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Characterization of polybrominated diphenyl ethers (PBDEs) and hydroxylated and methoxylated PBDEs in soils and plants from an e-waste area, China Texto completo
2014
Wang, Sen | Zhang, Shuzhen | Huang, Honglin | Niu, Zhenchuan | Han, Wei
In order to characterize polybrominated diphenyl ethers (PBDEs), and hydroxylated and methoxylated PBDEs (OH-PBDEs and MeO-PBDEs) in the soil–plant system, soil and plant samples were collected from an e-waste recycling area in China. Forty one PBDEs, twelve OH-PBDEs and MeO-PBDEs were detected in the soil and plant samples. Concentrations of PBDEs in roots were significantly correlated to their concentrations in the soils, but the percentages of lower brominated congeners in the plants were higher than those in the soils. Significant positive linear relationships exist between concentrations of ∑OH-PBDEs and ∑MeO-PBDEs with higher levels of ∑MeO-PBDEs than those of ∑OH-PBDEs in the soils, plant roots and leaves. A majority of the OH-/MeO-PBDEs had the hydroxyl or methoxy group at the ortho-positions to the biphenyl bond for most of the plant species. However the occurrence of meta- and para- substituted OH-/MeO-PBDEs in soils and plants were also confirmed.
Mostrar más [+] Menos [-]Perfluorinated compounds in serum and urine samples from children aged 5–13 years in South Korea Texto completo
2014
Kim, Da-Hye | Lee, Mi-Young | Oh, Jeong-Eun
Serum and urine samples from 120 children aged 5–13 years from Dae-gu, Korea, were analyzed for 16 perfluorinated compounds (PFCs). The total PFC concentrations in the serum were 4.26–29.70 ng/mL, and perfluorohexanesulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS, which was dominant overall, at 6.58 ng/mL), and perfluoroundecanoic acid (PFUndA) were detected in all serum samples. The total PFC concentrations in the urine ranged from below the detection limit to 14.9 ng/mL, and perfluoropentanoic acid (PFPeA) was predominant. The PFOS (p < 0.005) concentration was higher in the serum of children than that of Korean adults aged 20–29. Some of the PFC concentrations in the serum correlated negatively with body mass index and tended to increase with the duration of breastfeeding. However, there were no gender-specific differences in the PFC concentrations and no correlations between PFC concentrations in serum and urine.
Mostrar más [+] Menos [-]Calibration and field application of passive sampling for episodic exposure to polar organic pesticides in streams Texto completo
2014
Fernández, Diego | Vermeirssen, Etiënne L.M. | Bandow, Nicole | Muñoz, Katherine | Schäfer, Ralf B.
Rainfall-triggered runoff is a major driver of pesticide input in streams. Only few studies have examined the suitability of passive sampling to quantify such episodic exposures. In this study, we used Empore™ styrene-divinylbenzene reverse phase sulfonated disks (SDB disks) and event-driven water samples (EDS) to assess exposure to 15 fungicides and 4 insecticides in 17 streams in a German vineyard area during 4 rainfall events. We also conducted a microcosm experiment to determine the SDB-disk sampling rates and provide a free-software solution to derive sampling rates under time-variable exposure. Sampling rates ranged from 0.26 to 0.77 L d−1 and time-weighted average (TWA) concentrations from 0.05 to 2.11 μg/L. The 2 sampling systems were in good agreement and EDS exceeded TWA concentrations on average by a factor of 3. Our study demonstrates that passive sampling is suitable to quantify episodic exposures from polar organic pesticides.
Mostrar más [+] Menos [-]Urban vegetation for reducing heat related mortality Texto completo
2014
Chen, Dong | Wang, Xiaoming | Thatcher, Marcus | Barnett, Guy | Kachenko, Anthony | Prince, Robert
The potential benefit of urban vegetation in reducing heat related mortality in the city of Melbourne, Australia is investigated using a two-scale modelling approach. A meso-scale urban climate model was used to quantify the effects of ten urban vegetation schemes on the current climate in 2009 and future climates in 2030 and 2050. The indoor thermal performance of five residential buildings was then simulated using a building simulation tool with the local meso-climates associated with various urban vegetation schemes. Simulation results suggest that average seasonal summer temperatures can be reduced in the range of around 0.5 and 2 °C if the city were replaced by vegetated suburbs and parklands, respectively. With the limited buildings and local meso-climates investigated in this study, around 5–28% and 37–99% reduction in heat related mortality rate have been estimated by doubling the city's vegetation coverage and transforming the city into parklands respectively.
Mostrar más [+] Menos [-]Warfarin, a potential pollutant in aquatic environment acting through Pxr signaling pathway and γ-glutamyl carboxylation of vitamin K-dependent proteins Texto completo
2014
Fernández, Ignacio | Santos, Adriana | Cancela, M Leonor | Laizé, Vincent | Gavaia, Paulo J.
Warfarin, a potential pollutant in aquatic environment acting through Pxr signaling pathway and γ-glutamyl carboxylation of vitamin K-dependent proteins Texto completo
2014
Fernández, Ignacio | Santos, Adriana | Cancela, M Leonor | Laizé, Vincent | Gavaia, Paulo J.
Warfarin-induced vitamin K (VK) recycling impairment is used worldwide as a rodenticide and human thromboembolic prophylactic. Since VK metabolism/signaling pathways have been conserved throughout vertebrate evolution, its release to the environment might impact on aquatic organisms. Present study assessed the toxic effect of warfarin (0, 5, 25 and 125 mg L−1) on zebrafish development and characterized underlying mechanisms of action through qPCR analysis of VK-related genes. Expression of pregnane X receptor (pxr), the nuclear receptor binding vitamin K, was ubiquitous in zebrafish and suggests that warfarin exposure may interfere with several biological processes. Indeed, warfarin exposure of zebrafish larvae caused hemorrhages in brain, skeletal deformities and triggered ectopic calcifications, which may be the consequence of an altered γ-carboxylation of VK-dependent proteins and/or pxr signaling. This study provides new insights into warfarin effects as a bone homeostasis disruptor and soft tissue calcification inductor, and its potential risk for aquatic environments.
Mostrar más [+] Menos [-]Warfarin, a potential pollutant in aquatic environment acting through Pxr signaling pathway and γ-glutamyl carboxylation of vitamin K-dependent proteins Texto completo
2014
Fernández Monzón, Ignacio | Santos, Adriana | Cancela, M Leonor | Laizé, Vincent | Gavaia, Paulo J | Fundação para a Ciência e a Tecnologia (Portugal) | European Commission | Fernández Monzón, Ignacio [0000-0002-8088-7902}
10 páginas, 7 figuras, 1 tabla. | Warfarin-induced vitamin K (VK) recycling impairment is used worldwide as a rodenticide and human thromboembolic prophylactic. Since VK metabolism/signaling pathways have been conserved throughout vertebrate evolution, its release to the environment might impact on aquatic organisms. Present study assessed the toxic effect of warfarin (0, 5, 25 and 125 mg L(-1)) on zebrafish development and characterized underlying mechanisms of action through qPCR analysis of VK-related genes. Expression of pregnane X receptor (pxr), the nuclear receptor binding vitamin K, was ubiquitous in zebrafish and suggests that warfarin exposure may interfere with several biological processes. Indeed, warfarin exposure of zebrafish larvae caused hemorrhages in brain, skeletal deformities and triggered ectopic calcifications, which may be the consequence of an altered γ-carboxylation of VK-dependent proteins and/or pxr signaling. This study provides new insights into warfarin effects as a bone homeostasis disruptor and soft tissue calcification inductor, and its potential risk for aquatic environments. | The authors are gratefully to Patrícia Diogo for technical assistance during sampling procedures. IF acknowledges the financial support of the Portuguese Fundation for Science and Technology (FCT) through the post-doctoral grant SFRH/BDP/82049/2011. This work was partly funded by the FCT through SPECIAL K (PDTC/MAR/ 105152/2008) and AQUATOX (PTDC/MAR/112992/2009) projects and by the European Commission (ERDF-COMPETE) through PEstC/MAR/LA0015/2011 project. | Peer reviewed
Mostrar más [+] Menos [-]Canopy carbon budget of Siebold's beech (Fagus crenata) sapling under free air ozone exposure Texto completo
2014
Watanabe, Makoto | Hoshika, Yasutomo | Inada, Naoki | Koike, Takayoshi
To determine the effects of ozone (O3) on the canopy carbon budget, we investigated photosynthesis and respiration of leaves of Siebold's beech saplings under free air O3 exposure (60 nmol mol−1, during daytime) in relation to the within-canopy light gradient; we then calculated the canopy-level photosynthetic carbon gain (PCG) and respiratory carbon loss (RCL) using a canopy photosynthesis model. Susceptibilities of photosynthesis and respiration to O3 were greater in leaves of upper canopy than in the lower canopy. The canopy net carbon gain (NCG) was reduced by O3 by 12.4% during one growing season. The increased RCL was the main factor for the O3-induced reduction in NCG in late summer, while contributions of the reduced PCG and the increased RCL to the NCG were almost the same in autumn. These results indicate contributions of changes in PCG and RCL under O3 to NCG were different between seasons.
Mostrar más [+] Menos [-]Major sources of MeO/OH-BDEs in the East China Sea elucidated from their records and phytoplankton biomarkers Texto completo
2014
Fan, Ying | Huh, Chih-An | Lan, Jing | Zhao, Meixun | Zhao, Zongshan | Li, Guoliang | Sun, Jianteng | Jiang, Guibin
Hydroxylated (OH-) and methoxylated (MeO-) polybrominated diphenyl ethers (PBDEs) have caused much concern because of their potential toxicity and worldwide distribution. These compounds are recently suggested to originate from the natural process in the ocean. However, their source remains highly controversial. In this study, we analyzed the contents of nine MeO-BDEs, ten OH-BDEs, and phytoplankton biomarkers (PBs) in two sediment cores collected from the East China Sea (ECS). The detection of 6-MeO-BDE-47, 2′-MeO-BDE-68, and 6-OH-BDE-47 have been reported since the 1920s, prior to the production of PBDEs. Significant relations were found between MeO/OH-BDEs and indicators of marine organic matters. The similar down-core variations and significant correlations between MeO/OH-BDEs and PBs suggest the possibility that phytoplankton produced these natural compounds. Laboratory incubation further demonstrates that phytoplankton can produce MeO-BDEs. Comparisons between the content ratios of 6-MeO-BDE-47/2′-MeO-BDE-68 and brassicasterol/dinosterol indicate that the signature of MeO-BDEs is controlled by the phytoplankton community structure.
Mostrar más [+] Menos [-]Temporal and spatial variation in residential soil metal concentrations: Implications for exposure assessments Texto completo
2014
Aelion, C Marjorie | Davis, Harley T. | Lawson, Andrew B. | Cai, Bo | McDermott, Suzanne
Understanding temporal and spatial variation in soil chemicals is critical in exposure assessments. We measured eight metals in subsamples, duplicates (∼0.3 m), and repeat soil samples taken 1–6 years after initial sampling (∼5 m). We estimated variance components (VCs) of metal concentrations using nested analyses accounting for sampling area, land use and soil type, and calculated coefficients of variation (CVs) for repeat sample pairs. Total variance for all metals was similar, but VCs were proportioned differently by metal and sample type. Spatial variation explained the majority of variance in duplicate samples. CVs of metal concentrations were not significantly different over the long time interval, but repeat samples had larger VCs for unexplained error. Sampling area and land use were important for Ba and Mn, and Pb and Hg, respectively. Results suggest metals are stable over long times and suitable for exposure assessments, but that individual metal behavior should be considered.
Mostrar más [+] Menos [-]Concentrations and trophic magnification of cyclic siloxanes in aquatic biota from the Western Basin of Lake Erie, Canada Texto completo
2014
McGoldrick, Daryl J. | Chan, Cecilia | Drouillard, Ken G. | Keir, Michael J. | Clark, Mandi G. | Backus, Sean M.
We examine the concentrations and food web biomagnification of three cyclic volatile methylsiloxanes (cVMS) octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) using aquatic biota collected from Lake Erie. Concentrations of cVMS in biota were within the range reported for other studies of cVMS in aquatic biota. Trophic magnification factors (TMF) were assessed in various food web configurations to investigate the effects of food web structure. TMF estimates were highly dependent on the inclusion/exclusion of the organisms occupying the highest and lowest trophic levels and were >1 for D4 and D5, indicating biomagnification, in only 1 of the 5 food web configurations investigated and were <1 in the remaining 4 food web configurations. TMF estimates for PCB180 were also dependant on food web configuration, but did not correspond with those obtained for cVMS materials. These differences may be attributed to environmental exposure and/or lipid partitioning differences between PCB180 and cVMS.
Mostrar más [+] Menos [-]Bacterial metal resistance genes and metal bioavailability in contaminated sediments Texto completo
2014
Roosa, Stéphanie | Wattiez, Ruddy | Prygiel, Emilie | Lesven, Ludovic | Billon, Gabriel | Gillan, David C.
In bacteria a metal may be defined as bioavailable if it crosses the cytoplasmic membrane to reach the cytoplasm. Once inside the cell, specific metal resistance systems may be triggered. In this research, specific metal resistance genes were used to estimate metal bioavailability in sediment microbial communities. Gene levels were measured by quantitative PCR and correlated to metals in sediments using five different protocols to estimate dissolved, particle-adsorbed and occluded metals. The best correlations were obtained with czcA (a Cd/Zn/Co efflux pump) and Cd/Zn adsorbed or occluded in particles. Only adsorbed Co was correlated to czcA levels. We concluded that the measurement of czcA gene levels by quantitative PCR is a promising tool which may complement the classical approaches used to estimate Cd/Zn/Co bioavailability in sediment compartments.
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