Pollution
Pollution is the introduction of harmful substances or energy into the environment. Air, water, land, noise, and thermal pollution can damage organisms and reduce the quality of human life.
| Type | Examples of sources | Possible effects |
|---|---|---|
| Air | Smoke, vehicle exhaust, and burning waste | Respiratory illness, acid rain, and climate effects |
| Water | Sewage, oil, chemicals, and refuse | Unsafe water, disease, and death of aquatic organisms |
| Land | Plastics, industrial waste, and litter | Soil damage, pests, and blocked drainage |
| Noise | Traffic, machines, and loud music | Stress, hearing damage, and disturbed communication |
Sewage and refuse
Sewage contains faeces, urine, wastewater, microorganisms, and other organic material. It is a pollutant because it may spread pathogens, reduce oxygen in water, produce offensive odours, and encourage vectors. Refuse should be reduced, reused, recycled, composted, or disposed of in controlled sites.
Safe disposal
Methods include properly designed pit latrines, septic tanks, sewer systems, treatment plants, controlled landfill, and safe incineration where appropriate. Disposal systems should prevent contamination of wells, rivers, soil, and food.
Revision questions
- Define pollution.
- Name four types of pollution.
- Why is untreated sewage dangerous?
- State three safe methods of waste disposal.
