Soil Pollution

Soil pollution is the poisoning of soil with harmful chemicals in abnormally high amounts. It is a significant environmental concern since it has numerous health dangers. Exposure to soil having high levels of benzene, for example, increases the risk of acquiring leukaemia. 

It’s critical to realise that all soils include substances that are dangerous or toxic to humans and other living things. However, the concentrations of such compounds in unpolluted soil are so low that they pose no damage to the environment. The soil is said to be contaminated when the concentration of one or more harmful compounds is high enough to harm living creatures.

One of the following is frequently the root cause of soil pollution:

• Agriculture (overuse/improper application of pesticides)
• Industrial overproduction
• Waste management or disposal that is inefficient

Soil remediation (decontamination) issues are directly proportional to the level of soil pollution. The more contaminated an area is, the more resources are needed to clean it up.

What Pollutants Cause Soil Contamination?

Xenobiotics – compounds that are not naturally found in nature but are created by humans – are among the most dangerous soil contaminants. The name ‘xenobiotic’ comes from the Greek words ‘xenos’ (foreigner) and ‘bios’ (life) (life). Several xenobiotics have been identified as carcinogenic. 

This section lists the various types of pollutants that can be detected in polluted soil.

Heavy Metal (Heavy Metal)

Heavy metals (such as lead and mercury, in excessively high concentrations) in soil can make it highly poisonous to humans. Below is a list of metals that can be considered as soil contaminants.

• Arsenic, Mercury, Lead
• Antimony, Zinc, Nickel
• Cadmium, Selenium, Beryllium
• Thallium, Chromium, Copper

Mining activities, agricultural activities, electronic trash (e-waste), and medical waste are all potential sources of these metals.

Polycyclic Aromatic Hydrocarbons

PAHs (polycyclic aromatic hydrocarbons) are organic molecules with a cyclic structure.

• Only carbon and hydrogen atoms are present.
• Their chemical structures contain more than one aromatic ring.

Naphthalene, anthracene, and phenalene are all examples of PAHs. Polycyclic aromatic hydrocarbon exposure has been associated with a variety of cancers. In humans, these chemical substances can induce cardiovascular disorders.

Coke (coal) processing, automobile emissions, cigarette smoke, and shale oil extraction are all sources of PAHs in the soil.

Waste from Industry

Soil pollution can occur when industrial waste is discharged into the environment. The following are some of the most prevalent soil contaminants that can be found in industrial waste.

• Industrial solvents containing chlorine
• Dioxins are created during pesticide manufacturing and trash incineration.
• Plasticizers/dispersants
• Biphenyls polychlorinated (PCBs)

Pesticides

Pesticides are compounds (or mixtures of substances) used to kill or prevent pests from reproducing. Pesticides commonly used in agriculture include

• Herbicides are chemicals that are used to kill or control weeds and other undesirable plants.
• Insecticides are chemicals that are used to kill insects.
• Fungicides are chemicals that kill or slow the growth of parasitic fungi.

However, unintended pesticide diffusion into the environment (often referred to as “pesticide drift”) raises a number of environmental concerns, including water and soil degradation. The following are some of the most common soil pollutants identified in pesticides.

• Herbicides

• Triazines

• Carbamates
• Amides
• Acids that are aliphatic in nature
• Insecticides

• Organophosphates
• Hydrocarbons chlorinated
• Compounds containing arsenic
• Pyrethrum

• Fungicides

• Compounds containing mercury
• Thiocarbamates

Human health is endangered by these pollutants. Pesticides can cause disorders of the central nervous system, immune system problems, cancer, and birth defects, to name a few.

What Causes Soil Pollution and How Does It Happen?

Soil pollution can be divided into two broad categories:

• Soil contamination is a natural occurrence.
• Soil contamination caused by humans (caused by human activity)

Soil Pollution by Nature

Some contaminants naturally accumulate in soils via exceedingly unusual processes. This can happen due to the atmosphere’s unequal deposition of soil. The transmission of soil pollutants with precipitation water is another way for this sort of soil contamination to occur.

The buildup of compounds containing the perchlorate anion (ClO4–) in some dry, arid habitats is an example of natural soil pollution. It’s worth noting that some pollutants can be formed naturally in the soil as a result of certain environmental factors. During a thunderstorm, for example, perchlorates can occur in soils containing chlorine and certain metals.

Soil Pollution Caused by Humans

Almost all incidents of soil pollution are caused by humans. Soil contamination can be caused by a variety of human activities. The following are some examples of such procedures.

• The asbestos contamination of neighbouring soil can occur when ancient structures are demolished
• When lead-based paint is used during building, it can poison the soil with dangerous levels of lead
• Spillage of gasoline and diesel during transportation can pollute soils with petroleum’s hydrocarbons
• Metallic pollutants are frequently dispersed into neighbouring soils as a result of activities related with metal casting facilities (foundries)
• Heavy metal contamination can result from underground mining activity
• The improper disposal of highly toxic industrial/chemical waste can damage the land significantly. The accumulation of toxic wastes in landfills, for example, can result in waste seepage into the soil. This garbage has the potential to harm groundwater.
• Several dangerous chemicals are found in chemical insecticides. Chemical pesticides used in excess and inefficiently can lead to serious soil pollution
• Sewage from metropolitan areas has the potential to contaminate soil (if not disposed of correctly). Several carcinogenic chemicals may be present in these wastes
• Nuclear waste, e-waste, and coal ash are examples of waste that can harm soil

What are the Harmful Effects of Soil Pollution?

Soil contamination has a wide range of negative consequences that affect plants, animals, humans, and the entire ecosystem. Polluted soil offers a bigger threat to children since they are more prone to infections. This section discusses some of the most significant effects of soil pollution.

The Impact on Humans

Contaminants in the soil might be present in all three periods (solid, liquid, and gaseous). As a result, these contaminants can enter the human body through a variety of routes, including direct skin contact or inhalation of contaminated soil dust.

Human exposure to polluted soil has a number of short-term consequences.

• Symptoms include headaches, nausea, and vomiting.
• Coughing, chest pain, and wheezing are all symptoms.
• Irritation of the eyes and skin.
• Weakness and fatigue

Soil pollution has been connected to a number of long-term illnesses. The following are some of these disorders.

• High levels of lead exposure can cause lasting harm to the nervous system. 
• Depression of the central nervous system (Central Nervous System).
• Vital organs such as the kidney and liver are harmed.
• A greater chance of acquiring cancer.

Many soil contaminants, including petroleum hydrocarbons and industrial solvents, have been related to human congenital diseases. As a result, soil pollution can have a number of detrimental consequences for human health.

Plant and Animal Reactions

Because soil contamination is frequently accompanied by a reduction in nutrient availability, plant life ceases to grow in such soils. Plants can be poisoned by soils contaminated with inorganic aluminium. Furthermore, this form of pollution raises the salinity of the soil, making it unsuitable for plant growth.

Plants cultivated in polluted soil can acquire significant levels of soil contaminants through a process called bioaccumulation. All of the toxins accumulated in these plants are transmitted up the food chain when herbivores consume them. Many attractive animal species may be lost or extinct as a result of this. Furthermore, these contaminants have the potential to reach the top of the food chain and cause diseases in humans.

Ecological Consequences

1. Soil contamination can be a direct contributor to air and water pollution because volatile chemicals in the soil can be blown away into the sky by winds or seep into subsurface water reserves.
2. It also has the potential to contribute to acid rain (by releasing huge quantities of ammonia into the atmosphere).
3. Several microorganisms that improve soil texture and aid in the breakdown of organic materials are unable to thrive in acidic soils. As a result, soil pollution has a negative impact on soil quality and texture.
4. This type of pollution has a significant impact on crop productivity. Heavy metal contamination has rendered over 12 million tonnes of grain (worth roughly 2.6 billion USD) unsuitable for human consumption in China (as per studies conducted by the China Dialogue).

What Can Be Done to Reduce Soil Pollution?

To deal with soil cleanup, several technologies have been created. The following are some of the most important ways for decontaminating polluted soil.

• Polluted soils are excavated and then transported to isolated, deserted regions
• Pollutant extraction using thermal remediation – the temperature is raised to drive the contaminants into the vapour phase, where they can then be recovered via vapour extraction
• The use of microorganisms and plants for soil purification is known as bioremediation or phytoremediation
• The employment of fungi for heavy metal contamination accumulation is known as mycoremediation

Conclusion

Soil pollution is a serious environmental problem that affects everyone. Human activities and natural processes both contribute to soil contamination. However, it is primarily due to human activity. It occurs as a result of a variety of activities, such as the abuse of pesticides, which causes the soil to lose its fertility and increases the acidity or alkalinity of the soil, lowering its quality.

People should reuse and recycle items in order to avoid polluting the soil. Instead of disposable plastic or paper containers, glass and other reusable containers should be utilised. Local waste management organisations should recycle plastic and paper to reduce the amount of waste transported to landfills.