8.1  Effects of water pollution on the environment

This study session begins by describing the effect of water pollution on surface water ecosystems, such as lakes, rivers and streams. Pollution from human activities enters surface waters, either directly when wastes are dumped into lakes and rivers, or indirectly when wastes released on land or into the air are washed into surface waters.

An ecosystem was defined in Study Session 1 as ‘all living organisms and their physical environment and the interactions between them’. Pollution can disturb and unbalance those interactions in a number of ways.