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The Clean Water Act has made great strides in reducing point source water pollution, but this effect is overshadowed by the fact that nonpoint source pollution, which is not subject to regulation under the Act, has correspondingly increased. [41] One of the solutions to address this imbalance is point/nonpoint source trading of pollutants.
Nonpoint sources are the most significant single source of water pollution in the United States, accounting for almost half of all water pollution, [1] and agricultural runoff is the single largest source of nonpoint source water pollution. [2] This water pollution has a number of detrimental effects on human health and the environment.
Nonpoint source pollution is the leading cause of water pollution in the United States today, with polluted runoff from agriculture and hydromodification the primary sources. [ 44 ] : 15 [ 21 ] Regulation of Nonpoint Source Pollution in the United States
Water pollution also reduces the ecosystem services such as drinking water provided by the water resource. Sources of water pollution are either point sources or non-point sources. [4] Point sources have one identifiable cause, such as a storm drain, a wastewater treatment plant, or an oil spill. Non-point sources are more diffuse.
A point source of pollution is a single identifiable source of air, water, thermal, noise or light pollution. A point source has negligible extent, distinguishing it from other pollution source geometrics (such as nonpoint source or area source). The sources are called point sources because in mathematical modeling, they can be approximated as ...
Topsoil runoff from farm, central Iowa (2011). Water pollution in the United States is a growing problem that became critical in the 19th century with the development of mechanized agriculture, mining, and manufacturing industries—although laws and regulations introduced in the late 20th century have improved water quality in many water bodies. [1]
Beginning in the 20th century, designers of industrial and municipal sewage pollution controls typically utilized engineered systems (e.g. filters, clarifiers, biological reactors) to provide the central components of pollution control systems, and used the term "BMPs" to describe the supporting functions for these systems, such as operator training and equipment maintenance.
In some areas, especially along the U.S. coast, polluted runoff from roads and highways may be the largest source of water pollution. For example, about 75 percent of the toxic chemicals getting to Seattle, Washington's Puget Sound are carried by stormwater that runs off paved roads and driveways, rooftops, yards, and other developed land. [6]