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741.
Ramsis B. Salama 《Water, Air, & Soil Pollution: Focus》2005,5(1-2):27-44
Perth groundwater resources are obtained from three major aquifers that occur beneath the Perth metropolitan area: the Superficial
aquifer, Leederville aquifer and Yarragadee aquifer. Each aquifer has a unique seasonal water level pattern controlled by
soils, geomorphology and geology. Landuse is mainly responsible for variations in recharge; however, the hydraulic properties
control aquifer response and water level pattern to a greater degree. Groundwater in the three aquifers is generally of very
good quality except in localised areas. Salinity increases with depth and in direction of groundwater flow in the three aquifers.
The best water quality is in the Superficial aquifer in the Wanneroo well field area. The geochemistry and stable isotope
signatures from the three major aquifers revealed distinct water types that suggest very little hydraulic connection or mixing
of waters between these aquifers at the present abstraction and recharge regimes. The results also show that the Leederville
and Yarragadee aquifers were recharged during earlier cooler times while the Superficial aquifer is being recharged at present. 相似文献
742.
马建华 《中国环境管理干部学院学报》2005,15(1):38-41
采用顶空气相色谱法测定食品中甜蜜素含量,探讨了气液相平衡条件及色谱条件的选择,实验结果表明甜蜜素的标准溶液在0.1-0.4μg/l范围内具有良好的线性关系,回收率为87.5%-101.8%,相对标准偏差为2.6%. 相似文献
743.
采用改性活性炭粉末对用纯净水加氟化钠配制而成的含氟水溶液进行动态电吸附去除实验.研究不同电压、电吸附时间,以及Cl-和SO2-4对氟离子去除的影响,并探讨吸附动力学和吸附方程.实验结果表明:活性炭对氟离子的吸附等温方程符合Freundlich方程,吸附动力学符合一级动力学方程;活性炭对氟离子去除与所施加的电位、吸附时间等因素有关,施加的电位越大,去除效果越好;随着吸附去除时间的延长,氟离子浓度下降趋缓;Cl-对氟离子去除影响很小,而SO2-4对氟离子去除有显著的不利影响. 相似文献
744.
对实验室污染问题的思考和建议 总被引:10,自引:0,他引:10
余华 《中国环境管理干部学院学报》2005,15(1):58-60
分析了目前实验室存在的污染种类及危害,阐明实验室是一种不容忽视的污染源,且污染种类复杂,毒害较大.提出实验室污染防治措施. 相似文献
745.
浅谈高职高专院校中的语文素质教育 总被引:2,自引:0,他引:2
一方面阐释语文素质教育在高职高专教育中的重要性及其作用;另一方面阐释了作为一名大学语文教师应如何在教学中体现"素质教育",培养出具有较高综合素质的职业技术人才. 相似文献
746.
Loss of grassland species resulting from activities such as off-road vehicle use increases the need for models that predict
effects of anthropogenic disturbance. The relationship of disturbance by military training to plant species richness and composition
on two soils (Foard and Lawton) in a mixed prairie area was investigated. Track cover (cover of vehicle disturbance to the
soil) and soil organic carbon were selected as measures of short- and long-term disturbance, respectively. Soil and vegetation
data, collected in 1-m2 quadrats, were analyzed at three spatial scales (60, 10, and 1 m2). Plant species richness peaked at intermediate levels of soil organic carbon at the 10-m2 and 1-m2 spatial scales on both the Lawton and Foard soils, and at intermediate levels of track cover at all three spatial scales
on the Foard soil. Species composition differed across the disturbance gradient on the Foard soil but not on the Lawton soil.
Disturbance increased total plant species richness on the Foard soil. The authors conclude that disturbance up to intermediate
levels can be used to maintain biodiversity by enriching the plant species pool. 相似文献
747.
The Water Fluxes of the Yellow River to the Sea in the Past 50 Years, in Response to Climate Change and Human Activities 总被引:12,自引:1,他引:12
Jiongxin X 《Environmental management》2005,35(5):620-631
Since the 1970s, the water fluxes to the sea of the Yellow River have declined significantly. Based on data of precipitation, air temperature, the measured and “natural” river flow, the water diversion and consumption, and the areas of erosion and sediment control measures over the drainage basin, water fluxes to the sea of the Yellow River are studied in relation with the influences of changing climate and human activities. The Yellow River basin can be divided into different water source areas; multiple regression indicates that the variation in precipitation over different water source areas has different effect on water fluxes to the sea. In the period between 1970 and 1997, averaged air temperature over the whole Yellow River increased by about 1.0°C, from 16.5°C to 17.5°C, a factor that is negatively correlated with the water yield of the Yellow River. Water diversion and consumption has sharply increased and resulted in a significant decline in the water fluxes to the sea. Since the 1960s, erosion and sediment control measures have been practiced over the drainage basin. This factor, to a lesser degree, is also responsible for the decrease in water fluxes to the sea. A multiple regression equation has been established to estimate the change in water fluxes to the sea caused by the changes in precipitation, air temperature, water diversion and consumption, erosion, and sediment control measures, indicating that the contribution of water diversion and consumption to the variation in annual water flux to the sea is 41.3%, that of precipitation is 40.8%, that of temperature is 11.4%, and that of erosion and sediment control measures is 6.5%. 相似文献
748.
Summary The balance of evidence suggests a perceptible human influence on global ecosystems. Human activities are affecting the global
ecosystem, some directly and some indirectly. If researchers could clarify the extent to which specific human activities affect
global ecosystems, they would be in a much better position to suggest strategies for mitigating against the worst disturbances.
Sophisticated statistical analysis can help in interpreting the influence of specific human activities on global ecosystems
more carefully. This study aims at identifying significant or influential human activities (i.e. factors) on CO2 emissions using statistical analyses. The study was conducted for two cases: (i) developed countries and (ii) developing
countries. In developed countries, this study identified three influential human activities for CO2 emissions: (i) combustion of fossil fuels, (ii) population pressure on natural and terrestrial ecosystems, and (iii) land
use change. In developing countries, the significant human activities causing an upsurge of CO2 emissions are: (i) combustion of fossil fuels, (ii) terrestrial ecosystem strength and (iii) land use change. Among these
factors, combustion of fossil fuels is the most influential human activity for CO2 emissions both in developed and developing countries. Regression analysis based on the factor scores indicated that combustion
of fossil fuels has significant positive influence on CO2 emissions in both developed and developing countries. Terrestrial ecosystem strength has a significant negative influence
on CO2 emissions. Land use change and CO2 emissions are positively related, although regression analysis showed that the influence of land use change on CO2 emissions was still insignificant. It is anticipated, from the findings of this study, that CO2 emissions can be reduced by reducing fossil-fuel consumption and switching to alternative energy sources, preserving exiting
forests, planting trees on abandoned and degraded forest lands, or by planting trees by social/agroforestry on agricultural
lands. 相似文献
749.
Dalia Streimikiene 《Natural resources forum》2005,29(4):322-333
This article summarizes some of the results from the application of the indicators for sustainable energy development (ISED) tool for analyzing Lithuania's energy sector, in terms of trends, setting energy policy goals and monitoring progress towards these goals. This experience illustrates the potential applicability of the ISED methodology for energy policy development in economies in transition, using Lithuania as an example. The article presents a summary of the results achieved and conclusions arrived at from the analysis of six priority areas in the context of the research project coordinated by the International Atomic Energy Agency, and provides recommendations for the development of sustainable energy policy using the ISED approach. 相似文献
750.
John V. Westra Julie K.H. Zimmerman Bruce Vondracek 《Journal of the American Water Resources Association》2005,41(2):309-322
ABSTRACT: Farmers can generate environmental benefits (improved water quality and fisheries and wildlife habitat), but they may not be able to quantify them. Furthermore, farmers may reduce their incomes from managing lands to produce these positive externalities but receive little monetary compensation in return. This study simulated the relationship between agricultural practices, water quality, fish responses to suspended sediment and farm income within two small watersheds, one of a cool water stream and one of a warm water stream. Using the Agricultural Drainage and Pesticide Transport (ADAPT) model, this study related best management practices (BMPs) to calculated instream suspended sediment concentrations by estimating sediment delivery, runoff, base flow, and streambank erosion to quantify the effects of suspended sediment exposure on fish communities. By implementing selected BMPs in each watershed, annual net farm income declined $18,000 to $28,000 (1 to 3 percent) from previous levels. “Lethal” fish events from suspended sediments in the cool water watershed decreased by 60 percent as conservation tillage and riparian buffers increased. Despite reducing suspended sediments by 25 percent, BMPs in the warm water watershed did not reduce the negative response of the fisheries. Differences in responses (physical and biological) between watersheds highlight potential gains in economic efficiency by targeting BMPs or by offering performance based “green payments.” 相似文献