Land Pollution: Causes And Human Impact

Land pollution is a global issue caused by human activities that contaminate the land and degrade the soil. It occurs when solid or liquid waste materials are disposed of on land or underground, leading to the contamination of soil and groundwater. Land pollution has several sources, including littering, improper waste disposal, industrial activities, mining, agriculture, and construction. These activities release chemicals, toxins, and pollutants into the environment, damaging ecosystems, reducing biodiversity, and posing risks to human health. The accumulation of waste and the misuse of land resources contribute to the degradation of land surfaces, threatening the well-being of humanity and the planet.

Human activities such as littering, industrial waste, and farming

Littering

Littering is the improper disposal of waste products, and it is a major contributor to land pollution. While some littering occurs accidentally, such as when an unsecured object flies out of a truck bed, most littering is a deliberate act. About 76% of litter on roads comes from motorists and pedestrians, and it can have a range of harmful effects. Litter can contaminate soil and water sources, releasing chemicals and microparticles that are not natural to the environment. For example, cigarette butts can contain arsenic and formaldehyde, which can leach into the soil and water, impacting both humans and animals. Open-air burning of litter, which happens to about 40% of the world's litter, releases toxic emissions that cause respiratory issues and other health problems and contribute to acid rain. Plastic litter is a leading cause of animal deaths, with over 100,000 marine animals dying each year from ingestion or entanglement. Improperly discarded trash also provides breeding grounds for bacteria and diseases, which can spread through direct and indirect contact.

Industrial Waste

Industrial activities and manufacturing facilities generate substantial amounts of non-biodegradable, non-recyclable, and hazardous waste. When this waste is not appropriately managed and disposed of, it pollutes the land, air, and water. Industrial waste can take the form of solids, liquids, and gases, which are deposited on land, released into the air, or discharged into bodies of water. The improper disposal of hazardous waste, such as through illegal "midnight dumping" or accidental spills, has contaminated thousands of industrial land parcels, posing serious threats to public health and the environment. Industrial pollution contributes to ozone depletion, soil degradation, water contamination, and the emission of harmful pollutants that affect human and animal health. Additionally, increased industrial pollutants accelerate global warming and contribute to climate change.

Farming

Agricultural practices, including the use of pesticides, fertilizers, and animal manure, can lead to land pollution. When it rains, these pollutants can be transported into surface waters, contaminating lakes, rivers, and streams. Increased levels of nitrogen and phosphorus from fertilizer and manure can cause algal blooms, leading to hypoxic conditions that are harmful to aquatic life. Excessive sedimentation from erosion can also overwhelm aquatic ecosystems, smother breeding areas, and degrade coastal ecosystems, including coral reefs. Bacteria and nutrients from livestock and poultry manure can contaminate drinking water supplies and cause beach closures. Adopting regenerative agriculture strategies, such as improving soil health through cover crops and streamside buffer crops, can help reduce nutrient runoff and improve water quality.

Mining and extraction

Land pollution caused by mining and extraction is a significant issue that has various negative impacts on the environment, human health, and local communities. Mining activities, including prospecting, exploration, construction, operation, maintenance, expansion, abandonment, decommissioning, and repurposing of mines, can have both positive and negative effects on social and environmental systems.

One of the primary ways mining and extraction contribute to land pollution is through deforestation and land use change. Mining requires extensive land clearing to accommodate the mine site and associated infrastructure, leading to the destruction of forests and other critical ecosystems. This clearing of land consumes significant energy and water resources, emits air pollutants, and produces hazardous waste. From 2001 to 2020, mining and related activities resulted in the loss of nearly 1.4 million hectares of trees worldwide, releasing approximately 36 million tonnes of carbon dioxide equivalent (CO2e) per year into the atmosphere. Gold and coal extraction have been the biggest drivers of tree cover loss related to mining, with over 71% of mining-related deforestation attributed to these activities from 2001 to 2019.

Soil erosion is another significant consequence of mining and extraction practices. The removal of surface vegetation and topsoil during mining operations exposes the land to erosion, particularly in hilly landscapes. This erosion can lead to increased flooding and landslides, further contributing to habitat and tree cover loss. Additionally, erosion of exposed hillsides, mine dumps, and tailings dams can result in the siltation of drainages, creeks, and rivers, affecting water quality and availability for plant growth.

While well-regulated mines in some countries have implemented measures to minimise water contamination and environmental degradation, illegal small-scale mining operations, known as 'artisanal mining', continue to cause environmental pollution in many developing countries. These subsistence mining operations are often poorly managed, unsafe, and difficult to regulate due to their small scale.

To mitigate the land pollution caused by mining and extraction, it is essential to enforce strict environmental regulations, promote sustainable mining practices, and invest in research and innovation for clean mining technologies.

Construction and demolition

The initial phase of construction often involves clearing the land, which can lead to the removal of vegetation, disruption of natural landforms, and alteration of waterways. This clearance of land can result in soil erosion, with construction activities increasing the rate of erosion by 2 to 40,000 times compared to pre-construction conditions. Soil erosion, in turn, contributes to non-point source pollution, degrading surface water quality.

Construction activities also generate a substantial amount of waste, including unused materials, packaging, broken equipment, and rubble. If this waste is not properly managed, it ends up in landfills, contributing to the landfill crisis. Construction, demolition, and excavation activities in the UK, for example, produce an estimated 120 million tonnes of waste annually.

In addition to solid waste, construction and demolition processes can release hazardous chemicals and pollutants into the environment, leading to air pollution and water pollution. Diesel engines used to power heavy machinery and vehicles emit carbon monoxide, carbon dioxide, nitrogen oxides, and hydrocarbons. Additionally, the use of hazardous chemicals, such as paints, glues, oils, and thinners, can contaminate air and water sources.

The impact of construction and demolition on land pollution is further exacerbated by the disturbance of subsurface pollution. During excavation, construction work may uncover previously unknown pollution, leading to costly remediation processes.

To mitigate the effects of construction and demolition on land pollution, various measures can be implemented. These include enforcing pollution prevention strategies, adopting sustainable practices, and ensuring proper waste management. Real-time monitoring of air quality and regular soil testing can also help identify and address contamination issues promptly. Additionally, the implementation of sediment control measures and minimizing soil disturbance during construction can reduce soil pollution and erosion.

Chemical substances and toxins

Land pollution is caused by the dumping of trash, compost, and other toxins on the land, contaminating and polluting it. This contamination can occur through the improper disposal of municipal solid waste (MSW), construction and demolition (C&D) waste, and hazardous waste. Hazardous wastes include harmful and dangerous substances generated primarily as liquids but also as solids, sludges, or gases by various chemical manufacturing companies, petroleum refineries, paper mills, smelters, machine shops, dry cleaners, automobile repair shops, and many other industries or commercial facilities.

The use of pesticides, herbicides, volatile organic compounds (VOCs), and heavy metals such as arsenic, cadmium, lead, thallium, and mercury also contributes to land pollution. These chemical substances can contaminate water and land-based flora and fauna, causing harm to both humans and animals. For example, heavy metals like mercury can accumulate in fish, contaminating them as a food source for humans.

Soil pollution, a form of land pollution, occurs when the soil's upper layer is harmed. This can be caused by the overuse of chemical fertilizers, soil degradation due to running water, and pest control measures, leading to the loss of agricultural land, forest cover, and grazing pastures. The accumulation of solid and liquid waste products further contaminates groundwater and soil, increasing the level of toxic chemicals and hazardous substances.

Additionally, extraction methods such as coal mining and oil drilling can cause land pollution and damage the surrounding area's natural ecosystems. Acid mine drainage (AMD), used in coal mining, can react with surrounding rocks and sand, creating toxic sulfuric acid that is harmful to humans, plants, and wildlife. Similarly, nuclear research stations, nuclear power plants, and nuclear weapons production can contaminate soil with radioactive waste, which, due to its long half-life, can survive in the soil for extended periods.

Accidental spills, natural disasters, and terrorist activities can also lead to land contamination by releasing hazardous chemicals and toxins into the environment. Furthermore, military bases and defense sites have contributed to land pollution through the release of hazardous substances, discarded munitions, and building demolition debris.

Sewage treatment and waste management

One of the main challenges in sewage treatment is the diverse range of contaminants found in wastewater. Sewage can contain human waste, household chemicals, personal hygiene products, pharmaceuticals, pesticides, fertilizers, automotive chemicals, and trash. These contaminants can have harmful effects on both human health and aquatic ecosystems, leading to biodiversity loss and the contamination of water sources.

To address this issue, various treatment methods have been developed. One common approach is ammonia stripping, a physicochemical process that removes ammonia from sewage by converting ammonium ions into ammonia gas. This method is more cost-effective than nitrification-denitrification but is less efficient in cold weather. Other treatment processes involve the use of advanced technology to remove pollutants from sewage, although these methods can be extremely expensive.

In the context of waste management, sanitary landfills have emerged as a modern technique for the disposal of solid waste. These landfills are carefully engineered to control leachate, a highly contaminated liquid that forms during waste decomposition, and methane gas, which is produced through the anaerobic decomposition of solid waste. Sanitary landfills utilize impermeable bottom liners to prevent leachate from contaminating groundwater. The waste is compacted and covered with soil daily, and leachate is collected through a network of pipes for treatment.

However, the effectiveness of these treatments and waste management strategies is often hindered by the rapid urbanization and population growth, which have outpaced the development of treatment facilities. This has resulted in untreated sewage being released into the environment, contributing to water pollution and the spread of infectious diseases. To mitigate these issues, it is essential to invest in upgrading wastewater infrastructure, implementing innovative waste diversion practices, and expanding natural areas to prevent stormwater from rushing into sewers.

Frequently asked questions