ABSTRACT
Water bodies can be fully characterised by the three major components: hydrology, physico-chemistry, and biology. A complete assessment of water quality is based on appropriate monitoring of these components. All freshwater bodies are inter-connected, from the atmosphere to the sea, via the hydrological cycle. Thus water constitutes a continuum, with different stages ranging from rainwater to marine salt waters. The parts of the hydro-logical cycle which are considered in this book are the inland freshwaters which appear in the form of rivers, lakes or groundwaters. This chapter demonstrates the evolutionary nature of chemical water quality issues in industrialised countries. Water quality assessment includes the use of monitoring to define the condition of the water, to provide the basis for detecting trends and to provide the information enabling the establishment of cause-effect relationships. The chapter illustrates, in schematic form, the principal pathways of pollutants that influence freshwater quality.
