Due to improper/indiscriminate disposal of old and used computers or their parts, which of the following are released into the environment as e-waste? 1. Beryllium 2. Cadmium 3. Chromium 4. Heptachlor 5. Mercury 6. Lead 7. Plutonium Select the correct answer using codes given below.

The correct answer is B (1, 2, 3, 5 and 6 only). Beryllium, cadmium, chromium, mercury and lead are the heavy metals that a computer's parts carry into the waste stream.

• Beryllium (1): copper-beryllium alloys are used in connectors and contacts on circuit boards.
• Cadmium (2): found in some batteries, older semiconductors and resistors.
• Chromium (3): hexavalent chromium is used in metal casings and corrosion protection.
• Mercury (5): used in switches and in backlights of some display panels.
• Lead (6): used in solder and in CRT glass.

Option 4 is wrong because heptachlor is an organochlorine pesticide, banned under the Stockholm Convention, and has no role in computers. Option 7 is wrong because plutonium is not a computer component. That leaves B as the only option that lists just the e-waste metals.

The core concept is hazardous constituents of e-waste and their health and groundwater impacts. For Mains GS-III (environment), link this to Extended Producer Responsibility under the E-Waste (Management) Rules, now replaced by the 2022 Rules, which came into force in 2023.

Trap: aspirants pick D because every item sounds toxic, without checking whether heptachlor or plutonium actually belong in electronic waste.