The Soil Erosion

Soil is one of our most precious resources in this world. Soil erosion is a natural process and has occurred throughout geological history. The loss of this resource, though land degradation processes such as wind and water erosion, is one of the most serious environmental problems.

Types of Soil Erosion

In general, there are several types of soil erosion which are rain drop or splash erosion, sheet erosion, rill erosion, gully erosion and stream bank erosion. The rain drop or splash erosion is the erosion which preceded by the destruction of the crumb structure due to the impact of falling raindrop on the surface of soil is termed as splash erosion. The sheet erosion is the fairly uniform removal of soil in thin layers from the land surface, often scarcely perceptible, especially when caused by wind. The areas where loose, shallow topsoil overlies compact soil are most susceptible to sheet erosion. The rill erosion is a form of water erosion in which numerous very small and more or less straight channels are produced; the channels get obliterated by ordinary use. It can be removed by normal tillage operations. Apart from that, the gully erosion is a form of water erosion in which gullies are produced by combination of unattended rills. The stream bank erosion is stream banks are eroded by water either flowing over the sides of a stream or scouring at the base.

Cause of Soil Erosion

The main cause of the soil erosion is due to the human activities. The human activities such as agriculture activities bring lots of damage to soil and dirt. Many farmers attempt to restore soil fertility by adding fertilisers or artificial nutrients but some countries do not have this opportunity due to poverty or lack of education.  In South America soya is a quick-growing and valuable crop. Despite some artificial fertilisers being added the soil is not allowed enough time to recover its fertility or structure and is ultimately being eroded by this human activity. Deforestation also a kind of activities which caused soil erosion. The removal of trees without sufficient reforestation has resulted in damage to habitat, biodiversity loss and aridity (drying of soil).  This human activity quickly accelerates natural erosion in two ways.  Firstly the removal of trees is a removal of nutrients and minerals from the soil as the source of humus is greatly reduced.  The natural dead organic material that supplies the soil with its humus is generally leaves that have fallen from the trees, animal droppings, tree fruit or decaying trees in the soil.  Secondly, deforestation accelerates soil erosion by leaving large areas exposed to heavy rainfall (which can cause leaching or flash floods) or wind erosion.   Without the roots of the trees to keep the soil structure in place the soil is loose and easier to erode.  The tropical rain forests of Brazil are seeing huge areas of forest being cut down each day.  Each year about 13 million hectares of the world’s forests are lost due to deforestation.   

Figure 1: Deforestation in Brazil 2002 to 2008

Effect of Soil Erosion

            The soil erosion will cause the reduction in water quality. The eroded soil which contain the nutrients, fertilities and herbicides can be deposited. At the same time it can cause the reduction in the slope of land. In general, the heavier soil particles will be deposited during the soil erosion, while finer colloidal clay remain in suspension. The soil removed by gully erosion may be transported directly to rivers.

Solution of Soil Erosion

            However, there’s some ways to avoid or prevent soil erosion. One of the ways to avoid the erosion of soil is to reforestation. Reforestation is the deliberate planting of trees. This may occur in areas of deforestation, mountain slopes or as a general practise to plant a seedling for each tree cut down. EU legislation now controls the minimum height and age of tree that can be cut and also offers incentives to farmers to turn part of their land over for forestry. In areas like the Apennines in Italy or the mountainous terrain of the West of Ireland this is seen as a valuable alternative to crop or animal farming. The EU forestry grant aid is the initiative to attract farmers to grow and maintain areas of forestry. In the 1900’s only half of one percent of Ireland was classified as under forests but due to a change in laws and funds this has risen to over twelve percent. The policy of ‘cut one, plant two’ is hoping to see an increase in this figure and, in turn, the slowing down of the rate of soil erosion.

EFFECT OF NOISE POLLUTION

Noise pollution is unwanted or disturbing sound.  Sound becomes unwanted when it either interferes with normal activities such as sleeping, conversation, or disrupts or diminishes one’s quality time of life.  The fact that you can’t see, taste or smell it may help explain why it has not received as much attention as other types of pollution.  The air around us is constantly filled with sounds, even though most of us would probably not say we are surrounded by noise.  Though for some, the persistent and escalating sources of sound can often be considered an annoyance. This “annoyance” can have major consequences, primarily to one’s overall health

EFFECT OF NOISE POLLUTION

Generally, problems caused by noise pollution include stress related illnesses, speech interference, hearing loss, sleep disruption, and lost productivity. Most importantly, there are three major effects :

Hearing

The immediate and acute effect of noise pollution to a person, over a period of time, is impairment of hearing. Prolonged exposure to impulsive noise to a person will damage their eardrum, which may
result in a permanent hearing impairment.

Marine Animals

Marine scientists are concerned about excessive noise used by oil drills, submarines and other vessels on and inside the ocean. Many marine animals, especially whales, use hearing to find food, communicate, defend and survive in the ocean. Excessive noises are causing a lot of injuries and deaths to whales. For example, the effect of a navy submarine’s sonar can be felt 300 miles away from the source. SONAR is the use of sound by submarines and other fishing vessels to deterring the depth of water, the closeness of an object, or detect movement of other objects in the water. Many of these beached whales have suffered physical trauma, including bleeding around the brain, ears and other tissues and large bubbles in their organs.This is not only about whales, but the larger marine life are all affected in one way or the other.

Effects on general health

Health effects of noise include anxiety and stress reaction and in extreme cases fright. The physiological manifestations are headaches, irritability and nervousness, feeling of fatigue and decreases work efficiency. For example, being pounded by the siren of fire fighters, police or ambulance in your city all night everyday leave people (especially elderly people) stresses and tired in the morning.

Its is worth noting that these effects may not sound troubling, but the truth is, with time, the consequences can be very worrying.

Salmonela

Air Pollution

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WHAT IS AIR POLLUTION ?

Air pollution occurs when the air contains gases, dust, fumes or odour in harmful amounts. That is, amounts which could be harmful to the health or comfort of humans and animals or which could cause damage to plants and materials.

The substances that cause air pollution are called pollutants. Pollutants that are pumped into our atmosphere and directly pollute the air are called primary pollutants. Primary pollutant examples include carbon monoxide from car exhausts and sulfur dioxide from the combustion of coal.

Further pollution can arise if primary pollutants in the atmosphere undergo chemical reactions. The resulting compounds are called secondary pollutants. Photo chemical smog is an example of this.

HISTORICAL EXPLANATION

In the days before the proliferation of large cities and industry, nature's own systems kept the air fairly clean. Wind mixed and dispersed the gases, rain washed the dust and other easily dissolved substances to the ground and plants absorbed carbon dioxide and replaced it with oxygen.

With increasing urbanization and industrialization, humans started to release more wastes into the atmosphere than nature could cope with.

Since then, more pollution has been added to the air by industrial, commercial and domestic sources. As these sources are usually found in major cities, the gases that are produced are usually concentrated in the air around them. The adverse effects of air pollution were graphically illustrated in London in 1952 when, in just a few days, an estimated 4000 people died from effects of fine particle pollution.

It is when these concentrated gases exceed safe limits that we have a pollution problem. Nature can no longer manage air pollution without our help.

MORE ABOUT POLLUTANTS

Air pollutants mainly occur as a result of gaseous discharges from industry and motor vehicles. There are also natural sources such as wind-blown dust and smoke from fires.

Some forms of air pollution create global problems, such as upper atmosphere ozone depletion and global warming. These problems are very complex, and require international cooperative efforts to find solutions.

EXAMPLES OF AIR POLLUTANTS

There are two types of pollutants:

• Primary pollutants are those gases or particles that are pumped into the air to make it unclean. They include carbon monoxide from automobile (cars) exhausts and sulfur dioxide from the combustion of coal.
• Secondary pollutants: When pollutants in the air mix up in a chemical reaction, they form an even more dangerous chemical. Photo chemical smog is an example of this, and is a secondary pollutant.

CAUSES OF AIR POLLUTION 

•  What is the short term effect of the haze on my health?

Among healthy individuals, short term exposure (i.e. continuous exposure to unhealthy daily average PSI levels over a period of a few days) to high levels of haze particles may cause irritation of the eyes, nose, and throat in healthy individuals.  Such irritation resolves on its own in most cases.

Haze particles can affect the heart and lungs, especially in people who already have chronic heart or lung disease e.g. asthma, chronic obstructive pulmonary disease (COPD), or heart failure.

There may be up to 1-3 days of time between exposure to haze and health effects/ symptoms.

•  What are the long term effects of the haze?

Singapore is not affected by the haze throughout the year. Any exposure is short-term in nature (i.e. continuous exposure to unhealthy daily average PSI levels over a period of a few days) and such exposure may vary from year to year.  As international studies are based on long term exposure to air pollution, there is little robust data on the longer-term effects of short-term exposure to haze like the pattern seen in Singapore.

Studies have shown that persons living overseas with continuous exposure over several years to high ambient pollution from fine particles (i.e. particulate matter 2.5 (PM2.5); particles smaller than 2.5 micrometers), may have a higher risk of (i) cardiovascular effects, such as heart attacks, (ii) reduced lung development, as well as (iii) the development of chronic respiratory diseases, such as asthma, in children.

EFFECT OF AIR POLLUTION

Chemical reactions involving air pollutants can create acidic compounds which can cause harm to vegetation and buildings. Sometimes, when an air pollutant, such as sulfuric acid combines with the water droplets that make up clouds, the water droplets become acidic, forming acid rain. When acid rain falls over an area, it can kill trees and harm animals, fish, and other wildlife.
Acid rain destroys the leaves of plants.

When acid rain infiltrates into soils, it changes the chemistry of the soil making it unfit for many living things that rely on soil as a habitat or for nutrition. Acid rain also changes the chemistry of the lakes and streams that the rainwater flows into, harming fish and other aquatic life. It also can cause haze which is happening in our country, because of air pollution.

Rain can carry and deposit the Nitrogen in some pollutants on rivers and soils. This will adversely affect the nutrients in the soil and water bodies. This can result in algae growth in lakes and water bodies, and make conditions for other living organism harmful.

Chemical reactions involving air pollutants create a poisonous gas ozone (O3). Gas Ozone can affect people’s health and can damage vegetation types and some animal life too.

SOLUTION OF AIR POLLUTION

The most effective way to overcome the air pollution is by using the public modes of transportation. The public transportation consists of a variety of modes such as buses, commuter trains and so on. By using this method, the exhaust from individual vehicles which contain carbon monoxide and carbon dioxide can be reduced drastically. The carbon monoxide contain CO bond which can reducing oxygen delivery to the organs of human’s body. Hence, it is better for us to use the public transportation instead of individual vehicles. Due to the modern technology nowadays, the public transportation which use the newer diesel and electrically powered vehicles can produce much less pollution than individual vehicles per passenger mile. In fact, public transportation use in the United States reduces our nation’s carbon emissions by 37 million metric tons annually. This is equivalent to Washington, DC; New York City; Atlanta; Denver; and Los Angeles combined stopping using electricity. 

See: Health: Carbon Monoxide

       Benefit Of Public Transportation 1

       Benefit Of Public Transportation 2