In the long-term, leaching can deplete the amount of nutrients available to plant life as micro-organisms play an important role in the decomposition of organic material. Trees that do grow in acidified soil and more susceptible to viruses, fungi and insect pests and can grow more slowly or die as a result. More than 65% of trees in the UK have been affected this way.
Some of these plants could be vegetables which would later be consumed by humans. The results of acidification on the top soil can lead to reduced intake of water and nutrients, damage to fine root hairs and decomposition slowed down thus less nutrients for plants. The decline of trees in areas such as Scandinavia and Brazil have resulted in the leaching of vital nutrients as there is no canopy to protect the undergrowth. This has now led to soil erosion and loss of humus in soils. Hence the infertile soil has resulted in this decline of plant growth in these areas.
Acid rain also has multiple effects on the human environment. Buildings, often those made of materials such as marble and limestone are vulnerable to weathering. Urban areas are often more vulnerable due to higher levels of automobile exhaust³.
Dry deposition can lead to the corrosion of materials, although in areas with high levels of rainfall, the effect of building surfaces can often be worse. Building stone can be damaged when calcium carbonate in stone dissolves in acid rain to form a crust of calcium sulphate. These sulphated layers are more easily washed away by rainfall and other weather conditionsº.
Other social effects can be observed through the concerns over acid rain and health. Acidic precipitation is believed to have negative effects on humans, especially those with respiratory disorders. Although it doesn’t affect humans directly, the particulate matter (that includes smoke and sea salt etc) that is associated with acid rain could contribute to leaching of toxins such as mercury that could be carried by runoff into water, contributing to environmental sources of this toxin³. Far worse, the increasing incidents of respiratory problems possibly caused by the inhalation of tiny particles of sulphur and other pollutants, particularly from vehicle emissions has caused great concernº.
Aquatic plants and animals thrive in a narrow range of pH levels. They can vary drastically to slight changes, with some species more acid-tolerant than others. As a result of acidified lakes, organisms lower down in the food chain may decrease in number and those species higher up in the chain will be affected¹.
The combined effects of low pH and high concentrates of aluminium can produce conditions that are toxic to some species of fish. Effects can be gill irritation and difficulty in regulation of blood sugar levels. It is also believed that afforestation can accelerate the release of acids and poisonous metals into the water. Possibly, this is due to the increased leaching of certain elements such as calcium, which would otherwise help protect against the toxic acids. On the other hand, deforestation can lead to the pollution of watercourses. Such effects can be seen in aquatic systems in Norway and Sweden¹.
Approximately 20,000 tonnes of emissions from the United Kingdom have blown across to countries such as Norway and Sweden. Due to prevailing winds, eastern regions are more affected by acid rain as emissions travel thousands of miles from where originally produced, thus creating social and political problems as well.
Acid susceptible areas in the UK from the United Kingdom Acid Waters Review Group¹
It is possible that since the time that the diagram was produced, the areas that are susceptible have changed due to changes in emissions of sulphur dioxide and nitrogen oxides.
The measures that can be taken to solve or reduce the acid rain problem can be short-term and long-term measures. Short-term measures are used to immediately reduce levels of pollution and can be expensive in order to cope with environmental damage and disease. Removing lead from petrol and fitting scrubbers to power station chimneys can reduce levels drastically. Long-term measures are used to remove pollutants completely and are more cost-effective. Scrubbers can be fitted to coal-fired power stations to remove SO2 and NOx before they enter the atmosphere. Modern scrubbers remove 95% of emissions. Also converting power stations to use natural gas to generate electricity as it is less polluting instead of coal³.
The use of renewable energy, such as solar energy to power cars does not release any emissions and is useful, as non-renewable energy sources will eventually run out. It is important that we use more of renewable energy sources which are effectively used in Denmark. Nuclear power is also a cheaper solution as the energy costs less than fossil fuels.
Vehicle pollution can also be reduced by using unleaded petrol and has been known to reduce emissions by 98% in the USA. Catalytic converters are fitted into the exhaust system of a vehicle so the waste gases can be made into less harmful emissions. They can drastically reduce nitrogen oxide emissions by nearly 80%. More efficient engines or vehicles powered using natural gas, battery-power or fuel cells can be more cost-effective.
Liming acidified lakes can neutralize the acids in lakes and restore the original pH required by the sea creatures. Limestone or lime is added to lakes to reduce the acidity. Over 5,500 lakes in Sweden have been treated this way. Changing our lifestyle to reduce our energy consumption can also help but making it too sudden can cause economic problems.
²The graph represents the tonnes of lime used to neutralize acidified lakes each year since 1983. Possibly, the increase can be accounted for by the increase of harmful emissions contributing to acid rain and the increase in environmental damage to lakes. Adding lime repairs damages but is not a permanent solution.
²Some governments have also introduced taxes to help control emissions. For example, leaded fuel now costs more than unleaded. In Denmark, a tax has been introduced on the amount of SO2 emitted, so now it costs polluters more to buy coal for power stations and cheaper to use less polluting sources such as natural gas to encourage users to change their energy sources.
Incentives have also been considered in Japan and the USA. The government would encourage companies to use cleaner methods by reducing the price or placing a ‘subsidy’ on wind, solar and other forms of renewable energies.
It is also important that as individuals we try to take actions. However, most environmental problems are caused by the actions of millions of individual people. Therefore, what is important is that we reduce our contribution to the problems and aid in the solution.
New political goals have also been set such as to reduce S02 and NOx emissions such as the SO2 Protocol in Norway³.
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2FD1D-11D4-B1C800B0D049C8DF/Page/2.htm (United Kingdom acid waters review group) (1) /index/htm (2) )
