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排序方式: 共有1159条查询结果,搜索用时 31 毫秒
951.
Anders Stigebrandt Bengt Liljebladh Loreto de Brabandere Michael Forth ?ke Granmo Per Hall Jonatan Hammar Daniel Hansson Mikhail Kononets Marina Magnusson Fredrik Norén Lars Rahm Alexander H. Treusch Lena Viktorsson 《Ambio》2015,44(1):42-54
In a 2.5-year-long environmental engineering experiment in the By Fjord, surface water was pumped into the deepwater where the frequency of deepwater renewals increased by a factor of 10. During the experiment, the deepwater became long-term oxic, and nitrate became the dominating dissolved inorganic nitrogen component. The amount of phosphate in the water column decreased by a factor of 5 due to the increase in flushing and reduction in the leakage of phosphate from the sediments when the sediment surface became oxidized. Oxygenation of the sediments did not increase the leakage of toxic metals and organic pollutants. The bacterial community was the first to show changes after the oxygenation, with aerobic bacteria also thriving in the deepwater. The earlier azoic deepwater bottom sediments were colonized by animals. No structural difference between the phytoplankton communities in the By Fjord and the adjacent Havsten Fjord, with oxygenated deepwater, could be detected during the experiment.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-014-0524-9) contains supplementary material, which is available to authorized users. 相似文献952.
The designation of biodiesel as an environmental-friendly alternative to diesel oil has improved its commercialization and use. However, most biodiesel environmental safety studies refer to air pollution and so far there have been very few literature data about its impacts upon other biotic systems, e.g. water, and exposed organisms. Spill simulations in water were carried out with neat diesel and biodiesel and their blends aiming at assessing their genotoxic potentials should there be contaminations of water systems. The water soluble fractions (WSF) from the spill simulations were submitted to solid phase extraction with C-18 cartridge and the extracts obtained were evaluated carrying out genotoxic and mutagenic bioassays [the Salmonella assay and the in vitro MicroFlow® kit (Litron) assay]. Mutagenic and genotoxic effects were observed, respectively, in the Salmonella/microsome preincubation assay and the in vitro MN test carried out with the biodiesel WSF. This interesting result may be related to the presence of pollutants in biodiesel derived from the raw material source used in its production chain. The data showed that care while using biodiesel should be taken to avoid harmful effects on living organisms in cases of water pollution. 相似文献
953.
Biphasic effects of lanthanum on Vicia faba L. seedlings under cadmium stress, implicating finite antioxidation and potential ecological risk 总被引:3,自引:0,他引:3
In the present study, lanthanum (La) as a representative REE was used to explore the mechanisms for alleviation of Cd-induced oxidative damage by extraneous La at appropriate concentrations, and to assess ecological risk of combination of Cd and La at higher concentrations in roots of Vicia faba L. seedlings. The seedlings were hydroponically cultured for 15 d under nutrient solution, 6 μmol L−1 CdCl2, and combination of 6 μmol L−1 CdCl2 and increasing concentrations of La, respectively. The results showed that the supplementation with low concentrations of exogenous La (<120 μmol L−1) led to reduced contents of Cd, Ca, Cu, Zn, Mn or Fe element and increased activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) isozymes as well as heat shock protein 70 (HSP 70) production in the roots. However, the supplementation with higher La (>120 μmol L−1) showed the adverse effects. The contents of Cd elevated above the single Cd treatment in the roots, accompanying with the decline of antioxidant isozyme’s activities and HSP 70, and increment of carbonylated proteins and endoprotease isozyme’s activities. The results also showed that the root growth was not only related to carbonylated proteins, but also to indole acetic acid oxidase activities. Therefore, the supplemented extraneous La contributed to biphasic effects: stimulated antioxidation at lower concentrations and pro-oxidation at higher concentrations against Cd-induced oxidative stress in the roots. 相似文献
954.
几种牧草对铜尾矿重金属的抗性及其微生物效应 总被引:7,自引:1,他引:6
铜尾矿是一类重金属含量极高 ,对植物生长产生毒害的生境 .盆栽试验结果表明 ,4种牧草在纯尾矿以及由尾矿和对照土壤组成的混合尾矿上都能生长 ,但植物的长势随尾矿中重金属含量的增加而减弱 ,4种牧草对重金属的抗性依次表现为百喜草 >苇状羊茅 >黑麦草 >狗芽根 .此外 ,Biolog结果显示 ,土壤微生物群落代谢剖面 (AWCD)及群落丰富度、多样性指数与牧草的长势密切相关 ,种植牧草后能明显地提高土壤微生物群落功能多样性 ,提高幅度表现为百喜草 >苇状羊茅 >黑麦草>狗芽根 ,百喜草可望成为金属尾矿植被恢复的先锋牧草 . 相似文献
955.
Hydrogen generation from polyvinyl alcohol-contaminated wastewater by a
process of supercritical water gasification 总被引:6,自引:1,他引:5
Gasification of polyvinyl alcohol(PVA)-contaminated wastewater in supercritical water(SCW)was investigated in a continuous flow reactor at 723-873 K,20-36 MPa and residence time of 20-60 s.The gas and liquid products were analyzed by GC/TCD,and TOC analyzer.The main gas products were H_2,CH_4,CO and CO_2.Pressure change had no significant influence on gasification efficiency. Higher temperature and longer residence time enhanced gasification efficiency,and lower temperature favored the production of H_2. The effects of KOH catalyst on gas product composition were studied,and gasification efficiency were analyzed.The TOC removal efficiency(R_(TOC)),carbon gasification ratio(R_(CG))and hydrogen gasification ratio(R_(HG))were up to 96.00%,95.92% and 126.40% at 873 K and 60 s,respectively,which suggests PVA can be completely gasified in SCW.The results indicate supercritical water gasification for hydrogen generation is a promising process for the treatment of PVA wastewater. 相似文献
956.
猫跳河流域梯级水库磷的夏季变化特征 总被引:4,自引:0,他引:4
调查了我国第一条全流域梯级水电开发的河流--猫跳河中梯级水库对磷的拦截效应。于2007年丰水期7~9月在猫跳河流域采集水库坝前分层水样以及下泄水,分析和测试水样中的总磷和正磷酸盐。结果表明:丰水期猫跳河流域梯级水库内部总磷和可溶性正磷酸盐变化趋势相似,而下泄水的磷含量均大于该水库表层水体的磷含量。在猫跳河流域的梯级水库中,上游水库(红枫湖和百花湖)的磷含量明显高于各下游水库,即猫跳河流域各水库顺水流方向磷含量具有逐渐减少的特征,说明该流域梯级水库开发对于全流域磷具有梯级拦截效应;另一方面,各水库的富营养化指数表明该流域各水库均处于较高的富营养化状态,全流域富营养化状态差别与磷的分布特征相似,表现为顺水流方向减弱的规律。 相似文献
957.
958.
Cumulative Industrial Activity Alters Lotic Fish Assemblages in Two Boreal Forest Watersheds of Alberta,Canada 总被引:1,自引:0,他引:1
We evaluated the cumulative effects of land use disturbance resulting from forest harvesting, and exploration and extraction
of oil and gas resources on the occurrence and structure of stream fish assemblages in the Kakwa and Simonette watersheds
in Alberta, Canada. Logistic regression models showed that the occurrence of numerically dominant species in both watersheds
was related to two metrics defining industrial activity (i.e., percent disturbance and road density), in addition to stream
wetted width, elevation, reach slope, and percent fines. Occurrences of bull trout, slimy sculpin, and white sucker were negatively
related to percent disturbance and that of Arctic grayling, and mountain whitefish were positively related to percent disturbance
and road density. Assessments of individual sites showed that 76% of the 74 and 46 test sites in the Kakwa and Simonette watersheds
were possibly impaired or impaired. Impaired sites in the Kakwa Watershed supported lower densities of bull trout, mountain
whitefish, and rainbow trout, but higher densities of Arctic grayling compared to appropriate reference sites. Impaired sites
in the Simonette Watershed supported lower densities of bull trout, but higher densities of lake chub compared to reference
sites. Our data suggest that current levels of land use disturbance alters the occurrence and structure of stream fish assemblages. 相似文献
959.
简述了水环境中合成酚类抗氧化剂(SPAs)及其代谢产物,SPAs对鱼类的急性毒性效应、发育毒性效应及机制、内分泌干扰毒性效应和机制,以及代谢过程和产物毒性预测。指出,为准确实现对SPAs及其代谢物的化学品管理及生态风险评估,未来研究应聚焦于对合成酚类抗氧化剂及其代谢物在水生生物体内的分布及浓度检测,为该类化合物的生物富集和生物转化研究提供更多的背景资料;开展对SPAs潜在毒性分子机制的研究,并建立起分子水平上的毒理学效应与个体乃至种群水平上的不良后果之间的联系;探究并完善SPAs的代谢机制,并对现已明确的代谢产物(如BHT-Q)开展毒性效应评价。 相似文献
960.
Policy-makers are interested in cost-effective and socially acceptable ways of encouraging the public to adopt more environmentally-friendly lifestyles. One area which UK policy-makers are focussing on is ‘catalyst behaviour’, the notion that taking-up a new behaviour (such as recycling) may cause people to adopt other pro-environmental behaviours. Yet, evidence for such ‘spill-over’ effects is so far limited, and it is unclear when and how cross-situational motivations (e.g., pro-environmental identity) may predict behaviour and when contextual factors are more important. We report on a postal survey (N = 551) of pro-environmental behaviours amongst the UK public. We assess the influence of pro-environmental self-identify on consistency across a range of behaviours. Pro-environmental values, perceived behavioural control, subjective norm, attitudes, and demographic factors were also measured. Findings show self-identity to be a significant behavioural determinant over and above theory of planned behaviour variables for carbon offsetting behaviour. However, pro-environmental self-identity was only a significant predictor for certain other pro-environmental behaviours; background variables were also important predictors. Limitations of the study, and implications for theory and policy, are discussed. 相似文献