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971.
Water pollution in Pakistan and its impact on public health--a review   总被引:3,自引:0,他引:3  
Water pollution is one of the major threats to public health in Pakistan. Drinking water quality is poorly managed and monitored. Pakistan ranks at number 80 among 122 nations regarding drinking water quality. Drinking water sources, both surface and groundwater are contaminated with coliforms, toxic metals and pesticides throughout the country. Various drinking water quality parameters set by WHO are frequently violated. Human activities like improper disposal of municipal and industrial effluents and indiscriminate applications of agrochemicals in agriculture are the main factors contributing to the deterioration of water quality. Microbial and chemical pollutants are the main factors responsible exclusively or in combination for various public health problems. This review discusses a detailed layout of drinking water quality in Pakistan with special emphasis on major pollutants, sources of pollution and the consequent health problems. The data presented in this review are extracted from various studies published in national and international journals. Also reports released by the government and non-governmental organizations are included.  相似文献   
972.
High spatial and temporal resolution airborne imagery were acquired for the Ribble Estuary, North West England in 1997 and 2003, to assess the application of time-series airborne remote sensing to quantify total suspended sediment and radionuclide fluxes during a flood and ebb tide sequence. Concomitant measurements of suspended particulate matter (SPM) and water column turbidity were obtained during the time-series image acquisition for the flood and ebb tide sequence on the 17th July 2003 to verify the assumption of a vertically well mixed estuary and thus justifying the vertical extrapolation of spatially integrated estimate of surface SPM. The 137Cs activity concentrations were calculated from a relatively stable relationship between SPM and 137Cs for the Ribble Estuary. Total estuary wide budgets of sediment and 137Cs were obtained by combining the image-derived estimates of surface SPM and 137Cs with estimates of water volume from a two-dimensional hydrodynamic model (VERSE) developed for the Ribble Estuary. These indicate that around 10,000 tonnes of sediment and 2.72 GBq of 137Cs were deposited over the tidal sequence monitored in July 2003. This compared favourably with bed height elevation change estimated from field work. An uncertainty analysis on the total sediment and 137Cs flux yielded a total budget of the order of 40% on the final estimate. The results represent a novel approach to providing a spatially integrated estimate of the total net sediment and radionuclide flux in an intertidal environment over a flood and ebb tide sequence.  相似文献   
973.
An existing model of radiocaesium transfer to grasses was extended to include wheat and barley and parameterised using data from a wide range of soils and contact times. The model structure was revised and evaluated using a subset of the available data which was not used for model parameterisation. The resulting model was then used as a basis for systematic model reduction to test the utility of the model components. This analysis suggested that the use of 4 model variables (relating to radiocaesium adsorption on organic matter and the pH sensitivity of soil solution potassium concentration) and 1 model input (pH) are not required. The results of this analysis were used to develop a reduced model which was further evaluated in terms of comparisons to observations. The reduced model had an improved empirical performance and fewer adjustable parameters and soil characteristic inputs.  相似文献   
974.
Climate adaptation is a complex task surrounded by uncertainty. To support climate adaptation policies, a new scenario approach is pursued to explore possible discontinuous future developments of societal perspectives on climate adaptation issues. The scenario approach was tested for a case study on Dutch river management. In a series of scenario development workshops, a select group of stakeholders explored the perspectives on the management of the River Meuse in the past, present, and future. The process was supported by an analytical perspectives mapping tool to illustrate and analyze the development of perspectives over time. The process and analytical tools contributed to insight into the drivers of perspective change for the case study at hand. Moreover, the stakeholders highlighted the potential of the approach for water management policy for creating awareness about the plurality of perspectives and the dynamics of perspective change, monitoring perspectives and perspective change as part of a flexible policy approach, and anticipating on the occurrence of shock events. Further work is required to better represent the social dynamics of perspectives change, to better empirically ground the perspective change model, and to apply integrated water models in the scenario development process to assess water–society interactions.  相似文献   
975.
This paper analyses environmental and socio-economic barriers for plantation activities on local and regional level and investigates the potential for carbon finance to stimulate the increased rates of forest plantation on wasteland, i.e., degraded lands, in southern India. Building on multidisciplinary field work and results from the model GCOMAP, the aim is to (1) identify and characterize the barriers to plantation activities in four agro-ecological zones in the state of Karnataka and (2) investigate what would be required to overcome these barriers and enhance the plantation rate and productivity. The results show that a rehabilitation of the wasteland based on plantation activities is not only possible but also anticipated by the local population and would lead to positive environmental and socio-economic effects at a local level. However, in many cases, the establishment of plantation activities is hindered by a lack of financial resources, low land productivity and water scarcity. Based on the model used and the results from the field work, it can be concluded that certified emission reductions such as carbon credits or other compensatory systems may help to overcome the financial barrier; however, the price needs to be significantly increased if these measures are to have any large-scale impact.  相似文献   
976.
1 INTRODUCTIONIn the past, natural resources management initiatives havefocused on large but specific sector projects such as dams,reservoirs for water supply schemes, irrigation systems,crop production, at forestation, etc. Often these projectswere treated as technical and administrative issues ratherthan as a socio-economic and political one. However, thehigh social and environmental cost of such schemes haveled to a change of paradigm since the 1980s towards small-scale community projec…  相似文献   
977.
Trends in the anthropogenic transformation of flora in the city of Astrakhan and its environs over the past 100 years are discussed. In general, the process of flora synanthropization is observed, with natural aboriginal plant communities being replaced by anthropogenically altered communities.  相似文献   
978.
On the Solovetskiye Islands, subtundra forests and forest-tundra crooked forests are considered to be zonal biocenoses, as this region is intersected by the 12°C isotherm for July, which marks the boundary between the northern taiga and forest-tundra zones in northern Europe. The formation of extrazonal tundras on the islands is attributed to the cooling effect of the sea and the prevalence of cold northeasterly winds in the growing period. Herbaceous and herb-bilberry forests similar to their middle-taiga counterparts develop in this region due to a convective heat flow anomaly of high intensity (up to 40–50 W/m2). The phenomenon provides evidence for the existence of an active heat source in the crust under the archipelago. This source is probably a diapir fold involving the upward movement of the mantle.  相似文献   
979.
A mechanism of the formation of biological rhythms in hibernators at cold temperatures is proposed. Certain ecophysiological characteristics have been studied in three hibernating species: the ground squirrels Citellus undulatus Pallas, 1778 and C. parryi Richardson, 1825 and the chipmunk Tamias sibiricus Laxmann, 1769. The changes in body temperature and the temperature of litter in wintering nests during hibernation seasons have been studied. The dependences of metabolic rate on ambient temperature and the size and species of animals have been studied.  相似文献   
980.
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