Q. 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

[C] 1 and 3 only

[D] 1, 2 and 3

Answer: B
Notes:

Why this Question) Vedanta copper smelting plant in Tamil Nadu in news recently. 

Ans) b 

Exp) Option b is correct. 

Statement 1 is incorrect. In copper smelting process, first, the carbon (C) combusts with oxygen (O2) in the air to producecarbon monoxide(CO). Second, the carbon monoxide reacts with the ore and removes one of its oxygen atoms, releasing carbon dioxide. Hence, it does not release lethal quantity of CO in the environment. 

Statement 2 is correct. Copper smelters emit staggering amounts of toxic pollution i.e., lead, arsenic and selenium. These heavy metals and particulate matter from copper smelters contaminate the environment downwind and downstream. 

Statement 3 is correct. Copper smelters are the largest source of sulphur oxides (SOx) and trace elements. Suspended particles have a pollution scope of 2-3 km, while Sulphur dioxide has a range of as much as 15 km. 

Source:  Toxic Air Pollution from Copper Smelters Challenged | Earthjustice 

Air pollution emission from the copper smelter Complex Bor in Serbia (peertechzpublications.com) 

Subject) Environment