Environmental impact of urbanization, mining, waste disposal, fertilizers, mine waste and fly-ash | Geology Optional Notes for UPSC PDF Download

Environmental Impacts of Urbanization

• Definition of Urbanization

  Urbanization refers to the process of converting sparsely populated land into densely populated cities. This transformation occurs due to factors like population growth and migration into urban areas.

• Effects of Urbanization on Biodiversity

  • Urbanization leads to habitat loss and deforestation, reducing species populations, biodiversity, and altering interactions among organisms.
  • Some species evolve in response to urban environments. For instance, certain bird populations have adapted their beak shapes to efficiently consume seeds from human-made bird feeders.

• Impact on Disease Transmission

  Urbanization facilitates the rapid spread of diseases within and among densely populated areas, aided by the ease and volume of transportation.

• Transport of Invasive Species

  Urbanization contributes to the unintentional or deliberate transport of invasive species as people move and trade goods. Invasive species often thrive in disturbed urban environments, outcompeting native species.

• Creation of Urban Heat Islands

  Cities experience higher temperatures than surrounding areas due to urban heat islands caused by the absorption of sunlight by dark materials like asphalt in urban areas.

• Impact on Water Resources

  • Paving land with concrete increases water runoff, leading to erosion and reduced soil quality.
  • Decreased plant productivity and biomass disrupt the water cycle by reducing transpiration, while increased plant growth enhances water cycling.

Mining Environmental Impacts

• Significance of Mining

  Mining activities have substantial environmental repercussions.

• Construction Requirements

  Mining site establishment necessitates extensive construction, often leading to deforestation and the loss of wildlife habitats and biodiversity.

• Surface Mining Effects

  Surface mines, employing explosives and heavy machinery, create massive holes, causing soil erosion and degradation.

  • Mountaintop Removal Mining

    This method involves blasting off the entire top of a mountain, leading to severe environmental impact.

• Waste Generation

  Surface mining produces substantial waste materials, releasing harmful substances into the air and water.

• Acid Mine Drainage

  After abandonment, mines can result in acid mine drainage, contaminating water systems with heavy metals and harming ecosystems.

• Carbon Emissions

  The mining industry contributes significantly to carbon emissions through transportation, energy use, and fossil fuel production.

Industrial Waste Overview

• The disposal of liquid industrial waste into water bodies has reached alarming levels, posing a severe threat to marine ecosystems.
• Industries release harmful gases like carbon dioxide, sulphur dioxide, and nitrogen oxides, leading to air pollution.
• Nitrates and phosphates found in industrial effluents often cause eutrophication, adversely affecting water quality.
• Pollution from industries can result in various health issues such as skin problems, eye irritations, respiratory illnesses, and more.
• Industrial activities consume significant water resources and discharge wastewater containing toxic substances and heavy metals.

Environmental Impact

• Industrial waste is a major contributor to global warming, polluting natural water sources and harming ecosystems.
• It disrupts the balance of beneficial soil microorganisms, impacting soil health and fertility.
• Noise pollution from certain industries further adds to environmental degradation.
• Habitats of numerous animal species are being destroyed, leading to the extinction of various creatures.

Landfill Concerns

• Landfills, used for waste disposal, can emit foul odors and methane gas during decomposition.
• Leachate from decomposing waste has the potential to contaminate the surrounding environment.
• Improperly managed landfills may attract pests and create litter issues.

Incineration Effects

• Incinerating garbage, especially plastics, can release harmful compounds like dioxins, contributing to pollution.
• Incineration releases gases that can pollute the air and contribute to acid rain formation.
• Ash produced from incineration may contain heavy metals and other contaminants, posing further environmental risks.

RADIOACTIVE WASTE DISPOSAL

• Current Storage Methods:
  • Presently, there exists no permanent solution for storing radioactive waste. The predominant approach involves storing it temporarily with intentions to address its disposal later.
  • Historically, one common method involved using seas and oceans due to their vast capacity to dilute radiation. For instance, the British Nuclear Fuels facility at Sellafield habitually disposed of nuclear waste in the Irish Sea starting in the 1950s.
  • Similar practices were observed globally, like the dumping of radioactive materials from Soviet submarines and weapons in the Arctic Ocean, and the placement of numerous nuclear waste containers along the San Francisco coast.
• Issues with Current Approach:
  • Storing radioactive waste in oceans and seas poses significant risks as the radioactive elements spread throughout the marine ecosystem, leading to widespread contamination.

The Unpredictability of Nuclear Waste Disposal

• No certainty in the longevity of deep geological repositories
• Challenges in designing sites resistant to geological shifts and erosion
• Uncertainty in ensuring protection from future human interference
• Lack of complete safety guarantees for nearby communities

Environmental Contamination by Nuclear Waste

• Radioactive contamination risks when not sealed properly
• Potential spread of contamination to air, land, and water
• Long-term unnoticed release of radioactivity into ecosystems
• Increased contamination levels affecting food sources

When nuclear waste is stored in deep geological repositories, there is no definite assurance of their long-term stability. Engineers face the challenge of designing disposal sites capable of withstanding geological movements and erosion over extended periods. Moreover, the unpredictability of future human behavior raises concerns about the potential interference by descendants, jeopardizing the integrity of these sites.

Additionally, the environmental consequences of inadequate waste containment are severe. If radioactive materials leak into the surroundings, they can contaminate the air, soil, and water, posing risks to various life forms. Such contamination may go undetected for prolonged periods, exacerbated by differing environmental priorities among nations. Ultimately, the uncontrolled release of radioactivity can lead to higher contamination levels, impacting food chains and potentially harming human health.

Fertilizers

• Impact on Soil Quality

  Using excessive fertilizers can harm soil fertility by increasing acidity levels. It's advisable to conduct soil tests every three years to ensure correct fertilizer usage.

• Biology of Water Bodies

  • Overuse of fertilizers leads to eutrophication, releasing nitrates and phosphates into water bodies through runoff. This causes algae overgrowth, depleting oxygen levels and harming aquatic life.
  • This disrupts the food chain as fish, a primary food source for birds and animals, are affected by the toxic environment.

• Impact on Human Health

  • Fertilizer components like nitrogen can contaminate water sources, leading to health issues like blue baby syndrome, characterized by oxygen-deprived skin in infants.
  • Usage of lawn chemicals can also pose health risks, including cancer and chronic diseases, particularly in children.

• Climate Change Effects

  • Fertilizers contain gases like methane and nitrous oxide, contributing to greenhouse gas emissions and climate change.
  • Nitrous oxide, a byproduct of nitrogen, is a significant greenhouse gas after carbon dioxide and methane, exacerbating global warming.

Environmental Effects of Mine Waste

Mining Waste Management Issues

• Mining operations, whether open-pit or underground, often result in the creation of significant amounts of waste rock piles and tailings deposits.
• A prevalent challenge in the mining sector involves the management of waste material, primarily due to its large volume and chemical composition.

Impact on the Environment

• Mine tailings and waste are commonly disposed of on land or in areas that have been previously mined, although disposal in oceans, lakes, and rivers is also observed, albeit to a limited extent.
• The environmental effects of mining waste are influenced by various factors:
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  • Chemical and mineralogical composition of the waste
  • Physical properties of the waste
  • Volume of waste and the area it covers
  • Method of waste disposal
  • Climatic conditions that can alter disposal circumstances
  • Geographic and geological location
  • Potential impacts on existing targets, including humans and their surroundings

Environmental Risk Assessment

• Identifying the environmental risks associated with mining operations and ore processing involves:
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  • Characterizing and quantifying different types of waste
  • Understanding the processes involved in mining and processing
  • Evaluating the vulnerability of specific environments based on geological and hydrogeological conditions, as well as surrounding areas of interest

Pollutant Transfer Mechanisms

• Meteoric precipitation can play a role in transferring pollutants from tailings dams or processing plants to rivers in cases where waste management is ineffective.
• In the absence of an impermeable layer beneath a waste deposit, pollutants can be carried to rivers via groundwater as meteoric precipitation infiltrates the deposit.

Fly Ash Overview

• Fly Ash Environmental Impact

  • Fly ash, a byproduct of coal combustion, contains elements like arsenic, barium, boron, selenium, and mercury which can contaminate groundwater.
  • The impact on the environment varies based on the chemical composition of coal and discharge from thermal power plants.
  • Plants and animals in the vicinity can be affected by fly ash deposited on the topsoil.

• Fly Ash Exposure Concerns

  • Contains trace amounts of harmful heavy metals and chemicals such as arsenic, cadmium, lead, mercury, and uranium.
  • Exposure risks include hazardous compounds, crystalline silica, and lime.
  • Crystalline silica in fly ash can lead to lung conditions like silicosis and is classified as a human carcinogen.
  • The alkaline nature of fly ash, with a pH of 10-12, can potentially harm lungs if present in large amounts.
  • Fly ash possesses significant radiation levels compared to nuclear waste for the electricity produced.