Lecture
To open the Module Guide, click on the link highlighted by asterisk in the paragraph to the left of this box. In the pop-up screen, choose "Save" and save the document to your hard drive or flash drive. Then, open the document and fill it out as you read in your textbook. Do not simply open it from your browser; you will not be able to save your additions.
In this lecture we’ll be working on applying several course concepts. As you read through the readings, try to think about the concepts of Earth as a System (Environmental Unity), Population Growth, and Sustainability. You’ll be working through this Lecture and Readings by filling out the Module Guide*. This document will help you to organize the information presented in the two chapters and this Lecture. The guide is organized by pollutants, pollution control, case studies in pollution, and concludes with an Objective Guide, similar to the ones we have been using for previous modules.
Definitions
As you get started with filling out the Study Guide, let’s begin with some definitions.
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Point source of pollution - Combined sewer overflow pipe releasing sewer water into Fall Creek in Indianapolis. (Photo Credit: USGS)
A pollutant is any substance introduced into the environment which negatively affects the usefulness of a resource (e.g., water, air, or soil) or the health of plants, animals, humans, and/or an ecosystem in general (U.S. EPA). This is a much broader definition that your book gives as your book is defining a “water pollutant.” This means that a non-toxic, biodegradable paper cup can be a pollutant even if it doesn’t cause negative health effects. Imagine if someone threw 10,000 of them into Eagle Creek Reservoir. Even though the cup was biodegradable, the shear mass of cups would adversely affect our ability to use the reservoir as a resource. We’d have to expend money to clean it up. This also means that those plastic rings that hold together six-packs of canned soda pop can be a pollutant as aquatic animals can become physically trapped in the rings and drown. Finally, toxic substances can also be considered a pollutant because they can negatively affect the health of plants, animals, humans and ecosystems as a whole.
There are two types of pollution: point source and non-point source.
Point source pollution is simply any pollution that comes from a single, identifiable source. Your book defines it as a “discrete and confined” source. This simply means that we can identify the source; we can point to a pipe coming out of a factory, the exhaust of a car, or smoke stack and say, “Yeah, that’s the point from which the pollution is coming.” This is significant because these point sources can be controlled. It is relatively simple to put a plug on a pipe or to otherwise control that pollution. I say relatively because…
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Non-point source of pollution – Animal feed lot pond which collects manure. The run-off is stored there until it can be spread on the fields as fertilizer. (Photo Credit: D. Jones, Purdue University)
Non-point source pollution is not so easily controlled. Non-point sources of pollution are essentially all other sources of pollution. Your book defines this as “diffuse or intermittent.” This means that these sources do not come from a pipe or any identifiable point. These sources are intermittent because the can cause pollution as an effect of different environmental conditions. For example, a hog farm – of which we have many along the I-65 corridor – is a non-point source of pollution. The waste from hog farms is generally stored in ponds. As the waste decomposes, it can cause air pollution. The smell near a hog farm can be quite pungent – and not in a good way as you may have noticed. (Do you remember the Pigs in Politics video from the Scientific Method Module?) Because the air pollution is coming from a “diffuse” source, a large pond, it is a non-point source of pollution. The hog farm pond can also become an intermittent source of pollution to nearby streams if there were to be a sudden rainstorm that caused the pond to overflow, sending the waste into the stream. Here in Indiana, this is a pervasive and wide-spread problem. Many of our streams are polluted with E. coli from feedlot wastes. Because the waste ponds become a source of fecal waste pollution during the environmental condition of a rainstorm and the source of this type of pollution does not come from a pipe, the hog farm waste ponds is categorized as a non-point source of pollution to streams. (The link in this paragraph is not required reading.)