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Результаты 1481-1490 из 1,956
Silver behaviour along the salinity gradient of the Gironde Estuary Полный текст
2013
Lanceleur, Laurent | Schäfer, Jörg | Blanc, Gérard | Coynel, Alexandra | Bossy, Cécile | Baudrimont, Magalie | Glé, Corine | Larrose, Aurélie | Renault, Sophie | Strady, Emilie
Dissolved and particulate Ag concentrations (AgD and AgP, respectively) were measured in surface water and suspended particulate matter (SPM) along the salinity gradient of the Gironde Estuary, South West France, during three cruises (2008–2009) covering contrasting hydrological conditions, i.e. two cruises during intermediate and one during high freshwater discharge (~740 and ~2,300 m³/s). Silver distribution reflected non-conservative behaviour with 60–70 % of AgP in freshwater particles being desorbed by chlorocomplexation. The amount of AgP desorbed was similar to the so-called reactive, potentially bioavailable AgP fraction (60 ± 4 %) extracted from river SPM by 1 M HCl. Both AgP (0.22 ± 0.05 mg/kg) and AgP/ThP (0.025–0.028) in the residual fraction of fluvial and estuarine SPM were similar to those in SPM from the estuary mouth and in coastal sediments from the shelf off the Gironde Estuary, indicating that chlorocomplexation desorbs the reactive AgP. The data show that desorption of reactive AgP mainly occurs inside the estuary during low and intermediate discharge, whereas expulsion of partially AgP-depleted SPM (AgP/ThP ~0.040) during the flood implies ongoing desorption in the coastal ocean, e.g. in the nearby oyster production areas (Marennes-Oléron Bay). The highest AgD levels (6–8 ng/L) occurred in the mid-salinity range (15–20) of the Gironde Estuary and were decoupled from freshwater discharge. In the maximum turbidity zone, AgD were at minimum, showing that high SPM concentrations (a) induce AgD adsorption in estuarine freshwater and (b) counterbalance AgP desorption in the low salinity range (1–3). Accordingly, Ag behaviour in turbid estuaries appears to be controlled by the balance between salinity and SPM levels. The first estimates of daily AgD net fluxes for the Gironde Estuary (Boyle’s method) showed relatively stable theoretical AgD at zero salinity (Ag D ⁰ = 25–30 ng/L) for the contrasting hydrological situations. Accordingly, AgD net fluxes were very similar for the situations with intermediate discharge (1.7 and 1.6 g/day) and clearly higher during the flood (5.0 g/day) despite incomplete desorption. Applying Ag D ⁰ to the annual freshwater inputs provided an annual net AgD flux (0.64–0.89 t/year in 2008 and 0.56–0.77 t/year in 2009) that was 12–50 times greater than the AgD gross flux. This estimate was consistent with net AgD flux estimates obtained from gross AgP flux considering 60 % desorption in the estuarine salinity gradient.
Показать больше [+] Меньше [-]Assessment of phytotoxicity of ZnO NPs on a medicinal plant, Fagopyrum esculentum Полный текст
2013
Lee, Sooyeon | Kim, Sunghyun | Kim, Saeyeon | Lee, Insook
Fagopyrum esculentum commonly named as buckwheat plant is pseudocereal food crops and healthy herbs but is not known as a bioindicator of environmental condition. In the present study, the effects of ZnO nanoparticles (NPs) and microparticles (MPs) on plant growth, bioaccumulation, and antioxidative enzyme activity in buckwheat were estimated under hydroponic culture. The significant biomass reduction at concentrations of 10–2,000 mg/L was 7.7–26.4 % for the ZnO NP and 11.4–23.5 % for the ZnO MP treatment, (p < 0.05). ZnO NPs were observed in root cells and root cell surface by scanning electron microscopy and transmission electron microscopy analysis. Zn bioaccumulation in plant increased with increasing treatment concentrations. The upward translocation (translocation factor <0.2) of Zn in plant was higher with the ZnO NP treatment than that with the ZnO MP treatment. Additionally, reactive oxygen species generation by ZnO NPs was estimated as the reduced glutathione level and catalase activity, which would be a predictive biomarker of nanotoxicity. The results are the first study to evaluate the phytotoxicity of ZnO NPs to medicinal plant. F. esculentum can be as a good indicator of plant species in NP-polluted environment.
Показать больше [+] Меньше [-]Trace metals, anions and polybromodiphenyl ethers in settled indoor dust and their association Полный текст
2013
Kefeni, Kebede K. | Okonkwo, Jonathan O.
Contaminants in settled indoor dust are potentially health hazardous to human. Thus, identification and quantification of toxic chemicals in settled indoor dust is of great concern. In this study, the levels of major anions ([Formula: see text]), trace metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, As and Pb) and polybromodiphenyl ethers (PBDEs) in settled office and home dust were determined and correlations between the contaminants investigated. Depending on the available materials in both microenvironments, the most possible sources were identified. The results showed that the settled office dusts (n = 6 pooled samples from 85 offices) were more contaminated than home dusts (n = 8 homes). For anions, [Formula: see text] and Cl(-) accounted for 87 and 97 % of the total office and home dust contaminants, respectively. For trace metals, Fe, Cu, Zn and Mn, accounted for 98 % of the contaminants in both office and home dust samples. Fe exhibited the highest percentage of 76.7 and 87.3 % in office and home dust samples, respectively. For PBDEs, the mean concentrations detected in office and home dust ranged between 5.8-86.3 and 1.5-20.6 ng g(-1), respectively. The log-transformed correlation between the total concentrations of trace metals and major anions detected in offices and homes was positive for offices and negative for homes with a statistically significant values (r = 0.73, p < 0.01; r = -0.22, p < 0.01, respectively). The daily exposure rates determined for the most hazardous such as As, Cd, Pb and PBDEs congeners, relative to the individual concentrations reported in the literature in settled indoor dust, were found very lower. Therefore, maybe it is possible to expect less potential health risk. Investigation of formation of coordination compounds between trace metals and PBDEs congeners is possible; however, this requires further study.
Показать больше [+] Меньше [-]Perfluorinated alkylated substances in vegetables collected in four European countries; occurrence and human exposure estimations Полный текст
2013
Herzke, Dorte | Huber, Sandra | Bervoets, Lieven | D’Hollander, Wendy | Hajslova, Jana | Pulkrabova, Jana | Brambilla, Gianfranco | De Filippis, Stefania Paola | Klenow, Stefanie | Heinemeyer, Gerhard | Voogt, Pim de
Perfluorinated alkylated substances in vegetables collected in four European countries; occurrence and human exposure estimations Полный текст
2013
Herzke, Dorte | Huber, Sandra | Bervoets, Lieven | D’Hollander, Wendy | Hajslova, Jana | Pulkrabova, Jana | Brambilla, Gianfranco | De Filippis, Stefania Paola | Klenow, Stefanie | Heinemeyer, Gerhard | Voogt, Pim de
The human diet is recognised as one possible major exposure route to the overall perfluorinated alkylated substances (PFAS) burden of the human population, resulting directly from contamination of dietary food items, as well as migration of PFAS from food packaging or cookware. Most European countries carry out national monitoring programs (food basket studies) to monitor contamination with pollutants. Usually, for PFASs, non-coordinated approaches are used in Europe, since food basket studies are mainly carried out by national authorities following national requirements and questions, making comparisons between different countries difficult. A harmonised sampling campaign collecting similar food items in a uniform procedure enabling direct comparison between different regions in Europe was designed. We selected four countries (Belgium, Czech Republic, Italy and Norway), representing the four regions of Europe: West, East, South and North. In spring 2010 and 2011, 20 different types of vegetables were sampled in Belgium, Czech Republic, Italy and Norway. Perfluorinated carboxylic acids (PFCAs) were the main group of detected PFASs, with perfluorinated octanoic acid (PFOA) as the most abundant PFCA (with exception of samples from Czech Republic), followed by perfluorinated hexanoic acid and perfluorinated nonanoic acid. Dietary intake estimates for PFOA show only low human exposure due to vegetable consumption for adults and children, mostly governed by high intake of potatoes.
Показать больше [+] Меньше [-]Perfluorinated alkylated substances in vegetables collected in four European countries; occurrence and human exposure estimations Полный текст
2013
Herzke, D. | Huber, S. | Bervoets, L. | D’Hollander, W. | Hajslova, J. | Pulkrabova, J. | Brambilla, G. | Filippis, S. P. | Klenow, S. | Heinemeyer, G. | Voogt, P.
The human diet is recognised as one possible major exposure route to the overall perfluorinated alkylated substances (PFAS) burden of the human population, resulting directly from contamination of dietary food items, as well as migration of PFAS from food packaging or cookware. Most European countries carry out national monitoring programs (food basket studies) to monitor contamination with pollutants. Usually, for PFASs, non-coordinated approaches are used in Europe, since food basket studies are mainly carried out by national authorities following national requirements and questions, making comparisons between different countries difficult. A harmonised sampling campaign collecting similar food items in a uniform procedure enabling direct comparison between different regions in Europe was designed. We selected four countries (Belgium, Czech Republic, Italy and Norway), representing the four regions of Europe: West, East, South and North. In spring 2010 and 2011, 20 different types of vegetables were sampled in Belgium, Czech Republic, Italy and Norway. Perfluorinated carboxylic acids (PFCAs) were the main group of detected PFASs, with perfluorinated octanoic acid (PFOA) as the most abundant PFCA (with exception of samples from Czech Republic), followed by perfluorinated hexanoic acid and perfluorinated nonanoic acid. Dietary intake estimates for PFOA show only low human exposure due to vegetable consumption for adults and children, mostly governed by high intake of potatoes.
Показать больше [+] Меньше [-]The investigation of the possibility for using some wild and cultivated plants as hyperaccumulators of heavy metals from contaminated soil Полный текст
2013
Maric, Miroslava | Antonijević, Milan | Alagic, Sladjana
The copper production in Bor (East Serbia) during the last 100 years presents an important source of the pollution of environment. Dust, waste waters, tailing, and air pollutants influence the quality of soil, water, and air. Over 2,000 ha of fertile soil have been damaged by the flotation tailing from Bor’s facilities. The goal of the present work has been to determine the content of Pb, Cu, and Fe in wild plants (17 species) naturally growing in the damaged soil and in fodder crops (nine species) planted at the same place. The content of Pb, Cu, and Fe has been analyzed in damaged soil as well. This study has also searched for native (wild) and cultivated plants which are able to grow in contaminated soil in the area of the intense industrial activity of copper production in Bor, which means that they can accumulate and tolerate heavy metals in their above-ground tissues. It has been found out that the content of all metals in contaminated soil decreases considerably at the end of the experiment. As it has been expected, all plant species could accumulate investigated metals. All tested plants, both wild-growing and cultivated plants, seem to be quite healthy on the substrate which contained extremely high concentrations of copper.
Показать больше [+] Меньше [-]Ion-imprinted polymers for environmental monitoring of inorganic pollutants: synthesis, characterization, and applications Полный текст
2013
Mafu, Lihle D. | Msagati, Titus A. M. | Mamba, Bhekie B.
Ion imprinting has become one of the fast-growing technologies that have gained a lot of attention recently especially in the area of materials science. One of them is called the ion-imprinted polymers (IIPs). The IIPs are synthesized on the principles of enzyme phenomenon whereby a polymer is altered by a polymerization that takes place in the presence of a template that will be later removed to create cavities that will recognize only the analyte of interest. This specific and selective affinity for the target species decreases the chances of competition with other different types of ions. The imprinting technique started with the discovery of the bulk polymerization method where by the monomer, initiator, crosslinker, and template are mixed together and allowed to polymerize, and then the resulting polymer is ground and sieved to get particles with sizes suitable for the polymer's application. The IIPs have got some attractive qualities for use in environmental applications which include their stability and inexpensiveness and have a wide range of synthesis options with each suiting a certain unique application. Apart from environmental work, IIPs have applications in many other areas such as in membranes, in drug delivery, and in biosensors as alternatives to antibodies just to mention a few. This review focuses on the synthesis, types of imprinting, characterization, and applications of IIPs.
Показать больше [+] Меньше [-]Trace element concentrations in soils along urbanization gradients in the city of Wien, Austria Полный текст
2013
Simon, Edina | Vidic, Andreas | Braun, Mihály | Fábián, István | Tóthmérész, Béla
Urban soil is an important component of urban ecosystems. This study focuses on heavy metal contamination in soils of Wien (Austria) and results are compared to those for a few large European cities. We analysed the elemental contents of 96 samples of topsoil from urban, suburban and rural areas in Wien along a dynamic (floodplain forest) and a stable (oak–hornbeam forest) urbanization gradient. The following elements were quantified using ICP-OES technique: Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Pb, P, S and Zn. For heavy metals PI (pollution index) values were used to assess the level of pollution. The PI values indicated high level of pollution by Pb in the suburban and rural area of stable gradient and in the urban area of dynamic gradient; moderate level of pollution was indicated for Cd in the urban area of stable gradient. The level of pollution was moderate for Co in the suburban and rural area of the stable gradient, and for Cu in suburban area of stable gradient, and urban area of dynamic gradient. The pollution level of Zn was moderate in all areas. Urban soils, especially in urban parks and green areas may have a direct influence on human health. Thus, the elemental analysis of soil samples is one of the best ways to study the effects of urbanization. Our results indicated that the heavy metal contamination was higher in Wien than in a few large European cities.
Показать больше [+] Меньше [-]Effects of lead and cadmium exposure from electronic waste on child physical growth Полный текст
2013
Yang, Hui | Huo, Xia | Yekeen, Taofeek Akangbe | Zheng, Qiujian | Zheng, Minghao | Xu, Xijin
Many studies indicate that lead (Pb) and cadmium (Cd) exposure may alter bone development through both direct and indirect mechanisms, increasing the risk of osteoporosis later in life. The aim of this study was to investigate the association between Pb and Cd exposure, physical growth, and bone and calcium metabolism in children of an electronic waste (e-waste) processing area. We recruited 246 children (3–8 years) in a kindergarten located in Guiyu, China. Blood lead levels (BLLs) and blood cadmium levels (BCLs) of recruited children were measured as biomarkers for exposure. Serum calcium, osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline were used as biomarkers for bone and calcium metabolism. Physical indexes such as height, weight, and head and chest circumference were also measured. The mean values of BLLs and BCLs obtained were 7.30 μg/dL and 0.69 μg/L, respectively. The average of BCLs increased with age. In multiple linear regression analysis, BLLs were negatively correlated with both height and weight, and positively correlated with bone resorption biomarkers. Neither bone nor calcium metabolic biomarkers showed significant correlation with cadmium. Childhood lead exposure affected both physical development and increased bone resorption of children in Guiyu. Primitive e-waste recycling may threaten the health of children with elevated BLL which may eventually cause adult osteoporosis.
Показать больше [+] Меньше [-]Determination of benzotriazoles in dishwasher tabs from Germany and estimation of the discharge into German waters Полный текст
2013
Vetter, Walter | Lorenz, Joachim
A method was developed for the determination of benzotriazoles (BTs) in dishwasher tabs. BTs consist of 1H-benzotriazole and/or tolyltriazole, i.e., a technical mixture of the two isomers 4-methylbenzotriazole and 5-methylbenzotriazole (5-MBT). The method consisted of weighing of an aliquot of the tab, addition of the internal standard 5-MBT, precipitation of the soaps with CaCl₂and KOH, derivatization of the filtrate with acetic acid anhydride in a two-phase system, and analysis of the organic toluene layer by gas chromatography with mass spectrometry in the selected ion monitoring mode. Eleven of 12 different dishwasher tabs from the German market were tested positive with BTs ranging from 2 to 66 mg/tab. Dishwashing experiments were performed to show that at least 99 % of the BT amount used in the dishwasher did not remain on the dishes but was released into the wastewater treatment system. The annual release of BTs into the water system was estimated to be ~80 tons. Since 70 % or less of the BTs can be degraded in wastewater treatment plants, at least 24 tons are annually released into rivers in Germany.
Показать больше [+] Меньше [-]Photocatalytic degradation of contaminants of concern with composite NF-TiO₂ films under visible and solar light Полный текст
2013
Barndõk, H. | Peláez, M. | Han, C. | Platten, W. E. III | Campo, P. | Hermosilla, D. | Blanco, A. | Dionysiou, D. D.
This study reports the synthesis and characterization of composite nitrogen and fluorine co-doped titanium dioxide (NF-TiO₂) for the removal of contaminants of concern in wastewater under visible and solar light. Monodisperse anatase TiO₂ nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-TiO₂ by direct incorporation into the sol–gel or by the layer-by-layer technique. The composite films were characterized with X-ray diffraction, high-resolution transmission electron microscopy, environmental scanning electron microscopy, and porosimetry analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was evaluated in a synthetic water solution and in an effluent from a hybrid biological concentrator reactor (BCR). Minor aggregation and improved distribution of monodisperse titania particles was obtained with NF-TiO₂-monodisperse (10 and 50 nm) from the layer-by-layer technique than with NF-TiO₂ + monodisperse TiO₂ (300 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-layer method achieved significantly higher degradation rates in contrast with NF-TiO₂-monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO₂-P25. Using NF-TiO₂ layer-by-layer with monodisperse TiO₂ (50 nm) under solar light irradiation, the respective degradation rates in synthetic water and BCR effluent were 14.6 and 9.5 × 10⁻³ min⁻¹ for caffeine, 12.5 and 9.0 × 10⁻³ min⁻¹ for carbamazepine, and 10.9 and 5.8 × 10⁻³ min⁻¹ for atrazine. These results suggest that the layer-by-layer technique is a promising method for the synthesis of composite TiO₂-based films compared to the direct addition of nanoparticles into the sol.
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