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The universe is all worked up
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Acid rain | ||||||
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| What is acid rain? | ||||||
Rain is naturally slightly acidic because of carbon dioxide it contains. | It is believed that acid rain is when the pH is below 5.6 (ph natural rainfall). Acid rain affects forests, animals, buildings, but it also affects our health.
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Measure of acidity | category : nature | |||||
Acidity is measured with the pH scale. This scale is a measure of the acidity but also basicity liquids, pH 7 for a neutral solution as distilled water. | The pH (potential of hydrogen) is used to measure the acidity of water in a value between 0 and 14. Aqueous solutions including water is the solvent are classified into 3 groups: - The basic or alkaline solutions are between 7 and 14; - Solutions neutral pH = 7, - The acidic solutions: between 0 and 7.
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Dying fish | category : nature | |||||
Fish dying by the thousands in lakes in Europe and North America, the first warning given in years 60 and 70, on the destructive effects of acid rain. Salmon, trout and roach are particularly sensitive to acidification of freshwater. | In Vosges, too, there acidification of some streams. When the pH is decreasing, from 5.5 pH values but until very low 4.5 in some cases there has been a change of flora and fauna with a water shortage then fish disappearance of the most sought (salmonids). When rushes thrive in freshwater reported that abnormal acidity. The foam 'Sphagnum White' can invade lakes forming a thick green carpet on the substance causing the imbalance. |
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Forest degradation | category : nature | |||||
| The forest dieback is a complex phenomenon which leads to a general weakening of the existing trees and stands. In the 1980s, forests began to die, victims of the fallout of acid rain. Many forests in Europe were threatened particularly in Germany, Austria, Poland and Romania. One reason for this decline is the removal of soil by leaching of acid rain, nutrients such as magnesium, calcium and potassium, whose trees need to survive. Air pollution in large cities with more than 2 million people also has an impact on forests. | In Beijing, Shanghai, Guangzhou and Shenzhen, mixtures of carbon emissions and automobile exhaust, generate acid rain, more than half of Chinese cities are affected. Acid rain caused a degradation of soil and groundwater that can lead to the death of trees. Acid rain disrupts photosynthesis by breaking the chlorophyll. The leaves gradually lose their green color shades to take yellow, orange or red. This is accentuated by the drought. Their fragile bark becomes vulnerable to insects and diseases. The species most affected are conifers and conifers. |
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Degradation of cathedrals | category : nature | |||||
| Acidification of precipitation leads to erosion of metallic surfaces such as copper or zinc. The stones are eroded by rain and wind, but the presence of acid in rain increases their corrosive effect. In addition to high sulfur pollutants can be deposited and then combine with limestone and make the crumbly substance readily solvable by water. The crust that forms on the surface, stone worsens who ends up starting powder. | Many historic buildings are affected. The Parthenon in Athens traffic was banned, the Colosseum in Rome and most ancient monuments are seriously damaged by acid rain.
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Conclusion | category : nature | |||||
In the 1980s, industrialized countries aware of the problem, reached an agreement to limit pollution, especially that caused by automobile exhaust. | In 2007, in the Vosges, for example, rainfall is less acidic than in the past. The closure of a large number of power plants, smoke filtration plant, the desulphurization of gas oil, contributed to the divide by three sulfur concentration in rainwater on the massive Vosges, between 1993 and 2001. Over the same period, nitrogen oxides were reduced by a factor of two. |
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Many volatile chemical compounds such as heavy metals, hydrogen sulfide, chlorine, dioxins and acid gases found in the smoke released into the atmosphere by industry, fortunately less and less in rich countries.
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The universe is all worked up
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| Astronomy - november 25, 2007 |
