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Q27 (IAS/2021) Environment & Ecology › Pollution & Conservation › Hazardous chemical pollutants Official Key

Why is there a concern about copper smelting plants? 1. They may release lethal quantities of carbon monoxide into environment. 2. The copper slag can cause the leaching of some heavy metals into environment. 3. They may release sulphur dioxide as a pollutant. Select the correct answer using the code given below.

Result
Your answer: —  ·  Correct: B
Explanation

The correct answer is Option 2 (2 and 3 only). Copper smelting is a metallurgical process that involves chemical and environmental risks addressed in the statements below:

  • Statement 1 is incorrect: While smelting involves combustion, these plants are not primary sources of lethal quantities of carbon monoxide. Their primary gaseous emissions are related to the oxidation of sulfide ores.
  • Statement 2 is correct: Copper slag, a byproduct of the smelting process, contains traces of heavy metals like arsenic, cadmium, and lead. If not managed properly, these can leach into the soil and groundwater, causing significant environmental toxicity.
  • Statement 3 is correct: Most copper ores are sulfur-based (like Chalcopyrite). Roasting and smelting these ores releases massive amounts of sulphur dioxide (SO2), a major air pollutant that contributes to acid rain and respiratory issues.

Therefore, since statements 2 and 3 are scientifically validated environmental concerns associated with copper plants, Option 2 is the right choice.

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Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.
Q. Why is there a concern about copper smelting plants? 1. They may release lethal quantities of carbon monoxide into environment. 2. The …
At a glance
Origin: Mixed / unclear origin Fairness: Moderate fairness Books / CA: 6.7/10 · 0/10

Statement 3 (SO2) is a static textbook fact regarding sulphide ores. Statement 2 (Leaching) is standard environmental logic regarding mining waste. Statement 1 is the hurdle: do not look for a book line stating 'Copper plants release lethal CO'; instead, apply the 'Industrial Combustion' heuristic—any high-temperature furnace using carbon fuel *can* release CO.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Are copper smelting plants known to emit carbon monoxide (CO) at concentrations that can be lethal to humans?
Origin: Weak / unclear Fairness: Borderline / guessy
Indirect textbook clues
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Carbon monoxide (CO) > p. 64
Strength: 5/5
“• It is a colourless, odourless gas that is produced by the incomplete burning of carbon-based fuels including petrol, diesel, and wood. • It is also produced from the combustion of natural and synthetic products such as cigarettes. • It lowers the amount of oxygen that enters our blood. • It can slow our reflexes and make us confused and sleepy.”
Why relevant

Defines CO as a product of incomplete burning of carbon-based fuels (petrol, diesel, wood) and notes its toxic effect on human oxygen uptake.

How to extend

A student can infer that any industrial process using carbonaceous fuels (e.g., for smelting furnaces) could produce CO if combustion is incomplete, so one should check whether smelters use such fuels and monitor CO near furnaces.

Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3.4.4 Extracting Metals in the Middle of the Activity Series > p. 51
Strength: 4/5
“The metals in the middle of the activity series such as iron, zinc, lead, copper, are moderately reactive. These are usually present as sulphides or carbonates in nature. It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. Therefore, prior to reduction, the metal sulphides and carbonates must be converted into metal oxides. The sulphide ores are converted into oxides by heating strongly in the presence of excess air. This process is known as roasting. The carbonate ores are changed into oxides by heating strongly in limited air. This process is known as calcination.”
Why relevant

Describes roasting of sulphide ores by strong heating in air as a step in converting sulphides to oxides prior to metal extraction.

How to extend

A student could link high‑temperature ore processing (roasting/smelting) to potential combustion/chemical gas emissions and thus seek studies measuring CO and other gases from roasting/smelting operations.

Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 17: Contemporary Issues > 1. Air Pollution > p. 38
Strength: 3/5
“The presence in the Earth's atmosphere of man-caused or manmade contaminants which may adversely affect property, or the lives of plants, animals, or humans. Commonly air pollution include carbon dioxide, carbon monoxide, lead, nitrogen oxide, ozone, smoke, and sulphur dioxide. The tremendous increase of vehicles during the last three decades in the country has increased the air pollution, especially in the large cities. Consequently, the urban population is suffering more by cough, nausea, irritation of eyes, and various bronchial and visibility problems. Because of the emission of carbon-dioxide, carbon monoxide, nitrogen oxide, and suspended particles of lead and heavy metals, the urban environment is more polluted than the rural environment.”
Why relevant

Lists carbon monoxide among common man‑made air pollutants associated with combustion sources in urban/industrial contexts.

How to extend

Use this pattern to suspect industrial plants (including metal works) as potential CO sources and then check location‑specific emission inventories or ambient CO measurements near smelters.

Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 7: Resources > Table 7.7 > p. 16
Strength: 3/5
“Tajola: The Tajola Copper Plant is located in the Raigadh town in Maharashtra. The plant has imported copper cathodes. It manufactures copper rods. Chromite Chromite is an oxide of iron and chromium. It is widely used in metallurgical and chemical industries. The total reserve of chromite is estimated at 210 million tonnes (2016). Odisha, accounting for about 99% of the total production, is the largest producer of chromite. It is mined in Cuttack, Dhenkanal and Keonjhar districts. Karnataka is the second largest producer. In Karnataka, it is mined in Hassan district. Some chromite has been discovered in the Krishna district of Andhra Pradesh and the Tamenglong and Ukhrul districts of Manipur.”
Why relevant

Mentions an actual copper plant (Tajola Copper Plant), establishing that copper smelting/processing facilities exist as local industrial sources.

How to extend

Combine awareness of actual plants with the combustion/roasting clues above to target those specific plants for emission measurements or regulatory records on CO emissions.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > a) Sulphur > p. 102
Strength: 2/5
“Anthropogenic sourcesl • Forest fires • Combustion of oil, coal, and gas • (c) Formic acid • Biomass burning due to forest fires causes emission of formic acid (HCOOH) and formaldehyde (HCHO) into the atmosphere. • Large fraction of formaldehyde gets oxidation and forms formic acid in the These are three main compounds that cause acidification of rain in the atmosphere. (d) Other Acids: • Chlorine • Phosphoric acid • Hydrochloric acid (smokestacks). • Carbon monoxide and carbon dioxide (automobiles). These become carbonic acid. Re All Rights Reserved. No part of this material may be reproduced in any form or by any means, with out permission in \ riting.”
Why relevant

Refers to smokestacks and combustion sources emitting various gases and groups CO/CO2 with combustion emissions.

How to extend

Suggests consulting smokestack emission profiles or environmental impact assessments for smelters to see whether CO is reported and at what concentrations.

Statement 2
Does copper slag produced by copper smelting cause leaching of heavy metals into soil or water in the environment?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > 2. Water (aquatic) Pollution > p. 36
Presence: 4/5
“Such a polluted water is main cause of water-borne diseases like cholera, gastroenteritis, dysentery, fever, typhoid, and paratyphoid. Moreover, the dissolved organic compounds in sewage and sludge, reduces the amount of dissolved oxygen which may threaten the aquatic ecosystems.• (ii) Inorganic Compounds and Minerals: Inorganic compounds including acids, mineral fbres, and heavy metals are being discharged by mining and industrial wastes are the other important water pollutants. Te heavy metals like arsenic, cobalt, copper, lead, mercury, magnesium, etc. get dissolved into water through the natural process of weathering and anthropogenic factors. Tese heavy metals get concentrated in higher tropic levels within the food chain and can lead to such serious ailments as brain-damage, liver damage and may be fatal in many cases.• (iii) Nitrates: Nitrates constitute another serious source of water pollution, which are also considered as the health hazards.”
Why this source?
  • Explicitly links mining and industrial wastes to discharge of inorganic heavy metals into water and soil.
  • States heavy metals (including copper) can dissolve into water via weathering and anthropogenic processes, implying potential leaching from mining residues.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > z. Diffuse or non-point source. > p. 74
Presence: 4/5
“The sewage contains human and animal excreta, food residues, cleaning agents, detergents and other wastes. • Type of industry: Mining; Increase all dd#: Mine Wastes: Chlorides, various metals, ferrous sulphate, sulphuric acid, hydrogen sulphide, ferric hydroxide, surface wash offs, suspended solids, chlorides and heavy metals.; • Type,of industry: Iron and Steel; Increase all dd#: Suspended solids, iron cyanide, thiocyanate, sulphides, oxides of copper, chromium, cadmium, and mercury.; • Type,of pollutant: Oil, phenol and naphtha • Type 0 Putrescibility is the process of decomposition of organic matter present in water by microorganisms using oxygen. z) industrial Wastes: The industries discharge . several inorganic and organic poilutants, which may prove highly toxic to the liviirg beings.”
Why this source?
  • Lists mine wastes and industrial discharges containing various metals and oxides of copper as environmental pollutants.
  • Identifies surface wash-offs and suspended solids from mines as pathways for metal release to the environment.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > 5.15.6. Trigger Effect of Acid Rain on Pollutants: > p. 105
Presence: 3/5
“"sa 5 HftIffiIiRffirlll#.Effi • r Although acid deposition may not increase the production of methyl mercury, it may increase the partitioning of methyl mercury into the water column. • r The use of lime has helped in reducing the mercury levels in fish. (ii) Aluminium: • r Acidified waters are known to leach substantial amounts of aluminium from watersheds, • r Even at relatively low levels, aluminium has been implicated in dialysis dementia, a disorder of the central nervous system, which may be toxic to individuals with impaired kidney function. (iii) Cadmium: • Cadmium can enter the drinking water supply through corrosion of galvanized pipe or from the copper-zinc solder used in the distribution systems.• A decrease in water pH from 6.5 to 4.5 can result in a fivefold increase in cadmium and could cause renal tubular damage. (M Lead: • O Foetuses and infants are highly susceptible to drinking water lead contamination. • r High blood lead levels in children (>3o mug/ Mi) are believed to induce biochemical and neurophysiological dysfunction. • r However, lower than normal blood levels of lead can cause mental deficiencies and behavioural problems.”
Why this source?
  • Shows that acidification (lower pH) markedly increases leaching/mobilization of metals such as cadmium and aluminium.
  • Implicates environmental conditions (acid rain, pH change) that can enhance release of metals from solid residues into water.
Statement 3
Do copper smelting plants emit sulphur dioxide (SO2) as an air pollutant?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > a) Sulphur > p. 102
Presence: 5/5
“(a) Sulphur '.ilU-/ rz j! U • (i) Natural sources: • seas and oceans, • r volcanic eruptions, • r Biological processes in the soil 8.9., Decomposition of organic matter. • (ii) Man-made sources: • r burning of coal (6o0/o of SO,), and • . petroleum products $oolr of SO,), and • r The smelting of metal sulfide ores to obtain the pure metals. • e Industrial production of Sulfuric atid in metallurgical, chemical and fertilizer industries. • (b) Nitrogen Natural sources: • r lightenin&• r volcanic eruption, and• r Biological activity.”
Why this source?
  • Explicitly lists 'The smelting of metal sulfide ores to obtain the pure metals' as a man-made source of sulphur (SO2).
  • Directly connects metal smelting processes to SO2 emissions, which covers smelting plants producing metals.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Sulphurdioxide (SOz) > p. 64
Presence: 5/5
“• It is a gas produced from burning coal, mainly in thermal power plants. • It is also produced by industrial processes such as the production of paper and the smelting of metals. • It is a major contributor to smog and acid rain.”
Why this source?
  • States SO2 is produced by industrial processes including 'the smelting of metals'.
  • Links smelting operations with SO2 as a contributor to air pollution, reinforcing industrial origin.
Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 17: Contemporary Issues > 1. Air Pollution > p. 38
Presence: 4/5
“The presence in the Earth's atmosphere of man-caused or manmade contaminants which may adversely affect property, or the lives of plants, animals, or humans. Commonly air pollution include carbon dioxide, carbon monoxide, lead, nitrogen oxide, ozone, smoke, and sulphur dioxide. The tremendous increase of vehicles during the last three decades in the country has increased the air pollution, especially in the large cities. Consequently, the urban population is suffering more by cough, nausea, irritation of eyes, and various bronchial and visibility problems. Because of the emission of carbon-dioxide, carbon monoxide, nitrogen oxide, and suspended particles of lead and heavy metals, the urban environment is more polluted than the rural environment.”
Why this source?
  • Identifies sulphur dioxide as a common air pollutant among industrial contaminants.
  • Provides context that SO2 is a recognized pollutant emitted by industrial activities, supporting the smelting link.
Pattern takeaway: UPSC mixes 'Static Science' (S3) with 'General Awareness of Hazards' (S1, S2). They test if you understand the *nature* of an industry (dirty, high heat, chemical waste) rather than memorizing its exact emission inventory.
How you should have studied
  1. [THE VERDICT]: Standard + Applied Logic. S3 is direct from Shankar/NCERT; S1 requires deducing combustion byproducts.
  2. [THE CONCEPTUAL TRIGGER]: Metallurgical Pollution & Waste Management (Specific focus on Sulphide ores vs Oxide ores).
  3. [THE HORIZONTAL EXPANSION]: Aluminum (Red Mud, Fluorides); Coal Plants (Fly Ash: Arsenic, Lead, Mercury); Gold (Cyanide, Mercury); Cement (Limestone calcination -> CO2); Steel (Slag: Silicates, Phosphorus).
  4. [THE STRATEGIC METACOGNITION]: When books list 'Air Pollutants' (CO, SO2, NOx), map them to *processes* (Combustion, Smelting, Vehicles), not just lists. If a plant burns coke/coal, CO is a valid 'potential' emission.
Concept hooks from this question
📌 Adjacent topic to master
S1
👉 Carbon monoxide: sources and acute health effects
💡 The insight

Carbon monoxide is produced by incomplete combustion of carbon-based fuels and reduces the amount of oxygen entering the blood, causing symptoms from confusion and sleepiness to severe hypoxia.

High-yield for environment and public health questions: explains a common urban pollutant, its physiological impacts, and why combustion control matters for human safety; links to air quality, health policy, and mitigation measures.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Carbon monoxide (CO) > p. 64
  • Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 17: Contemporary Issues > 1. Air Pollution > p. 38
🔗 Anchor: "Are copper smelting plants known to emit carbon monoxide (CO) at concentrations ..."
📌 Adjacent topic to master
S1
👉 Roasting and smelting of sulphide ores
💡 The insight

Roasting converts metal sulphide ores into oxides by strong heating in air, a fundamental metallurgical step used for metals such as copper.

Essential for questions on mineral processing and industrial pollution: connects metallurgical chemical reactions to potential emissions and environmental impacts; useful for linking resource extraction to pollution control policy.

📚 Reading List :
  • Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3.4.4 Extracting Metals in the Middle of the Activity Series > p. 51
  • Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Activity 3.9 > p. 42
🔗 Anchor: "Are copper smelting plants known to emit carbon monoxide (CO) at concentrations ..."
📌 Adjacent topic to master
S1
👉 Anthropogenic sources of air pollutants
💡 The insight

Combustion from vehicles, industrial smokestacks, and biomass burning are major human sources of gases including carbon monoxide and carbon dioxide.

Core concept for environment and geography sections: helps classify pollution sources, assess urban air quality issues, and frame mitigation strategies; applicable in questions on emissions inventories and regulatory priorities.

📚 Reading List :
  • Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 17: Contemporary Issues > 1. Air Pollution > p. 38
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > a) Sulphur > p. 102
🔗 Anchor: "Are copper smelting plants known to emit carbon monoxide (CO) at concentrations ..."
📌 Adjacent topic to master
S2
👉 Heavy-metal pollution from mining and industrial wastes
💡 The insight

Mining and industrial waste streams release inorganic heavy metals that can enter soil and water.

High-yield for environmental polity and GS papers: explains a major source of water/soil contamination, links to public health and regulation of mining industries, and supports answers on pollution control and remediation policy.

📚 Reading List :
  • Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > 2. Water (aquatic) Pollution > p. 36
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > z. Diffuse or non-point source. > p. 74
🔗 Anchor: "Does copper slag produced by copper smelting cause leaching of heavy metals into..."
📌 Adjacent topic to master
S2
👉 Acidification increases metal mobility and leaching
💡 The insight

Lowered pH or acid deposition increases the dissolution and transport of metals from solid residues into aquatic systems.

Important for questions on acid rain, water quality and ecosystem impacts; connects atmospheric processes to geochemistry and human health effects, and informs mitigation measures like liming and pH control.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > 5.15.6. Trigger Effect of Acid Rain on Pollutants: > p. 105
🔗 Anchor: "Does copper slag produced by copper smelting cause leaching of heavy metals into..."
📌 Adjacent topic to master
S2
👉 Copper and metal oxides as components of industrial wastes
💡 The insight

Copper forms oxides during smelting and metal oxides are present in industrial discharges that contribute to pollution.

Useful for technical-leaning environment questions: ties metallurgy chemistry to environmental fate, helps explain why smelting byproducts (like slags) can be sources of soluble metal pollutants and informs remediation strategy discussions.

📚 Reading List :
  • Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Activity 3.9 > p. 41
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > z. Diffuse or non-point source. > p. 74
🔗 Anchor: "Does copper slag produced by copper smelting cause leaching of heavy metals into..."
📌 Adjacent topic to master
S3
👉 Smelting of metal sulfide ores as a source of SO2
💡 The insight

Smelting metal sulfide ores releases sulphur dioxide into the air.

High-yield for questions on industrial pollution sources; links metallurgical processes to air-quality impacts and regulatory/mitigation discussions. Helps answer questions about which industries contribute to SO2 emissions and policy measures for emission control.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > a) Sulphur > p. 102
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > Sulphurdioxide (SOz) > p. 64
🔗 Anchor: "Do copper smelting plants emit sulphur dioxide (SO2) as an air pollutant?"
🌑 The Hidden Trap

Red Mud (Bauxite Residue). Just as Copper Slag was asked here, Red Mud is the high-pH, toxic byproduct of Aluminum production that poses a major leaching threat to soil/water.

⚡ Elimination Cheat Code

The 'Possibility Operator' Hack. Statement 1 uses 'May release'. In Science & Tech, unless the outcome is physically impossible (e.g., 'Releases Gold gas'), 'May' statements are generally correct. Combined with the certainty of S3 (Sulphide = SO2), you are logically pushed towards Option D.

🔗 Mains Connection

Link 'Copper Slag' to **Circular Economy (GS3)**. The Draft Notification on Fly Ash and Slag utilization mandates using these industrial wastes in road construction and cement to reduce environmental load (Waste to Wealth).

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