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201.
Understanding the effects of watershed land uses (e.g., agriculture, urban industry) on stream ecological conditions is important for the management of large river basins. A total of 41 and 56 stream sites (from first to fourth order) that were under a gradient of watershed land uses were monitored in 2009 and 2010, respectively, in the Liao River Basin, Northeast China. The monitoring results showed that a total of 192 taxa belonging to four phyla, seven classes, 21 orders and 91 families were identified. The composition of macroinvertebrate community in the Liao River Basin was dominated by aquatic insect taxa (Ephemeroptera and Diptera), Oligochaeta and Molluscs. The functional feeding group GC (Gatherer/Collector) was dominant in the whole basin. Statistical results showed that sites with less watershed impacts (lower order sites) were characterized by higher current velocity and habitat score, more sensitive taxa (e.g., Ephemeroptera), and the substrate was dominated by high percentage of cobble and pebble. The sites with more impacts from agriculture and urban industry (higher order sites) were characterized by higher biochemical (BOD5) and chemical oxygen demand (COD), more tolerant taxa (e.g., Chironominae), and the substrate was dominated by silt and sand. Agriculture and urban-industry activities have reduced habitat condition, increased organic pollutants, reduced macroinvertebrate abundance, diversity, and sensitive taxa in streams of the lower Liao River Basin. Restoration of degraded habitat condition and control of watershed organic pollutants could be potential management priorities for the Basin.  相似文献   
202.
采用新型蜂窝陶瓷载体气升式内循环反应器(IAL-CHS)对受污染的城市地表水进行生物修复,该反应器能快速有效地修复受污染水体.考查了氨氮的变化历程、HRT与氨氮去除率间的关系,确定了最佳HRT为20 min.在HRT为20 min、接触反应时间仅为14 min条件下,该反应器对氨氮、TP、COD、TOC、浊度、UV254的去除率分别为86.7%~96.2%、4.5%~34.4%、15.5%~63.6%、5.8%~38.1%、9.4%~88.3%、3.8%~48.5%.  相似文献   
203.
Assessment of the health risks resulting from exposure to ambient polycyclic aromatic hydrocarbons (PAHs) is limited by the lack of environmental exposure data among different subpopulations. To assess the exposure cancer risk of particulate carcinogenic polycyclic aromatic hydrocarbon pollution for the elderly, this study conducted a personal exposure measurement campaign for particulate PAHs in a community of Tianjin, a city in northern China. Personal exposure samples were collected from the elderly in non-heating (August–September, 2009) and heating periods (November–December, 2009), and 12 PAHs individuals were analyzed for risk estimation. Questionnaire and time-activity log were also recorded for each person. The probabilistic risk assessment model was integrated with Toxic Equivalent Factors (TEFs). Considering that the estimation of the applied dose for a given air pollutant is dependent on the inhalation rate, the inhalation rate from both EPA exposure factor book was applied to calculate the carcinogenic risk in this study. Monte Carlo simulation was used as a probabilistic risk assessment model, and risk simulation results indicated that the inhalation-ILCR values for both male and female subjects followed a lognormal distribution with a mean of 4.81?×?10?6 and 4.57?×?10?6, respectively. Furthermore, the 95 % probability lung cancer risks were greater than the USEPA acceptable level of 10?6 for both men and women through the inhalation route, revealing that exposure to PAHs posed an unacceptable potential cancer risk for the elderly in this study. As a result, some measures should be taken to reduce PAHs pollution and the exposure level to decrease the cancer risk for the general population, especially for the elderly.  相似文献   
204.
In order to evaluate the potential adverse health effects of odor emissions from wastewater pump stations (WWPSs) to human, a health risk assessment was performed to study the odors emitted from an urban WWPS in a residential area, Tianjin (in North China). First, 15 types of volatile organic compounds in the WWPS were collected and analyzed using gas chromatography-mass spectrometry. Next, Monte Carlo probabilistic modeling was applied to evaluate the potential health effects of four odors (chlorobenzene, dichloromethane, hydrogen sulfide, and carbon disulfide), which had higher concentrations. The results revealed that the 95th percentile of the total non-carcinogenic risk was approximately 1.73, which poses a threat to human health. In addition, hydrogen sulfide had the highest non-carcinogenic risk value of the four; the hazard quotient of hydrogen sulfide was estimated to be 1.60 at the 95th percentile, higher than the upper confidence limit (1.0). The 95th percentile of the carcinogenic risk was approximately 5.47E-08, much lower than the maximum acceptable level (1.0E-06). Finally, the influence of the input variables on the output was evaluated using sensitivity analysis, and contaminant concentration, reference concentration, and inhalation unit risk were the most influential variables.  相似文献   
205.
关于灾害系统的若干问题   总被引:2,自引:0,他引:2  
本文简述了灾害系统的某些基本概念,提出了灾害学系统划分的基本原则,讨论了灾害系统的一些重要特征。指出灾害系统是一个非常复杂的大系统,它不仅是一个随着时间演化的开放系统,而且具有非线性、不确知性、不确定性和社会性。灾害系统的分析、综合和广义模型化是当前的重要课题。  相似文献   
206.
对太原地区的化工厂、制药厂、焦化厂排放废水中有机污染物进行了系统检测。在太原化工厂排放废水中检测出21种有机污染物,苯酚、氯苯占排放量的32.1%;在制药厂废水中检测出23种有机污染物,氯苯、硝基乙苯占排放量的53.2%;在焦化厂排放废水中检测出43种有机污染物,11种多环芳烃占排放量的57.0%,7种酚类占排放量的21.9%。  相似文献   
207.
本文分析了水资源承载力和战略环评的相关概念,以及水利工程对环境的影响.通过对目前水电项目环境影响评价现状进行分析,指出了战略环评在水电项目中将要发挥的重要作用.并且进一步探讨了水电项目环境影响研究的趋势,为今后合理开发水电资源,促进人类社会的可持续发展提供了评价的思路.  相似文献   
208.
电磁处理水实验平台建设与研究   总被引:3,自引:0,他引:3  
通过对国内外磁处理水技术发展的调研工作,自行组建了一套可调节电源额定电压、电源频率、电场强度、磁化流速、磁作用时间的利用高梯度磁场处理工业水的实验平台,用该平台对炼铁厂循环冷却水进行了模拟处理实验,实验结果分析表明,该实验技术可以用来对磁作用机理作深入分析,并优化系统工艺参数.  相似文献   
209.
In order to give out the correct conclusion for evaluating Chinese eco-environmental situation, in this paper, a special assessmental procedure has been used to analyse following 7 basic environmental problems: (1) Natural hazards; (2) Soil erosion; (3) Forest shrinkage and grassland degradation; (4) Water resources shortage; (5) Desertification; (6) Environmental pollution; (7) Farmland decrease. The basic strategies for improving Chinese environmental situation have been suggested.  相似文献   
210.
本文以具有北方半干旱山区代表性和典型性的隋家窝铺小流域为例,在简要分析了生态系统退化的现状、特征和原因的基础上,根椐生态经济学原理,提出了退化小流域生态系统重建与农业资源开发的原则、方向、途径及措施。通过5a的实践,在生态经济沟、防护林体系、人工草地、抗旱农田和高产栽培示范区等建设中取得了明显的生态和经济效益。  相似文献   
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