Water Quality

The availability of a water supply adequate in terms of both quantity and quality is essential to human existence. Early people recognized the importance of water from a quantity viewpoint. Civilization developed around water bodies that could support agriculture and transportation as well as provide drinking water. Recognition of the importance of water quality developed more slowly. Early humans could judge water quality only through the physical senses of sight, taste, and smell. Not until the biological, chemical, and medical sciences developed were methods available to measure water quality and to determine its effects on human health and well-being.
Like all sciences, the science of water quality has developed its own terminology and the means of quantifying these terms. The purpose of this lecture is to introduce the students and readers to the modern concepts of water quality. The means by which the nature and extent of contaminants in water are measured and expressed are presented along with the sources of various contaminants that find their way into water. An understanding of the material in this lecture will be essential in subsequent lectures dealing with water quality changes in both natural and engineered systems.