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811.
Leandro Carbo Eucarlos L. Martins Eliana F. G. C. Dores Cláudio A. Spadotto Oscarlina L. S. Weber Ermelinda M. De-Lamonica-Freire 《Journal of environmental science and health. Part. B》2013,48(5):499-507
Sorption of acetamiprid ((E)-N1-[(6-chloro-3-pyridyl)methyl]-N2-cyano-N1-methylacetamidine), carbendazim (methyl benzimidazol-2-ylcarbamate), diuron (N-(3,4-dichlorophenyl)-N, N-dimethyl urea) and thiamethoxam (3-(2-chloro-thiazol-5-ylmethyl)-5-methyl-[1,3,5]oxadiazinan-4-ylidene-N-nitroamine) was evaluated in two Brazilian tropical soils, Oxisol and Entisol, from Primavera do Leste region, Mato Grosso State, Brazil. To describe the sorption process, batch experiments were carried out. Linear and Freundlich isotherm models were used to calculate the K d and K f coefficients from experimental data. The K d values were utilized to calculate the partition coefficient normalized to soil organic carbon (K oc ). For the pesticides acetamiprid, carbendazim, diuron and thiamenthoxan the K oc (mL g? 1) values ranged in both soils from 98 – 3235, 1024 – 2644, 145 – 2631 and 104 – 2877, respectively. From the studied pesticides, only carbendazim presented correlation (r2 = 0.82 and p < 0.01) with soil organic carbon (OC) content. Acetamiprid and thiamethoxam showed low sorption coefficients, representing a high risk of surface and ground water contamination. 相似文献
812.
西藏东南部森林可燃物特点及气候变化对森林火灾的影响 总被引:4,自引:0,他引:4
根据西藏林芝地区的DEM数据和植被分布数据分析了该地区可燃物的水平分布和垂直分布规律,并根据火发生纪录分别计算了火发生周期和发生概率,根据火灾高发期的降水和气温数据分析降水和气温的变化趋势,本地区易发生火灾的可燃物主要有高山松云南松林,草甸灌丛,云冷杉林等.该地区的火灾轮回期为17178 a,火发生概率为0.00006,远远低于东北林区,但由于该地区处于高海拔地区,生态系统脆弱,林木蓄积量大,积累能量高,潜在的火强度高.林芝地区夏季降水减少,火灾高发期(2~5月)降水有所增加,但增温明显,气温升高对高海拔地区的影响比低海拔地区更大,对于森林可燃物而言,气温增高使高海拔地区的森林火险增大,森林防火面临的形势更加严峻. 相似文献
813.
建立了固相萃取-高效液相色谱-质谱联用法对雌三醇、氟哌噻吨、炔雌醇、雄烯二酮、雌二醇、雌酚酮、睾酮共7种类固醇激素的检测方法。样品经C18萃取小柱富集净化,采用内标法定量时,方法的检出限为0.66~1.95 ng/L,R0.998,回收率为78.5%~94.6%,相对标准偏差为1.1%~7.7%。采用该方法对上海市地表水进行测定,在2个采样点中检出雌酚酮(1.88 ng/L)和雄烯二酮(1.48 ng/L)。 相似文献
814.
关于核燃料循环建设项目竣工环境保护验收监测的思考 总被引:1,自引:0,他引:1
针对核燃料循环建设项目竣工环境保护验收监测活动中存在的问题作探讨,明确了验收监测活动的起点,建议加强验收监测方案编制的培训。指出应重视流出物的持续监测和环保设施运行效率的验证,验收监测方案应参考环评文件中的环境监测计划,结合设施运行后的现状合理编制,并重视与污染源项有关的其他监测问题。提出了进一步完善核燃料循环标准体系、持续加强环保验收能力建设等建议。 相似文献
815.
816.
A novel technique has been developed for determining the 212Pb activity of fresh waters. This is of interest to environmental monitoring programmes that utilise gross α-activity methods to screen for anthropogenic radionuclides. The contribution from 212Pb varies, and is difficult to experimentally measure due to its relatively short half-life (t½ = 10.6 h) and low environmental activity (<0.1 Bq l−1). The use of a three-stage technique that encompasses a unique form of pre-concentration, separation and analysis by liquid scintillation counting allows a lower detection limit of 0.006 Bq l−1 with a chemical yield of 92.5 ± 5.6%. The measurement can be obtained within 7 h of sample collection, and is calculated using the radioactive decay of 212Bi. Other naturally occurring radionuclides may also be extracted using the pre-concentration stage of the technique, with efficiencies above 90% at a range of pH values. 相似文献
817.
稳恒磁场作用下微生物燃料电池的产电特性和电化学阻抗谱分析 总被引:2,自引:0,他引:2
对混合菌接种的双室微生物燃料电池加载磁场强度为175 mT的稳恒磁场,利用电化学交流阻抗等电化学分析方法,考察了在磁场作用下微生物燃料电池(MFC)产电性能的变化,分析了磁场对MFC各部分内阻的影响。加载磁场使已启动完成的MFC的产电明显增强,开路电压提高了10%。加载磁场后最大功率密度为2.08 W/m2,大于加载前的1.58 W/m2,表观内阻由170Ω降至80Ω。电化学阻抗谱分析确定了阳极、阴极和全电池的等效电路模型,拟合结果发现阳极极化内阻约为5Ω。加载磁场使MFC的阴极极化内阻由74.98Ω降至56.73Ω。 相似文献
818.
The fossil fuel divestment movement has been a vibrant novel development in climate change politics in recent years, particularly in North America. Here, the character of the discourse used to promote divestment as a strategy is explored. The divestment discourse is shown to rest on four overlapping narratives, those of war and enemies, morality, economics and justice. All four are clearly discernible in statements from movement activists, in coverage of divestment campaigns by major news sources and in the movement’s aims, objectives and strategies covered in alternative media. The war narrative, with the formulation of fossil fuel companies as enemies to be overcome to ensure survival, is the dominant narrative. By polarising climate action and identifying an antagonist against which to mobilise, divestment discourse has articulated climate change as an explicitly political phenomenon, in contrast to the primarily consensus and collaboration-based approaches that have predominated in climate politics. 相似文献
819.
Noriyuki Momoshima Fumio Inoue Jun Shimada 《Journal of environmental radioactivity》2010,101(8):615-621
Atmospheric 85Kr concentration at Fukuoka, Japan was determined by an improved 85Kr analytical method using liquid scintillation counting (LSC). An average value of 1.54 ± 0.05 Bq m−3 was observed in 2008, which is about two times that measured in 1981 at Fukuoka, indicating a 29 mBq y−1 rate of increase as an average for these 27 years. The analytical method developed involves collecting Kr from air using activated charcoal at liquid N2 temperature and purifying it using He at dry ice temperature, followed by Kr separation by gas chromatography. An overall Kr recovery of 76.4 ± 8.1% was achieved when Kr was analyzed in 500-1000 l of air. The Kr isolated by gas chromatography was collected on silica gel in a quartz glass vial cooled to liquid N2 temperature and the activity of 85Kr was measured with a low-background LS counter. The detection limit of 85Kr activity by the present analytical method is 0.0015 Bq at a 95% confidence level, including all propagation errors, which is equivalent with 85Kr in 1.3 l of the present air under the analytical conditions of 72.1% counting efficiency, 0.1597 cps background count rate, and 76.4% Kr recovery. 相似文献
820.
ZHANG Yuan-xun SHAO Min ZHANG Yuan-hang ZENG Li-min HE Ling-yan ZHU Bin WEI Yong-jie ZHU Xian-lei 《环境科学学报(英文版)》2007,19(2):167-175
Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters (PMzs) from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon (EC) and organic carbon (OC) was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum (GC-MS). Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols (0.18%-0.63% of the total fine particle mass). Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index (CPI) of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches. 相似文献