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41.
42.
综述大气中有机胺可能的来源、健康危害及其在大气中的均相和非均相化学转化机制,阐述有机胺的反应产物对二次有机气溶胶及其对大气气溶胶的物理和化学性质的改变,此类改变增强大气气溶胶间接气候效应(如成云结核能力等)。大气中的有机胺主要通过与大气氧化剂的反应和非均相反应过程的溶解或置换进入颗粒相,而后随着湿沉降(如云滴、雾滴、雨滴等)到达地面或海面。 相似文献
43.
为检验二元联合作用藻红外测试方法的可行性,用Cu~(2+)、Fe3+、Mn~(2+)、Al3+、Cr3+、Hg~(2+)、Cd~(2+)、Pb~(2+)、Zn~(2+)进行了二元联合作用测试实验。结果显示:联合药液的参照浓度与单药液的参照浓度比为0.5:0.25的有15组二元组合,为2.0:1.0的有10组二元组合,为1.0:0.5的有11组二元组合;在9种重金属的36组二元联合作用测试结果中出现拮抗作用、相加作用、协同作用,表明联合作用类型表现出多样性;14组拮抗作用中单组的再现性为50%~100%、多组的再现性的出现率为93%、单组的重现性为67%~100%、多组的重现性的出现率为100%,21组相加作用中单组的再现性为50%~100%、多组的再现性的出现率为86%、单组的重现性为67%~100%、多组的重现性的出现率为100%,1组协同作用重现性67%;36组联合作用测试结果的再现性为50%~100%、再现性的出现率为86%,重现性为67%~100%、重现性的出现率为100%。上述分析可知,9种重金属的36种二元联合作用测试结果具有较好的多样性、再现性、重现性,表明测试条件、藻温测试方法、三指标评价法能够保证藻响应温差和藻响应药品评价结果的质量,参照浓度分析方法、联合作用评价方法能够控制联合作用分析结果的质量;藻响应的有毒有害物都存在敏感浓度,用参照浓度分析方法可分析出藻响应有毒有害物的参照浓度。因此,藻红外测试技术可以用于测试重金属、农药、有机药品、抗生素等的二元联合作用。 相似文献
44.
To analyze the factors affecting US public concern about the threat of climate change between January 2002 and December 2013, data from 74 separate surveys are used to construct quarterly measures of public concern over global climate change. Five factors should account for changes in levels of concern: extreme weather events, public access to accurate scientific information, media coverage, elite cues, and movement/countermovement advocacy. Structural equation modeling indicates that elite cues, movement advocacy efforts, weather, and structural economic factors influence the level of public concern about climate change. While media coverage exerts an important influence, it is itself largely a function of elite cues and economic factors. Promulgation to the public of scientific information on climate change has no effect. Information-based science advocacy has had only a minor effect on public concern, while political mobilization by elites and advocacy groups is critical in influencing climate change concern. 相似文献
45.
Inspired by the phenomenon of heavy reduction in the area of cultivated land following the entry of Korea and Japan to the WTO,countries with a large population and inadequate amount of cultivated land similar to China,this paper raises the problem of the potential effects on cultivated land in China following its entry to the WTO.The paper attempts analysis,using economic principles,of the effects of Chinese WTO membership on cultivated land from four aspects;tariff concessions,quota increment,comparative advantage,and the substitution principle.And the conclusion is mat China's entry to WTO may lead to a reduction in cultivated land.Finally,some countermeasures are proposed to resolve the problem. 相似文献
46.
Ruixin Guo Xinkun Ren Hongqiang Ren 《Journal of environmental science and health. Part. B》2013,48(9):883-890
As important members of the zooplankton community and sources of food for fish, rotifers are used extensively in ecotoxicological research to assess the health of the environment and safety of compounds. However, most rotifer toxicity tests are only conducted using rotifer neonates derived from unexposed mothers, thus ignoring the potential transfer of contaminants from mother to offspring. To understand better the mother to offspring exposure, a multigenerational study was conducted using three successive generations (F0, F1 and F2) of the common freshwater rotifer Brachionus calyciflorus to investigate the toxic effects of the widely used organophosphate pesticide, dimethoate (O, O-dimethyl S-methylcarbamoylmethyl phosphorodithioate). When the F0 generation was exposed to five pesticide concentrations, the population growth rate (r) displayed symptoms of hormesis, characterized by the conversion of low-concentration stimulation to high-concentration inhibition. Despite this observation, the exposure to any given concentration of dimethoate reduced the population growth rates of the F1 and F2 generation rotifers. Significant differences existed between the F0, F1 and F2 rotifers for the population growth rate under dimethoate stress: F2 individuals were more sensitive than F1, whereas the F1 individuals were more sensitive than F0. The results indicated that the parental exposure to a given toxic stress could result in increased sensitivity and decreased fitness in the offspring. This study illustrates the utility of multigenerational toxicity tests, which may better reflect and more accurately predict the effects of long-term pesticide exposure to aquatic organisms at the population level. 相似文献
47.
48.
Anna Giovanetti Sergey Fesenko Lisbet D. Asencio 《Journal of environmental radioactivity》2010,101(6):509-516
The accumulations of both natural (U) and depleted (DU) uranium in the earthworms (Eisenia fetida) were studied to evaluate corresponding biological effects. Concentrations of metals in the experimental soil ranged from 1.86 to 600 mg kg−1. Five biological endpoints: mortality, animals’ weight increasing, lysosomal membrane stability by measuring the neutral red retention time (the NRRT), histological changes and genetic effects (Comet assay) were used to evaluate biological effects in the earthworms after 7 and 28 days of exposure. No effects have been observed in terms of mortality or weight reduction. Cytotoxic and genetic effects were identified at quite low U concentrations. For some of these endpoints, in particular for genetic effects, the dose (U concentration)-effect relationships have been found to be non-linear. The results have also shown a statistically significant higher level of impact on the earthworms exposed to natural U compared to depleted U. 相似文献
49.
Felicity Hayes Gina MillsHarry Harmens Kirsten Wyness 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2420-2426
Few studies have investigated effects of increased background ozone in the absence of episodic peaks, despite a predicted increase throughout the northern hemisphere over the coming decades. In this study Leontodon hispidus was grown with Anthoxanthum odoratum or Dactylis glomerata and exposed in the UK to one of eight background ozone concentrations for 20 weeks in solardomes. Seasonal mean ozone concentrations ranged from 21.4 to 102.5 ppb. Ozone-induced senescence of L. hispidus was enhanced when grown with the more open canopy of A. odoratum compared to the denser growing D. glomerata. There was increased cover with increasing ozone exposure for both A. odoratum and D. glomerata, which resulted in an increase in the grass:Leontodon cover ratio in both community types. Carry-over effects of the ozone exposure were observed, including delayed winter die-back of L. hispidus and acceleration in the progression from flowers to seed-heads in the year following ozone exposure. 相似文献
50.
Mobility of Cd and Cu in formulated sediments coated with iron hydroxides and/or humic acids: a DGT and DGT-PROFS modeling approach 总被引:1,自引:0,他引:1
The diffusive gradients technique in thin films (DGT) was used to investigate the kinetic resupply of Cd and Cu to pore water from the solid phase. For the sake of simplification, experiments were performed using formulated sediments that differed in the presence or absence of humic acids (HA) and/or of iron hydroxides (i.e., goethite and ferrihydrite). The effects of the time after the contamination of the solid phase (aging effect) on formulated sediments that were coated with goethite and HA and spiked with Cd were also evaluated. Kinetic DGT results were interpreted using the newly developed, multi-compartmental model DGT-PROFS.Due to Cu humate formation, the addition of HA slightly increased the Cu concentration in the pore water independent of the effect of the iron hydroxide coating on the formulated sediments and slightly decreased that of Cd. The impact of 8-190 d of aging resulted in a significant decrease in the Cd concentration of the pore water over an increasing incubation time.Modeling our results with DGT-PROFS led to the following conclusions concerning the impact of HA and iron hydroxides on Cd and Cu availability. First, in the presence of HA and absence of iron hydroxides, Cd is associated mainly with weak sites, while Cu is bound to strong sites. Similarly, in the presence of both iron hydroxides and HA, Cu appeared to be more heavily associated with the strong sites than did Cd. When the incubation time increased from 8 to 190 d, a proportion of Cd initially adsorbed onto weak sites transferred to the strong sites, suggesting that the adsorption of Cd on sediments is controlled partially by slow kinetic processes. 相似文献