(a) State eight human activities that may pollute water bodies (b) Explain the measures that may be used to prevent pollution of water bodies. (c) Mention f...

(a) Eight human activities that may pollute water bodies

1. Discharge of untreated sewage and human excreta into rivers and streams.
2. Dumping of industrial effluents and chemical wastes into water bodies.
3. Washing of clothes and bathing with detergents and soaps in streams.
4. Application of fertilizers on farms which are washed by run-off into water (causing eutrophication).
5. Spraying of pesticides and herbicides that drain into water bodies.
6. Oil spillage from tankers, refineries and pipelines.
7. Dumping of refuse and solid domestic waste into rivers and lakes.
8. Discharge of hot water (thermal pollution) from factories and power stations.

Others include mining activities that release heavy metals, and dumping of dead animals into water.

(b) Measures to prevent pollution of water bodies

• Treatment of sewage and effluents before they are discharged, so that harmful materials are removed.
• Enactment and enforcement of laws that prohibit the dumping of waste into water bodies, with penalties for offenders.
• Public enlightenment and education on the dangers of water pollution and the need for clean water.
• Proper disposal of refuse in designated dumps or by controlled incineration rather than in rivers.
• Controlled and moderate use of fertilizers and pesticides, and the use of biodegradable chemicals.
• Provision of pit latrines and toilets sited away from streams to prevent faecal contamination.
• Prompt control of oil spillage and proper maintenance of pipelines and tankers.

(c) Four methods of purifying water

1. Boiling - heating water to kill micro-organisms.
2. Filtration - passing water through sand and gravel beds to remove suspended particles.
3. Chlorination - adding chlorine or chlorine compounds to kill germs.
4. Distillation - boiling water and condensing the steam to give pure water.

Sedimentation with alum (coagulation) is also acceptable.