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981.
Characterization and distribution of polycyclic aromatic hydrocarbon in sediments of Haihe River, Tianjin, China 总被引:7,自引:0,他引:7
JIANG Bin ZHENG Hai-long HUANG Guo-qiang DING Hui LI Xin-gang SUO Hong-tu LI Rui 《环境科学学报(英文版)》2007,19(3):306-311
In this study sediment samples were collected from 13 sites of Haihe River in Tianjin City, China, sixteen of priority polycyclic aromatic hydrocarbons (PAHs) listed in USEPA were analyzed by means of GC-MS. The total concentrations of PAH ranged from 774.81 to 255371.91 ng/g dw, and two to four rings of PAHs were dominant in sediment samples. Molecular ratios, such as phenanthrene/anthracene, fluoranthene/pyrene and low-molecular-weight PAH/high-molecular-weight PAH, were used to study the possible sources of pollution. It indicated a mixed pattern of parolytic and petrogenic inputs of PAHs in sediments in Haihe River. The petrogenic PAHs may be mainly derived from the leakage of refined products, e.g., gasoline, diesel fuel and fuel oil vehicle traffics or gas stations from urban area. The pyrolytic PAHs might be from the discharge of industrial wastewater and the emission of atmospheric particles from petrochemical factories. In addition, the levels of PAHs in the urban and industrial areas are far beyond the values reported from other rivers and marine systems reported. This situation may be due to polluted discharging from some petrochemical industrial manufactories and worse traffic conditions in Tianjin. 相似文献
982.
Evaluation of oasis ecosystem risk by reliability theory in an arid area: A case study in the Shiyang River Basin, China 总被引:2,自引:0,他引:2
Ecosystem risk is a new concept in understanding environmental problems. It is important to study and develop quantitative methods for regional ecosystem risk analysis. In this study, some new indicators and methods for measuring oasis ecosystem risk were established using reliability theory. These indicators are linked to water resource, which is the key restricting factor in arid area oasis ecosystems. They have clear meanings and can also be compared in different arid area oases. A case study in the Liangzhou oasis of the Shiyang River Basin in China shows how to calculate these ecosystem risk indicators. The results of the case study are as follows: the reliability indicator, risk indicator, stability indicator, and integrated loss indicator of the Liangzhou oasis are 0.686, 0.314, 0.743, and 0.301, respectively. This means that the reliability degree of the oasis's ecosystem safety is 68.6%; the degree of risk that it is unsafe is 31.4%; the stability degree is 74.3%; and 30.1% of the oasis's area is supported by over-exploiting underground water and damaging the lower reaches of the ecosystem. This result can be used as a guide in controlling and managing ecosystem risk in the research area. 相似文献
983.
Number concentration and size distributions of submicron particles in Jinan urban area: Characteristics in summer and winter 总被引:1,自引:0,他引:1
GAO Jian WANG Jin CHENG Shu-hui XUE Li-kun YAN Huai-zhong HOU Lu-jian JIANG Yu-quan WANG Wen-xing 《环境科学学报(英文版)》2007,19(12):1466-1473
The aerosol number concentration and size distribution were measured with the newly developed Wide-range Particle Spectrometer in summer and winter of 2006 at the urban site of Jinan City.Here reported the characteristics of fine particles of the different observation seasons.Relative high number concentrations for the particles in the diameter range of 10-500 nm were observed in both seasons.It was found that the dominant number distributed in particle diameter smaller than 100 nm and the percentage over the number concentration of all air particles is much higher than what has been measured in other urban sites over the world.The number mean diameter in summer was much smaller than in winter,strongly suggesting the different origin of ultrafine particles in different seasons.That is, particles in ultrafine mode mainly came from nucleation and new particle formation in summer while from traffic emission in winter. The diurnal variation also supported this point.Number concentration in the diameter range of 10-200 nm got their peak values at noontime,well correlated with the mixing ratio of SO_2 and the intensity of solar radiation in summer.While in winter,those in the same diameter range showed the main peaks during the traffic hours happened in the morning and evening. 相似文献
984.
985.
Ming-Der Li Author Vitae Author Vitae Kai-Kuo Chang Author Vitae Author Vitae Ming-Chang Jeng Author Vitae 《Journal of Safety Research》2008,39(6):623-630
Introduction
Fatalities from traffic accidents in less-motorized societies are an important global issue. We aimed to characterize the geographic differences of fatalities in such societies to facilitate the development of targeted interventions.Method
This study linked police reports, hospital data, and vital registration data from Taiwan with special reference to accident factors in pre-hospital deaths and medical care in hospital deaths.Results
A higher percentage of pre-hospital deaths were observed following rural as compared to urban traffic accidents. The deaths due to rural accidents can be attributed to lower use of restraints (i.e., helmets or seat belts), lower percentage of motorcyclists, and more highway accidents. A higher percentage of victims in rural accidents were transported to distant medical centers rather than to local hospitals.Conclusion
Specific interventions, such as intelligent emergency medical systems, campaigns for helmets and seat belt usage, enforcement of helmets and seat belt use, and speed control measures should be targeted to rural areas.Impact on industry
Cooperation between the vehicle industry and emergency medical providers in rural traffic accident rescue teams may decrease the numbers of deaths in these regions. 相似文献986.
Ahmad K. Hegazy Mahmoud A. Medany Hanan F. Kabiel Mona M. Maez 《Natural resources forum》2008,32(4):316-326
This study focuses on the management of the local agroecosystems in order to adapt planting or sowing practices for the projected climate change scenarios. It is projected that there will be increased air temperature throughout all four seasons in the coming 100 years, from the southern towards the northern parts of Egypt. The objective of this study is to investigate the influence of that increased air temperature on the spatial and temporal distribution of four of the major economic crops in Egypt. The study species are cotton (Gossypium barbadense L., cv. Giza 89), wheat (Triticum aestivum L., cv. Gemiza 9), rice (Oryza stiva L., cv. Sakha 101) and maize (Zea mays L., cv. Hybrid 10). Optimum air temperature allowing maximum growth for each of the study crop cultivars and the current and projected air temperature patterns in the future years were used for projection of the seasonal and crop distribution maps in the years 2005, 2025, 2050, 2075 and 2100. Results showed that sowing dates of a target crop may be managed in order to allow maximum predicted planting area in the same region. The current maximum area suitable for planting the Cotton crop in Egypt (104 thousand Fadden/year; one Fadden = 0.96 hectare or 0.42 acre) showed few variations over the coming hundred years. In this case, the sowing dates should be changed from the hotter months (February to April) to the cooler months (January to February). Alternatively, a great reduction in the area planted by Wheat crop was predicted in the coming 100 years. Despite the early planting, a reduction of about 147 thousand Fadden/year was projected by the year 2075. On the other hand, with earlier sowing dates, the maximum areas that are planted by Rice and Maize may not be greatly affected by the projected increase in air temperature. 相似文献
987.
Eco-health evaluation for the Shanghai metropolitan area during the recent industrial transformation (1990-2003) 总被引:2,自引:0,他引:2
Shanghai is a cosmopolitan city and one of the most important economic centers in China, but is saddled with serious environmental problems resulting from a recent industrial transformation. This paper examines the interactive relationships between economic growth, eco-efficiency of urban metabolism, and environmental performance of the Shanghai metropolitan area since the 1990s using 15 indicators. This study has revealed an enhanced eco-efficiency of water and energy use as well as an improved overall environmental quality in the central urban districts of Shanghai. Both TGDP (total GDP) and GDP per capita increased rapidly at the annual rate of 16.28% and 15.91%, respectively. In contrast, energy consumed per 10000RMB YUAN GDP (ECG), water consumed per 10000RMB YUAN GDP (WCG), wastewater discharged per 10000RMB YUAN GDP (WWDG), and waste gases emitted per 10000RMB YUAN GDP (WGEG) decreased at the annual rate of 9.34%, 10.69%, 14.57%, and 8.52%, respectively. The rapid decline in ECG, WCG, WWDG, and WGEG indicates an enhanced eco-efficiency of urban metabolism. However, uncontrolled emission of wastes from domestic instead of industrial sources adversely affected the overall environmental quality. In addition, suburban areas have undergone rapid economic growth at the cost of human health deterioration, as measured by mortalities and relative mortality ratios of three major diseases (tumor, respiratory disease, and trauma/toxicosis). With Shanghai serving as the "locomotive" driving the economy of the Yangtze River Basin, effective pollution control policies and a network of regional coordination are urgently needed in the globalization and ecological security of the entire area. 相似文献
988.
The study focuses on understorey-overstorey plant community dynamics in a dry tropical forest to facilitate appropriate management decisions. We compare community composition and species diversity of the understorey vegetation among five dry tropical forest sites in northern India. A total of 1500 quadrats distributed over 15 one-ha permanent plots in five sites differing in the degree of disturbance, were used to enumerate the understorey tree species and the results were compared with overstorey tree layer. The non-metric multidimensional scaling (NMS) ordination revealed that human disturbance intensity, as well as the overall disturbance regimes, and soil water holding capacity controlled the organisation of dry tropical forest understorey composition through effects on soil organic matter. The alpha-diversity and its components decreased with increasing human disturbance intensity, reflecting utilisation pressure and decreased soil fertility, as also revealed by the analysis of overstorey tree layer. There was a significant positive relationship between overstorey and understorey diversity. Results suggest that in the future, the existing understorey tree communities may replace the current dry tropical forest communities under prevailing environmental conditions. The study also asserts that the rate of species accumulation will be greater in more disturbed sites as well as at small spatial scale within each disturbance level. 相似文献
989.
990.