Environmental Chemistry: Hydrosphere and Chemical Composition of Water Bodies

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Environmental Chemistry Hydrosphere and Chemical Composition (Chemistry)

Hydrosphere and Chemical Composition of Water Bodies



Table of Contents

  • Learning Outcomes

  • Introduction

Chemical Composition of water bodies

  • Dissolved Gases

  • Metal Ions

Chemical Composition of specific water body

  • Ground Water

  • Surface Water

  • Wetlands


Learning Outcomes

After studying this module, you shall be able to:

  • Know about the hydrosphere and distribution of water on earth.

  • Learn the various components found in water bodies.

  • Know the origin of various metal ions present in rivers.





  • Hydrosphere is a term used to describe the combined mass of water found on, under and over the surface of a planet.

  • It refers to the discontinuous layer of water at or near the earth’s surface.

  • It includes surface water (which may exist in the liquid state or solid state in form of ice), groundwater and water vapour present in the atmosphere.

  • The hydrosphere covers about 70% of the surface of the earth.



  • In his award winning book, ‘Water’, Mark de Villiers described the hydrosphere as a closed system in which water exists and says it has been built with the specific purpose of regulating life.

  • The total amount of water, according to him, has not changed since geological times.

  • Water can be polluted, abused and misused but certainly not created or destroyed, it can only migrate.

Ancient civilizations

Ancient Civilizations

  • Water is the basic necessity for life. It has been referred to as ‘the elixir of civilization’.

  • All ancient civilizations have flourished on river plains.

  • Several cities and civilizations have disappeared due to water scarcity resulting from climatic changes.

  • Water is the most abundant substance present on the earth’s surface and is distributed in various forms like oceans, seas, rivers, lakes, streams, groundwater, ice caps, glaciers, soil moisture and water vapour in the atmosphere.

  • The hydrosphere holds about 1.39 x 109 km3 of water.

  • The oceans and seas hold about 97% of the hydrosphere in form of salt water.

  • The dominant part of fresh water is stored in ice caps and glaciers.

  • Only 0.3 to 0.4% of fresh water is found in lakes and streams while 0.05% is present in rivers.

  • The water content of wetlands and swamps is about 0.03% while the atmosphere contains about 0.004%.

  • This trivial amount plays an important role in the hydrological cycle.

Material Transportation

Material Transportation

  • The earth’s water is not pure but contains dissolved and suspended impurities which may be inorganic or organic.

  • The movement of water plays an important role in the transportation of these materials on the earth’s surface.


1. How much percentage of water, the oceans and seas hold of the hydrosphere?

a) 80%

b) 50%

c) 95%

d) 97%

Answer: D

2. How much percentage does the hydrosphere covers of the surface of earth?

a) 70%

b) 50%

c) 95%

d) 20%

Answer: A


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