ABSTRACT
Water in every phase of the hydrological cycle, from precipitation through terrestrial surface and groundwater systems to the marine environment, has a quality dimension that can be described by reference to numerous physical, chemical and biological properties, and is controlled by a myriad of natural factors and human influences. Water quality is of fundamental importance in the provision of potable supplies to sustain human life and in the health of aquatic ecosystems. It also significantly affects a wide range of human uses of water in industry, agriculture, transport and recreation. At the same time, these uses and other human activities, directly or indirectly, provide manifold sources of water contamination. Where the consequences or side-effects of human scientific, industrial and social habits result in conditions within the water environment that are harmful or unpleasant to life, the term ‘water pollution’ is used (Sweeting 1994). Acute water quality problems, however, may also arise from natural climatic or geological conditions.
