic activities (e.g. dehydrogenase, acid phosphatase, urease and cellulase), did not allow plant growth, induced E. fetida mortality in the highest concentration tested (100 % w/w), and its soil leachate was very toxic towards D. magna and V. fischeri. The combined application of FeSO₄1 % w/w with other treatments (e.g. CaCO₃1 % w/w and paper mill 1 % w/w) allowed a decrease in extractable As and metals, and a soil pH value closer to neutrality. As a consequence, dehydrogenase activity, plant growth and some of the bioassays identified those as better soil treatments to this type of multi-contaminated soil.
Mostrar más [+] Menos [-]Decomposition of non-ionic surfactant Tergitol TMN-10 by the Fenton process in the presence of iron oxide nanoparticles Texto completo
2014
Kos, L. | Michalska, K. | Perkowski, J.
The aim of our studies was to determine the efficiency of decomposition of non-ionic surfactant by the Fenton method in the presence of iron nanocompounds and to compare it with the classical Fenton method. The subject of studies was water solutions of non-ionic detergent Tergitol TMN-10 used in textile industry. Water solutions of the surfactant were subjected to treatment by the classical Fenton method and to treatment in the presence of iron nanocompounds. In the samples of liquid solutions containing the surfactant, chemical oxygen demand (COD) and total organic carbon (TOC) were determined. The Fenton process was optimized based on studies of the effect of compounds used in the treatment, doses of iron and nanoiron, hydrogen peroxide and pH of the solution on surfactant decomposition. Iron oxide nanopowder catalyzed the process of detergent decomposition, increasing its efficiency and the degree of mineralization. It was found that the efficiency of the surfactant decomposition in the process with the use of iron nanocompounds was by 10 to 30 % higher than that in the classical method. The amounts of formed deposits were also several times smaller.
Mostrar más [+] Menos [-]Release of vanadium from oxidized sediments: insights from different extraction and leaching procedures Texto completo
2014
Cappuyns, V. | Swennen, R.
Although the attention for vanadium (V) as a potentially harmful element is growing and some countries adopted threshold values for V in soils, sediments, groundwater, or surface water, V is generally of little importance in environmental legislation and the knowledge about the behavior of V in the environment is still limited. In the present study, the release of V from oxidized sediments, sediment-derived soils, and certified reference materials was investigated by means of several types of leaching tests and extractions that are frequently used for soil and sediment characterization. The pHₛₜₐₜleaching tests and single and sequential extractions applied in this study show that V generally displays a very limited actual and potential mobility in sediment. “Mobile” V concentrations, as estimated by the amount of V released by a single extraction with CaCl₂0.01 mol L⁻¹, were low, even in the most contaminated sediment samples. Only under strongly acidifying conditions (pH 2), such as in the case of ingestion of soil or sediment or in accidental spills, a substantial release of V can be expected.
Mostrar más [+] Menos [-]Application of canonical correspondence analysis to determine the ecological contribution of phytoplankton to PCBs bioaccumulation in Qinhuai River, Nanjing, China Texto completo
2014
Zhao, Zhenhua | Jiang, Ying | Xia, Liling | Mi, Tengfei | Yan, Wenming | Gao, Yanzheng | Jiang, Xin | Fawundu, Elchico | Hussain, Javid
The distribution and interactions of phytoplankton and 14 polychlorinated biphenyls (PCBs) were investigated using canonical correspondence analysis in autumn in the Qinhuai River, Nanjing, China. Concentrations of PCBs in water and algal samples ranged from 33.78 to 144.84 ng/L and from 0.21 to 19.66 ng/L (0.06 to 3.04 ng/mg biomass), respectively. The predominant residual species of PCBs in water samples were tri- through hexachlorobiphenyls, and the predominant residuals in algae were tri-, tetra-, and heptachlorobiphenyls. The degree of eutrophication affected phytoplankton composition and PCB bioaccumulation, and led to sample site- and algal species specificity of PCB residues in the study area. Chlorophyta, Bacillariophyta, and Euglenophyta had strong capacities to take up PCBs, whereas Cyanophyta was less involved in the transfer of these compounds. Bioaccumulation of PCBs by algae may be affected by water quality, chlorination, phytoplankton composition, and the structure of the PCBs and the algal cell walls.
Mostrar más [+] Menos [-]Multivariate optimization of the decolorization process by surface modified biomaterial: Box–Behnken design and mechanism analysis Texto completo
2014
Akar, Sibel Tunali | Sayin, Fatih | Türkyılmaz, Serpil | Akar, Tamer
A natural biosorbent obtained from Pyracantha coccinea was modified with an anionic surfactant to facilitate its dye removal ability. Modified biosorbent was successfully employed for the decolorization of Methyl Violet (MV)-contaminated solutions. A three-variable Box–Behnken design for response surface methodology was used to examine the function of independent operating variables. Optimum pH and biosorbent amount were found to be 6.0 and 0.055 g, respectively. The effects of temperature and ionic strength on the dye removal performance of biosorbent were also investigated. A biosorption equilibrium was attained within 30 min and experimental data fitted well to the pseudo-second-order model. The Langmuir isotherm model fitted adequately to the equilibrium data. The maximum monolayer biosorption capacity of the modified biosorbent was found to be 254.88 mg g⁻¹. Good biosorption yields were also recorded in continuous biosorption system. Ion exchange and complexation could be suggested as possible mechanisms for the biosorption. The developed modified biosorbent was regenerated up to 80.30 % by 0.005 M HCl. At real wastewater conditions, it has 86.23 ± 0.21 and 94.51 ± 1.09 % dye removal yields in batch and column systems, respectively. Modified biomaterial can be used as an effective biosorbent for the removal of MV dye from aqueous solution with high biosorption performance.
Mostrar más [+] Menos [-]Decomposition of China’s CO2 emissions from agriculture utilizing an improved Kaya identity Texto completo
2014
Li, Wei | Ou, Qingxiang | Chen, Yulu
In recent decades, China’s agriculture has been experiencing flourishing growth accompanied by rising pesticide consumption, fertilizer consumption, energy consumption, etc. and increasing CO₂emissions. Analyzing the driving forces of agricultural CO₂emissions is key requirements for low-carbon agricultural policy formulation and decomposition analysis is widely used for this purpose. This study estimates the agricultural CO₂emissions in China from 1994 to 2011 and applies the Logarithmic Mean Divisia Index (LMDI) as the decomposition technique. Change in agricultural CO₂emissions is decomposed from 1994 to 2011 and includes a measure of the effect of agricultural subsidy. Results illustrate that economic development acts to increase CO₂emissions significantly. Agricultural subsidy acts to reduce CO₂emissions effectively and has increased in recent years. Policy is needed to significantly optimize agricultural subsidy structure and change agricultural development pathway, if China’s low-carbon agriculture target is to be achieved. This requires not only decreasing pesticide consumption, fertilizer consumption, energy consumption, etc. but also transformation of China’s agricultural development path for optimal outcomes.
Mostrar más [+] Menos [-]Cytogenetic biomonitoring of primary school children exposed to air pollutants: micronuclei analysis of buccal epithelial cells Texto completo
2014
Demircigil, Gonca Çakmak | Erdem, Onur | Gaga, Eftade O. | Altuğ, Hicran | Demirel, Gülçin | Özden, Özlem | Arı, Akif | Örnektekin, Sermin | Döğeroğlu, Tuncay | van Doorn, Wim | Burgaz, Sema
There is an increasing attempt in the world to determine the exposures of children to environmental chemicals. To analyze the genotoxic effect of air pollution, micronucleus (MN) assay was carried out in buccal epithelial cells (BECs) of children living in an urban city of Turkey. Children from two schools at urban-traffic and suburban sites were investigated in summer and winter seasons for the determination of BEC-MN frequency (per mille) and frequency of BEC with MN (per mille). The same children were also recruited for lung function measurements within a MATRA project (“Together Towards Clean Air in Eskisehir and Iskenderun”) Measured NO₂and SO₂concentrations did not exceed the European Union (EU) limit levels either in urban-traffic or suburban regions. Higher O₃concentrations were measured in the suburban site especially in the summer period. Particulate matter (PM₂.₅and PM₁₀) levels which did not differ statistically between two regions were above the EU limits in general. Although BEC-MN frequencies of children living in the suburban sites were higher in general, the difference between two regions was not significant either in the summer or winter periods. BEC-MN frequencies of the urban-traffic children were found to be significantly higher in summer period (mean ± SD, 2.68 ± 1.99) when compared to winter period (1.64 ± 1.59; p = 0.004). On the other hand, no seasonality was observed for the suburban children. Similar results have been obtained in the BEC frequency with MN in our study. In summer, BEC-MN frequencies were significantly increased with the decrease in pulmonary function levels based on forced expiratory flow between 25 and 75 % of vital capacity (FEF₂₅–₇₅ %) levels (p < 0.05). As a conclusion, children living in urban-traffic and suburban areas in the city of Eskişehir exhibited similar genotoxicity. Seasonal variation in genotoxicity may be interpreted as relatively high ozone levels and increasing time spent at outdoors in the summer.
Mostrar más [+] Menos [-]Fluctuating asymmetry in Robinia pseudoacacia leaves—possible in situ biomarker? Texto completo
2014
Klisarić, Nataša Barišić | Miljković, Danijela | Avramov, Stevan | Živković, Uroš | Tarasjev, Aleksej
In this study, we analyzed fluctuating asymmetry (FA) of black locust (Robinia pseudoacacia) leaf traits as a measure of developmental instability in polluted and unpolluted habitats. We aimed to evaluate the potential of this method as a biomarker and its applicability on widely distributed species under in situ conditions. Leaf samples were taken from seven sites—three categorized as unpolluted (natural protected and rural) and four categorized as polluted covering the broad spectrum of intense pollution (industrial and traffic), from 1,489 individual trees in total. Results revealed significant differences in FA with expected higher values in polluted environments. Applicability of FA of R. pseudoaccacia leaf traits as a biomarker for testing potential pollution level, as well as the amount and distribution of sampling effort needed for its application, are discussed.
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