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331.
为了明确新型阻燃剂磷酸三(2-氯丙基)酯(TCPP)的生态风险,本研究采用斑马鱼为模式生物,评价了TCPP对成鱼和胚胎的毒性效应。急性毒性研究结果表明,TCPP对斑马鱼成鱼的96 h致死中浓度(LC50)为47.06 mg·L~(-1),而对胚胎96 h-LC50为26.01 mg·L~(-1),且会影响胚胎的正常发育,导致孵化出的仔鱼产生畸形。成鱼14 d延长毒性试验结果表明,TCPP对斑马鱼成鱼的无可观察效应浓度(NOEC)为1.00 mg·L~(-1),染毒暴露后肝脏和性腺指数随TCPP浓度增加轻微下降,但肝脏中卵黄蛋白原(VTG)的含量和性腺中芳香化酶的活性随TCPP浓度增加普遍升高。此外,TCPP的暴露还会导致斑马鱼脑垂体中合成促性腺激素的相关基因表达量增加。因此,TCPP对斑马鱼成鱼和胚胎的急性毒性均为低毒级,但长期暴露会干扰内分泌系统的调控功能,影响斑马鱼的正常发育。 相似文献
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中国在汶川地震后日益重视地震遗迹的旅游开发问题,龙门山地区是发展地震遗产旅游的关键区域。后汶川地震时期,地震遗产旅游的健康发展受到龙门山地区复杂多变的地质灾害环境的困扰。因此,对于地震遗产旅游的开发与管理等相关问题的研究不应只局限于短时间的震后恢复重建,而应以地震灾害事件的发展演变过程为时间轴,在其不同阶段均设置相应的动态应对措施。在回溯地震遗产旅游研究进展及该区域地震专题旅游发展现状的基础上,将系统工程的"三维结构体系"运用于解决"地震遗产旅游发展三维结构体系的构建",在此基础上提出了"地震遗产旅游综合集成发展模式"。研究结果为地震专题旅游开发中其它具体模式的理论框架,也为地震遗产旅游动态地应对地震等次生地质灾害的潜在威胁提供指导,其实践价值有赖于后续研究与实践的完善。 相似文献
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生物沸石床污水脱氮效果及机理 总被引:33,自引:4,他引:29
研究了生物沸石床对模拟村镇生活污水中各形态氮及COD等污染物的去除效果结果表明,生物沸石床对NH3--N去除效果明显且稳定,去除率大于95%,对NO3--N的去除则受水力停留时间的影响较大从机理分析,生物沸石对NH3-N的去除主要依靠化学吸附、离子交换以及生物硝化的协同作用,而对NO3--N的去除主要依赖反硝化作用.生物沸石的硝化作用明显,并受溶解氧浓度限制,沸石床中部沸石硝化强度只有表层沸石的1/2;其反硝化能力则随实验条件中C/N的不同而变化明显,当COD/TN=5时,反硝化作用最强,在时间变化规律上,前6h反硝化速率最大. 相似文献
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Zi WU Zhi LI Li ZENG Ling SHAO Hansong TANG Qing YANG Guoqian CHEN 《Frontiers of Environmental Science & Engineering》2011,5(4):597-603
Distinct from the case with width-dominated shallow wetland flows, the longitudinal evolution of contaminant concentration in the most-typical pattern of wetland as dominated by free-water-surface-effect is characterized by a multi-scale analysis in the present study. An environmental dispersion model for the evolution of the mean concentration is deduced as an extension of Taylor's classical formulation by Mei’s multi-scale analysis. Corresponding environmental dispersivity is found identical to that determined by the method of concentration moments. 相似文献
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Recently, a building-based air quality model system which can predict air quality in front of individual buildings along both sides of a road has been developed. Using the Macau Peninsula as a case study, this paper shows the advantages of building-based model system in data capture and data mining. Compared with the traditional grid-based model systems with input/output spatial resolutions of 1–2 km, the building-based approach can extract the street configuration and traffic data building by building and therefore, can capture the complex spatial variation of traffic emission, urban geometry, and air pollution. The non-homogeneous distribution of air pollution in the Macau Peninsula was modeled in a high-spatial resolution of 319 receptors·km-2. The spatial relationship among air quality, traffic flow, and urban geometry in the historic urban area is investigated. The study shows that the building-based approach may open an innovative methodology in data mining of urban spatial data for environmental assessment. The results are particularly useful to urban planners when they need to consider the influences of urban form on street environment. 相似文献
339.
The adsorptive characteristics of biochar produced from garden green waste (S-char) and a mixture of food waste and garden green waste (FS-char) were investigated. Adsorption of Cu2+, Zn2+, and Mn2+ onto the two biochars reached equilibrium within 48 hours. The metal adsorption was effectively described by the pseudo-second-order kinetic and Freundlich isotherm models which suggest heterogeneous chemisorption. The initial solution pH influenced adsorption of Zn2+ and Mn2+ but not of Cu2+. Simulation via a surface complexation model showed that the fraction of XOCu+ adsorbed onto biochar was increased with increasing pH until it reached the adsorption maximum at pH 8.5, while the endpoint for the maximum of XOMn+ was higher than pH 12. 相似文献
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China has the fifth largest forest area in the world and any change in China's forestry development will have inevitable impacts on global ecological sustainability. China has undergone excessive logging of natural forests and also made tremendous efforts in afforestation during the past half century. China's forestry is now going through a variety of transitions and several forestry programs have been implemented to drive forestry transitions. The goal of these actions is to protect ecological services of forests and sustain China's forestry development. These forestry programs are spatially sophisticated and cannot be successfully implemented without accurate and transparent forest/forestry information. A variety of digital technologies, including forest modeling, remote sensing, geographic information systems, global positioning systems, and visualization, have been applied in handling diverse information in China's forestry. Digital forestry is not just a theoretical concept in China. Our digital forestry experience in northeast China suggests that digital technology is both usable and useful in China's forestry development. Digital technology is playing an important interactive role in China's top-down forestry administration system. The analog-to-digital transition in technology is expected to lead to the success of forestry programs and forestry transitions in China. 相似文献