Rainwater Pollution: Assessing Acidic Levels Beyond PH=7 - Research Paper

Introduction

Environmental chemistry majorly looks at air and water quality. This study will, however, focus on water quality, especially rainwater that gets polluted through natural causes and human activities to form acid rains. A pH value of 5.6 is the commonly recognized value for clean precipitation (Eney & Petzold, 95). A pH value of pH=7 is the value considered for pure deionized water. However, it may not be the best way to describe the acidity of rainwater since what is dangerously acidic for one environment may not be for another environment. Acid rains generally have a lower pH value due to the high levels of acid in it, which makes it harmful for the living organisms. It can negatively affect plants, animals, and infrastructure. It has, therefore, remained to be a controversial issue with no ultimate solution arrived. The rain is formed by precipitation containing acidic components like nitric acid and sulfuric acid (Bradford).

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The term acid rain was introduced by a Scottish scientist Robert Angus Smith in 1852. Smith decided to use this term when he was examining rainwater chemistry in Scotland and England industrial cities. After a long time of studying, acid rain became recognized as a regional environmental issue in the early 1970s and was realized to affect eastern North America and Western Europe (Bradford). Though human activities majorly cause acidic precipitations, there are also natural disasters that are factors, and an example is the volcanoes which blast pollutants into the air. According to the Environmental Protection Agency (EPA), acid rains are created when nitrogen oxides (NOX) and sulfur dioxides (SO2) emitted into the atmosphere react with oxygen, water, and other chemicals, forming nitric and sulfuric acids. These acids then mix with water in the atmosphere together with other materials before it falls on the ground (Environmental Protection Agency).

Chemical Reactions Involved in the Problem

Nitric acid (HNO3) accounts for about 25% of the total acid rains (Casiday & Frey). Some natural processes lead to the formation of small amounts of nitric acid in rainwater. Internal combustion engines of cars and other power plants also produce large amounts of NO gas which forms nitric acid through the equation below:

NO (g) +02(g) NO2 (g)

3NO 2(g) + H20 2HNO3 (aq) + NO (g)

Therefore, from these equations, it is evident that a naturally occurring process can become more harmful if human activities come in to stimulate the processes. The other 75% of the acidity of rain is majorly accounted for by the presence of sulfuric acid H2SO4 in rainwater (Casiday & Frey). There is indeed a natural process that produces sulfuric acid like volcanic activities and organic decays. But human activities such as combustion of fossil fuels attribute the larger percentage of sulfuric acid production. When fossils are burnt, the sulfur in them reacts with oxygen in air forming sulfur dioxides (SO2). In the United States, 80% of the total SO2 is accounted for by combustion of fossil fuels (Casiday & Frey). Sulfur dioxides react with water forming sulfuric acid. Since sulfuric is a strong acid, it readily dissociates in water producing hydrogen H+ ion and HSO4- ion.

H2SO4 HSO4- + H+

The HSO4- ion may dissociate further producing SO42- and H+. The presence of H2SO4 leads to the concentration of H+ ions to dramatically increase, dropping the pH of the water to harmful levels.

HSO4- SO42- +H+

Effects on the Environment and Humans

The acid rain changes the composition of water bodies and soil making them inhabitable by plants and other living organisms. Acid rain is also very hard on plants as it washes away the hard protective layer on the leaves, leaving them weak and stunting their growth. When the level of acidity of water bodies is raised, the aquatic life like fish tends to die fast. The reactions that lead to the formation of these chemicals are harmful to human beings. That is because nitrogen oxides, and sulfur dioxides, which are the major causes of acid rain, can damage human lungs (Bradford).

Government Regulations

The government regulates the quality of air through the Clean Air Markets Division that maintains air quality through market-based programs. One such program is the Acid Rain Program and the Clean Air Interstate Rule. One of the central roles of these programs is to do complete and accurate monitoring, reporting, and auditing of emissions. All the sources regulate under these programs have to follow the monitoring and regulations in Part 75 of Volume 40 of the Code of Federal Regulations (CFR) (Environmental Protection Agency). This part requires the continuous monitoring and reporting of carbon dioxide (CO2), sulfur dioxides (SO2), and nitrogen oxide (NOx) emissions.

Potential Solution

One potential solution for reducing the amount of acid in the rain is to use low sulfur coal. To reduce the amount of sulfur oxides emitted from power plants, it is necessary to burn coal with a very low percentage of sulfur in it. Sulfur with a small percentage in it (0-1%) is mined from the surface of the ground in the Western states of Montana and Wyoming (Ophardt).

The group that is working on this solution is the government of the United States through its environment Agency, which is the Environmental Protection Agency. The government has an interest in this solution as it wants to improve the environment in which its citizens are living and reduce the health hazards associated with the effects of acid rain. The government has made some progress in slowing the emission of sulfur oxides as a result of the Clean Air Act and the 1990 Amendments (Ophardt). There has been a steady decrease in sulfate content of rain and air in the Northeast. There has also been a steady decrease in acidifying lakes.

Benefits and Challenges Involved

The implementation of this process will have both negative and positive impacts on the people and the economy of the country. For example, to reverse the trend of using high-sulfur to the low-sulfur coal, it will mean that the government and corporations using sulfur have to part with the high costs involved in the transportation of the low-sulfur coal from Montana and Wyoming. That as a result, would increase the cost of producing power. Again, if a complete switch is made, then many coal miners in the Midwestern states of Illinois, West Virginia, Ohio, and Kentucky will lose their jobs. However, the one great benefit involved in this process is that the amount of acid in air and water bodies will fall, leading to an improved quality of water and environment. This will mean that the people will have a better quality of life (Ophardt).

Works Cited

Bradford, Alina. "Acid Rain: Causes, Effects and Solutions." LiveScience (2018). https://www.livescience.com/63065-acid-rain.html

Casiday Rachael and Frey Regina. "Acid Rain: Inorganic Reactions Experiment." Washington University (1998). http://www.chemistry.wustl.edu/~edudev/LabTutorials/Water/FreshWater/acidrain.html

Eney, A. B., and Petzold D. E. "The problem of acid rain: an overview." Environmentalist 7.2 (1987): 95-103. https://link.springer.com/article/10.1007/BF02240291

Environmental Protection Agency. "Clean Air Markets: Emissions monitoring." United States Environmental Protection Agency (2019). https://www.epa.gov/airmarkets/emissions-monitoring

Environmental Protection Agency. "What is Acid Rain?" United States Environmental Protection Agency (2017). https://www.epa.gov/acidrain/what-acid-rain

Ophardt Charles E. "Acid Rain - Solutions." Virtual Chembook, El mhurst College (2003). http://chemistry.elmhurst.edu/vchembook/197acidrainsoln.html