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Building materials. VOC emissions, diffusion behaviour and implications from their use 全文
2012
Katsoyiannis, Athanasios | Leva, Paolo | Barrero-Moreno, Josefa | Kotzias, Dimitrios
Five cement- and five lime-based building materials were examined in an environmental chamber for their emissions of Volatile Organic Compounds (VOCs). Typical VOCs were below detection limits, whereas not routinely analysed VOCs, like neopentyl glycol (NPG), dominated the cement-based products emissions, where, after 72 h, it was found to occur, in levels as high as 1400 μg m⁻³, accounting for up to 93% of total VOCs. The concentrations of NPG were not considerably changed between the 24 and 72 h of sampling. The permeability of building materials was assessed through experiments with a dual environmental chamber; it was shown that building materials facilitate the diffusion of chemicals through their pores, reaching equilibrium relatively fast (6 h).
显示更多 [+] 显示较少 [-]Distribution of PCBs and PBDEs in soils along the altitudinal gradients of Balang Mountain, the east edge of the Tibetan Plateau 全文
2012
Zheng, Xiaoyan | Liu, Xiande | Jiang, Guibin | Wang, Yawei | Zhang, Qinghua | Cai, Yaqi | Cong, Zhiyuan
Surface soils were collected in Balang Mountain to explore the environmental process of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) during air transport. The average concentrations of ∑₂₅PCBs and ∑₁₃PBDEs in soils were 163 pg/g and 26 pg/g, respectively. The significant correlations between the concentrations of pollutants and total organic carbon (TOC) indicated the importance of TOC in accumulation potential of POPs. The slopes from fitted curves of PCBs were highly related with logKₒₐ, demonstrating that TOC dominates the soil-air exchange of PCBs. The TOC-normalized concentrations of contaminants in samples from below-treeline were higher than those from alpine meadow, probably due to the forest filter effect. The increasing trends of the concentrations with altitude from the alpine meadow samples, could be attributed to the mountain cold-trapping effect. And the weak cold-trapping effect of POPs might be due to the less precipitation in 2008 when comparing with those in 2006.
显示更多 [+] 显示较少 [-]Sorption kinetics of ofloxacin in soils and mineral particles 全文
2012
Pan, Bo | Wang, Peng | Wu, Min | Li, Jing | Zhang, Di | Xiao, Di
The environmental behavior of antibiotics is not well known and the precise environmental risk assessment is not practical. This study investigated the sorption kinetics of ofloxacin, a widely used antibiotics, on soil particles with different organic carbon contents as well as soil components (a humic acid, ferric oxide and kaolinite). Two-compartment sorption kinetics were mathematically recognized (except ferric oxide because of its very fast sorption). The apparent sorption rate and the contribution of fast sorption compartment decreased with the increased organic carbon content with the exception of humic acid, suggesting that the slow sorption sites were partially located in organo-mineral complex. The OFL concentration-dependent sorption kinetics suggested that the slow sorption compartment was not controlled by diffusion process as indicated by slower sorption at higher OFL loading. The difference between OFL sorption kinetics and those of hydrophobic organic contaminants was discussed and possible mechanism of OFL two-compartment sorption was proposed.
显示更多 [+] 显示较少 [-]Ozone visible symptoms and reduced root biomass in the subalpine species Pinus uncinata after two years of free-air ozone fumigation 全文
2012
Díaz-de-Quijano, Maria | Schaub, Marcus | Bassin, Seraina | Volk, Matthias | Peñuelas, Josep
Concentrations of ozone often exceed the thresholds of forest protection in the Pyrenees, but the effect of ozone on Pinus uncinata, the dominant species in subalpine forests in this mountainous range, has not yet been studied. We conducted an experiment of free-air ozone fumigation with saplings of P. uncinata fumigated with ambient O₃ (AOT40 May–Oct: 9.2 ppm h), 1.5 × O₃ₐₘb (AOT40 May–Oct: 19.2 ppm h), and 1.8 × O₃ₐₘb (AOT40 May–Oct: 32.5 ppm h) during two growing seasons. We measured chlorophyll content and fluorescence, visible injury, gas exchange, and above- and below-ground biomass. Increased exposures to ozone led to a higher occurrence and intensity of visible injury from O₃ and a 24–29% reduction of root biomass, which may render trees more susceptible to other stresses such as drought. P. uncinata is thus a species sensitive to O₃, concentrations of which in the Pyrenees are already likely affecting this species.
显示更多 [+] 显示较少 [-]Ozone deposition to an orange orchard: Partitioning between stomatal and non-stomatal sinks 全文
2012
Fares, Silvano | Weber, Robin | Park, Jeong-Hoo | Gentner, Drew | Karlik, Jan | Goldstein, Allen H.
Orange trees are widely cultivated in regions with high concentrations of tropospheric ozone. Citrus absorb ozone through their stomata and emit volatile organic compounds (VOC), which, together with soil emissions of NO, contribute to non-stomatal ozone removal. In a Valencia orange orchard in Exeter, California, we used fast sensors and eddy covariance to characterize water and ozone fluxes. We also measured meteorological parameters necessary to model other important sinks of ozone deposition. We present changes in magnitude of these ozone deposition sinks over the year in response to environmental parameters. Within the plant canopy, the orchard constitutes a sink for ozone, with non-stomatal ozone deposition larger than stomatal uptake. In particular, soil deposition and reactions between ozone, VOC and NO represented the major sinks of ozone. This research aims to help the development of metrics for ozone-risk assessment and advance our understanding of citrus in biosphere-atmosphere exchange.
显示更多 [+] 显示较少 [-]Class 1 and 2 integrons, sul resistance genes and antibiotic resistance in Escherichia coli isolated from Dongjiang River, South China 全文
2012
Su, Hao-Chang | Ying, Guang-Guo | Tao, Ran | Zhang, Rui-Quan | Zhao, Jian-Liang | Liu, You-Sheng
Antibiotic susceptibility, detection of sul gene types and presence of class 1, 2 and 3 integrons and gene cassettes using PCR assays were investigated in 3456 Escherichia coli isolates obtained from 38 sampling sites of the Dongjiang River catchment in the dry and wet seasons. 89.1% of the isolates were resistant and 87.5% showed resistance to at least three antibiotics. sul2 was detected most frequently in 89.2% of 1403 SXT-resistant isolates. The presence of integrons (class 1 and 2) was frequently observed (82.3%) while no class 3 integron was found. In these integrons, 21 resistance genes of 14 gene cassette arrays and 10 different families of resistance genes were identified. Three gene cassette arrays, aac(6')-Ib-cr-aar-3-dfrA27-aadA16, aacA4-catB3-dfrA1 and aadA2-lnuF, were detected for the first time in surface water. The results showed that bacterial resistance in the catchment was seriously influenced by human activities, especially discharge of wastewater.
显示更多 [+] 显示较少 [-]Legacy and current-use flame retardants in house dust from Vancouver, Canada 全文
2012
Shoeib, Mahiba | Harner, Tom | Webster, Glenys M. | Sverko, Ed | Cheng, Yu
Fifteen polybrominated diphenyl ethers (PBDEs) and eighteen non-PBDEs were measured in 116 dust samples collected from homes in Vancouver, Canada during 2007–2008 as part of the Chemicals Health and Pregnancy (CHirP) study. The highest concentrations of PBDEs in house dust were observed for BDE 209, with a median concentration of 1350 ng/g. This is about two times greater than the median concentration of the PentaBDE (represented by the most abundant compounds in this formulation, ΣBDE 47, 99 and 100). In the case of non-PBDE FRs, a detection frequency between 81% and 100% was observed for nine analytes including: HBCD, BTBPE, BEHTBP, EHTBB, HBB, PBTO, PBBe, ATE and DP. The high detection of new FRs in indoor environments reflects their ubiquitous presence in indoor environment due to regulation of the PBDEs. Exposure to FRs are estimated based on these data for adults and toddlers.
显示更多 [+] 显示较少 [-]Bees, honey and pollen as sentinels for lead environmental contamination 全文
2012
Lambert, Olivier | Piroux, Mélanie | Puyo, Sophie | Thorin, Chantal | Larhantec, Michaëlle | Delbac, Frédéric | Pouliquen, Hervé
Three beehive matrices, sampled in eighteen apiaries from West France, were analysed for the presence of lead (Pb). Samples were collected during four different periods in both 2008 and 2009. Honey was the matrix the least contaminated by Pb (min = 0.004 μg g⁻¹; max = 0.378 μg g⁻¹; mean = 0.047 μg g⁻¹; sd = 0.057). The contamination of bees (min = 0.001 μg g⁻¹; max = 1.869 μg g⁻¹; mean = 0.223 μg g⁻¹; sd = 0.217) and pollen (min = 0.004 μg g⁻¹; max = 0.798 μg g⁻¹; mean = 0.240 μg g⁻¹; sd = 0.200) showed similar levels and temporal variations but bees seemed to be more sensitive bringing out the peaks of Pb contamination. Apiaries in urban and hedgerow landscapes appeared more contaminated than apiaries in cultivated and island landscapes. Sampling period had a significant effect on Pb contamination with higher Pb concentrations determined in dry seasons.
显示更多 [+] 显示较少 [-]A sediment ecotoxicity assessment platform for in situ measures of chemistry, bioaccumulation and toxicity. Part 1: System description and proof of concept 全文
2012
Burton, G. Allen, Jr | Rosen, Gunther | Chadwick, D Bart | Greenberg, Marc S. | Taulbee, W Keith | Lotufo, Guilherme R. | Reible, Danny D.
In situ-based testing using aquatic organisms has been widely reported, but is often limited in scope and practical usefulness in making decisions on ecological risk and remediation. To provide this capability, an integrated deployment system, the Sediment Ecotoxicity Assessment (SEA) Ring was developed, which incorporates rapid in situ hydrological, chemical, bioaccumulation, and toxicological Lines-of-Evidence (LoE) for assessing sediment and overlying water contamination. The SEA Ring system allows for diver-assisted, or diverless, deployment of multiple species of ecologically relevant and indigenous organisms in three different exposures (overlying water, sediment–water interface, and bulk sediment) for periods ranging from two days to three weeks, in a range of water systems. Measured endpoints were both sublethal and lethal effects as well as bioaccumulation. In addition, integrated passive sampling devices for detecting nonpolar organics (solid phase micro-extraction fibers) and metals (diffusive gradients in thin films) provided gradient measures in overlying waters and surficial sediments.
显示更多 [+] 显示较少 [-]The impact of organochlorines cycling in the cryosphere on global distributions and fate – 2. Land ice and temporary snow cover 全文
2012
Hofmann, Lorenz | Stemmler, Irene | Lammel, Gerhard
Global fate and transport of γ-HCH and DDT was studied using a global multicompartment chemistry-transport model, MPI-MCTM, with and without inclusion of land ice (in Antarctica and Greenland) or snow cover (dynamic). MPI-MCTM is based on coupled ocean and atmosphere general circulation models. After a decade of simulation 4.2% γ-HCH and 2.3% DDT are stored in land ice and snow. Neglection of land ice and snow in modelling would underestimate the total environmental residence time, τₒᵥ, of γ-HCH and overestimate τₒᵥ for DDT, both on the order of 1% and depending on actual compartmental distribution. Volatilisation of DDT from boreal, seasonally snow covered land is enhanced throughout the year, while volatilisation of γ-HCH is only enhanced during the snow-free season. Including land ice and snow cover in modelling matters in particular for the Arctic, where higher burdens are predicted to be stored.
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