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.
- (a) 1 and 2 only
- (b) 2 and 3 only ✓ UPSC's answer
- (c) 1 and 3 only
- (d) 1, 2 and 3
Why the answer is (b)
• Copper is smelted from sulphide ores (chalcopyrite), so roasting releases large amounts of sulphur dioxide, a major pollutant causing acid rain and respiratory harm (item 3).
• Copper slag contains residual heavy metals such as arsenic, lead and cadmium that can leach into soil and groundwater (item 2) — a key charge in the Sterlite (Thoothukudi) case.
• Item 1 is wrong: carbon monoxide is not a characteristic emission of copper smelting in lethal quantities; the process concern is SO2 and particulates.
• Hence 2 and 3 only, option (b).
Why the other options are wrong
- (a) 1 and 2 only
- Item 1 is wrong: CO is not the characteristic smelter pollutant; SO2 is.
- (c) 1 and 3 only
- Item 1 is wrong; slag leaching (item 2) is a real concern.
- (d) 1, 2 and 3
- Item 1 is wrong, so all three cannot be correct.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2021, held on 10 October 2021. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.