Consider the following statements regarding mercury pollution: 1. Gold mining activity is a source of mercury pollution in the world. 2. Coal-based thermal power plants cause mercury pollution. 3. There is no known safe level of exposure to mercury. How many of the above statements are correct?
Contents9
- AOnly one
- BOnly two
- CAll three
- DNone
Show answer
Answer: (C) All three
All three are correct:
Artisanal gold mining is a major source of mercury pollution, contributing over 35% of global human-caused mercury emissions.
Coal-fired power plants emit mercury during combustion — coal has higher mercury content than other fossil fuels.
There is NO safe level of mercury exposure for humans — it is highly toxic and provides no benefit to the body.
Answer is (c) All three.
Mercury is one of the most toxic heavy metals with no safe exposure level, affecting the nervous system permanently even in tiny amounts.
The Minamata Convention on Mercury came into force in 2017, making mercury pollution control a key international environmental priority that UPSC frequently tests.
The question tests knowledge of major mercury sources - artisanal gold mining contributes over 35% of global mercury emissions, while coal power plants are the second largest source.
Sources of Mercury Pollution
Environment mercury pollution gold mining coal-based thermal power plants
Major Sources of Mercury Pollution Worldwide
Artisanal gold mining contributes over 35% of global mercury emissions
Coal-fired power plants emit mercury during combustion
Mercury is released when coal burns due to its natural mercury content
Other sources include cement production and waste incineration
Mercury pollution comes from both natural and human sources, with anthropogenic activities now dominating global emissions. Understanding the major industrial sources helps explain why mercury contamination has become a worldwide environmental concern.
Major Mercury Emission Sources
Source | Contribution | Process | Why Mercury is Released |
|---|---|---|---|
Artisanal Gold Mining | >35% of global emissions | Mercury used to extract gold from ore | Direct use & poor handling practices |
Coal Power Plants | ~24% of global emissions | Coal combustion for electricity | Coal naturally contains mercury |
Cement Production | ~11% of global emissions | Limestone heating process | Mercury in raw materials |
Waste Incineration | ~5% of global emissions | Burning municipal waste | Mercury in discarded products |
Gold Mining Process
In artisanal gold mining, mercury is mixed with gold ore to form an amalgam. When heated, mercury vaporizes leaving behind gold — but the mercury vapor escapes into the atmosphere. This primitive extraction method is used by millions of small-scale miners worldwide.
Trap: Students may think only industrial sources cause mercury pollution — but artisanal mining is the largest single source
Trap: Coal plants emit mercury even with pollution controls — mercury is naturally present in coal
Trap: Gold mining uses mercury intentionally as an extraction tool, unlike other sources where it's an unwanted byproduct
Mercury Toxicity & Health Effects
Environment mercury safe level of exposure
Mercury Toxicity: No Safe Exposure Level
No safe level of mercury exposure exists for humans
Mercury causes neurological damage, especially in children
Methylmercury in fish is the most dangerous form
Mercury bioaccumulates up the food chain
Unlike some substances where small amounts are harmless, mercury provides no biological benefit and is toxic at any level. The WHO and other health agencies have concluded there is no threshold below which mercury exposure is safe, making it a unique environmental pollutant.
Why Mercury is Extremely Dangerous
Crosses blood-brain barrier: Mercury directly damages brain tissue and nervous system
Bioaccumulates: Concentrates in body tissues over time, not easily eliminated
Biomagnifies: Becomes more concentrated as it moves up food chains
Affects development: Particularly harmful to fetal brain development and children
Multiple exposure routes: Inhalation, ingestion, and skin contact all dangerous
Mercury Forms & Toxicity
Mercury Form | Source | Exposure Route | Primary Health Impact |
|---|---|---|---|
Elemental Mercury | Mining, industrial processes | Inhalation of vapor | Lung damage, neurological effects |
Methylmercury | Fish consumption | Ingestion | Brain damage, developmental disorders |
Inorganic Mercury | Contaminated water, soil | Ingestion, skin contact | Kidney damage, digestive issues |
Trap: Unlike other pollutants, mercury has zero safe threshold — not even trace amounts
Trap: Methylmercury (in fish) is often more dangerous than elemental mercury from mining
Trap: Mercury toxicity is cumulative — small exposures over time are still harmful
Minamata Convention on Mercury
Environment
Global Mercury Control: Minamata Convention
Minamata Convention (2017) is global treaty to control mercury pollution
India ratified the convention in 2018
Aims to phase out mercury in industrial processes
Named after Minamata disease in Japan from mercury poisoning
The Minamata Convention is the most important international agreement on mercury pollution. Named after the Japanese city where severe mercury poisoning occurred in the 1950s, it represents global commitment to reduce mercury emissions and protect human health.
Key Provisions of Minamata Convention
Area | Requirement | Timeline | India's Status |
|---|---|---|---|
Mercury Mining | Ban new mines, phase out existing | By 2032 | Compliant - no major mines |
Coal Power Plants | Emission controls for new plants | Immediate | Implementing standards |
Artisanal Gold Mining | Reduce mercury use, formalize sector | Ongoing | National action plan required |
Mercury Products | Phase out batteries, thermometers | By 2020-2025 | Mostly compliant |
India's Mercury Control Measures
Hazardous Waste Rules: Mercury waste regulated under hazardous waste management
Coal plant standards: New emission norms for thermal power plants include mercury limits
Import restrictions: Controls on mercury imports for non-essential uses
Waste management: Guidelines for mercury-containing device disposal
Trap: Minamata Convention entered force in 2017, not when it was signed in 2013
Trap: India ratified the convention — meaning it's legally binding, not just signed
Trap: Convention focuses on anthropogenic mercury — natural emissions are not regulated