Soil Pollution is defined as the presence of pollutants, contaminants, and toxic chemicals in the soil in high concentrations. These are a threat to the ecosystem and the health of humans. All the soils whether unpolluted or polluted contains some amount of contaminants naturally. The contaminants might include inorganic ions, metals, salts, carbonates, phosphates, nitrates, sulfates, organic compounds, and many more. These types of compounds are mainly created through various activities of the microbial organisms in the soil and organism decomposition like animals and plants.
Many organisms enter the soil from the atmosphere through rain, wind, water bodies on the surface, and shallow groundwater. When the quantity of soil contaminants exceeds the natural levels, soil pollution is created. Soil pollution is mainly caused due to two causes. They are man-made pollutants and natural pollutants. Let us have a brief discussion below:
Anthropogenic soil or Man-made pollution arises from different types of procedures that can be industrial or accidental. Man-made pollution collaborates with the natural processes to increase the level of toxification in the soil. Sites for construction are the main cause of soil pollution in the city areas. Any type of chemical substance that is manhandled at the construction site may increase the level of soil pollution. The chemicals that travel through the air are more resistant to bioaccumulation and degradation of living organisms like PAHs.
Dust from the construction site spread very easily throughout the air due to its smaller size of the particles (less than 10 micron). This type of dust from the soil triggers various diseases like bronchitis, cancer, asthma and many respiratory diseases. Also, the destruction of older buildings releases harmful minerals called asbestos that play as a poison when mixed with the soil. Asbestos can also be distributed through the wind. Some of the men made causes for soil pollution as below.
- Accidental leakage and spillage during transport, use, and storage of chemicals like gasoline or diesel.
- Due to activities in the mining like processing and crushing of the materials mainly the raw ones like heavy metals releasing toxic chemicals.
- Manufacturing and foundry processes that include furnaces results in the dispersal of contaminants in the ecosystem
- Different types of activities in agriculture like diffusion of pesticides, insecticides, fertilizers, and herbicides
- Deliberate or accidental dumping of the chemical wastes like illegal dumping
- Toxic emissions from the vehicles due to transportation activities
- Damaged paint chips that are falling from the walls of the building especially the lead-based ones
- The proper storage of waste in the landfills as any ignorance may cause the toxic chemical to enter into the underground water or may produce polluted vapors
There are some rare cases where an accumulation of the chemicals naturally in the soil leads to pollution. Natural processes may react together with human released toxic chemicals that may increase or decrease the level of toxicity in the soil. This is only possible due to the complex nature of the environment of the soil. The presence of different chemicals and several natural factors also reacts with the emitted pollutants. Different types of natural pollutants are as follows.
- Natural production of chemicals in the soil like perchlorate, source of chlorine, energy due to thunderstorm and a metallic object
- Atmospheric deposition led to the imbalances in the soil. This is due to natural compound accumulation and leakage of precipitation water. This results in the increased accumulation and concentration of the perchlorate in the environment of the soil
- Leakage from the sewer lines onto the surface that will add more chlorine to the water resulting in the generation of trihalomethanes like chloroform
Sources of different types of soil pollutants
Soil pollution may be caused due to numerous contaminants and pollutants. The main pollutants that cause the maximum amount of soil pollution are due to activities in agricultural practices. Various chemicals are infested into the crops along with pesticides that are the number one cause of soil pollution. Other reasons include hazardous chemicals used in industrial and urban wastes and radioactive emissions that contaminate the soil to the highest level. Some of the major pollutants that cause pollution in the soil are:
- Agricultural practices: The crops in the soil are cultivated to a huge extent with fertilizers, pesticides, slurry debris, herbicides, and manure.
- Waste in the Urban Areas: Waste in the city regions consists of rubbish and garbage compounds, sewage from the domestic and industrial wastes, and dried sludge.
- Biological compounds: Biological compounds in the soil react with digested sludge and manures from the bird, animal and human excretion and contaminate it.
- Radioactive Pollutants: Radioactive agents like thorium, Nitrogen, Radium, and Uranium infiltrates into the soil and creates harmful effects.
- Wastes from the industries: Wastes from the industry areas that pollute the soil include pesticides, textiles, petroleum, glass, cement, and many more.
What are the different types of Soil Contaminants?
There are innumerable pollutants that can make the soil hazardous. However, we have described a brief on the different types of soil contaminants below.
- Mercury: The potential sources of mercury include medical wastes, volcanoes, mining, alkali, processing of metals, geologic deposits, vegetables that are grown in the polluted soil and plants.
- Copper, Nickel, and Zinc: Copper, Nickel, and Zinc in the soil are mainly found due to foundry and construction activities, and mining.
- Insecticides and Herbicides: The potential sources of insecticides and herbicides are agriculture and gardening.
- Lead: Lead enters the soil through the mining, agriculture, foundry and construction activities, lead paint and exhaust.
- Arsenic: The potential sources of arsenic in the soil are power plants operated by coal, electronic industries, agriculture, mining, lumber facilities, foundry activities and accumulation due to natural resources.
Effects of Soil Pollution
Soil pollution can hurt humans as well just like plants and other animals. Soil pollution may cause damage to any person irrespective of health, age, pollutant type, or the contaminant ingested or inhaled. The effects of soil pollution are more susceptible to children. This is due to more exposure to the soil while playing and lower levels of immunity against the diseases. Thus if you live near the vicinity of the industrial area, it is always mandatory to test the soil before settling there.
Soil pollution may lead to different types of health disorders. A few like nausea, fatigue, eye irritation, headaches, skin problems, neuromuscular blockage, liver and kidney damage, and various types of cancer.
Soil can be considered as the natural sink for the contaminants. This is due to the concentration and accumulation of the pollutants that end up inside the soil coming from different sources. Small particles of contaminants assemble in the soil. And depending on the conditions of the environment and degradable nature of the pollutant increases the level of pollution in the soil. If the soil becomes polluted, all the vegetables and fruits will also become polluted. We will, in turn, consume those polluted products and mankind may suffer from various diseases. This will disrupt the entire ecosystem of the earth.
Read our detailed article on: Various Types of Pollution – Air, Water, Soil, Noise etc