Spills point source

Spills may represent the greatest point source release of methyl parathion to groundwater and surface water. An accidental spill caused by a warehouse fire in Nebraska released methyl parathion to a drainage ditch that emptied into the Missouri River (Kawahara et al. 1967). In another incident, 10 tons of methyl parathion spilled in the Mediterranean Sea near Eg q)t as a result of a collision between two ships (Badawy et al. 1984). 

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). 

In addition to large oil spills, petroleum hydrocarbons are released into the aquatic environments from natural seeps as well as non-point-source urban runoffs. Acute impacts from massive one-time spills are obvious and substantial. The impacts from small spills and chronic releases are the subject of much speculation and continued research. Clearly, these inputs of petroleum hydrocarbons have the potential for significant environmental impacts, but the effects of chronic low-level discharges can be minimized by the net assimilative capacities of many ecosystems, resulting in little detectable environmental harm. 

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. 

Initially, a substance is concentrated at one point along a straight line that extends to infinity to both sides. For convenience, the position of the point is defined as x = 0. One real-world problem is the spill of toxic substance into a narrow lake. This problem is called the one-dimensional (or 1-D) point-source problem. With time, the substance would diffuse out and be diluted. The concentration variation as a function of time is shown in Figure l-7a. The mathematical description of the concentration of the substance as a function of x and t is... 

Another widely used solution is for an instantaneous planeAine/point source (such as spill of a toxic pollutant, or diffusion of rare Earth elements from a tiny inclusion of monazite or xenotime into a garnet host) to diffuse away in either one dimension, two dimensions, or three dimensions (Figure l-6b). If the source is initially in a plane, which may be defined as x = 0 (note that x = 0 represents a plane in three-dimensional space), then diffusion is one dimensional. If the source is initially a line, which may be defined as x = 0 and y=0, then diffusion is... 

When environmental contamination occurs, it is the result of either point-source or non-point-source pollution. Point-source pollution comes from a specific, identifiable place (point). A pesticide spill that moves into a storm sewer is an example of point-source pollution. Non-point-source pollution comes from a wide area. The movement of pesticides into streams after broadcast applications is an example of non-point-source pollution. 

Air Point source emission stack, vent (e.g., laboratory hood, distillation unit, reactor, storage tank vent), material loading/unloading operations (including rail cars, tank trucks, and marine vessels). Fugitive emissions pumps, valves, flanges, sample coUection, mechanical seals, relief devices, tanks. Secondary emissions waste and wastewater treatment units, cooling tower, process sewer, sump, spill or leak areas. Equipment wash solvent or water, lab samples. 

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... 

Petroleum hydrocarbon sources to North American and worldwide waters were summarized in a report by NRC (2002). In many cases of large petroleum spills, the specihc source of petroleum spill is evident, and no geochemical fingerprinting is required to establish the source. Nevertheless, the inventory of petroleum compounds and biomarkers that are eventually sequestered in bottom sediments need not reflect sole derivation from a single source, even in cases of massive oil spills in the area (e.g., Kvenvolden et al., 1995 Wang et al., 1999). Where a mass balance of petroleum sources is required to properly design remediation or identify a point source, molecular methods for distinguishing sources of hydrocarbons have come to the fore. 

The intense public interest in chemical contamination of our nation s ground water has been well documented by the media. Pesticide contamination of ground water through agricultural use is a unique situation in comparison to contamination by point source leaching from dumps, landfills, and spills. Consequently, data bases for agricultural pesticide contamination are small, and published research and textbooks are limited. 

The focus of this paper is on spills and point source losses of pesticides, which are generally associated with the manufacture and... 

---