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641.
ABSTRACT: The waters of the Colorado River are divided among seven states according to a complex ‘Law of the River’ drawn from interstate compacts, international treaties, statutes, and regulations. The Law of the River creates certain priorities among the states and the Republic of Mexico, and in the event of a severe sustained drought, the Law of the River dictates the distribution of water and operation of the elaborate reservoir system. Earlier work indicated that there is remarkable resilience in the system for established uses of water in the Lower Basin of the Colorado River. This work shows, based on an application of the Law of the River using computer modeling of operations of facilities on the Colorado River, that there may be serious environmental consequences and related legal restraints on how the water is used in times of shortage and that the existing legal and institutional framework governing the Colorado River does not adequately address all the issues that would be raised in a severe sustained drought. Several possible legal options for dealing with drought in the context of the Law of the River are identified.  相似文献   
642.
ABSTRACT: The deposition and chemistry of precipitation were estimated for one year in two forest ecosystems in the South-Central United States. Precipitation, throughfall, litter leachate, and soil leachate were analyzed for a small catchment of pine-hardwoods in southeastern Oklahoma and for a catchment of loblolly pines (Pinus taeda L.) in northern Mississippi. In the pine-hardwood forest, 98 percent of the acid deposition was neutralized, 50 percent in the forest canopy, and 48 percent in the forest floor. In the pine forest, 75 percent of the acid deposition was neutralized, all in the forest floor. The pine-hardwood ecosystem accumulated sulfate, nitrate, and ammonia ions, and lost base cations. During seasons of deficient precipitation, dry deposition appeared to enrich the concentrations of hydrogen, nitrate, sulfate, and ammonia ions in throughfall samples at both locations.  相似文献   
643.
In Brazil most Construction and Demolition Waste (C&D waste) is not recycled. This situation is expected to change significantly, since new federal regulations oblige municipalities to create and implement sustainable C&D waste management plans which assign an important role to recycling activities. The recycling organizational network and its flows and components are fundamental to C&D waste recycling feasibility. Organizational networks, flows and components involve reverse logistics. The aim of this work is to introduce the concepts of reverse logistics and reverse distribution channel networks and to study the Brazilian C&D waste case.  相似文献   
644.
Land use in Korean tidal wetlands: impacts and management strategies   总被引:3,自引:0,他引:3  
The coastal landscapes in southwestern Korea include a diverse array of tidal wetlands and salt marshes. These coastal zones link the ecological functions of marine tidal wetlands and freshwater ecosystems with terrestrial ecosystems. They are rich in biological diversity and play important roles in sustaining ecological health and processing environmental pollutants. Korean tidal wetlands are particularly important as nurseries for economically important fishes and habitats for migratory birds. Diking, draining, tourism, and conversion to agricultural and urban uses have adversely affected Korean tidal wetlands. Recent large development projects have contributed to further losses. Environmental impact assessments conducted for projects affecting tidal wetlands and their surrounding landscapes should be customized for application to these special settings. Adequate environmental impact assessments will include classification of hydrogeomorphic units and consideration of their responses to biological and environmental stressors. As is true worldwide, Korean laws and regulations are changing to be more favorable to the conservation and protection of tidal wetlands. More public education needs to be done at the local level to build support for tidal wetland conservation. Some key public education points include the role of tidal wetlands in maintaining healthy fish populations and reducing impacts of nonpoint source pollution. There is also a need to develop procedures for integrating economic and environmental objectives within the overall context of sustainable management and land uses.  相似文献   
645.
Fresh beef cattle (Bos taurus) manure has traditionally been applied to cropland in southern Alberta, but there has been an increase in application of composted manure to cropland in this region. However, the quality of runoff under fresh manure (FM) versus composted manure (CM) has not been investigated. Our objective was to compare runoff quality under increasing rates (0, 13, 42, 83 Mg ha(-1) dry wt.) of FM and CM applied for two consecutive years to a clay loam soil cropped to irrigated barley (Hordeum vulgare L.). We determined total phosphorus (TP), particulate phosphorus (PP), dissolved reactive phosphorus (DRP), total nitrogen (TN), NH4-N, and NO3-N concentrations and loads in runoff after one (1999) and two (2000) applications of FM and CM. We found significantly (P < or = 0.05) higher TP, DRP, and NH4-N concentrations, and higher DRP and TN loads under FM than CM after 2 yr of manure application. The TP loads were also higher under FM than CM at the 83 Mg ha(-1) rate in 2000, and DRP loads were higher for FM than CM at this high rate when averaged over both years. Application rate had a significant effect on TP and DRP concentrations in runoff. In addition, the slope values of the regressions between TP and DRP in runoff versus application rate were considerably higher for FM in 2000 than for FM in 1999, and CM in both 1999 and 2000. Significant positive relationships were found for TP and DRP in runoff versus soil Kelowna-extractable P and soil water-extractable P for FM and CM in 2000, indicating that interaction of runoff with the soil controlled the release of P. Total P and DRP were the variables most affected by the treatments. Overall, our study found that application of CM rather than FM to cropland may lower certain forms of P and N in surface runoff, but this is dependent on the interaction with year, application rate, or both.  相似文献   
646.
Both enzymatic hydrolysis and solution (31)P nuclear magnetic resonance (NMR) spectroscopy have been used to characterize P compounds in animal manures. In this study, we comparatively investigated P forms in 0.25 M NaOH/0.05 M EDTA extracts of dairy and poultry manures by the two methods. For the dairy manure, enzymatic hydrolysis revealed that the majority of extracted P was inorganic P (56%), with 10% phytate-like P, 9% simple monoester P, 6% polynucleotide-like P, and 18% non-hydrolyzable P. Similar results were obtained by NMR spectroscopy, which showed that inorganic P was the major P fraction (64-73%), followed by 6% phytic acid, 14 to 22% other monoesters, and 7% phosphodiesters. In the poultry manure, enzymatic hydrolysis showed that inorganic P was the largest fraction (71%), followed by 15% phytate-like P and 1% other monoesters, and 3% polynucleotide-like P. NMR spectroscopy revealed that orthophosphate was 51 to 63% of extracted P, phytic acid 24 to 33%, other phosphomonoesters 6 to 12%, and phospholipids and DNA 2% each. Drying process increased orthophosphate (8.4% of total P) in dairy manure, but decreased orthophosphate (13.3% of total P) in poultry manure, suggesting that drying treatment caused the hydrolysis of some organic P to orthophosphate in dairy manure, but less recovery of orthophosphate in poultry manure. Comparison of these data indicates that the distribution patterns of major P forms in animal manure determined by the two methods were similar. Researchers can utilize the method that best fits their specific research goals or use both methods to obtain a full spectrum of manure P characterization.  相似文献   
647.
Hexachlorocyclohexanes (HCHs; alpha- and gamma-isomers), endosulfans (alpha- and beta-isomers and the sulfate residue), hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDTs), and polychlorobiphenyls (PCBs) were measured in waters from three European remote mountain lakes situated in the Alps, Pyrenees, and Caledonian mountains. Sampling encompassed both ice-free and ice-covered periods at different water column depths. High HCH concentrations were found in all lakes, those in the Alps and Pyrenees (990-2,900 pg/L) being among the highest recorded in continental waters. Endosulfans and endosulfan sulfate (120-1,150 pg/L) were the second major group of organochlorine contaminants, showing a remarkable stability upon atmospheric long-range transport. The concentrations of HCB, DDTs, and PCB (4-8, 0.6-16, and 26-110 pg/L, respectively) were low in comparison with other continental waters. Hexachlorocyclohexanes, endosulfans, and HCB were essentially found in the dissolved phase. Phase partitioning of the more hydrophobic compounds exhibited a dependence on temperature and water-suspended particles. Comparison between different sampling seasons and water depths indicated a remarkable concentration uniformity within lake, but major interlake differences. Normalization to turnover rates showed higher interlake similarity. Preferential accumulation of the less volatile compounds in the Alp lake and significant increase of baseline contributions of organochlorine compounds and residues in the Caledonian lake are also evidenced from these turnover rates.  相似文献   
648.
Manure additions to cropland can reduce total P losses in runoff on well-drained soils due to increased infiltration and reduced soil erosion. Surface residue management in subsequent years may influence the long-term risk of P losses as the manure-supplied organic matter decomposes. The effects of manure history and long-term (8-yr) tillage [chisel plow (CP) and no-till (NT)] on P levels in runoff in continuous corn (Zea mays L.) were investigated on well-drained silt loam soils of southern and southwestern Wisconsin. Soil P levels (0-15 cm) increased with the frequency of manure applications and P stratification was greater near the surface (0-5 cm) in NT than CP. In CP, soil test P level was linearly related to dissolved P (24-105 g ha(-1)) and bioavailable P (64-272 g ha(-1)) loads in runoff, but not total P (653-1893 g ha(-1)). In NT, P loads were reduced by an average of 57% for dissolved P, 70% for bioavailable P, and 91% for total P compared with CP. This reduction was due to lower sediment concentrations and/or lower runoff volumes in NT. There was no relationship between soil test P levels and runoff P concentrations or loads in NT. Long-term manure P applications in excess of P removal by corn in CP systems ultimately increased the potential for greater dissolved and bioavailable P losses in runoff by increasing soil P levels. Maintaining high surface residue cover such as those found in long-term NT corn production systems can mitigate this risk in addition to reducing sediment and particulate P losses.  相似文献   
649.
There is a profound debate over how to assign greenhouse gas (GHG) responsibilities; therefore, we have decided to follow IPCC guidelines, as they offer the only standardized method. We have identified each type of greenhouse emission and its level of absorption. We have studied the province and its districts and municipalities. We have determined that the energy sector is that with the highest level of emissions, even if the per capita emissions of the Province of Siena are very low. This is caused by a very low level of industrialization and the presence of a local geothermal production of energy. In order to highlight this aspect, we have considered scenarios both with and without geothermal production. Our research was then focused on single districts (groups of homogenous municipalities) and municipalities, where we found great differences among the greenhouse emissions of the areas. We have constructed a map of the greenhouse emissions of the whole province. It has been interesting to note that there are 14 municipalities with net negative emissions, seven with low positive emissions, 12 with medium positive emissions and three with elevated positive emissions. These latter correspond to the main city and to two of the most industrialized municipalities.  相似文献   
650.
Water resource management in Kabul river basin, eastern Afghanistan   总被引:1,自引:0,他引:1  
Severe drinking water shortage affects all resident of the Kabul river basin. Two and a half decades of civil war in Afghanistan (it began in late 1978) have resulted in widespread environmental degradation and water resource development throughout the country. The war has already finished and, therefore, water resource management for supplying water is one of the most important tasks for Afghanistan’s government. The Kabul river basin which is the most populated area in the country is located in the eastern part of Afghanistan. This article deals with the water resource properties of the Kabul river basin and also water demand in the important cities of the basin, such as Kabul, the capital and the largest city in the country. Also a few suggestions for providing water for domestic and agriculture purposes in short term, medium time and long term have been discussed.  相似文献   
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