Relating Science To Technology
Acid rain is precipitation that has increased acidic levels. This can occur not only in the form of rain, but as snow, sleet, hail or any other type of precipitation. This acidity is a result of pollution in the air from machinery and factories or emissions from cars. Acid rain can be very harmful to the environment and our health, and is an important concern to be dealt with. For a substance to be labeled acidic, it must have a pH level of less than 7. Clean rain water tends to have a pH level of around 5.6, acid rain has a pH level of around 4.3. This potent of an acid can lead to damage and deterioration of plants and trees, and even damage inflicted to certain buildings and structures. According to lakescientist.com, 50-75% of acid rain annually comes from the USA and is carried upwards by various wind patterns and currents. The great lakes have become “areas of concern” with the Canadian and American governments and have started projects to reduce the air pollution to restore the lakes conditions.
Although there are several causes of acid rain, the majority of chemical emissions come from man-made machines. Burning coal and other fossil fuels for energy is one of the easier addressed ones. Coal burning plants are especially known for their release of pollutants into the air. Another chemical releasing industry is the oil refineries and manufacturing plants. These three examples are under watch of the government and many laws are being passed to attempt to decrease the amount of chemicals being let out into the air. A major contributor to the burning of fossil fuels is the automobile and machinery group. Billions of cars, trucks and other automobiles are used daily to commute to work, and drive people where they need to get to. Machinery such as bulldozers and cement trucks burn a great deal of gas daily, which all contribute to the growing pollution problem. A small contributor to this problem is actually a natural concern. Natural phenomenons such as erupting volcanoes or rotting vegetation can actually release the same emissions as cars or factories. Although these are not as pressing concerns because the only contribute a small amount.
There are two major types of acid rain, carbonic acid and sulfuric acid. Carbonic acid is a result of carbon dioxide dissipating into rain water.
CO2 + H20 → H2CO3
Sulfuric acid, on the other hand, is a serious threat to public and environmental health because of how low its pH level is.
2H + SO4 → H2SO4
Sulphuric acid rain can cause slow or even stop plant growth and reproduction, and damage buildings, particularly those made of limestone.
Acid rain has a big impact on the great lakes and surrounding areas. The rise of acidity in the water can cause the prevention of reproduction of aquatic animals such as fish and frogs. This puts certain species at risk for endangerment and extinction, causing disturbance to the food chain. Many different species of birds have to relocate to find enough fish or other small animals to feed themselves and their families, causing certain species to invade areas, and so on. Certain species such as the Daphnia zooplankton can’t live in the current Lake Ontario water conditions because of the lack of calcium in the water. This introduced a new type of plankton called the Holopedium zooplankton, which has “body armour” to help it survive in more acidic conditions, but make it less appetizing for other animals. Acid rain in the great lakes also affects the aquatic and surrounding plant life. Certain species of trees such as the Eastern White Pine and the Eastern Hemlock absorb certain acids through their pines and roots. This causes slow growth and even death for these trees. With so many dying trees, cities around the great lakes have to deal with the deforestation and acid treatment of their trees.
The pollution and falling pH levels also affect the industries around the great lakes. Beaches are being shut-down because of all of the pollution and dead wildlife showing up on the sand.
The acidity eventually clogs the gills of the fish and they die and wash to the surface. The Holopedium zooplankton, mentioned earlier, has become an invasive species in Lake Ontario and can turn people away from swimming. They have clinged to people while swimming, giving you a jelly-like substance on you when you exit the water. The acid rain also affects the forestation industry surrounding the great lakes. Trees grown, intended for being turned into usable wood, are being found dying or sick because of the acid intake.
One of the neutralization attempts we are making is called liming. Although still under final research, many of the tested areas are responding well to this idea. Liming consists of introducing limestone, which has a higher alkalinity, into the acidic waters in hopes of neutralizing the lake’s pH level. In many areas, liming has been said to increase/fix reproduction levels of certain fish and aquatic plants.
H2SO4 + CaCO3 → CaSO4 + H2CO3
Limestone (calcium sulfate) is soluble and therefore, crumbles and dissolves in the lake water.
H2CO3 → CO2 gas + H20
While liming is a promising restoration solution to the acid problems, there are still some drawbacks to the method. Liming, initially, is a cheaper solution but when you take in account of the cost of repeating this every several years, the cost begins to increase. Because of this, many places have started to only treat the most important areas of concern, which can differ because of the natural rainfall or wind patterns that year. The limestone can also be washed away by currents and melting snow, so areas of concern can only be limed in specific spots and only during specific times of the year. Another expense added to the limestone is the way it is put into the lakes. Liming can be done by planes, boats or even helicopters, and can be very expensive depending on the dispensing method.
Currently, the Canadian and American government have been working together to find a way to clean the great lakes. Acidity accumulation is a big concern in bodies of water that lack soils with alkalinity. This is common in parts of the Canadian Precambrian Shield and in several lakes in British Columbia. To fix this, the governments came up with the Great Lakes Water Quality Agreement and the Canada-Us Air Quality Agreement. The Air Quality Agreement promises to decrease emissions of NOx and SO2, which are the main chemicals found in acid rain. The Water Quality Agreement promises to set aside money to focus on areas of concern throughout the lakes. Shown in the map below, the Hamilton Harbour is currently one of the areas of concern and is under improvement work.