Soil pollution refers to any physical or chemical change in soil conditions that may adversely affect the growth of plants and other organisms living in or on that soil. Soil pollution and water pollution are closely connected. Acid rain and excessive use of chemical fertilizers result in the soil’s inability to hold nutrients. It allows toxic pesticides or atmospheric fallout to rapidly seep into the groundwater or run off into rivers and coastal wastes. Some of the persistent pollutants remain in the soil and degrade it. Also, you will know the effect of soil pollution on environment.
Most soil pollutants are agricultural chemicals, primarily fertilizers, and pesticides. It is now known that these chemicals attach themselves to soil particles and persist for a long in the soil, continuously releasing contaminants into the surface water, groundwater, and topsoil. Dumping waste (including garbage, untreated sewage, industrial effluents, nuclear waste, and mining waste) pollutes the soil when dangerous substances from the dumps leak.
Expert Views on Causes of Soil Pollution
Like other types of pollution, this is not due to one reason, but various human activities and natural incidences work in this direction. Let’s discuss the causes of soil pollution:
1. Physical Causes
Physical causes are those factors that bring changes in the quality of soil, causing degradation. Both natural and human factors play their role in it. Deforestation on a very large scale changes the natural processes like rain, climate, temperature, and natural power of soil.
Due to the lack of trees or forests and heavy rain, the surface soil of the earth mixes in the sea by flowing with water, or it flows away to distant regions. Only the crust of the earth or the upper layer of the earth has fertility power. It takes centuries for its reformation. Such problems arise mostly in developing countries.
2. Domestic Wastes
We use many goods in our daily life. After using these goods, we throw their packing, wrappers or other waste material in the open by contacting the earth’s upper layer, changing its composition, fertility and other qualities. These things include home garbage, kitchen garbage, foul paper, soft board and china bone wares, metallic cans, stove ash, cloth rags, wood’s worn out furniture, the broken tools of motors, vegetables seeds and peels, wasted food and other things in marriages and other social ceremonies.
All these things produce soil and land pollution. In most countries, there is no proper system for releasing waste material. According to one survey, every individual throws out 50 kilograms of domestic garbage in America. Likewise, in other countries, garbage is out on a large scale.
3. Urban Wastes
Urban waste is similar to domestic waste. In an urban area, garbage, newspapers, market waste and polythene are thrown in the open in great amounts. Then, it mixes in drainage water, and spread on a large part of the earth. So the link between various layers of the earth breaks down due to this and the lack of air or gas, and therefore the fertility of the earth/soil weakens day by day.
Developed countries have evolved some recycling of garbage, but now they too are facing problems in dumping massive amounts of waste and garbage, so much so that they have to export them. Every day in India, 2 lac/tonne of garbage is released from 4 metropolitan cities. Besides, about 60 cities, with more than 3 lakh population, each produce huge amounts of garbage. There is no proper system to destroy this garbage or to reuse it properly.
4. Chemical Sources
The use of chemicals is increasing rapidly. The maximum use of chemicals is to be seen in agriculture to increase production and control pests. All these chemicals are toxic. They accumulate in the soil. Constant use of these chemicals changes the physical composition of the soil. The toxic elements reach the grain, causing harm to human health.
To solve the food problem that causes overpopulation, the use of chemicals is essential, but the excessive use of chemicals is causing a threat to life. In other words, the life-giving soil is gradually becoming life-taking soil. On the other hand, fertility power is weakening. In India, where the green revolution has occurred, the soil has become toxic, and the day is not very far when even every kind of fertilizer and crop production increase. So the excessive use of chemicals is a major factor in soil pollution.
5. Industrial Wastes
Industrial factors are not only responsible for water pollution and air pollution, but they also play an important role in soil pollution. Textile mills, thermal power plants, fertilizer industries, petrol and oil industries, and rubber and plastic industries are such industries that generate large quantities of waste material. These waste materials are unfit for habitation and agriculture. It will causes soil pollution. Various kinds of carbon, toxic acid, minerals and oxides, calcium sulphate, and various acids increase in amounts on the land.
Master Effect of Soil Pollution
Sewage and industrial effluents highly affect human health. Various types of chemicals like acids, pesticides, alkalis, insecticides, fungicides, weedicides, heavy metals etc., in the industrial discharges affect soil fertility by causing changes in physical, chemical, and biological properties.
Indiscriminate use of pesticides, especially, is a matter of concern as it is the effect of soil pollution. Some persistent toxic chemicals inhibit the non-target organisms, soil flora, and fauna and reduce soil productivity. These chemicals accumulate in the food chain and ultimately affect human health.
Sewage sludge has many pathogenic bacteria, viruses, and intestinal worms, which may cause various diseases. Decomposing organic matter in soil also produces toxic vapours. Radioactive fallout on vegetation is the source of radioisotopes that enter grazing animals’ food chains.
Some radioisotopes replace essential elements in the body and cause abnormalities, e.g., strontium-90, instead of calcium getting in the bones and tissues. The bones become brittle and prone to fracture. Radioisotopes which attach to the clay become a radiation source in the environment.
Controlling Measures of Soil Pollution. Chemicals or their degradation products from soil may percolate and contaminate groundwater resources. It shows the effect of soil pollution. Nitrogen and phosphorus from the fertilizers in the soil reach nearby water bodies with agricultural run-off and cause eutrophication. The following measures can be applied:
- Effluents should be properly treated before discharging them on the soil.
- Solid wastes should be properly collected and disposed of appropriately.
- From the wastes, recovery of useful products should be made.
- Biodegradable organic waste should be used to generate biogas.
- Cattle dung should be used for methane generation. Night soil (human feces) can also be used in the biogas plant to produce inflammable methane gas. It will reduce the effect of soil pollution.
- Microbial degradation of biodegradable substances is also one of the scientific approaches for reducing soil pollution.