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991.
992.
Gal F Joublin F Haas H Jean-Prost V Ruffier V 《Journal of environmental radioactivity》2011,102(2):107-118
The south east basin of France shelters deep CO2 reservoirs often studied with the aim of better constraining geological CO2 storage operations. Here we present new soil gas data, completing an existing dataset (CO2, 222Rn, 4He), together with mineralogical and physical characterisations of soil columns, in an attempt to better understand the spatial distribution of gas concentrations in the soils and to rule on the sealed character of the CO2 reservoir at present time.Anomalous gas concentrations were found but did not appear to be clearly related to geological structures that may drain deep gases up to the surface, implying a dominant influence of near surface processes as indicated by carbon isotope ratios. Coarse grained, quartz-rich soils favoured the existence of high CO2 concentrations. Fine grained clayey soils preferentially favoured the existence of 222Rn but not CO2. Soil formations did not act as barriers preventing gas migrations in soils, either due to water content or due to mineralogical composition. No abundant leakage from the Montmiral reservoir can be highlighted by the measurements, even near the exploitation well. As good correlation between CO2 and 222Rn concentrations still exist, it is suggested that 222Rn migration is also CO2 dependent in non-leaking areas - diffusion dominated systems. 相似文献
993.
Combined effects of titanium dioxide and humic acid on the bioaccumulation of cadmium in Zebrafish 总被引:4,自引:0,他引:4
Hu X Chen Q Jiang L Yu Z Jiang D Yin D 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1151-1158
The combined effects of titanium dioxide (TiO2) nanoparticles and humic acid (HA) on the bioaccumulation of cadmium (Cd) in Zebrafish were investigated. Experimental data on the equilibrium Cd bioaccumulation suggest that only the dissolved Cd effectively contributed to Cd bioaccumulation in HA solutions whereas both the dissolved and TiO2 associated Cd were accumulated in TiO2 or the mixture of HA and TiO2 solutions, due likely to the additional intestine uptake of the TiO2-bound Cd. The equilibrium Cd bioaccumulation in the mixed system was comparable to that in the corresponding HA solutions, and significantly lower than that in the corresponding TiO2 solutions (n = 3, p < 0.05). The presence of either HA or TiO2 (5-20 mg L−1) in water slightly increased the uptake rate constants of Cd bioaccumulation whereas combining HA and TiO2 reduced the uptake rate constants. 相似文献
994.
Pleijel H 《Environmental pollution (Barking, Essex : 1987)》2011,159(4):897-902
This study considered effects of reduced [O3] on wheat yield. Open-top chamber charcoal filtered air treatments were compared with non-filtered treatments for field-grown wheat. 30 experiments meeting requirements were found, representing nine countries in North America, Europe and Asia. 26 experiments reported improved yield and 4 experiments reduced yield by filtration, a significant positive effect. Average yield improvement was 9%. Average daytime [O3] was reduced by filtration from 35 to 13 nmol mol−1. Filtration efficiency was 63% for O3 and 56% for SO2. For NOx it was observed that NO2 was reduced and NO increased by filtration. Thus, filters convert NO2 to NO. Most experiments reported low or very low [SO2] and [NOx]. Thus, O3 can be concluded to be the main phytotoxic component in the experiments. Elevated [NO2] was observed in one experiment. The conclusion is that current [O3] over large parts of the world adversely affect wheat yield. 相似文献
995.
During the last two decades, the importance of sulphur dioxide as a pollutant has moved away from its association with suspended particulate matter, to it being a precursor of SO
4
2-
aerosol (acidic e.g. sulphuric acid, or neutralised e.g. ammonium sulphate). Co-located concentration data of sulphur dioxide and SO
4
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, at nine monitoring sites situated in predominantly rural areas in the United Kingdom, collected over the time period 1979–1995, have been analysed. The time series for both species are discussed for the sites. Further analysis has shown that there is a degree of correlation between sulphur dioxide and SO
4
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for most of the sites considered. This correlation is of approximately the same level for most of the sites taken independently and together, and in most cases the slopes and intercepts associated with the simple empirical model equations arising from the correlation analysis, are of the same order of magnitude. The implementation of these site-dependent model equations within dispersion models for the prediction of the concentration of airborne sulphate aerosol from knowledge of sulphur dioxide concentration is discussed. Furthermore, the correlation analysis revealed the influence of transported sulphate aerosol on the local concentration, especially during high concentration episodes. 相似文献
996.
Coal is not only an important energy source in China but also a major source of air pollution. Because of this, China’s national
sulfur dioxide (SO2) emissions have been the highest in the world for many years, and since the 1990s, the territory of China’s south and southwest
has become the third largest acid-rain-prone region in the world. In order to control SO2 emissions, the Chinese government has formulated and promulgated a series of policies and regulations, but it faces great
difficulties in putting them into practice. In this retrospective look at the history of SO2 control in China, we found that Chinese SO2 control policies have become increasingly strict and rigid. We also found that the environmental policies and regulations
are more effective when central officials consistently give environmental protection top priority. Achieving China’s environmental
goals, however, has been made difficult by China’s economic growth. Part of this is due to the practice of environmental protection
appearing in the form of an ideological “campaign” or “storm” that lacks effective economic measures. More recently, better
enforcement of environmental laws and regulations has been achieved by adding environmental quality to the performance assessment
metrics for leaders at all levels. To continue making advances, China needs to reinforce the economic and environmental assessments
for pollution control projects and work harder to integrate economic measures into environmental protection. Nonetheless,
China has a long way to go before economic growth and environmental protection are balanced. 相似文献
997.
利用自制光催化气体反应器体系,以活性炭纤维负载TiO2作催化剂,在紫外光照射下模拟降解室内污染气体甲醛,测试了活性炭纤维负载TiO2催化剂的催化活性,探讨了紫外光光强、催化剂的酸度、反应器内湿度及反应时间等控制反应的主要因素对甲醛降解率的影响。结果表明,活性炭纤维与TiO2的协同作用大大提高了对甲醛的降解效果;紫外光强增倍对甲醛降解率有一定提高,但提高幅度仅为11.71%;活性炭纤维用pH=5的TiO2溶胶浸泡做催化剂对甲醛的降解效果最好,60 min内降解率达到68.37%;反应器内的湿度为81%甲醛降解率最高,反应60 min后达82.2%;随着反应时间的延长,甲醛降解率的上升幅度不断减小,最高只能达到94.59%。 相似文献
998.
Stability of titania nanoparticles in soil suspensions and transport in saturated homogeneous soil columns 总被引:2,自引:0,他引:2
Jing Fang Bei Wen Jin-ming Lin 《Environmental pollution (Barking, Essex : 1987)》2009,157(4):1101-1109
The stability of TiO2 nanoparticles in soil suspensions and their transport behavior through saturated homogeneous soil columns were studied. The results showed that TiO2 could remain suspended in soil suspensions even after settling for 10 days. The suspended TiO2 contents in soil suspensions after 24 h were positively correlated with the dissolved organic carbon and clay content of the soils, but were negatively correlated with ionic strength, pH and zeta potential. In soils containing soil particles of relatively large diameters and lower solution ionic strengths, a significant portion of the TiO2 (18.8-83.0%) readily passed through the soils columns, while TiO2 was significantly retained by soils with higher clay contents and salinity. TiO2 aggregate sizes in the column outflow significantly increased after passing through the soil columns. The estimated transport distances of TiO2 in some soils ranged from 41.3 to 370 cm, indicating potential environmental risk of TiO2 nanoparticles to deep soil layers. 相似文献
999.
燃油锅炉燃烧过程SO2的生成与排放特征 总被引:1,自引:0,他引:1
燃料燃烧过程是大气污染物的重要来源之一,对人体健康、空气质量和气候变化产生非常重要的影响。以62台燃油锅炉(≤10.5 MW)的燃料特性分析数据和SO2排放实测数据为基础,通过统计分析方法,研究了燃油燃烧过程中燃油硫含量S和过量空气系数α对硫的转化率、SO2排放因子和排放浓度的影响,获得了基于燃料消耗量、燃料发热量的SO2排放因子EFC、EFH以及SO2标态折算浓度C′SO2与硫含量S间的关联式。结果表明,在过量空气系数α>1的燃油燃烧过程中,EFC、EFH、C′SO2与燃油硫含量S呈现出显著的线性正相关性,而与过量空气系数α无关,其关系式分别为:EFC=18.86602×S,EFH=443.78751×S ,C′SO2=1 509.28337×S;硫转化率η和基于燃料硫含量的SO2排放因子EFS则与燃油硫含量S和过量空气系数α无关,其平均值分别为96.3%和1.93 kg/kg。 相似文献
1000.
Povinec PP Chudý M Sivo A Simon J Holý K Richtáriková M 《Journal of environmental radioactivity》2009,100(2):125-130
Radiocarbon variations in the atmospheric CO(2) with attenuating amplitudes and decreasing mean values with typical maxima in summer and minima in winter have been observed since 1967 in two localities of Slovakia, in Bratislava and Zlkovce, situated about 60 km NE from Bratislava, only 5 km from the Bohunice Nuclear Power Plant (NPP). The (14)C record in Bratislava has been influenced mainly by fossil CO(2) emissions, in contrast to the Zlkovce record which has been more variable, as it has clearly been affected by operation of the Bohunice NPP. However, during specific meteorological conditions with NE transport of air masses to Bratislava, the effect of the Bohunice NPP has been visible in Bratislava as well. Maximum (14)C concentrations (up to 120% above a natural background) were observed around A1 NPP which used CO(2) with admixture of air as a cooling agent. The (14)C concentrations around four pressurized light water reactors were up to 30% above the background. The Delta(14)C values in the heavily polluted atmosphere of Bratislava were up to 10% and at Zlkovce up to 5% lower than the European clean air represented by the Jungfraujoch Delta(14)C data. Later the Delta(14)C values were similar at both sites, and from 2003 they were close to the European clean air levels. The observed Delta(14)C behaviour in the atmosphere provides a unique evidence of decreased fossil fuel CO(2) emissions in the region, as well as the long-term effect of the Bohunice NPP on the Bratislava and Zlkovce stations. The estimated annual radiation doses to the local public due to digestion of radiocarbon contaminated food have been estimated to be around 3 microSv. 相似文献