Spills nonpoint source

Pesticides in wastewaters come typically from point sources of contamination such as disposal sites and landfills where industrial or agricultural wastes are buried without any consideration, as well as discharges from industrial effluents from pesticide production plants. Furthermore, nonpoint sources derived from regular agricultural activities, especially in intensive agricultural areas, and accidental spills can also be significant. Urban use of pesticides is also possible in large cities where the use of herbicides and insecticides may result in runoff into the sewers. These sewers in turn may expel pesticides into wastewater treatment plants (WWTPs). 

Organic contaminants can be released to the surface in different ways, and contamination can be classified as point source and nonpoint source (or diffuse source). As an example of a nonpoint source, we discuss the case of pesticides applied during agricultural activity over large areas an example of point source contamination is given by the behavior of petroleum products that reach the subsurface as a result of leakage (or a spill) from pipes or from a gas station. 

Widely distributed and frequent point source spills can be considered nonpoint sources when the scale of concern is large in space or time. For example, the United States generates 1.3 billion gallons (4.9 X 10 L) of used motor oil each year, of which —13% is disposed of improperly (Motor Oil Facts, http //www.epa.gov/seahome/ housewaste/src/oilfact.htm). This large quantity of improperly disposed motor oil could be a regional... 

Sources of pollutants are commonly divided into two categories point sources and nonpoint sources. Point sources of pollution refer to discrete, localized, and often readily measurable discharges of chemicals. Examples of point sources are industrial outfall pipes, treated sewage outfalls from wastewater treatment plants, and untreated storm water discharge pipes. A spill of chemicals, due fo an accident on or near a surface water body, can also be regarded as a point source because its initial areal extent is limited. Point sources are often modeled by "plume" or "cloud" models that explicitly consider where and when a chemical release occurs, and then mathematically model the concentration of the chemical as a function of time and location. 

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