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Decreased rates of terpene emissions in Ornithopus compressus L. and Trifolium striatum L. by ozone exposure and nitrogen fertilization Полный текст
2014
Llusia, Joan | Bermejo-Bermejo, Victoria | Calvete-Sogo, Héctor | Peñuelas, Josep
Increasing tropospheric ozone (O3) and nitrogen soil availability (N) are two of the main drivers of global change. They both may affect gas exchange, including plant emission of volatiles such as terpenes. We conducted an experiment using open-top chambers to analyze these possible effects on two leguminous species of Mediterranean pastures that are known to have different O3 sensitivity, Ornithopus compressus and Trifolium striatum. O3 exposure and N fertilization did not affect the photosynthetic rates of O. compressus and T. striatum, although O3 tended to induce an increase in the stomatal conductance of both species, especially T. striatum, the most sensitive species. O3 and N soil availability reduced the emission of terpenes in O. compressus and T. striatum. If these responses are confirmed as a general pattern, O3 could affect the competitiveness of these species.
Показать больше [+] Меньше [-]Exposure of general population to PBDEs: A Progressive Total Diet Study in South Korea Полный текст
2014
Nguyen, Khanh-Hoang | Pyo, Heesoo | Kim, Jongchul | Shin, EunSu | Chang, Yoon Seok
This study assessed the level of 24 polybrominated diphenyl ethers (PBDEs) in Korean foods following a Progressive Total Diet Study (TDS). The experiments comprised 96 types of dietetically representative foods, all were either cooked or edible raw. PBDEs were widely encountered in foodstuffs with the highest concentration in plant oils, fishes and shellfishes. Of all congeners tested for, BDE-47 was the most predominant and encountered in almost all food items except meats. The presence of nona-BDEs at significant levels indicated that Korean environments are still contaminated by deca-BDE. The daily dietary intake of PBDEs was estimated to be 63 ng d−1. The highest PBDEs intake was observed in the 19–39 year old group and gradually decreased as age increased. Our study suggests that the TDS approach using foods in the table-ready form should be used for a better estimation of dietary exposure to PBDEs.
Показать больше [+] Меньше [-]Climatic factors influence leaf structure and thereby affect the ozone sensitivity of Ipomoea nil ‘Scarlet O'Hara’ Полный текст
2014
Moura, Bárbara B. | Alves, Edenise S.
Phenotypic plasticity of the leaves can interfere with the plant sensitivity to ozone (O3) toxic effect. This study aimed to assess whether the leaf structure of Ipomoea nil changes due to climatic variations and whether these changes affect the species' sensitivity. Field exposures, in different seasons (winter and spring) were made. The leaves that developed during the winter were thinner, with a lower proportion of photosynthetic tissues, higher proportion of intercellular spaces and lower density and stomatal index compared to those developed during the spring. The temperature and relative humidity positively influenced the leaf thickness and stomatal index. The visible injuries during winter were positively correlated with the palisade parenchyma thickness and negatively correlated with the percentage of spongy parenchyma; during the spring, the symptoms were positively correlated with the stomatal density. In conclusion, the leaf structure of I. nil varied among the seasons, interfering in its sensitivity to O3.
Показать больше [+] Меньше [-]Assessing the relationship and influence of black carbon on distribution status of organochlorines in the coastal sediments from Pakistan Полный текст
2014
ʻAlī, ʻUs̲mān | Syed, Jabir Hussain | Junwen, Liu | Sánchez-García, Laura | Malik, Riffat Naseem | Chaudhry, Muhammad Jamshed Iqbal | Arshad, Masood | Li, Jun | Zhang, Gan | Jones, K. C. (Kevin C.)
Levels of total organic carbon (TOC) and black carbon (BC) were determined together with those of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the selected eighteen coastal sites (n = 285) along the Arabian Sea from Pakistan. Results showed that the total concentration of TOC, BC, ∑OCPs and ∑26PCBs ranged between 0.3 and 2.9% dw, 0.1–0.2% dw, 0.9–110 ng g−1 dw and 6.2–1200 ng g−1 dw, respectively. Correlation analysis of BC (r = 0.26–0.89) and TOC (r = 0.06–0.69) revealed a stronger association with studied compounds. The sedimentary depositional fluxes (D) for ∑OCPs and ∑26PCBs were calculated as 1.7 and 4.9 tons yr−1, respectively. In the coastal belt of Pakistan, sedimentary mass inventories (I) indicated the presence of 13 and 37 metric tons of ∑OCPs and ∑26PCBs, respectively.
Показать больше [+] Меньше [-]Atrazine contamination at the watershed scale and environmental factors affecting sampling rates of the polar organic chemical integrative sampler (POCIS) Полный текст
2014
Dalton, Rebecca L. | Pick, Frances R. | Boutin, Céline | Saleem, Ammar
Polar organic chemical integrative samplers (POCIS) were used to estimate atrazine contamination at 24 stream/river sites located across a watershed with land use ranging from 6.7 to 97.4% annual crops and surface water nitrate concentrations ranging from 3 to 5404 μg/L. A gradient of atrazine contamination spanning two orders of magnitude was observed over two POCIS deployments of 28 d and was positively correlated with measures of agricultural intensity. The metabolite desisopropyl atrazine was used as a performance reference compound in field calibration studies. Sampling rates were similar between field sites but differed seasonally. Temperature had a significant effect on sampling rates while other environmental variables, including water velocity, appeared to have no effect on sampling rates. A performance reference compound approach showed potential in evaluating spatial and temporal differences in field sampling rates and as a tool for further understanding processes governing uptake of polar compounds by POCIS.
Показать больше [+] Меньше [-]Antimony uptake, efflux and speciation in arsenic hyperaccumulator Pteris vittata Полный текст
2014
Tisarum, Rujira | Lessl, Jason T. | Dong, Xiaoling | de Oliveira, Letuzia M. | Rathinasabapathi, Bala | Ma, Lena Q.
Even though antimony (Sb) and arsenic (As) are chemical analogs, differences exist on how they are taken up and translocated in plants. We investigated 1) Sb uptake, efflux and speciation in arsenic hyperaccumulator Pteris vittata after 1 d exposure to 1.6 or 8 mg/L antimonite (SbIII) or antimonate (SbV), 2) Sb uptake by PV accessions from Florida, China, and Brazil after 7 d exposure to 8 mg/L SbIII, and 3) Sb uptake and oxidation by excised PV fronds after 1 d exposure to 8 mg/L SbIII or SbV. After 1 d exposure, P. vittata took 23–32 times more SbIII than SbV, with all Sb being accumulated in the roots with the highest at 4,192 mg/kg. When exposed to 8 mg/L SbV, 98% of Sb existed as SbV in the roots. In comparison, when exposed to 8 mg/L SbIII, 81% of the total Sb remained as SbIII and 26% of the total Sb was effluxed out into the media. The three PV accessions had a similar ability to accumulate Sb at 12,000 mg/kg in the roots, with >99% of total Sb in the roots. Excised PV fronds translocated SbV more efficiently from the petioles to pinnae than SbIII and were unable to oxidize SbIII. Overall, P. vittata displayed efficient root uptake and efflux of SbIII with limited ability to translocate and transform in the roots.
Показать больше [+] Меньше [-]Pathways of Pb and Mn observed in a 5-year longitudinal investigation in young children and environmental measures from an urban setting Полный текст
2014
Gulson, Brian | Mizon, Karen | Taylor, Alan | Korsch, Michael | Davis, J Michael | Louie, Honway | Wu, Michael | Gómez, Laura | Antin, Luminita
We monitored 108 children ≤5 years on a 6-month basis for up to 5 years in a major urban setting. Samples (n ∼ 7000) included blood, urine, handwipes (interior, and after exterior playing), 6-day duplicate diet, drinking water, interior house and day care dust-fall accumulation using petri dishes, exterior dust-fall accumulation, exterior dust sweepings, paint, soil and urban air. The geometric mean blood Pb (PbB) was 2.1 μg/dL and blood Mn (MnB) was 10.0 μg/L. Following a path modelling approach, mixed model analyses for a fully adjusted model showed the strongest associations for PbB were with interior house dust and soil; for MnB there were no significant associations with any predictors. Predictor variables only explained 9% of the variance for Pb and 0.7% for Mn. Relationships between environmental measures and PbB in children are not straightforward; soil and dust sweepings contribute only about 1/5th of the amounts to PbB found in other studies.
Показать больше [+] Меньше [-]Formation of brominated pollutants during the pyrolysis and combustion of tetrabromobisphenol A at different temperatures Полный текст
2014
Ortuño, Nuria | Moltó, Julia | Conesa, Juan A. | Font, Rafael
Formation of brominated pollutants during the pyrolysis and combustion of tetrabromobisphenol A at different temperatures Полный текст
2014
Ortuño, Nuria | Moltó, Julia | Conesa, Juan A. | Font, Rafael
Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant worldwide. A detailed examination of the degradation products emitted during thermal decomposition of TBBPA is presented in the study. Runs were performed in a laboratory furnace at different temperatures (650 and 800 °C) and in different atmospheres (nitrogen and air). More than one hundred semivolatile compounds have been identified by GC/MS, with special interest in brominated ones. Presence of HBr and brominated light hydrocarbons increased with temperature and in the presence of oxygen. Maximum formation of PAHs is observed at pyrolytic condition at the higher temperature. High levels of 2,4-, 2,6- and 2,4,6- bromophenols were found. The levels of polybrominated dibenzo-p-dioxins and furans have been detected in the ppm range. The most abundant isomers are 2,4,6,8-TeBDF in pyrolysis and 1,2,3,7,8-PeBDF in combustion. These results should be considered in the assessment of thermal treatment of materials containing brominated flame retardants.
Показать больше [+] Меньше [-]Formation of brominated pollutants during the pyrolysis and combustion of tetrabromobisphenol A at different temperatures Полный текст
2014
Ortuño García, Nuria | Moltó Berenguer, Julia | Conesa, Juan A. | Font, Rafael | Conesa, Juan A. | Moltó Berenguer, Julia | Ortuño García, Nuria | Universidad de Alicante. Departamento de Ingeniería Química | Residuos, Pirólisis y Combustión
Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant worldwide. A detailed examination of the degradation products emitted during thermal decomposition of TBBPA is presented in the study. Runs were performed in a laboratory furnace at different temperatures (650 and 800 °C) and in different atmospheres (nitrogen and air). More than one hundred semivolatile compounds have been identified by GC/MS, with special interest in brominated ones. Presence of HBr and brominated light hydrocarbons increased with temperature and in the presence of oxygen. Maximum formation of PAHs is observed at pyrolytic condition at the higher temperature. High levels of 2,4-, 2,6- and 2,4,6- bromophenols were found. The levels of polybrominated dibenzo-p-dioxins and furans have been detected in the ppm range. The most abundant isomers are 2,4,6,8-TeBDF in pyrolysis and 1,2,3,7,8-PeBDF in combustion. These results should be considered in the assessment of thermal treatment of materials containing brominated flame retardants. | Support for this work was provided by the Generalitat Valenciana (Spain), research project Prometeo/2009/043/FEDER, and by the Spanish Ministry of Education and Science, research project CTQ2008-05520.
Показать больше [+] Меньше [-]Year-round grazing to counteract effects of atmospheric nitrogen deposition may aggravate these effects Полный текст
2014
van Dobben, H.F. | Wamelink, G.W.W. | Klimkowska, A. | Slim, P.A. | van Til, M.
Year-round grazing to counteract effects of atmospheric nitrogen deposition may aggravate these effects Полный текст
2014
van Dobben, H.F. | Wamelink, G.W.W. | Klimkowska, A. | Slim, P.A. | van Til, M.
Excessive nitrogen input in natural ecosystems is a major threat to biodiversity. A coastal dune area near Amsterdam in the Netherlands suffers from high atmospheric nitrogen deposition affecting sensitive habitats such as fixed coastal dunes with herbaceous vegetation (‘grey dunes’). To mitigate its effect year round grazing was applied from 2007 until 2012. In winter, when natural food supply is low, the cattle received supplementary hay that caused additional inputs of nitrogen. Estimates based on nitrogen contents of hay, as well as of manure, showed the input through winter feeding (c. 3–14 kg N ha-1.y-1) is in the same order of magnitude as both the actual deposition (c. 17 kg N ha-1.y-1) and the critical load for a number of herbaceous habitat types (10–15 kg N ha-1.y-1). Locally, the effect of winter feeding adds to the effect of nitrogen redistribution within the area caused by the cattle's terrain usage. We conclude that winter feeding may aggravate effects of atmospheric nitrogen deposition. Keywords: Vegetation management; Manure; Nitrogen; Eutrophication; Natura 2000; Grey dune
Показать больше [+] Меньше [-]Year-round grazing to counteract effects of atmospheric nitrogen deposition may aggravate these effects Полный текст
2014
van Dobben, H.F. | Wamelink, G.W.W. | Klimkowska, A. | Slim, P.A. | van Til, M.
Excessive nitrogen input in natural ecosystems is a major threat to biodiversity. A coastal dune area near Amsterdam in the Netherlands suffers from high atmospheric nitrogen deposition affecting sensitive habitats such as fixed coastal dunes with herbaceous vegetation (‘grey dunes’). To mitigate its effect year round grazing was applied from 2007 until 2012. In winter, when natural food supply is low, the cattle received supplementary hay that caused additional inputs of nitrogen. Estimates based on nitrogen contents of hay, as well as of manure, showed the input through winter feeding (c. 3–14 kg N ha−1.y−1) is in the same order of magnitude as both the actual deposition (c. 17 kg N ha−1.y−1) and the critical load for a number of herbaceous habitat types (10–15 kg N ha−1.y−1). Locally, the effect of winter feeding adds to the effect of nitrogen redistribution within the area caused by the cattle's terrain usage. We conclude that winter feeding may aggravate effects of atmospheric nitrogen deposition.
Показать больше [+] Меньше [-]Assessment of floating plastic debris in surface water along the Seine River Полный текст
2014
Gasperi, Johnny | Dris, Rachid | Bonin, Tiffany | Rocher, Vincent | Tassin, Bruno
Assessment of floating plastic debris in surface water along the Seine River Полный текст
2014
Gasperi, Johnny | Dris, Rachid | Bonin, Tiffany | Rocher, Vincent | Tassin, Bruno
This study is intended to examine the quality and quantity of floating plastic debris in the River Seine through use of an extensive regional network of floating debris-retention booms; it is one of the first attempts to provide reliable information on such debris at a large regional scale. Plastic debris represented between 0.8% and 5.1% of total debris collected by weight. A significant proportion consisted of food wrappers/containers and plastic cutlery, probably originating from voluntary or involuntary dumping, urban discharges and surface runoff. Most plastic items are made of polypropylene, polyethylene and, to a lesser extent, polyethylene terephthalate. By extrapolation, some 27 tons of floating plastic debris are intercepted annually by this network; corresponding to 2.3 g per Parisian inhabitant per year. Such data could serve to provide a first evaluation of floating plastic inputs conveyed by rivers.
Показать больше [+] Меньше [-]Assessment of floating plastic debris in surface water along the Seine River. Полный текст
2014
Gasperi, Johnny | Dris, Rachid | Bonin, Tiffany | Rocher, Vincent | Tassin, Bruno | Laboratoire Eau, Environnement et Systèmes Urbains (LEESU) ; AgroParisTech-Université Paris-Est Marne-la-Vallée (UPEM)-École nationale des ponts et chaussées (ENPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12) | SIAAP - Direction du Développement et de la Prospective ; Syndicat interdépartemental pour l'assainissement de l'agglomération parisienne (SIAAP)
International audience | This study is intended to examine the quality and quantity of floating plastic debris in the River Seine through use of an extensive regional network of floating debris-retention booms; it is one of the first attempts to provide reliable information on such debris at a large regional scale. Plastic debris represented between 0.8% and 5.1% of total debris collected by weight. A significant proportion consisted of food wrappers/containers and plastic cutlery, probably originating from voluntary or involuntary dumping, urban discharges and surface runoff. Most plastic items are made of polypropylene, polyethylene and, to a lesser extent, polyethylene terephthalate. By extrapolation, some 27 tons of floating plastic debris are intercepted annually by this network; corresponding to 2.3 g per Parisian inhabitant per year. Such data could serve to provide a first evaluation of floating plastic inputs conveyed by rivers.
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