Nature & Environment
Effects of pollutants on the aquatic environment
...often able to return to a clean and unpolluted condition as the pollutants are flushed out and carried down to the sea. In addition, because of the organisms present (e.g. bacteria capable of breaking down organic matter), river water has some capacity for self-purification – unless too many of these organisms are killed off too quickly. Some pollutants are objectionable because they overload the self-purification processes ......
