IMPLICATIONS ON SOCIETY

Implications of Acid Rain on Society

Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain. Acid rain typically has a pH of around 4.0. Acid rain may not be acidic enough to harm us directly through contact, however it can harm the forest and vegetation, damaging our lake and streams. This will affect the food chain and eventually affect the human population. Acid rain can also cause damages to buildings and objects.

Effects of Acid Rain on Plants and Trees

Acid rain does not kill trees directly but instead, it will weaken the trees by limiting the amount of nutrients available in their surroundings, releasing toxic metals such as aluminium from the soil and damaging the leaves of the trees.

Acid rain will dissolve the nutrients and minerals within the soil and will wash them away before the trees can absorb them.

When acid rain is contact with the soil,

→  Aluminum that was present in the soil will be released

→  Aluminum is toxic to trees and will affect the root growth of the trees

→  Nutrients uptake through the roots will be affected, causing nutritional deficiencies in shoots and leaves.

When the leaves of the trees are constantly in contact with acid rain,

→  Protective waxy coating layer on the leaves will be wear off.

→  Leaves become more susceptible to damage by its surroundings.

→  Damaged leaves will not be able to photosynthesize properly, preventing the trees from receiving enough energy to stay healthy.

Buffering Capacity

Forests and streams have the buffering effect to protect them from acid rain.

What is a buffer? It is a solution that neutralises mediums by removing excess H+ ions and excess OH- ions.

In the case of acid rain, it is important that buffering capacity is not lost so that excess H+ ions can be removed, ensuring pH does not get too low when rainwater flows through streams or soil.

This buffering capacity depends on:

→  Thickness of soil

→  Composition of the soil

→  Type of bedrock underneath streams

In mountainous areas such as parts of the Northeast United States, the soil is thin, hence its buffering capacity is weaker; less able to adequately neutralize the acid in the rain water. As a result, these areas are particularly vulnerable as the acid and aluminum can accumulate in the soil, streams, or lakes.

Effects of Acid Rain on Fish and Wildlife

Most lakes and streams have a pH between 6 and 8 but when they come into contact with acid rain, the pH value will be lowered.

Aquatic wildlife will be drastically affected by the sudden change in pH level as their biological processes will be affected by it. One example on how biological processes will be affected:

→  At pH 5, most of the fish eggs will not hatch and lower pH can even cause the death of matured fishes.

Toxic elements such as aluminum wash off from the soil, into nearby water bodies and poison the aquatic wildlife living in it. Some species can tolerate acidic waters better than others. However, in an interconnected ecosystem, what impacts some species eventually impacts many more throughout the food chain—including non-aquatic species, such as birds.

Episodic Acidification (Applicable to Singapore in Heavy Rain)

Seasonal melting snow and heavy rain downpours which is acidic can result in episodic acidification.

Lakes that do not normally have a high level of acidity may temporarily experience:

→  A sudden reduction in buffering capacity

→  Short duration of higher acidity (i.e., lower pH) which can result in a short-term stress on the ecosystem where a variety of organisms or species may be injured or killed

While Singapore may not have as many large lakes and streams as other parts of the world, we still do have a substantial amount of nature that can be affected by acid rain.

Effects of Acid Rain on Materials

Acid rain can:

→  Corrode metal and cause paint and stone to deteriorate more quickly

→  Dirty the surfaces of buildings and other structures such as monuments

The consequences of this damage can be costly:

→  Damaged materials that need to be repaired or replaced,

→  Increased maintenance costs

→  Loss of detail on stone and metal statues, monuments and tombstones.

Dry Deposition

Not all acidic deposition is wet. Dry deposition occurs when dust particles become acidic. Dry particles become acidic when they react with the nitric and sulfuric acid from acid rain. Dry deposition can damage surfaces of statues, buildings, and other man made structures.

Effects of Acid Rain on Human Health

Acid rain is formed due to the large amount of sulfur dioxide and nitrogen oxides present in the air that reacts with the water and oxygen in the air. Human beings are not directly affected by acid rain as acid rain is too diluted to cause any serious health problems.

However, sulfur dioxide and nitrogen oxides that are present in the air can cause serious health problems such as,

→  Irritating the respiratory pathway which will trigger coughing, wheezing and shortness of breath

→  Long term exposure to nitrogen oxides can cause deficiency in respiratory functions

Sources

https://www3.epa.gov/acidrain/education/site_students/glossary.html#com

https://www3.epa.gov/acidrain/education/site_students/glossary.html#aci

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