NEOCODE

Environmental Pollution MCQs

1. Water Pollution

1. The main source of water pollution is:

Correct Answer: b) Industrial waste

Explanation:
Industrial waste contributes about 50% of water pollution globally, containing toxic chemicals, heavy metals, and organic pollutants. Other major sources include agricultural runoff (fertilizers, pesticides) and municipal sewage (pathogens, nutrients).

2. Eutrophication is caused by excess:

Correct Answer: b) Nitrates and Phosphates

Explanation:
Eutrophication occurs when excess nutrients (mainly N and P from fertilizers and sewage) cause algal blooms. As algae die and decompose, oxygen is depleted, creating "dead zones." The Gulf of Mexico has a 6,000-7,000 sq mile dead zone from Mississippi River runoff.

3. BOD (Biochemical Oxygen Demand) measures:

Correct Answer: a) Organic pollutant levels in water

Explanation:
BOD measures the amount of oxygen microorganisms need to decompose organic matter in water over 5 days at 20°C. Clean water has BOD <5 mg/L, while raw sewage may exceed 300 mg/L. High BOD indicates severe organic pollution and oxygen depletion risk.

4. Minamata disease is caused by:

Correct Answer: b) Mercury

Explanation:
First identified in Minamata, Japan (1956), this neurological disease results from methylmercury poisoning. A chemical factory discharged mercury into the bay, which bioaccumulated in fish. Over 2,000 victims suffered paralysis, convulsions, and birth defects.

5. The Ganga Action Plan was launched in:

Correct Answer: b) 1985

Explanation:
Phase I of the Ganga Action Plan (1985-2000) aimed to reduce pollution in 25 cities along the Ganges. Despite spending ₹900 crore, it failed due to poor implementation. Namami Gange (2014) is the current ₹20,000 crore initiative with better wastewater treatment.

2. Soil Pollution

6. Soil pollution is mainly caused by:

Correct Answer: b) Pesticides and industrial waste

Explanation:
Soil pollution sources include: (1) Agricultural chemicals (2.5 million tons pesticides/year globally), (2) Industrial waste (heavy metals, hydrocarbons), (3) Mining (acid mine drainage), and (4) Improper waste disposal. 33% of global soils are degraded (FAO).

7. DDT is a:

Correct Answer: b) Persistent organic pollutant (POP)

Explanation:
Dichlorodiphenyltrichloroethane (DDT) is a synthetic pesticide banned in most countries under the Stockholm Convention (2001). It bioaccumulates in food chains, persists for decades in soil, and causes eggshell thinning in birds. India still uses it for malaria control.

8. Soil erosion can be prevented by:

Correct Answer: b) Afforestation

Explanation:
Afforestation (planting trees) reduces soil erosion by: (1) Root systems binding soil, (2) Canopy reducing rainfall impact, and (3) Leaf litter improving soil structure. The Great Green Wall project aims to plant 8,000 km of trees across Africa to combat desertification.

3. Noise Pollution

9. The permissible noise level in residential areas during the day is:

Correct Answer: b) 55 dB

Explanation:
India's noise standards (CPCB): Residential areas - 55 dB (day)/45 dB (night); Commercial - 65/55 dB; Industrial - 75/70 dB. For comparison, normal conversation is 60 dB, while traffic is 70-85 dB. Chronic exposure >70 dB causes hearing damage.

10. Chronic exposure to noise pollution causes:

Correct Answer: b) Hearing loss & hypertension

Explanation:
WHO estimates 1.6 million healthy life years are lost annually in Western Europe from traffic noise. Effects include: (1) Permanent hearing damage (>85 dB), (2) 10-15% increased hypertension risk, (3) Sleep disturbances, and (4) Impaired cognitive development in children.

4. Radiation Pollution

11. Chernobyl disaster (1986) was related to:

Correct Answer: b) Nuclear radiation leak

Explanation:
The Chernobyl accident (Ukraine) was the worst nuclear disaster in history. Reactor 4 exploded, releasing 400× more radiation than Hiroshima. Over 350,000 people were evacuated, and a 30km exclusion zone remains. Increased thyroid cancer cases were observed in affected regions.

12. UV radiation can cause:

Correct Answer: b) Skin cancer

Explanation:
UV-B radiation (280-315 nm) damages DNA in skin cells, causing mutations that lead to melanoma (deadliest skin cancer). A 10% decrease in ozone could cause 300,000 more skin cancer cases globally. The ozone hole peaks over Antarctica each September-October.

7. Emerging Pollutants

13. Microplastics are a major threat to:

Correct Answer: b) Marine life

Explanation:
Microplastics (<5mm) enter oceans via wastewater (35% from synthetic clothes) and degrade into nanoplastics. Over 700 marine species are affected, from plankton to whales. The Great Pacific Garbage Patch is 1.6 million km² (3×France). Humans ingest ~5g plastic/week (credit card's worth).

14. Electronic waste (e-waste) contains hazardous:

Correct Answer: b) Lead and Mercury

Explanation:
E-waste is the fastest-growing waste stream (53.6 million metric tons in 2019). A single computer contains: 1.5-2 kg lead (CRTs), 0.3-1g mercury (switches), and other toxics like cadmium and brominated flame retardants. 80% is improperly recycled in developing countries.

5. Fireworks & Pollution

15. Fireworks release harmful:

Correct Answer: b) Heavy metals & particulates

Explanation:
Fireworks contain: Strontium (red), Barium (green), Copper (blue), and Aluminum (sparkles). A single fireworks event can increase PM2.5 by 300-1000%. Delhi's 2016 Diwali saw PM2.5 at 999 μg/m³ (WHO safe limit: 25 μg/m³). Alternatives include laser shows and eco-friendly crackers.

16. Diwali fireworks increase levels of:

Correct Answer: b) PM2.5 & SO₂

Explanation:
Studies show Diwali fireworks cause: (1) PM2.5 spikes 4-12× above safe limits, (2) SO₂ increases from sulfur in gunpowder, and (3) Metal contamination (Al, Sr, Ba). In 2020, Delhi's post-Diwali AQI reached 435 (severe) despite COVID restrictions and a partial ban.