Soil is a vital part of most ecosystems as it provides the nutrients needed for all living creatures. It supports plant growth, regulates temperature, and supports water and energy resources. Soil is a crucial natural resource, and keeping it healthy is important. However, human activities are disturbing the natural balance of soil. Soil pollution happens when harmful substances, like chemicals and waste, get into the soil. These pollutants can come from various sources, including mining, and make the soil unhealthy. Poor and unplanned use of soil leads to pollution, reduced biological activity, and changes in the soil’s physical and chemical properties. This can harm plants, animals, and people who rely on the soil for food and living.
Soil pollution, primarily resulting from mining activities, has become a significant environmental concern globally. Mining processes, including the extraction, processing, and disposal of minerals and ores, release a variety of pollutants into the soil.
- Excavation and Topsoil Removal: A giant shovel, during mining scooping up topsoil—the nutrient-rich layer where plants thrive—gets scraped away. This removal disrupts the delicate balance of soil ecosystems.
- Waste Management: Waste from mining—tailings, ends up in heaps. These piles can leach heavy metals lead, zinc, and copper) into the soil. Soil as a sponge, soaking up these pollutants.
- Atmospheric Deposition: Air pollution occurs due to the tiny particles settling onto the ground. Mining activities release airborne pollutants that eventually land on the soil.
Sources and Types of Pollutants
Mining activities introduce several types of pollutants into the soil, including heavy metals, acid mine drainage, and chemicals used in ore processing. Figure 1 depicts the different soil, sediment and water pollution in the mining areas.
- Heavy Metals: Mining operations release heavy metals such as lead (Pb), mercury (Hg), cadmium (Cd), arsenic (As), and nickel (Ni). These metals persist in the environment due to their non-degradable nature and can accumulate to toxic levels over time.
- Acid Mine Drainage (AMD): The exposure of sulfide minerals to air and water during mining leads to the formation of sulfuric acid. This acid leaches heavy metals from the surrounding rocks into the soil and water bodies, causing severe environmental damage.
- Chemical Pollutants: Chemicals used in ore processing, such as cyanide in gold mining, can contaminate the soil. Improper disposal or accidental spills of these chemicals can lead to long-term soil pollution.
Impact on Living Organisms
Plants: Plants can absorb and accumulate these toxic heavy metals such as cadmium and lead from contaminated soil, affecting their growth and development. This bioaccumulation not only affects plant health but also poses risks to herbivores and humans who consume these plants. High concentrations of these metals can inhibit photosynthesis, reduce nutrient uptake, and cause chlorosis and necrosis in plants (Nagajyoti et al., 2010).
Animals: Animals like burrowing rodents, insects, and creepy-crawlies—face a double curse. Their habitats get disrupted, and they ingest contaminated soil. Animals that graze on contaminated soil or plants can suffer from various health issues. For instance, high levels of mercury can cause neurological damage in wildlife (Scheuhammer et al., 2007). Contaminants bioaccumulate in the tissues of animals and biomagnify as they move up the food chain. This can lead to high concentrations of pollutants in top predators, causing reproductive and developmental problems.
Humans: Humans can be directly exposed to soil pollutants through dermal contact, inhalation of dust, or ingestion of contaminated soil, leading to various health issues such as skin disorders, respiratory problems, and gastrointestinal issues (Alloway, 2013). When crops absorb heavy metals, they end up on our plates. The consumption of crops and animals contaminated with heavy metals and other pollutants can lead to chronic health conditions, including cancer, kidney damage, and neurological disorders. Additionally, contaminated soil near mining areas affects nearby communities. It’s like a toxic domino effect. Table 1 demonstrates the risk of excessive accumulation of potentially toxic metals on human body along with the effected body organs.
Microorganisms: An active community of earthworms, bacteria, fungi, and other soil organisms residing beneath the soil helps in breaking organic matter, cycle nutrients, and keep the soil healthy. But heavy metal contamination can reduce microbial diversity and alter microbial community structure, impairing soil functions. These pollutants can inhibit soil enzyme activities, affecting processes such as organic matter decomposition and nitrogen fixation (Chen et al., 2014).
Table 1 Heavy metals prone to carcinogenic risk (As, Cd, Cr, Ni, & Be) as suggested by United States Environmental Protection Agency and some other potentially toxic metals, risk of human health effects and impacted body organs
| Heavy metals | Health effects | Impacted Body organs |
| Arsenic (As) | skin lesions, cardiovascular diseases, neurotoxicity, and an increased risk of cancer | skin, lungs, liver, kidneys, and bladder |
| Cadmium (Cd) | kidney damage, bone fragility, respiratory problems, and an increased risk of cancer | kidneys, liver, lungs, and bones |
| Chromium (Cr) | respiratory issues, skin rashes, and an increased risk of lung cancer | lungs, skin, kidneys, and liver |
| Nickel (Ni) | allergic reactions, respiratory issues, cardiovascular diseases, and an increased risk of cancer | skin, lungs, and kidneys |
| Beryllium (Be) | chronic beryllium disease (berylliosis), lung cancer, and acute beryllium disease | lungs and skin |
| Lead (Pb) | neurological damage, developmental delays in children, anaemia, and kidney damage | brain, kidneys, liver, and nervous system |
| Mercury (Hg) | neurological and developmental disorders, kidney damage, respiratory issues, and gastrointestinal problems. | brain, kidneys, lungs, and nervous system |
| Copper (Cu) | gastrointestinal distress, liver and kidney damage, and neurological disorders | liver, kidneys, brain, and gastrointestinal tract. |
| Uranium (U) | kidney damage, neurological disorders, cognitive impairment, radiation effects, cancer risk | kidneys, bones, and potentially other organs where uranium accumulates |
Case Studies from India
Case Study 1: Uranium Mining in Jaduguda, Jharkhand
Jaduguda, located in the East Singhbhum district of Jharkhand, is known for its extensive uranium mining activities since the 1960s. The mining activities have raised significant environmental and health concerns due to the release of radioactive waste and heavy metals into the surrounding environment. Studies have shown elevated levels of radioactive isotopes, such as radon and radium, as well as heavy metals like arsenic and lead in the soil and water samples collected from the region (Kumar et al., 2013). The contamination has had severe repercussions on the local population and ecosystem. Residents living near the mining sites have reported higher incidences of health issues, including congenital deformities, cancer, and respiratory problems. The soil contamination has also adversely affected agriculture, leading to reduced crop yields and poor soil health.
Mitigation Efforts
UCIL has initiated several measures to mitigate the environmental impact, such as improving waste management practices and conducting regular monitoring of soil and water quality. However, the effectiveness of these measures remains a subject of debate among environmentalists and local communities.
Case Study 2: Iron Ore Mining in Bellary, Karnataka
Bellary, in Karnataka, is one of India’s largest iron ore mining regions. The rapid expansion of mining activities, particularly during the mining boom in the early 2000s, led to extensive deforestation, reducing the land’s agricultural productivity, soil erosion, and pollution. Affecting the agricultural productivity resulted to livelihood crisis for many residents as agriculture was a primary source of income. Moreover, the deposition of mining waste and overburden has further exacerbated the problem, causing soil compaction and loss of fertility. Contaminants from mining waste, including heavy metals, have leached into the soil, making it unsuitable for farming. The dust generated from mining operations has also settled on agricultural fields, impacting crop growth and quality.
Legal and Regulatory Actions
The environmental degradation in Bellary prompted legal interventions. In 2011, the Supreme Court of India imposed a ban on mining in the region to curb illegal mining practices and protect the environment. Subsequently, measures were taken to rehabilitate mined areas and regulate mining activities more strictly (Kumar, 2017).
Case Study 3: Bauxite Mining in Niyamgiri Hills, Odisha
Niyamgiri Hills in Odisha are rich in bauxite deposits. The proposed bauxite mining by Vedanta Resources has been a subject of intense conflict due to its environmental impact and the displacement of indigenous communities, primarily the Dongria Kondh tribe. Large tracts of forest land were cleared, leading to soil erosion and degradation and increased the risk of landslides. Moreover, the mining activities threaten the local water sources by causing siltation and contamination with heavy metals and chemicals used in ore processing (Padel & Das, 2010). The Dongria Kondh tribe relies heavily on the Niyamgiri Hills for their livelihood, practicing traditional agriculture and gathering forest products. The proposed mining posed a direct threat to their way of life and the biodiversity of the region. The hills are home to several endangered species of flora and fauna, which are at risk due to habitat destruction.
Community Resistance and Legal Battles
The strong resistance from the Dongria Kondh tribe, supported by various environmental and human rights organizations, led to a landmark decision by the Indian Supreme Court in 2013. The court upheld the rights of the indigenous communities, allowing them to decide the fate of the mining project. In subsequent village councils, the communities unanimously rejected the mining proposal, highlighting the importance of protecting their cultural and environmental heritage (Padel & Das, 2010).
Case Study 4: Coal Mining in Jharia, Jharkhand
Jharia, in the Dhanbad district of Jharkhand, is one of India’s largest coal mining regions. The area is known for its extensive coal mines, which have been operational for over a century. However, the region is also infamous for its underground coal fires, which have been burning for decades, causing severe soil and air pollution. The burning coal releases toxic gases and heavy metals, which settle on the soil, contaminating it. The heat from the fires also alters the soil structure, making it unsuitable for vegetation. Additionally, the air pollution from the fires poses serious health risks to the local population, including respiratory diseases and skin disorders (Mishra, 2009). The pollution and land subsidence caused by coal fires have displaced thousands of families in Jharia. The contaminated soil and air have made the area uninhabitable, forcing residents to relocate. The loss of agricultural land has also impacted the livelihoods of many who depended on farming.
Mitigation and Rehabilitation Efforts
Efforts to extinguish the coal fires and rehabilitate the affected areas have been ongoing but with limited success. The Bharat Coking Coal Limited (BCCL) has undertaken several projects to control the fires and resettle displaced families. However, the scale of the problem and the complexity of underground fires make it a challenging task (Mishra, 2009).
Solutions and Hope
Soil pollution due to mining activities is a pressing environmental issue that poses significant risks to living organisms. The case studies from India illustrate the severe environmental and social impacts of mining activities. Soil pollution due to heavy metals, acid mine drainage, and chemical pollutants has led to the degradation of ecosystems, affecting plants, animals, and human populations. Effective mitigation and rehabilitation measures are crucial to address these issues and protect the environment and public health. Phytoremediation involving plants, soil washing using water or chemical solutions, bioremediation utilizing microorganisms, proper containment, treatment and better waste management, minimal waste disposal, are essential to address this issue and restore contaminated soils. Continuous monitoring, strict regulatory frameworks by the Government, and active community participation are essential to ensure sustainable mining practices and minimize environmental damage. Continued research and policy measures are crucial to minimize the environmental impact of mining and protect ecosystem health.
References
- Alloway, B. J. (2013). Heavy Metals in Soils: Trace Metals and Metalloids in Soils and their Bioavailability. Springer Science & Business Media.
- Chen, Y., Luo, Y., Teng, Y., & Wang, J. (2014). Soil enzyme activities as affected by heavy metal pollution. Journal of Soil Science and Plant Nutrition, 14(4), 843-853.
- Kumar, A. (2017). Impact of Mining on Environment in Bellary. International Journal of Applied Environmental Sciences, 12(6), 1083-1091.
- Kumar, R., Prasad, S., Yadav, M., & Sahu, B. L. (2013). Assessment of the Radiological Impact of the Uranium Mining and Ore Processing at Jaduguda, India. Radiation Protection Dosimetry, 157(1), 43-50.
- Mishra, S. (2009). Environmental Impact of Coal Mining: A Case Study of Jharia Coal-Field. Journal of Environmental Research and Development, 4(2), 218-229.
- Nagajyoti, P. C., Lee, K. D., & Sreekanth, T. V. M. (2010). Heavy metals, occurrence and toxicity for plants: a review. Environmental Chemistry Letters, 8(3), 199-216.
- Padel, F., & Das, S. (2010). Out of This Earth: East India Adivasis and the Aluminium Cartel. Orient Blackswan.
- Scheuhammer, A. M., Meyer, M. W., Sandheinrich, M. B., & Murray, M. W. (2007). Effects of environmental methylmercury on the health of wild birds, mammals, and fish. Ambio: A Journal of the Human Environment, 36(1), 12-19.