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[en] Retention of SO42- was investigated in Galician soils throughout an intense regime of acidification. Experiments consisted of the addition of an H2SO4 solution (pH 2.7) to columns of 6 soils of contrasting properties over 1,2 or 5 months. Leachates were obtained continuously throughout the experiment for analysis, and analysis made of the solid fractions after 1, 2 or 5 months. The greatest capacities for retention of SO42- were found in soil developed from serpentine and micaschist; the lowest in soils from granite, slate and sandy sediments. The surface horizons, especially those rich in organic matter, displayed low retention of SO42-. The amount of SO42- adsorbed throughout the experiment depended on the content of crystalline forms of Fe and with the Fe and Al extracted with dithionite-citrate. The low retention of SO42- in the organic horizons and the slightly negative relation with the organic matter suggest an inhibitory effect of the organic matter on the SO42- retention process. Results of the study show that, under conditions of moderate acidity, SO42- retention occurs in the form of adsorption; in strongly acidic conditions, the precipitation of aluminium-sulphate minerals may provide an additional retention mechanism. 41 refs., 3 figs., 4 tabs
[en] The effects of rain acidity on field-grown Summered apple trees (Malus domestica Borkh) under natural conditions were investigated. One group of four trees was exposed to ambient rainfall. Four other groups were covered with rainshields and received water, pH 5.6, 4, and 3, respectively, as simulated rain. Simulated acid rain, particularly at pH 3, adversely affected fruit production in terms of individual fruit weight, fruit set, fruit appearance (necrosis and russetting of the peel) and dry weight. Ambient rain was not found to cause significant reductions in apple weight. Ambient rain was not found to cause significant reductions in apple fruit production in this study
[en] Two integrated assessment models, one for climate change on a global scale (IMAGE 2) and another for the regional analysis of the impacts of acidifying deposition (RAINS), have been linked to assess the impacts of reducing sulphur emission on ecosystems in Asia and Europe. While such reductions have the beneficial effect of reducing the deposition of acidifying compounds and thus the excedance of critical loads of ecosystems, they also reduce the global level of sulphate aerosols and thus enhance the impact of increased emissions of greenhouse gases, and consequently increase the risk of potential vegetation changes. The calculations indicate that about 70% of the ecosystems in Asia would be affected by either acid deposition or climate change in the year 2100 (up from 20% in 1990) for both sulphur emission scenarios (controlled and uncontrolled), whereas in Europe the impacted area would remain at a level of about 50%, with a dip early next century. (author)
[en] This report reviews the theory of emissions trading. The experience of the US experience trading program is examined, and an early assessment of the US acid rain program is considered. A bibliography with >170 references is included. (UK)
[en] There are many environmental benefits arising from the generation of electricity from nuclear power. These are accompanied by a minimal detrimental environmental impact, which is strictly regulated and monitored to a far greater degree than any other comparable industry. Because it does not produce greenhouse gases or acid rain emissions, the generation of electricity from nuclear energy is a vital component of a sustainable energy future for our planet. (Author)
[en] A three-dimensional model for heat and mass transport in microscale ice lattices of dry snow is formulated consistent with conservation laws and solid-vapor interface constraints. A finite element model that employs continuous mesh deformation is developed, and calculation of the effective diffusion rates in snow, metamorphosing under a temperature gradient, is performed. Results of the research provide basic insight into the movement of heat and water vapor in seasonal snowcovers. Agreement between the numerical results and measured data of effective thermal conductivity is excellent. The enhancement to the water vapor diffusion rate in snow is bracketed in the range of 1.05--2.0 times that of water vapor in dry air
[en] The growth mechanism and properties of the oxide films on iron and AISI 304 stainless steel were studied in simulated acid rain (pH 4.5) by means of electrochemical techniques and atomic absorption spectrometry. The layer-pore resistance model was applied to explain a potentiodynamic formation of surface oxides. It was found that the growth of the oxide film on iron takes place by the low-field migration mechanism, while that on the stainless steel takes place by the high-field mechanism. Kinetic parameters were determined. Impedance measurements revealed that Fe surface film has no protective properties at the open circuit potential, while the resistance of stainless steel oxide film is very high. The concentration of the metallic ions released into solution and measured by atomic absorption spectroscopy was in accordance with the results obtained from the electrochemical techniques.
[en] In 1984, the Canadian Forest Service initiated a national forest health monitoring program, the Acid Rain National Early Warning System (ARNEWS), to monitor the health of the forest and determine the effects of acid rain and regional air pollutants on the forest. Monitoring is done by personnel of the Forest Insect of Disease Survey, who are experienced in the evaluation of forest health. They assess trees in permanent sample plots for forest damage and identify the causes. Causes of tree mortality are also determined. If damage is found for which no apparent cause is evident, research is initiated to determine the source of the damage. To date, ARNEWS has reported on the health of 18 conifer and 9 hardwood species from across Canada, including areas known to receive some of the highest levels of atmospheric pollution in Canada. Results indicate that there is no large-scale decline in the health of our forests and, where pollution-like symptoms were observed, they could usually be accounted for by natural factors. Tree mortality in these natural stands is also normal. However, the monitoring system depends on being able to recognize damage and to determine the cause. The more easily this can be done, the more efficacious is the system. As our researchers assess the trees, they need to know what all type of damage looks like since many pollution symptoms are easily confused with natural effects. The research done on leaf cuticles should help expand this knowledge base. (orig.)
[en] This paper compares the cost of meeting pollution targets by the imposition of a uniform charge rate and by differentiated charge rates. These costs are then compared with a simple standards setting in the form of critical loads in order to see in an empirical way if economic instruments work better than regulations. Empirical results are provided with associated conclusions and policy implications
[en] Full text : The chemical conversions of organic fuels during the refining processes complex gas mixtures containing hydrogen sulfide generate as a by-product. In accordance with the environmental safety requirements these gas mixtures have to be purified from hydrogen sulfide before use or environmental discharge. As it is known because of combustion gases containing hydrogen-sulfide oxides of sulfide emit into the atmosphere and they combine with water vapors in the air and this process consequently results in pH change of H2SO3 precipitations and acid rains. The processes of purification of gas mixtures being the product of oil refining processes and mainly containing hydrocarbons from hydrogen sulfide by a photochemical method and molecular hydrogen generation have been under this investigation.The model gas mixture under investigation has been prepared at a vacuum plant in the laboratory. During the researches the partial pressure of H2S capable of completely absorbing the given wave-length of the radiation has been first specified. It has been established that temperature and irradiation time have their influence on the progress rate of the processes.At this wave-length hydrocarbons undergo no photochemical conversions. This is manifested with the absence of excitation levels causing dissociation due to radiation absorption at the wave-length used in hydrocarbon gases . The fact that these levels belong to hydrogen sulfide contained in gas mixtures has been experimentally proved.The role of hot hydrogen atoms and the mechanism of the processes under progress within the process of molecular hydrogen generation due to the photolytic decomposition of hydrogen sulfide have been discussed.