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Sources of Nonpoint Source Polution |
Related to water resources, nonpoint source pollution is the introduction of impurities into a surface-water or an aquifer, usually through a non-direct route and from sources that are "diffuse" in nature, meaning there is not a direct discharge pipe. Discharges from nonpoint sources are usually intermittent, associated with a rainfall or snowmelt event, and occur less frequently and for shorter periods of time than do point source discharges. Nonpoint sources of pollution are often difficult to identify, isolate and control.
"Nonpoint Source" is commonly abbreviated as "NPS." Examples of NPS pollution include: automobile emissions, road dirt and grit, and runoff from parking lots; runoff and leachate from agricultural fields, barnyards, feedlots, lawns, home gardens and failing septic systems; and runoff and leachate from construction, mining and logging operations. Most NPS pollutants fall into six major categories: sediment, nutrients, acid and salts, heavy metals, toxic chemicals and pathogens, according to the U.S. Department of Agriculture (USDA), and other state and federal agencies.
Sediment, nitrate-nitrogen, phosphorus, and fecal coliform are the biggest sources of NPS pollution in the Upper Olentangy River Watershed. It is important to understand the affects of each of these. In this issue we will discuss fecal coliform. Nitrates will be discussed in the next issue.
Fecal coliform counts are an indicator of harmful bacteria that can make people and animals sick. It can be found in well water, but more commonly is found in the stream water of the Upper Olentangy, coming mainly from poorly maintained septic systems (for more information see the article on septic system maintenance) with a small contribution from and agricultural runoff. High concentrations of greater than 1000 colonies per 100ml of water can make adults and large animals sick. Less than a count of 1 can cause illness in children and adolescent animals as well as the elderly and anyone with a weakened or compromised immune system. It is common to have higher counts in the summer because of the decrease in rain that concentrates the bacteria in streams.
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