5. New Environment Notes 11

Elaborate Notes

WATER POLLUTION

Water pollution is defined under The Water (Prevention and Control of Pollution) Act, 1974 of India as “such contamination of water or such alteration of the physical, chemical or biological properties of water or such discharge of any sewage or trade effluent or of any other liquid, gaseous or solid substance into water (whether directly or indirectly) as may, or is likely to, create a nuisance or render such water harmful or injurious to public health or safety, or to domestic, commercial, industrial, agricultural or other legitimate uses, or to the life and health of animals or plants or of aquatic organisms.” The agents causing such alterations are termed pollutants.

• Sources of Water Pollution

  The sources of pollution are broadly categorized based on their identifiability and spatial distribution.

  • Point Sources: These are discrete, identifiable conveyances from which pollutants are discharged. Because the origin is a single point, they are relatively easier to monitor, regulate, and control.

    • Historical Context: Early environmental legislation, such as the initial versions of the Clean Water Act (1972) in the United States, primarily focused on these sources because they were the most visible and technically manageable forms of pollution during the industrial era.
    • Examples:
      • Industrial Effluents: A pipe discharging chemical waste from a factory directly into a river. For instance, the discharge of untreated effluents from tanneries in Kanpur into the Ganga River has been a long-standing issue.
      • Municipal Sewage Outlets: A city’s sewage treatment plant (STP) outlet releasing treated or untreated wastewater.
      • Oil Spills: Accidental discharges from tankers, such as the Exxon Valdez oil spill in 1989, or offshore drilling rigs, like the Deepwater Horizon spill in 2010, are catastrophic point-source events.

  • Non-Point Sources: These sources are diffuse, originating from a wide land area, and their pollutants are typically carried into water bodies by rainfall or snowmelt. Their diffuse nature makes them exceedingly difficult to regulate and control.

    • Historical Context: The significance of non-point source pollution was recognized more prominently in the latter half of the 20th century as point sources began to be controlled. Agricultural modernization, characterized by the Green Revolution’s intensive use of fertilizers and pesticides, exacerbated this problem.
    • Examples:
      • Agricultural Runoff: Rainwater washing fertilizers (nitrates, phosphates) and pesticides (e.g., DDT, endosulfan) from farms into nearby streams and lakes. This is a major cause of eutrophication in water bodies across Punjab and Haryana.
      • Urban Runoff: Stormwater from cities carrying oil, grease, heavy metals from vehicles, and other contaminants from roads and parking lots into water systems.
      • Atmospheric Deposition: Pollutants from the air, like sulfur dioxide and nitrogen oxides, forming acid rain which then falls over large areas, acidifying lakes and rivers. This was a major issue identified in Scandinavia in the 1960s and 1970s, caused by industrial emissions from the UK and Central Europe.

• Impacts of Specific Pollutants

  Certain pollutants have well-documented and severe health impacts, leading to specific diseases often named after the locations of their first major outbreaks.

  • Mercury (Hg): Causes Minamata disease, a neurological syndrome. The most infamous outbreak occurred in Minamata Bay, Japan, between 1932 and 1968, where the Chisso Corporation discharged methylmercury in its industrial wastewater. The mercury bioaccumulated in shellfish and fish, which were then consumed by the local population, leading to severe neurological damage, birth defects, and death. This event was instrumental in the creation of the global Minamata Convention on Mercury (2013).
  • Lead (Pb): Causes Dyslexia (learning disorders) and damages the nervous system, kidneys, and reproductive system. Historically, lead was widely used in paints, gasoline, and plumbing, leading to widespread environmental contamination. The work of scholar-activists like Clair Patterson in the mid-20th century was crucial in exposing the dangers of lead pollution and campaigning for its removal from consumer products.
  • Cadmium (Cd): Causes Itai-Itai disease (“it hurts-it hurts” disease), characterized by severe bone pain and kidney failure. This was first documented in Toyama Prefecture, Japan, in the 1950s, caused by cadmium released into rivers by mining companies. The cadmium contaminated rice paddies, entering the food chain.
  • Fluoride (F⁻): Excess intake leads to Fluorosis, which can be dental (discoloration of teeth) or skeletal (severe bone and joint deformities). In India, many states like Rajasthan, Gujarat, and Andhra Pradesh have high natural fluoride concentrations in groundwater, making it a significant public health issue.
  • Arsenic (As): Long-term exposure through drinking water causes Black-foot disease, a severe form of peripheral vascular disease, as well as skin lesions and cancer. Widespread arsenic contamination in groundwater is a major crisis in West Bengal and Bangladesh, linked to the geology of the Ganga-Brahmaputra river basin.
  • Nitrate (NO₃⁻): High concentrations in drinking water can cause Methemoglobinemia, or Blue-baby syndrome, in infants. Nitrates are converted to nitrites in the infant’s gut, which then interfere with the oxygen-carrying capacity of blood (hemoglobin), leading to oxygen deprivation and a bluish skin color. This is primarily linked to fertilizer runoff contaminating groundwater.

• Impacts of Water Pollution

  • Decreased Dissolved Oxygen (DO):

    • DO is the concentration of free, non-compound oxygen present in water, crucial for the survival of most aquatic organisms. It is typically measured in milligrams per liter (mg/L).
    • The Central Pollution Control Board (CPCB) of India has designated water quality criteria based on DO levels. For instance, water fit for drinking after disinfection should have a DO of 6 mg/L or more, while water suitable for propagation of wildlife and fisheries requires at least 4 mg/L.
    • The introduction of biodegradable organic pollutants (e.g., sewage, food processing waste) leads to a spike in the population of aerobic decomposer bacteria. These bacteria consume DO to break down the organic matter. This consumption is quantified by Biochemical Oxygen Demand (BOD).
    • BOD is the amount of DO needed by aerobic biological organisms to break down organic material present in a given water sample at a certain temperature over a specific time period. A high BOD indicates a high level of organic pollution.
    • Chemical Oxygen Demand (COD) is a broader measure. It is the amount of oxygen required to oxidize both organic (biodegradable and non-biodegradable) and inorganic chemicals in water via a strong oxidizing agent (like potassium dichromate).
    • Crucially, COD is always greater than BOD because it accounts for all oxidizable matter, not just the portion that bacteria can decompose. The ratio of BOD/COD can indicate the biodegradability of the wastewater.

  • Eutrophication:

    • This is the process of nutrient enrichment (primarily nitrogen and phosphorus) in an aquatic ecosystem. Natural eutrophication is a slow, geological process over thousands of years as a lake ages and fills with sediment and organic matter.
    • Cultural or Accelerated Eutrophication is a rapid process caused by human activities. The term was popularized by limnologists like Arthur D. Hasler in the mid-20th century.
    • Sources: Discharge of untreated municipal sewage (rich in phosphates from detergents and human waste), runoff from fertilized agricultural lands, and industrial effluents.
    • Impacts: The excess nutrients trigger explosive growth of phytoplankton and algae, a phenomenon known as an algal bloom. This bloom covers the water surface, blocking sunlight from reaching submerged plants and leading to their death. When the massive algae population dies, it sinks and is decomposed by aerobic bacteria, which consume vast amounts of DO, leading to hypoxic (low oxygen) or anoxic (no oxygen) conditions. This results in large-scale fish kills and the creation of “dead zones”, such as the one in the Gulf of Mexico caused by nutrient runoff from the Mississippi River basin.
    • Harmful Algal Blooms (HABs): Some species of algae, like cyanobacteria, produce potent neurotoxins and hepatotoxins that can be fatal to fish, birds, and mammals, including humans. Clostridium botulinum, an anaerobic bacterium, can thrive in anoxic conditions created by eutrophication, causing botulism in waterfowl.

  • Bioaccumulation and Biomagnification:

    • Bioaccumulation refers to the buildup of a substance (like a pesticide or heavy metal) in a single organism over its lifetime, as it absorbs the substance faster than it can excrete it.
    • Biomagnification (or bioamplification) is the increase in concentration of that substance in organisms at successively higher levels in a food chain.
    • Rachel Carson’s seminal book “Silent Spring” (1962) was instrumental in bringing this concept to public attention. She documented how the pesticide DDT, used to control insects, was accumulating in the environment. It was found in low concentrations in water, became more concentrated in plankton, even more in small fish, and reached toxic levels in predatory birds like eagles and ospreys. The high DDT levels interfered with calcium metabolism, causing them to lay eggs with shells so thin they broke during incubation, leading to a drastic decline in their populations.
    • Properties of biomagnifying substances: They must be persistent (long-lived), biologically active, mobile, and fat-soluble (so they are stored in fatty tissues rather than being excreted). This group includes Persistent Organic Pollutants (POPs) like DDT and PCBs, and heavy metals like mercury and lead. The Stockholm Convention on Persistent Organic Pollutants (2001) is a global treaty to eliminate or restrict the production and use of POPs.

AIR POLLUTION

Air pollution refers to the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. The Air (Prevention and Control of Pollution) Act, 1981 of India defines it as the presence in the atmosphere of any air pollutant.

• Primary and Secondary Pollutants

  • Primary Pollutants: These are emitted directly into the atmosphere from a source. Their impact is often direct.

    • Examples: Sulfur dioxide (SO₂) from burning coal, carbon monoxide (CO) from vehicle exhausts, and particulate matter (PM) from construction sites.

  • Secondary Pollutants: These are not directly emitted but are formed in the atmosphere when primary pollutants react with each other or with other atmospheric components (like water vapor and sunlight).

    • Examples:
      • Ozone (O₃): Tropospheric or ground-level ozone is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight. It is a major component of photochemical smog.
      • Acid Rain: Formed when sulfur dioxide (SO₂) and nitrogen oxides (NOx) react with water, oxygen, and other chemicals to form sulfuric and nitric acids. The term ‘acid rain’ was coined by Scottish chemist Robert Angus Smith in 1872.
      • Smog: A portmanteau of “smoke” and “fog”. London or classical smog is a mix of smoke, fog, and SO₂, while Los Angeles or photochemical smog is formed by the reaction of NOx and VOCs under sunlight.

• Major Air Pollutants, Sources, and Impacts

Pollutant	Sources	Harmful Impacts
Carbon Monoxide (CO)	Incomplete combustion of carbon-based fuels (petrol, diesel, wood). Major source is vehicle exhaust.	A highly toxic gas that binds to hemoglobin in blood with an affinity 200-250 times greater than oxygen, forming carboxyhemoglobin. This reduces the oxygen-carrying capacity of blood, leading to hypoxia, headaches, dizziness, and death at high concentrations.
Carbon Dioxide (CO₂)	Burning of fossil fuels (coal, oil, natural gas), deforestation, cement production.	The primary greenhouse gas responsible for anthropogenic global warming and climate change. It also dissolves in oceans, forming carbonic acid, which leads to ocean acidification, threatening marine life like corals and shellfish.
Oxides of Sulfur (SOx)	Primarily from burning sulfur-containing fossil fuels, especially coal in thermal power plants and industrial boilers. Smelting of metals and volcanic eruptions are natural sources.	SO₂ is a major precursor to acid rain, which damages forests, soils, and buildings (e.g., the Taj Mahal). It is a respiratory irritant, aggravating conditions like asthma and bronchitis. In plants, it causes chlorosis (yellowing of leaves due to loss of chlorophyll).
Oxides of Nitrogen (NOx)	High-temperature combustion processes, such as in automobile engines and power plants. Agricultural fertilizers and denitrification are also significant sources.	NO₂ is a reddish-brown irritant gas. NOx contributes to the formation of acid rain, photochemical smog, and eutrophication of water bodies. It causes respiratory problems and can reduce plant growth and productivity.
Hydrocarbons (VOCs)	Unburnt fuel from vehicles, evaporation of solvents, paints, and industrial processes. Methane is a major hydrocarbon. Benzene and ethylene are toxic VOCs.	Many hydrocarbons are precursors to photochemical smog. Some, like benzene, are known carcinogens. Ethylene can cause premature aging and fruit dropping in plants.
Particulate Matter (PM)	A complex mixture of solid particles and liquid droplets. Sources include construction, road dust, stubble burning, industrial and vehicle exhaust, and power plants. PM is classified by size: PM₁₀ and PM₂.₅ (particles with diameters less than 10 and 2.5 micrometers, respectively).	The smaller the particle, the deeper it can penetrate into the lungs. PM₂.₅ is particularly dangerous as it can enter the bloodstream. It causes respiratory diseases (asthma, bronchitis), cardiovascular problems, and cancer. It also reduces visibility, contributing to haze and smog.
Black & Brown Carbon	Black Carbon (BC): A component of PM₂.₅ formed from the incomplete combustion of fossil fuels, biofuels, and biomass (e.g., diesel engines, coal plants). Brown Carbon (BrC): Formed from the combustion of biomass and organic matter (e.g., forest fires, stubble burning).	Both are potent short-lived climate pollutants. They absorb solar radiation, warming the atmosphere. When deposited on snow and ice, they reduce the surface’s albedo (reflectivity), accelerating melting of glaciers and sea ice.

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Prelims Pointers

• Pollution: Any undesirable change in physical, chemical, or biological characteristics of air, land, water, or soil.
• Pollutant: The agent causing pollution.

Water Pollution

• Point Source: Single, identifiable source of pollution (e.g., industrial discharge pipe, sewage outlet).
• Non-Point Source: Diffuse source of pollution, spread over a large area (e.g., agricultural runoff, urban stormwater).
• Disease-Pollutant Match:
  • Mercury → Minamata Disease
  • Cadmium → Itai-Itai Disease
  • Lead → Dyslexia, Nervous system damage
  • Nitrate → Blue-baby Syndrome (Methemoglobinemia)
  • Arsenic → Black-foot Disease, Skin cancer
  • Fluoride → Fluorosis (Skeletal and Dental)
• Dissolved Oxygen (DO): Amount of oxygen dissolved in water. Measured in mg/L.
• Biochemical Oxygen Demand (BOD): Oxygen required by aerobic bacteria to decompose biodegradable organic matter.
• Chemical Oxygen Demand (COD): Oxygen required to decompose both biodegradable and non-biodegradable organic matter through chemical oxidation.
• Key Relationship: For a given polluted water sample, COD value is always greater than BOD value.
• Eutrophication: Nutrient enrichment of water bodies, leading to algal blooms and oxygen depletion.
• Cultural Eutrophication: Accelerated eutrophication due to human activities.
• Bioaccumulation: Gradual accumulation of a substance in a single organism.
• Biomagnification: Increase in the concentration of a substance at successive trophic levels of a food chain.
• Compounds that Biomagnify: Persistent Organic Pollutants (POPs) like DDT, heavy metals (Mercury, Lead). These are typically fat-soluble and not easily biodegradable.

Air Pollution

• Primary Pollutants: Emitted directly from a source (e.g., CO, SO₂, NOx, PM).
• Secondary Pollutants: Formed in the atmosphere from chemical reactions of primary pollutants (e.g., Ozone (O₃), Sulfuric Acid, Nitric Acid, Smog).
• Carbon Monoxide (CO): Product of incomplete combustion; reduces oxygen-carrying capacity of blood.
• Sulfur Dioxide (SO₂): From burning sulfur-containing fuels (coal); causes acid rain and respiratory issues.
• Nitrogen Oxides (NOx): From high-temperature combustion; cause acid rain and photochemical smog.
• Particulate Matter (PM): PM₂.₅ and PM₁₀ are major pollutants; PM₂.₅ is more harmful as it can enter the bloodstream.
• Black Carbon: A type of PM₂.₅, a short-lived climate pollutant that absorbs heat and reduces albedo of ice.
• Brown Carbon: A type of organic aerosol from biomass burning; also absorbs heat.
• Chlorosis in Plants: Yellowing of leaves caused by pollutants like SO₂.

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Mains Insights

GS Paper I (Geography and Indian Society)

1. Urbanization-Pollution Nexus: Rapid and unplanned urbanization in India has overwhelmed the capacity of municipal bodies to provide adequate water and sanitation infrastructure. This leads to the direct discharge of untreated sewage into rivers (a point source) and increased contaminated urban runoff (a non-point source), as seen in the Yamuna River in Delhi.
2. Socio-Economic Impacts: Water pollution disproportionately affects marginalized communities who depend directly on natural water sources for drinking, agriculture, and livelihood (e.g., fishing communities). Diseases like fluorosis and arsenicosis create a massive public health burden, reducing productivity and trapping families in a cycle of poverty and poor health.
3. Regional Disparities: The nature of pollution varies geographically. The Indo-Gangetic plain suffers from agricultural runoff (pesticides, nitrates) and industrial pollution, while peninsular India faces issues of groundwater contamination with naturally occurring minerals like fluoride and arsenic in certain regions.

GS Paper II (Governance and Policy)

1. Regulatory Challenges: While India has robust legal frameworks like The Water Act (1974) and Air Act (1981), their implementation is weak. State Pollution Control Boards (SPCBs) are often underfunded, understaffed, and lack the technical capacity for effective monitoring and enforcement.
2. The Challenge of Non-Point Sources: The current regulatory paradigm is geared towards controlling point sources. Managing non-point pollution like agricultural runoff requires a paradigm shift towards promoting sustainable agricultural practices (e.g., organic farming, efficient irrigation), better land-use planning, and community participation, which are far more complex to legislate and enforce.
3. Role of Judiciary and Tribunals: The Supreme Court and the National Green Tribunal (NGT) have played a proactive role in environmental governance through public interest litigation (PILs), landmark judgments (e.g., M.C. Mehta cases), and the application of principles like ‘Polluter Pays’ and the ‘Precautionary Principle’. However, their orders often face implementation hurdles from the executive.

GS Paper III (Economy and Environment)

1. Development vs. Environment Debate: The need for industrial growth and energy security often conflicts with environmental protection. The debate centers on striking a balance—adopting cleaner technologies, enforcing environmental standards (e.g., Bharat Stage emission norms for vehicles), and internalizing environmental costs into economic calculations.
2. Economic Costs of Pollution: Air and water pollution have significant economic consequences, including increased healthcare expenditure, loss of productivity due to illness, damage to agriculture (e.g., crop yield loss due to acid rain and smog), and loss of tourism revenue (e.g., the yellowing of the Taj Mahal). A circular economy model, which emphasizes reuse and recycling, can be a sustainable solution to minimize industrial waste and pollution.
3. Transboundary Pollution: Pollutants do not respect political boundaries. Acid rain from one country can affect another. River pollution upstream affects downstream states or countries. This necessitates bilateral and multilateral cooperation and treaties for effective management, for instance, in the management of shared river basins like the Ganga-Brahmaputra.

GS Paper IV (Ethics, Integrity, and Aptitude)

1. Environmental Ethics: The issue of pollution raises fundamental ethical questions about humanity’s relationship with nature. It involves the concept of inter-generational equity—the moral obligation to leave a healthy and safe environment for future generations.
2. Corporate Environmental Responsibility: Industries have an ethical duty to go beyond mere legal compliance and adopt sustainable practices that minimize their environmental footprint. The ‘Polluter Pays’ principle is not just a legal doctrine but an ethical one, asserting that those who cause environmental damage must bear the costs of remediation.
3. Ethical Governance: The lack of enforcement of environmental laws often points to a nexus of corruption between polluters and regulators. Upholding integrity, transparency, and accountability in environmental governance is crucial for protecting the ‘right to a clean environment’, which the Supreme Court has interpreted as a fundamental right under Article 21.