The West Bengal University of Health Sciences

Environmental Health

MPH (1st Semester) February–March Examination 2022 | Detailed Answers

1(a) What do you mean by NOAEL?

NOAEL stands for No Observed Adverse Effect Level.
It is the highest dose or concentration of a substance at which no harmful or adverse effects are observed in humans or experimental animals during a study.

Importance:

Used in toxicology and risk assessment
Helps determine safe exposure limits for chemicals and drugs
Basis for setting permissible exposure standards

1(b) Swimming pool contamination and sanitation mechanism

🏊 Causes of Contamination

Human Sources: Sweat, saliva, urine, faecal matter, skin infections
Environmental Sources: Dust, leaves, rainwater, animal waste
Microbial: Bacteria, viruses, fungi, protozoa

Diseases spread: Conjunctivitis, skin/ear infection, gastroenteritis

🧼 Mechanism of Swimming Pool Sanitation

Filtration: Sand filters remove suspended particles
Chlorination: Chlorine destroys microorganisms
pH Control: Ideal pH 7.2–7.8 improves chlorine efficiency
Water Circulation: Prevents stagnation
Regular Cleaning: Pool floor and walls
Monitoring: Regular testing for chlorine and microbial contamination
Personal Hygiene: Shower before entering, avoid swimming when ill

1(c) Effect of Air Pollution on COVID-19 outcome

🌫️ Major Air Pollutants

PM2.5, PM10, NO₂, SO₂, Ozone

🦠 Effects on COVID-19 Outcome

Increased susceptibility (respiratory tract damage)
Severe respiratory disease (lung inflammation)
Increased mortality in polluted regions
Aggravation of comorbidities (asthma, COPD, heart disease)
Weakening of immune system
Long-term post-COVID respiratory complications

Preventive measures: Reduction of air pollution, use of masks, improved ventilation, public health awareness.

2(a) Break point chlorination

Definition: Process of adding chlorine to water until all impurities and organic matter are oxidized and free residual chlorine appears.

Stages:
1. Chlorine reacts with organic matter
2. Chloramines are formed
3. Further chlorine destroys chloramines
4. Free residual chlorine appears – this point is called the breakpoint

Importance: Ensures effective disinfection, removes bad taste/odour, makes water microbiologically safe.

2(b) Why use face mask despite being vaccinated with booster dose

Vaccines are not 100% protective – breakthrough infections may occur
Masks reduce spread of droplets and aerosols – prevent transmission
New variants may partially escape immunity
Protection of vulnerable people (elderly, immunocompromised)
Added layer of protection – vaccine + mask provides better safety
High-risk settings (crowded places) increase transmission risk

2(c) "Plastic Pollution is a Public Health Priority today" – Explain

🚮 Sources

Plastic bags, bottles, packaging materials, industrial waste

🏥 Public Health Effects

Water pollution (blocks drainage, contaminates water bodies)
Soil pollution (reduces fertility)
Air pollution (burning releases toxic gases)
Harm to marine life (ingestion, death)
Microplastic exposure (enters food chain)
Vector breeding (stagnant water in plastics promotes mosquito breeding)

✅ Preventive Measures

Reduce single-use plastics
Recycling and reuse
Public awareness
Strict waste management laws

3(a) Occupational Health Hazards of Jute Mill workers

⚠️ Hazards

Respiratory: Byssinosis, chronic bronchitis, asthma, cough
Physical: Noise, heat stress, vibration
Mechanical: Injuries from machines, cuts, fractures
Eye: Irritation from dust
Skin: Dermatitis, allergic reactions
Ergonomic: Back pain, muscle strain
Psychological: Stress, fatigue

🛡️ Prevention

Ventilation
Dust control
PPE use
Machine guarding
Regular health check-up

3(b) Major Health Hazards of Pesticides used in Agriculture

⚡ Acute Health Hazards

Nausea, vomiting, headache
Dizziness, skin/eye irritation
Respiratory distress

🕰️ Chronic Health Hazards

Nervous system: neuropathy, tremors
Respiratory: asthma, chronic lung disease
Liver and kidney damage

⚠️ Additional Chronic Effects

Reproductive: infertility, congenital anomalies
Cancer: leukemia, lymphoma
Endocrine disruption: hormonal imbalance

Prevention: PPE, safe storage/handling, health education, regular medical examination.

4. Climate Change – Differentiation, Effects, and Prevention Strategies

🌍 What is Climate Change?

Long-term changes in temperature, rainfall, humidity and other atmospheric conditions over decades or longer periods.

📊 Difference between Climate and Weather

Weather	Climate
Short-term atmospheric condition	Long-term average weather pattern
Changes daily	Changes over years
Example: rain today	Example: increasing global temperature

🏥 Effects of Climate Change on Health

Heat-related illness (heat stroke, dehydration)
Vector-borne diseases (malaria, dengue)
Respiratory diseases (asthma, allergy)
Malnutrition (crop failure, food shortage)

Water-borne diseases (diarrhoea, cholera)
Mental health problems (post-disaster stress)

🌿 Effects on Nature

Melting of glaciers • Sea level rise • Floods and droughts
Loss of biodiversity • Forest fires • Disturbance of ecosystems

🏛️ Government Level Strategies

Renewable energy promotion (solar, wind, hydropower)
Afforestation programs
Pollution control laws
Sustainable transport policies
Climate action plans
Waste management programs

🧑 Individual Level Strategies

Save electricity
Use public transport
Plant trees
Reduce plastic use
Recycle and reuse
Spread environmental awareness

📌 Conclusion: Climate change control requires combined effort from government and society. Understanding NOAEL, water sanitation, air pollution effects, plastic pollution, occupational hazards (jute mills, pesticides), and climate change is essential for environmental health practice.