Question

What are the major causes of water pollution explain?

Answer 1

Explanation:

The major causes of water pollution are:

i.) Biological agents:

• These include bacteria, parasitic fungi and protozoa. The main sources include human sewage, animal and plant wastes, decaying organic matter, industrial wastes (oil refineries, oil spills, oil pollutants, paper mills, food processing units), natural land and urban run off and waste water discharges from slaughter houses.

• The depletion of oxygen occurs in the water bodies as the oxygen requiring bacteria feed on biological wastes. Due to this, aquatic life is destroyed, thus imparting a foul odour to water.

• Bacteria such as Escherichia coli and Streptococcus faecalis present in human excreta cause gastrointestinal diseases.

ii.) Chemical agents:

• Inorganic materials like acids, salts, metals like lead and mercury..

• Organic chemicals like agrochemicals (pesticides, herbicides etc), detergents, chlorine containing compounds, oil, grease and plastics.

• Radioactive substances which are released into aquatic systems as a result of nuclear waste from research laboratories and hospitals.

iii.) Physical agents:

• These include suspended solids, particulates and heat.

• The main sources are soil erosion, run-offs from agriculture, mining and power plants, suspended organic and mineral solids which absorb toxic substances like heavy metals and pass them through food chain.

☢ Note:

i. Water pollution results in the degradation of the quality of water.

ii. The polluted water is harmful to human beings, animals and aquatic life.

iii. It is not suitable for irrigation, agriculture, industries and for human consumption.

Answer 2

The major causes of water pollution are:

i.) Biological agents:

These include bacteria, parasitic fungi and protozoa. The main sources include human sewage, animal and plant wastes, decaying organic matter, industrial wastes (oil refineries, oil spills, oil pollutants, paper mills, food processing units), natural land and urban run off and waste water discharges from slaughter houses.

The depletion of oxygen occurs in the water bodies as the oxygen requiring bacteria feed on biological wastes. Due to this, aquatic life is destroyed, thus imparting a foul odour to water.

Bacteria such as Escherichia coli and Streptococcus faecalis present in human excreta cause gastrointestinal diseases.

ii.) Chemical agents:

Inorganic materials like acids, salts, metals like lead and mercury..

Organic chemicals like agrochemicals (pesticides, herbicides etc), detergents, chlorine containing compounds, oil, grease and plastics.

Radioactive substances which are released into aquatic systems as a result of nuclear waste from research laboratories and hospitals.

iii.) Physical agents:

These include suspended solids, particulates and heat.

The main sources are soil erosion, run-offs from agriculture, mining and power plants, suspended organic and mineral solids which absorb toxic substances like heavy metals and pass them through food chain.