Water Pollution and the Geosphere

Water pollution is addressed in detail in Chapter 4. Mnch water pollntion arises from interactions of groundwater and surface water with the geosphere. These aspects are addressed briefly here. 

The relationship between water and the geosphere is twofold. The geosphere may be severely damaged by water pollution. This occurs, for example, when water pollutants produce contaminated sediments, such as those polluted by heavy metals or polychlorinated biphenyls. In some cases, the geosphere serves as a source of water pollutants. Examples include acids produced by exposed metal sulfides in the geosphere or synthetic chemicals improperly discarded in landfills. 

The sources of water pollution are divided into two main categories. The first of these consists of point sources, which enter the environment at a single, readily identified entry point. An example of a point sonrce is a sewage-water outflow. Point sources tend to be those directly identified as to their origins from hnman activities. Nonpoint sources of pollution are sonrces from broader areas. Such a source is water contaminated by fertilizer from fertilized agricnltnral land or water contaminated with excess alkali leached from alkaline soils. Nonpoint sonrces are relatively harder to identify and monitor. Pollutants associated with the geosphere are usually nonpoint sources. 

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