I. Radioactive Pollution – Meaning

• Increase in natural radiation levels posing threat to life
• Contamination by radioactive substances in solids, liquids, gases, or body tissues
• Defined by the International Atomic Energy Agency (IAEA)

Two Core Problems Of Nuclear Energy

• Accidental leakage
• Safe disposal of radioactive waste

II. Sources Of Radioactive Pollution

A. Artificial Sources

• Nuclear power plant accidents
• Nuclear weapons testing (fallout)
• Uranium and thorium mining
• Medical uses (X-rays, radiation therapy)
• Nuclear laboratories and reactors

Important radionuclides in fallout:

• Strontium-90
• Caesium-137
• Iodine-131

B. Natural Sources

• Cosmic rays
• Radionuclides in Earth’s crust:

– Uranium-238
– Thorium-232
– Radium-224
– Potassium-40
– Carbon-14

III. Radioactivity – Basic Concept

Spontaneous emission of:

• Alpha particles
• Beta particles
• Gamma rays

Due to the disintegration of unstable atomic nuclei.

IV. Ionizing Vs Non-Ionizing Radiation

A. Non-Ionizing Radiation

Definition

Electromagnetic waves with longer wavelengths.

Examples:

• Near infrared
• Radio waves
• Microwaves
• Higher wavelength ultraviolet

Characteristics

• Cannot ionize atoms
• Can excite atoms and molecules
• Low penetration power

Effects

• Sunburn
• Snow blindness
• Eye damage
• Thermal heating (microwave oven)

Mobile Tower Radiation

• Non-ionizing
• Causes thermal and non-thermal effects
• Possible impacts:
  – Headache
  – Fatigue
  – Genetic and reproductive concerns
  – Disturbance in birds’ navigation

B. Ionizing Radiation

Definition

Radiation that removes electrons from atoms → forms ions.

Types

Electromagnetic:

• Short wavelength ultraviolet
• X-rays
• Gamma rays

Particle radiation:

• Alpha particles
• Beta particles
• Neutrons

Characteristics

• High penetration power
• Break chemical bonds
• Damage macromolecules (DNA, proteins)

V. Biological Damage

A. Somatic Damage

Affects body cells (non-reproductive)

Examples:

• Radiation sickness
• Hair loss
• Lung fibrosis
• Cataract
• Cancer

B. Genetic Damage

Affects reproductive cells

• Mutations
• Abnormalities in the next generation
• Heritable defects

VI. Radiation Dose

Unit:

• Rem (radiation equivalent in man)

Low dose:

• Cells repair damage

High dose:

• Radiation sickness
• Permanent cell damage
• Cancer

VII. Damage Potential Of Particles

Alpha

• Blocked by paper
• Harmful if ingested/inhaled

Beta

• Penetrates skin
• Blocked by glass or thin metal

Gamma

• Highly penetrating
• Blocked only by thick concrete

VIII. Half-Life

• Time required for half of the radioactive atoms to decay
• Ranges from seconds to thousands of years
• Long half-life radionuclides → major environmental threat

IX. Nuclear Power Plant Accidents

Major global accidents:

• Three Mile Island (1979)
• Chernobyl (1986)
• Fukushima Daiichi (2011)

Causes:

• Reactor core overheating
• Fuel rod meltdown
•  Release of radioactive materials

X. Safe Disposal Of Nuclear Waste

Types

Low-Level Waste

• Medical
• Research
• Protective clothing

High-Level Waste

• Spent fuel rods
• Nuclear weapons waste

Proposed Methods

• Deep geological burial
• Disposal in space
• Ocean dumping
• Burial under polar ice
• Conversion into harmless isotopes

Current practice:

• Storage ponds
• Reprocessing plants

XI. Important Points

• Non-ionizing radiation cannot remove electrons
• Ionizing radiation causes DNA breakage
• Gamma rays have the highest penetration
• Alpha most dangerous internally
• Mobile tower radiation is non-ionizing
• Long half-life radionuclides cause persistent pollution