8 - Water Pollution

Abstract

Water pollution causes the introduction of a very wide variety of toxic chemicals to those drinking, cooking, and bathing with impure water. This chapter covers water pollution from many sources such as mining, manufacturing, farming, power production, and runoff from urban and suburban sprawl. Nearly every source of water on earth has been contaminated with xenabiotics. Mining activities frequently impact water resources and contaminate surface water and groundwater systems. Coal mining discharges are acidic and some contain high concentrations of dissolved metals that are reflective of the mineral content of the coal. In some areas, gold mining is accompanied by an amalgamation process using mercury, which causes human to get exposed to it through uptake of contaminated water. Steel and other metal processing plants, food processing plants, textile manufacturing plants, and chemical manufacturing plants are point sources of toxicants to the aquatic environment. The conversion of wood to fiber produces hundreds of chemical compounds that are discharged as effluents into surface water. Farming is responsible for the release of four categories of water pollutants into the water environment: silts, pathogens, nutrients, and pesticides. Further, power production is responsible for the introduction of toxic chemicals into drinking water via several routes that include petroleum production, coal mining, petroleum combustion, and coal combustion. Drinking water has been disinfected with chlorine to protect against waterborne infectious diseases, but in 1970s, it was found that that resulted in the formation of the disinfection by-products (DBPs). The results of human activities have resulted in the release of thousands of pollutants into the environment. In the United States, tap water tests from 1998 through 2003 on more than 39,000 water systems in 42 states, serving more than 231 million people detected 260 different pollutants.