The West Bengal University of Health Sciences

Environmental Health

MPH (1st Semester) Examination, February 2020 | Detailed Answers

1(a) Different methods of sampling of water for surveillance

📊 Sampling Methods

Random Sampling: Samples collected randomly from different sources – simple and economical.
Systematic Sampling: Fixed intervals (every week or every 2 km) – useful for routine monitoring.
Stratified Sampling: Area divided into strata, samples from each group – ensures representation.
Composite Sampling: Multiple samples mixed – gives average quality, useful for industrial/sewage analysis.
Grab/Spot Sampling: Single sample at one time/place – shows water quality at that moment.
Continuous Sampling: Continuous collection over period – used in treatment plants and industries.

🧪 Precautions During Sampling

Use sterile containers
Avoid contamination
Label properly with date, time and source
Transport quickly to laboratory

1(b) How bacteriological surveillance of water is conducted?

Collection: Sterile bottles, sodium thiosulphate for chlorinated water
Transportation: Cold condition, examination within 6 hours
Laboratory Examination: Presumptive Coliform Test (lactose broth), Confirmatory Test, Completed Test (culture)
Membrane Filter Technique: Water filtered through membrane, bacteria cultured
Reporting: MPN (Most Probable Number) of coliforms per 100 ml – absence = safe water

1(c) "Coliform organism has been chosen as primary bacteriological indicator" – Justify

Present abundantly in human and animal intestine
Easily detectable in laboratory
Survive longer in water than pathogens
Presence indicates possible presence of disease-causing organisms
Testing is simple, cheap and reliable
E. coli specifically indicates recent faecal contamination

2(a) Sources and effects of arsenic on health

🏭 Sources of Arsenic

Natural: Arsenic-containing rocks, groundwater contamination
Industrial: Mining, pesticides, smelting, coal burning
Food: Contaminated irrigation water, fish/seafood

⚠️ Health Effects

Acute: Vomiting, diarrhoea, abdominal pain, shock
Chronic (Arsenicosis): Melanosis, keratosis, peripheral neuropathy, hypertension, skin/lung/bladder cancer

Prevention: Safe drinking water, arsenic removal, public awareness

2(b) Minamata Disease

Cause: Methyl mercury poisoning from contaminated fish (Minamata Bay, Japan)
Source: Industrial mercury discharge
Clinical Features: Numbness, ataxia, tremors, deafness, blindness, paralysis, mental retardation in children
Prevention: Control industrial pollution, safe waste disposal, monitor seafood contamination

2(c) "Fluoride acts as a double-edged sword" – Justify

✅ Beneficial Effects

Prevents dental caries
Strengthens teeth and bones
Optimum level: 0.7–1.2 mg/L

❌ Harmful Effects

Dental fluorosis (mottling)
Skeletal fluorosis (joint pain, bone deformity)
Crippling fluorosis (severe disability)

3(a) Occupational health hazards of Traffic Police

⚠️ Hazards

Physical: Heat, sunlight, noise, vibrations
Chemical: Vehicle exhaust, CO, lead, smoke
Biological: Infectious diseases from public
Ergonomic: Prolonged standing → back pain, muscle strain
Psychological: Stress, anxiety, mental fatigue
Accident: Road traffic accidents

🛡️ Preventive Measures

Face masks
Rotational duty
Health check-ups
Adequate rest
Traffic management

3(b) What is "Pneumoconiosis"?

Definition: Occupational lung disease from long-term inhalation of dust (coal, silica, asbestos).
Types: Silicosis, Anthracosis, Asbestosis.
Symptoms: Cough, breathlessness, chest tightness.
Prevention: Dust control, ventilation, respiratory masks, periodic medical examination.

3(c) Role of "Pre-placement examination" in prevention of occupational health hazards

Assess physical fitness
Detect existing disease
Match worker with suitable job
Prevent occupational diseases
Establish baseline health data
Components: Medical history, physical exam, lab tests, chest X-ray
Importance: Reduces accidents, protects susceptible workers, improves productivity

4(a) Disaster Cycle

🛡️ 1. Mitigation

Reduce impact (flood control, earthquake-resistant buildings)

📋 2. Preparedness

Planning, training, emergency drills, stockpiling

🚨 3. Response

Immediate action – rescue, relief, medical aid

🏗️ 4. Recovery

Restoration – rehabilitation, reconstruction

4(b) "Global warming is a priority public health issue of today" – Explain

🌡️ Causes

Burning fossil fuels
Deforestation
Industrialization
Vehicle pollution

🏥 Health Effects

Heat-related illness (heat stroke, dehydration)
Vector-borne diseases (malaria, dengue)
Respiratory diseases (asthma, allergy)
Food/water insecurity (malnutrition, diarrhoea)
Natural disasters (floods, cyclones, droughts)

4(c) Different methods for prevention of noise pollution

Engineering: Silencers, soundproofing, machine maintenance
Administrative: Zoning regulations, restrict loudspeakers, time restrictions on industries
Environmental: Plantation of trees, green belts
Personal Protective: Ear plugs, ear muffs
Public Health: Awareness campaigns, enforcement of laws, regular noise monitoring

📌 Key Takeaway: Environmental health surveillance, pollution control, occupational safety, and disaster management are essential pillars of public health. Understanding water quality indicators, toxic metal effects, noise control, and global warming helps in formulating effective health policies.