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121.
渤海滩涂沉积物中石油污染物的迁移-转化规律研究 总被引:2,自引:0,他引:2
采用紫外分光光度法对2003年夏季渤海滩涂表层沉积物和海水中石油烃含量进行了分析,探讨了海水中可溶油在滩涂沉积物中的迁移转化特征及其影响因素。结果表明,沉积物中石油烃含量在(55.8~2563.4)×10-6,平均值为555.82×10-6,与海洋沉积物质量(GB18668-2002)500×10-6相比,超标率为50%,超标倍数为1.05~5.13倍;受潮流作用和沉积环境的影响,石油烃含量自岸向海呈由低到高的分布特征;研究区是典型的淤泥质海岸带,由于其沉积物颗粒细,有机质含量高,很容易吸附石油烃;沉积物中石油烃是难生物降解的多环芳烃类。 相似文献
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下扬子区中上元古界,可以分为四个构造层次.中元古界早期构造层,为一套巨厚的地槽型火山碎屑岩及砂泥质复理石建造,形成于1900-1400Ma;中元古界晚期构造层,为滨海——浅海——半深海砂泥质复理石建造.形成于1400-1000Ma;晚元古界早期构造层,为山前凹地或山间盆地磨拉石堆积,形成于1000-800Ma;晚元古界晚期(震旦系)构造层,则为砂泥质、硅质、碳酸盐岩夹冰碛砾岩建造,形成于800-600Ma.这些构造层之间不同形式的接触关系都代表着不同性质的构造运动,九岭群和修水间的修水运动,形成扬子准地台的雏型;上溪群和历口群邓家组间的祁门运动是形成扬子准地台的主褶皱幕;历口群铺岭组和震且系间的休宁运动,只使地壳抬升.这些不同性质的构造运动,也是推动地质历史演化的主要动力. 相似文献
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废弃电器电子产品的非法越境转移已成为国际社会关注的重要环境问题之一,与之相伴而生的废弃电器电子产品与旧电器电子产品的鉴别问题也成为国际环境公约的热点议题.在此背景下,针对废旧电器电子产品越境转移的管理制度和鉴别标准,对相关国际公约以及美国、日本和欧盟等典型出口方与泰国、马来西亚和中国等典型进口方进行了比较分析.结果表明,发达国家和发展中国家关于废旧电器电子产品越境转移的政策存在对立性,尽管《巴塞尔公约》在努力减少这种对立性,以保护发展中国家环境利益,但电子废物非法越境转移的风险仍然存在.结合中国废旧电器电子产品进口管理现状,提出了完善中国现有管理体系的政策建议. 相似文献
127.
Myat Sandar Win Zhengyang Tian Hui Zhao Kai Xiao Jiaxian Peng Yu Shang Minghong Wu Guangli Xiu Senlin Lu Shinich Yonemochi Qingyue Wang 《环境科学学报(英文版)》2018,30(9):13-31
Atmospheric humic-like substances(HULIS) are not only an unresolved mixture of macroorganic compounds but also powerful chelating agents in atmospheric particulate matters(PMs); impacting on both the properties of aerosol particles and health effects by generating reactive oxygen species(ROS). Currently, the interests of HULIS are intensively shifting to the investigations of HULIS-metal synergic effects and kinetics modeling studies, as well as the development of HULIS quantification, findings of possible HULIS sources and generation of ROS from HULIS. In light of HULIS studies, we comprehensively review the current knowledge of isolation and physicochemical characterization of HULIS from atmospheric samples as well as HULIS properties(hygroscopic, surface activity, and colloidal) and possible sources of HULIS.This review mainly highlights the generation of reactive oxygen species(ROS) from PMs, HULIS and transition metals, especially iron. This review also summarized the mechanism of ironorganic complexation and recent findings of OH formation from HULIS-metal complexes. This review will be helpful to carry out the modeling studies that concern with HULIS-transition metals and for further studies in the generation of ROS from HULIS-metal complexes. 相似文献
128.
目的对某天线进行加速贮存试验研究,利用试验数据进行寿命评估,得到产品的加速因子。方法通过步降应力试验方法对某天线的12台产品进行了四个不同应力量级的高温加速贮存试验,获得产品的退化数据。分别采取两种加速模型对试验数据进行处理,对比确定最优评估方法。结果采用基于漂移布朗运动的加速模型评估得到产品的激活能,从而求出加速因子和贮存寿命。结论步降应力试验方法能加速产品损伤的累积,便于快速获得产品的性能退化数据,而基于漂移布朗运动的评估方法为天线类产品的寿命评估提供了一种新的参考方法。 相似文献
129.
Since their official eradication from the US in 1943, the cattle-tick species Boophilus microplus and Boophilus annulatus, vectors of bovine babesiosis, frequently have penetrated a quarantine zone established along the Texas–Mexico border designed to exclude them. Inspection and quarantine procedures have eradicated reinfestations successfully within the US, but increasing acaricide resistance in Mexican B. microplus populations poses a threat to future eradication efforts. Better understanding of interrelationships among Boophilus populations, their hosts, and vegetation communities in south Texas could improve prediction of the behavior of reintroduced Boophilus populations and increase management options. To this end, we constructed a simulation model to evaluate how microclimate, habitat (i.e. vegetation) heterogeneity, and within-pasture cattle movement may influence dynamics of Boophilus ticks in south Texas. Unlike previous Boophilus tick models, this model simulates dynamics at an hourly time-step, calculates all off-host dynamics as functions of temperature and relative humidity, and runs with ground-level microclimate data collected bi-hourly in three different habitat types. Sensitivity analysis of the model showed that temperatures and relative humidities created by habitat type, as well as engorged female mass, influenced tick population dynamics most strongly. Host habitat selection, initial number of larvae per cow, and the number of cells into which the simulated pasture was divided also had a strong influence. Population dynamics appeared moderately sensitive to the proportion of Bos indicus in cattle genotypes and the larval attachment rate, while appearing relatively insensitive to factors such as mortality rate of engorged females. When used to simulate laboratory experiments from the literature, the model predicted most observed life-history characteristics fairly well; however, it tended to underestimate oviposition duration, incubation duration, and egg mortality and overestimate larval longevity, especially at low temperatures and high humidities. Use of the model to predict Boophilus population dynamics in hypothetical south Texas pastures showed that it reasonably generated qualitative patterns of stage-wise abundances but tended to overestimate on-host tick burdens. Collection and incorporation of data that appear not to exist for Boophilus ticks, such as larval lipid content and lipid-use rates, may improve model accuracy. Though this model needs refinements such as a smaller spatial resolution, it provides insight into responses of B. microplus or B. annulatus populations to specific weather patterns, habitat heterogeneity, and host movement. 相似文献
130.
G. Wittemyer W. M. Getz F. Vollrath I. Douglas-Hamilton 《Behavioral ecology and sociobiology》2007,61(12):1919-1931
The structure of dominance relationships among individuals in a population is known to influence their fitness, access to
resources, risk of predation, and even energy budgets. Recent advances in global positioning system radio telemetry provide
data to evaluate the influence of social relationships on population spatial structure and ranging tactics. Using current
models of socio-ecology as a framework, we explore the spatial behaviors relating to the maintenance of transitive (i.e.,
linear) dominance hierarchies between elephant social groups despite the infrequent occurrence of contests over resources
and lack of territorial behavior. Data collected from seven families of different rank demonstrate that dominant groups disproportionately
use preferred habitats, limit their exposure to predation/conflict with humans by avoiding unprotected areas, and expend less
energy than subordinate groups during the dry season. Hence, our data provide strong evidence of rank derived spatial partitioning
in this migratory species. These behaviors, however, were not found during the wet season, indicating that spatial segregation
of elephants is related to resource availability. Our results indicate the importance of protecting preexisting social mechanisms
for mitigating the ecological impacts of high density in this species. This analysis provides an exemplar of how behavioral
research in a socio-ecological framework can serve to identify factors salient to the persistence and management of at risk
species or populations.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献