Environmental Health

1. Major determinants of health

2. Guiding principles for environmental risk assessment

• Scientific Validity: Evidence-based reliable data
• Transparency: Open methods and findings
• Precautionary Principle: Action even with incomplete certainty
• Comprehensive Approach: Consider all hazards/exposure pathways
• Public Participation: Community involvement
• Ethical Consideration: Protect vulnerable populations
• Consistency: Standardized methods
• Uncertainty Analysis: Acknowledge limitations
• Risk Communication: Effective messaging to public/policymakers
• Continuous Monitoring: Periodic review

Steps: Hazard Identification → Dose-response Assessment → Exposure Assessment → Risk Characterization

3. Faecal pathogens, WASH pathway & nutrition

Diseases from Faecal Pathogens

• Water-borne: Cholera, Typhoid, Dysentery, Hepatitis A/E, Polio
• Parasitic: Ascariasis, Hookworm, Giardiasis
• Diarrhoeal: Acute gastroenteritis

Pathway: Poor WASH → Infections → Malnutrition

Contaminated water + poor sanitation → faecal exposure → recurrent diarrhoea/worm infestation → poor nutrient absorption → malnutrition & stunting

Interpretation: Bihar has high water coverage but poor sanitation and highest stunting. Tamil Nadu has better sanitation and lowest stunting → sanitation plays a major role in child nutrition.

4. Methyl mercury – formation & health effects

Methyl mercury: Organic, highly toxic form of mercury that accumulates in living organisms.

Formation (Biomethylation): Industrial mercury enters water → microorganisms convert to methyl mercury → accumulates in fish → humans exposed via contaminated seafood.

5(a) Public health problems from indiscriminate plastic usage

• Water pollution (drainage blocks, flooding)
• Vector breeding (stagnant water in plastics → mosquitoes)
• Air pollution (burning releases toxic gases/carcinogens)
• Soil pollution (reduced fertility)
• Harm to marine life (ingestion, death)
• Microplastic exposure (enters food chain)
• Occupational hazards for waste handlers

Prevention: Ban single-use plastics, recycling, public awareness, scientific waste disposal.

5(b) Particulate air pollutants & health effects

Definition: Tiny solid/liquid particles suspended in air (dust, smoke, soot, aerosols). Types: PM10, PM2.5.

6. Hazardous Process (Factories Act, 1948) + Toxic gases + First aid

Hazardous Process: Any process involving hazardous substances where exposure may cause injury to health or environment.

Physiological Classification of Toxic Gases

• Irritant: Chlorine, ammonia, SO₂
• Asphyxiant: CO, CO₂
• Systemic poisons: Hydrogen cyanide, H₂S
• Anaesthetic: Benzene vapour

First Aid for Gas Poisoning

• Remove victim to fresh air
• Maintain airway/breathing, give oxygen if available
• Artificial respiration if breathing stops
• Remove contaminated clothes
• Wash eyes/skin with plenty of water
• Immediate medical care

7. Biomedical waste categorization & Red category

Categories: Yellow, Red, White (Translucent), Blue

Red Category Items: IV tubes, catheters, syringes without needles, gloves, plastic tubing, urine bags (contaminated recyclable plastic waste).

Treatment: Autoclaving/microwaving → shredding → recycling.

Public Health Importance: Prevents infection transmission (HIV, Hepatitis B/C), reduces environmental pollution, prevents needle-stick/occupational hazards, maintains hospital hygiene, reduces illegal reuse of medical plastics.

8. Pesticides – health risks & alternatives

Pesticide: Chemical substances to kill/control pests (insecticides, herbicides, fungicides).