UGC NET Paper 1 Unit 9 Topic 4 : Impacts of pollutants on human health.

☠️ Impacts of Pollutants on Human Health

Comprehensive analysis of major pollutants and their effects on human body systems. Covers air, water, soil, and noise pollution with specific diseases, vulnerable groups, and UGC NET relevant case studies.

🔑 Key Concept: Pollutants cause ~24% of global deaths (WHO) through:
• Direct toxicity
• Bioaccumulation
• Synergistic effects
• Long-term exposure risks

1. Air Pollutants & Health Effects

Pollutant	Major Sources	Health Impacts	Vulnerable Groups
PM2.5/PM10 (Particulate Matter)	Vehicles, industry, construction	• Lung cancer • Asthma • COPD • Heart disease	Children, elderly, asthma patients
NO₂/SO₂ (Nitrogen/Sulfur oxides)	Power plants, vehicles	• Bronchitis • Acid rain-induced skin diseases • Eye irritation	Outdoor workers, urban dwellers
O₃ (Ground-level ozone)	Photochemical smog	• Reduced lung function • Chest pain • Throat irritation	Athletes, outdoor laborers
CO (Carbon monoxide)	Incomplete combustion	• Headaches • Cardiovascular damage • Fatal at high doses	Pregnant women, anemia patients
Pb (Lead)	Old paints, batteries	• Neurological damage • Developmental delays • Anemia	Children (<6 years), pregnant women

⚠️ Case Study - Delhi's Air Pollution:
• PM2.5 levels often exceed 300μg/m³ (WHO safe limit: 5μg/m³)
• Estimated 30,000 annual deaths in NCR
• School closures during severe smog episodes

2. Water Pollutants & Health Risks

Major Contaminants:

Pollutant	Disease/Condition	Notable Cases
Arsenic	• Skin lesions • Cancer • Peripheral neuropathy	West Bengal (India), Bangladesh
Fluoride	• Dental fluorosis • Skeletal deformities	Rajasthan, Telangana (India)
Nitrates	• Blue baby syndrome • Gastric cancer	Punjab (Agricultural runoff)
Heavy Metals (Hg, Cd)	• Minamata disease (Hg) • Itai-itai disease (Cd)	Japan (1950s), Industrial areas
Coliform Bacteria	• Cholera • Dysentery • Typhoid	Flood-affected regions

💡 Did You Know? Waterborne diseases cause 3.4 million deaths annually (WHO), mostly in developing countries. Diarrhea alone kills 525,000 children yearly due to contaminated water.

3. Soil Pollutants & Exposure Pathways

Contaminant	Primary Exposure	Health Effects
Pesticides (DDT, Endosulfan)	Food chain, direct contact	• Endocrine disruption • Cancer • Parkinson's disease
Industrial Waste (Dioxins, PCBs)	Bioaccumulation in meat/dairy	• Immune system damage • Reproductive disorders
Heavy Metals (As, Pb, Cr)	Crop uptake, dust inhalation	• Kidney failure • Neurological damage • Bone diseases
Electronic Waste (Cd, Hg)	Improper recycling	• DNA damage • Developmental abnormalities

⚠️ Bhopal Gas Tragedy (1984):
• Methyl isocyanate leak from Union Carbide plant
• Immediate: 3,787 deaths
• Long-term: 15,000+ deaths, birth defects in generations
• Current: Groundwater still contaminated with heavy metals

4. Noise Pollution Impacts

Health Consequences:

• Physiological: Hypertension, hearing loss, increased cortisol levels
• Psychological: Sleep disturbance, stress, reduced cognitive performance
• Special Risk Groups: Shift workers, students, cardiac patients

Noise Level	Source	Safe Exposure Time
85 dB	Heavy traffic	8 hours (Workplace limit)
100 dB	Construction sites	15 minutes
120 dB	Rock concerts	Immediate damage risk

5. Vulnerable Populations

High-Risk Groups:

1. Children: Developing organs, higher metabolic rate, more hand-to-mouth activity
2. Pregnant Women: Placental transfer of toxins (e.g., mercury affects fetal brain)
3. Elderly: Reduced detoxification capacity, pre-existing conditions
4. Outdoor Workers: Farmers, traffic police, construction workers
5. Low-Income Groups: Often live near pollution hotspots with limited healthcare

🔥 Previous Year UGC NET Questions:

1. Which pollutant causes "Itai-itai" disease? (Ans: Cadmium)
2. Minamata disease is caused by exposure to: (Ans: Methylmercury)
3. Blue baby syndrome is linked to: (Ans: Nitrate contamination)
4. The safe limit for PM2.5 (24-hr avg) as per WHO is: (Ans: 15 μg/m³)
5. Which group is most vulnerable to lead poisoning? (Ans: Children under 6)

6. Prevention & Mitigation

Intervention Strategies:

Approach	Examples	Health Benefit
Policy	• National Clean Air Programme • BS-VI norms • Plastic bans	Systemic reduction in exposure
Technology	• Scrubbers in industries • Electric vehicles • Water purifiers	Source control
Personal Protection	• N95 masks • Water filters • Noise-canceling headphones	Individual risk reduction
Community Action	• Tree planting • Waste segregation • Monitoring apps	Localized improvements

📌 Exam Tips:

• Remember disease-pollutant pairs (e.g., Silicosis - SiO₂ dust)
• Note threshold limits for key pollutants (WHO/CPCB standards)
• Understand bioaccumulation vs biomagnification
• Review major environmental disasters and their health impacts