Soil Pollution: Causes And Human Impact

Soil pollution is a critical environmental concern, threatening human health and well-being. It is primarily caused by human activities, such as industrial waste, agricultural practices, and improper garbage disposal, leading to the contamination of soil with toxic substances. These toxic substances, including heavy metals, pesticides, and chemical fertilizers, accumulate in the soil, degrading its quality and posing risks to both human and ecological health. The impact of soil pollution varies across regions, with Europe, Eurasia, Asia, and North Africa facing significant challenges. The consequences of soil pollution are severe, including reduced crop yields, water and air quality degradation, and various diseases in humans and animals. Addressing soil pollution is crucial to safeguard health, food security, and the planet's ecosystems.

Industrial waste and chemical spills

Soil pollution is mostly caused by chemical substances produced by human activity. Almost all cases of soil pollution are anthropogenic in nature, with human activities leading to the contamination of the soil. Industries are believed to be one of the leading causes of soil pollution due to the improper management and disposal of toxic wastes generated during industrial activities.

The use of chemicals is projected to increase by 85% by 2030, with China and the European Union remaining the largest consumers. The global annual production of chemicals doubled from 2000 to 2017, with the majority being petroleum compounds, special chemicals, and polymers. Petroleum hydrocarbon pollution of soil is a widespread global environmental concern. Crude oil and petroleum products, including gasoline, diesel, or lubricants, can be released into the environment through accidents, managed spills, or as unintended by-products of industrial, commercial, or private actions.

The demolition of old buildings can contaminate nearby soil with asbestos, and the use of lead-based paint during construction activities can also pollute the soil with hazardous concentrations of lead. Activities associated with metal casting factories often cause the dispersion of metallic contaminants into nearby soils. Coal combustion produces the largest waste in the world within the energy sector, and precautions in handling coal fly ash waste are essential to avoid extensive soil and groundwater pollution. The disposal of ash on land and in ponds causes the dispersion of trace elements through leachates and erosion, causing pollution of the soil, the surrounding surface, and groundwater.

Soil pollution is a global threat, particularly in regions like Europe, Eurasia, Asia, and North Africa. It is a serious environmental concern as it harbours many health hazards. Soil pollutants enter our bodies through the food chain, causing illnesses to appear. The spread of antibiotics in the environment increases pathogens' resistance to these drugs, and soil pollution agents jeopardize world food security by reducing the amount and quality of harvests.

Pesticides and fertilisers

Pesticides are often considered a quick and easy solution for weed and pest control. However, they have contaminated almost every part of our environment, from the soil and air to surface and groundwater. Pesticide residues can remain in the soil for long periods, depending on the type of soil and pesticide. They can also contaminate groundwater when washed off treated foliage by rainfall or irrigation. Accidental releases from leaking pipes, spills, and damaged containers, as well as the inappropriate disposal of unwanted pesticides and their packaging, further contribute to soil pollution.

The use of pesticides poses significant risks to non-target organisms. This includes beneficial soil microorganisms, insects, plants, fish, and birds. For example, certain herbicides can cause sublethal effects on fish, such as erratic swimming and laboured breathing, increasing their chances of being eaten. Pesticides can also indirectly affect aquatic mammals like dolphins, which accumulate increased concentrations of persistent organic pollutants through the food chain.

Fertilisers, both mineral and organic, are another major source of soil pollution. Chemical fertilisers applied in excessive amounts can pollute the soil and atmosphere. They can decrease soil biodiversity and fertility, reducing crop yields and affecting food safety. The inappropriate disposal of fertiliser packaging and the use of wastewater for irrigation can also lead to soil pollution.

The impact of pesticides and fertilisers on the environment and food chains is not fully understood, which highlights the need for further studies in this field. Adopting integrated pest management methods and improving the management of nutrients and pests can help reduce the reliance on these chemicals and mitigate their impact on soil health.

Mining and heavy metals

Mining activities can cause soil pollution through the release and dissemination of toxic heavy metals and chemicals, which can have detrimental effects on the environment and human health.

Mining generates large volumes of waste, which, if not properly managed, can lead to the release of hazardous substances. For example, the exposure of pyrite to air and water results in acid mine drainage (AMD), which is highly acidic and can dissolve heavy metals from the surrounding environment, contaminating water sources and harming ecosystems. This can have a significant impact on flora and fauna, as well as rendering water undrinkable. AMD can persist long after mining activities have ceased, causing long-term environmental degradation.

Heavy metals commonly associated with soil pollution from mining include cadmium (Cd), mercury (Hg), arsenic (As), copper (Cu), lead (Pb), chromium (Cr), and zinc (Zn). These metals can accumulate in the soil, leading to elevated levels that exceed natural background contents. Studies have found high concentrations of these metals in areas surrounding coal mines and gold mining operations, indicating the impact of mining activities on soil pollution.

The presence of heavy metals in the soil can have detrimental effects on plant life. Plants tend to accumulate these metals in their aerial organs, which can then be transferred to humans through the consumption of fruits and vegetables. Certain metals, such as cadmium, can cause mineral deficiencies in plants, while high concentrations of lead can result in physiological and biochemical deficiencies. The sensitivity to heavy metals varies among plant species, with most plants having low concentration tolerance.

Soil pollution from mining can also impact the diversity and health of microbial life, such as fungi and bacteria, in the affected areas. This can lead to reduced plant growth and health, as these microorganisms play crucial roles in nutrient cycling and soil structure maintenance.

To mitigate the environmental and health impacts of soil pollution from mining and heavy metals, it is essential to implement stringent environmental standards and regulations in the mining industry. This includes enhancing monitoring and assessment techniques, adopting sustainable practices, and exploring innovative remediation strategies, such as phytoremediation and soil modification techniques.

Construction and demolition

Construction activities also generate a significant amount of waste and debris, including unused materials, packaging, rubble, and scrap materials. If not properly managed, this waste can end up in landfills, contributing to the landfill crisis and potentially leaching contaminants into the soil. Additionally, spills and improper disposal of hazardous materials, such as oils, solvents, paints, adhesives, and other chemicals, can directly contaminate the soil at construction sites.

Demolition works can release asbestos fibres into the soil, posing a significant health risk. Furthermore, the use of heavy machinery and diesel engines during construction and demolition emits pollutants like carbon monoxide, carbon dioxide, nitrogen oxides, and hydrocarbons, contributing to air pollution. The particulate matter generated during demolition and land clearing can also cause air pollution, with small particles of dust containing sulfates and silicates.

The impact of construction and demolition on soil pollution can be mitigated through various measures. These include implementing sediment and erosion control techniques, minimizing soil disturbance, and regularly testing and monitoring the soil for contamination. Proper waste management and spill response procedures are also crucial to prevent soil contamination. Additionally, surrounding construction sites with vegetation can act as a natural filter, reducing the amount of pollution that reaches nearby areas.

In some cases, construction projects may encounter historically contaminated soil, and proper remediation techniques must be employed to address this issue. Contaminated soil can be treated on-site or off-site using biological or chemical methods. Overall, addressing soil pollution caused by construction and demolition activities requires a combination of sustainable practices, regulations, and pollution control technologies.

Natural causes

Soil pollution is predominantly caused by human activity. However, natural events can also introduce pollutants into the soil. These include mineral weathering, volcanic eruptions, and wildfires. Soil erosion, caused by deforestation, is another natural cause of soil pollution. It removes the topsoil layer, exposing the underlying polluted layers.

Unsustainable farming practices, such as intensive cultivation and overgrazing, can also strip the land of its natural nutrients, leaving it no longer suitable for future crops. This can be mitigated by using manure and other natural fertilizers instead of chemical fertilizers.

Desert dust storms can carry harmful pollutants, such as heavy metals, across continents. For example, dust from the Sahara and Sahel deserts has been linked to elevated levels of mercury, selenium, and lead in North American soil.

In addition, perchlorates can be formed in soils containing chlorine and certain metals during a thunderstorm.

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