Pub. date: 2008 | Online Pub. Date: May 28, 2008 | DOI: 10.4135/9781412963930 | Print ISBN: 9781412941655 | Online ISBN: 9781412963930| Publisher:SAGE Publications, Inc.About this encyclopedia
Karen A. Swanson
Water quality is a general term to describe the purity of water, usually in a natural setting. Water that contains low concentrations of impurities or pollutants is generally said to be of high quality; water with many impurities or high concentrations of impurities is considered to be of low quality. Evaluation of water quality most often considers its suitability for a particular use. As a result, a body of water may be considered high quality for an industrial application, yet at the same time, be of too low a quality to serve as a drinking water source. Degradation of the quality of a body of water most often results from pollution, defined here as an undesirable change in the physical, chemical, or biological state of a system. Sources of pollution can be human-made or natural and are classified as either point sources or nonpoint sources. A point source is Nonpoint ...