细化搜索
结果 41-50 的 1,908
Quantitative determination of regional contributions to fine and coarse particle mass in urban receptor sites
2013
Kavouras, I.G. | Lianou, M. | Chalbot, M.-C. | Vei, I.C. | Kotronarou, A. | Hoek, G. | Hameri, K. | Harrison, R.M.
In this study, we demonstrate that regression analysis of trajectories residence time estimates the contributions of geographical sectors to fine and coarse particle mass in urban receptor sites. We applied the methodology to coarse and fine particles in Amsterdam, Athens, Birmingham and Helsinki. The sectors with the highest contributions on PM2.5 and PM10–2.5 for Amsterdam and Birmingham were Central/Eastern Europe and the Atlantic Ocean/North Sea, respectively. For Athens, the four sectors within 500 km accounted for the largest fraction of PM2.5. The Mediterranean Sea and North Africa added more than half of PM10–2.5 in Athens. For Helsinki, more than 50% of PM2.5 and PM10–2.5 were from sources outside Finland. This approach may be applied to assess the impact of transport on particle mass levels, identify the spatial patterns of particle sources and generate valuable data to design national and transnational efficient emission control strategies.
显示更多 [+] 显示较少 [-]Dioxin-induced acute cardiac mitochondrial oxidative damage and increased activity of ATP-sensitive potassium channels in Wistar rats
2013
Pereira, Susana P. | Pereira, Gonçalo C. | Pereira, Cláudia V. | Carvalho, Filipa S. | Cordeiro, Marília H. | Mota, Paula C. | Ramalho-Santos, João | Moreno, António J. | Oliveira, Paulo J.
The environmental dioxin 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is classified as a Group 1 human carcinogen and teratogenic agent. We hypothesize that TCDD-induced oxidative stress may also interfere with mitochondrial ATP-sensitive potassium channels (mitoKATP), which are known to regulate and to be regulated by mitochondrial redox state. We investigated the effects of an acute treatment of male Wistar rats with TCDD (50 μg/kg i.p.) and measured the regulation of cardiac mitoKATP. While the function of cardiac mitochondria was slightly depressed, mitoKATP activity was 52% higher in animals treated with TCDD. The same effects were not observed in liver mitochondria isolated from the same animals. Our data also shows that regulation of mitochondrial ROS production by mitoKATP activity is different in both groups. To our knowledge, this is the first report to show that TCDD increases mitoKATP activity in the heart, which may counteract the increased oxidative stress caused by the dioxin during acute exposure.
显示更多 [+] 显示较少 [-]Social [and health] relevance of psychotropic substances monitoring in air
2013
Cecinato, Angelo | Balducci, Catia | Mollica, Roberto | Serpelloni, Giovanni
Drug abuse assessment methods based on measuring illicit substances in waste waters are consolidated. The approach of ambient air monitoring looks questionable, nonetheless it can be explored if the variables determining the drug burdens are accounted for, or suitable co-contaminants are adopted to normalize concentrations to environmental and human contours. The general approach linking the airborne drug concentrations to consumption is presented and the case of cocaine is discussed according to measurements conducted in Italy. The cocaine/nicotine concentration ratio, identified as the most suitable tool, fitted well with anti-drug Police operations and people noticed for drug-related crimes, and with the abuse prevalence estimated in the cities investigated. According to that, the conversion factors of drug concentrations into prevalence estimates seem assessable, provided sufficient databases over space and time are collected. Further investigations are necessary to understand if airborne drugs cause adverse sanitary effects.
显示更多 [+] 显示较少 [-]Assessment of PCDD/Fs levels in soil at a contaminated sawmill site in Sweden – A GIS and PCA approach to interpret the contamination pattern and distribution
2013
Henriksson, S. | Hagberg, J. | Bäckström, M. | Persson, I. | Lindström, G.
Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) were analysed in soil from a Swedish sawmill site where chlorophenols (CPs) had been used more than 40 years ago. The most contaminated area at the site was the preservation subarea where the PCDD/F WHO2005-TEQ level was 3450 times higher than the current Swedish guideline value of 200 ng TEQ/kg soil for land for industrial use. It was also shown that a fire which destroyed the sawmill might have affected the congener distribution at the concerned areas. To get a broader picture of the contamination both GIS (spatial interpolation analysis) and multivariate data analysis (PCA) were applied to visualize and compare PCDD/F levels as well as congener distributions at different areas at the site. It is shown that GIS and PCA are powerful tools in decisions on future investigations, risk assessments and remediation of contaminated sites.
显示更多 [+] 显示较少 [-]Biodegradation of carbamate pesticides by natural river biofilms in different seasons and their effects on biofilm community structure
2013
Tien, Chien-Jung | Lin, Mon-Chu | Chiu, Wan-Hsin | Chen, Colin S.
This study investigated the ability of natural river biofilms from different seasons to degrade the carbamate pesticides methomyl, carbaryl and carbofuran in single and multiple pesticide systems, and the effects of these pesticides on algal and bacterial communities within biofilms. Spring biofilms had the lowest biomass of algae and bacteria but showed the highest methomyl degradation (>99%) and dissipation rates, suggesting that they might contain microorganisms with high methomyl degradation abilities. Degradation of carbofuran (54.1–59.5%) by biofilms in four seasons was similar, but low degradation of carbaryl (0–27.5%) was observed. The coexistence of other pesticides was found to cause certain effects on pesticide degradation and primarily resulted in lower diversity of diatoms and bacteria than when using a single pesticide. The tolerant diatoms and bacteria potentially having the ability to degrade test pesticides were identified. River biofilms could be suitable biomaterials or used to isolate degraders for bioremediating pesticide-contaminated water.
显示更多 [+] 显示较少 [-]Levels of metals in blood samples from Mallards (Anas platyrhynchos) from urban areas in Poland
2013
Binkowski, Łukasz J. | Meissner, Włodzimierz
In this paper we present the studies conducted on blood samples taken from Mallards (Anas platyrhynchos). Birds were captured for ringing purposes (n = 43) in two small and two big towns (including highly urbanized areas). For comparison samples of blood from birds shot on fish ponds were used (n = 26). Based on the body mass all sampled individuals can be assessed as being in good condition. Levels of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb) and zinc (Zn) in blood samples were measured with AAS. Concentrations of metals did not differ statistically between sexes and made up a following order: Fe > Zn > Cu > Cr ≈ Ni > Pb > Cd. Mallards from towns revealed lower concentrations of Zn and Cu but higher concentration of Fe. There was no difference in exposition to Pb between birds from towns and fish ponds.
显示更多 [+] 显示较少 [-]Protective role of fine silts for PAH in a former industrial soil
2013
Pernot, Audrey | Ouvrard, Stéphanie | Leglize, Pierre | Faure, Pierre
An original combined organic geochemistry and soil science approach was used to elucidate PAH availability controlling factors in a multi-contaminated industrial soil. Water granulodensimetric fractionation was applied to obtain five water-stable material fractions. These were characterized by elemental, molecular and mineral analysis, and microscopic observations. Among the different fractions, fine silts distinguished themselves by higher carbon and nitrogen contents, lower C/N ratio, an enrichment in total PAH and especially high molecular weight compounds, a coal tar signature and the lowest PAH availability. This fine silt fraction seemed to play a protective role for PAH that might be explained by its size and/or its specific reactivity. The mineral phases present in this fraction were proposed to explain the protection of organic matter. This led to a specific molecular signature of OM, having higher sorption properties both processes (sorption and mineral-bound protection) resulting in a lower PAH availability.
显示更多 [+] 显示较少 [-]An intercomparison of satellite-derived ground-level NO2 concentrations with GMSMB modeling results and in-situ measurements – A North American study
2013
Wang, Baozhen | Chen, Zhi
This paper investigates the biases associated with the ground-level nitrogen dioxide (NO2) concentrations derived from the satellite Ozone Monitoring Instrument (OMI) NO2 data through comparisons with the modeling and the monitoring results for the state of California in 2008. The seasonal and annual average ground-level NO2 concentrations are both analyzed from the OMI using the local NO2 profile obtained from the GEOS-Chem simulation. The OMI-derived ground-level NO2 concentrations are then compared with the NO2 concentrations predicted by a GIS-Based Multi-Source and Multi-Box model (GMSMB) and the in-situ measurements, correlation coefficients among the three sets of results are all above 0.84 with an average slope of 0.81 ± 0.04. Particularly, various biases associated with the three data sets have been analyzed, and the OMI-derived NO2 concentrations and the GMSMB modeling results have been proven to be essential for assessing regional air pollutant exposure risks with the aid of the extensive remote sensing database.
显示更多 [+] 显示较少 [-]Abiotic degradation of antibiotic ionophores
2013
Bohn, Pernille | Bak, Søren A. | Björklund, Erland | Krogh, Kristine A. | Hansen, Martin
Hydrolytic and photolytic degradation were investigated for the ionophore antibiotics lasalocid, monensin, salinomycin, and narasin. The hydrolysis study was carried out by dissolving the ionophores in solutions of pH 4, 7, and 9, followed by incubation at three temperatures of 6, 22, and 28 °C for maximum 34 days. Using LC–MS/MS for chemical analysis, lasalocid was not found to hydrolyse in any of the tested environments. Monensin, salinomycin, and narasin were all stable in neutral or alkaline solution but hydrolysed in the solution with a pH of 4. Half-lives at 25 °C were calculated to be 13, 0.6, and 0.7 days for monensin, salinomycin, and narasin, respectively.Absorbance spectra from each compound indicated that only lasalocid is degraded by photolysis (half-life below 1 h) due to an absorbance maximum around 303 nm, and monensin, salinomycin, and narasin are resistant to direct photolysis because they absorb light of environmentally irrelevant wavelengths.
显示更多 [+] 显示较少 [-]Levels of prenatal mercury exposure and their relationships to neonatal anthropometry in Wujiang City, China
2013
Guo, Bao-Qiang | Cai, Shi-Zhong | Guo, Jun-Liang | Xu, Jian | Wu, Wei | Li, Hui | Zhou, Xin | Kim, Dae-Seon | Yan, Chong-Huai | Lü, Hong-Dao
We determined the levels of prenatal Hg exposure in Wujiang City, located in the southeast of Taihu Lake in China's Jiangsu Province, and analyze the relationship between prenatal exposure to Hg and neonatal anthropometry, including birth weight, body length, and head circumference. From June 2009 to July 2010, a total of 213 mother-infant pairs were enrolled. The geometric means of Hg levels in maternal hair, fetal hair, placentas, and cord blood were 496.76 μg/kg, 233.94 μg/kg, 3.58 μg/kg, and 1.54 μg/L, respectively. The Hg levels detected in our study were significantly lower than those reported by previous studies. In addition, no significant correlations were found between Hg levels in maternal hair, fetal hair, placenta, or cord blood and neonatal anthropometrics. Together, our findings may be important for understanding the effects of prenatal exposure to Hg on newborns' development and have implications concerning the recommended dose for Hg.
显示更多 [+] 显示较少 [-]