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Soil Pollution

What is soil pollution?

Soil pollution or soil contamination is a part of land degradation caused by acid rain, excess and wrong use of agricultural fertilizer, insecticides ( the chemical compounds that kill insects), and herbicides (chemical substances that kill plants) to affect the natural soil environment. Petroleum, polynuclear hydrocarbon, and heavy metals are the most common substances which cause soil or water pollution.

Soil pollution or contamination sources, prevention, and effects of acid rain or fertilizer on soil acidity

All the soil contains different types of harmful or toxic polluted substances for human beings and other living organisms. However, the natural concentration of such substances does not threaten the surroundings of our ecosystem. Soil pollution effect or damage a living organism, when the concentration of one or more of such toxic molecule is large enough.

Causes of soil pollution

Acid rain, waste disposal, accidental oil spills, industrial, and agricultural activity are the main causes of soil pollution that have adverse effects on our environment in several ways. The main factors that cause soil pollution may include

  1. Acidic or alkaline water molecules
  2. Repeated or excessive use of fertilizer
  3. Inadequate drainage systems in agricultural fields,
  4. Spraying of insecticides, and herbicides

The different causes and their adverse effects on soil are discussed below in this learning chemistry article.

Causes and effects of soil pollution

The soil of our environment influences almost all the activities of our daily life but we fail to understand the importance of soil. Therefore, the soil gets polluted and effect our daily life in several ways.

Generally, soil pollution has harmful effects on human health, the growth of plants by decreasing soil fertility, and changes the structure of the soil. Some major causes and adverse effects of soil pollution are given below,

Waste disposal

Wastes are produced by everyday industrial and human activities such as washing clothes and excreting urine and farces. The discharge of large quantities of wastes into rivers, lakes, and landfill causes water and soil pollution in our environment. Such types of pollutants have adverse effects on ground water and human health.

Effects of acid rain

We know that the air of our environment contains gaseous sulfur dioxide (SO2) and nitrogen dioxide (NO2). Sulfur dioxide present in the air undergoes photolytic or catalytic oxidation to form sulfur trioxide (SO3). It reacts with rainy water or moisture to form sulfuric acid rain,
SO3 + H2O → H2SO4

It is responsible for soil and water pollution. NO2 also reacts with rainy water or moisture in presence of oxygen or ozone produces nitric acid (HNO3) rain.

The sulfuric acid and nitric acid formed by the above formula come down to the atmosphere to damage standing crops or change the pH scale of soil.

Effects of fertilizers on soil

Repeated and excess use of the same fertilizer pollutes the soil of our environment. Some fertilizer increases the acidity of soil and some made the soil alkaline.

When we used ammonium sulfate [NH4(SO4)] fertilizer for the production of crops into the soil, again and again. The ammonium ion (NH4+) is used up by crops but sulfate ion (SO4−2) gets accumulated into the soil responsible for increasing the acidity of the soil. The sulfate ion makes the soil highly acidic, hence the soil unfit for plant growth.

If we use sodium nitrate (NaNO3) or potassium nitrate (KNO3) again and again, the nitrate ion (NO3) is used up by successive crops but sodium and potassium ions get accommodated into the soil. These fertilizers make the soil alkaline and hence the soil cannot be used for the high production of food.

Agricultural activities

We use a lot of water for irrigation along with fertilizer, but there should be a good drainage system for the outlet of unused water. Otherwise, the soil becomes highly saline (salt-containing) which affects the growth of plants and is responsible for soil pollution. Therefore, the inadequate drainage system in the agricultural field is another source of soil pollution.

Effect of pesticides on food

When we speared different types of pesticides and herbicides to save the fruits and vegetable plants from harmful insects and herbs. Pesticides and herbicides enter into the living tissue of the growing plants in our environment.

Pesticides and herbicides cause soil pollution and toxic effects on our health. When we eat these grains, fruits, or vegetables, it may damage our heart, kidney, etc. Therefore, we advised that before eating these types of polluted foods growing from soil pollution, they should be washed with a sufficient quantity of water.

How to reduce soil acidity?

Soil acidity can be easily removed by adding basic material like limestone to neutralize the soil. Calcium carbonate or limestone is widely used because it is easy to handle and economically lower than other basic substances.

Solutions to soil pollution

Soil pollution can be prevented or minimized by the following methods,

  • Reducing the emission of sulfur dioxide and nitrogen dioxide causes acid rain to increase soil acidity.
  • The use of excess nitrate, sulfate, and phosphate fertilizer should be avoided because it increases or decreases the acidity of the soil.
  • To minimize the use of synthetic detergents, properly recycle batteries and other harmful chemicals which cause soil pollution.
  • Before throwing industrial wastes into the soil, they should be treated chemically to neutralize harmful substances present in them. These should be throwing the places which are authorized for them.
  • Encourage the eco-friendly model for the industry, farming.
  • Using proper drainage system for agriculture.
  • Improving urban planning and wastewater treatment.
  • Decreasing the use of harmful pesticides and herbicides that cause soil pollution.