This lesson explores pathogens, a major type of nonpoint source pollution affecting the Lower Grand River Watershed. Fecal coliform and Escherichia coli (abbreviated as E. coli) bacteria data from sampling sites in the Lower Grand River Watershed are analyzed, and a task force is simulated to address pathogen issues.
Students answer these essential questions in the context of the Lower Grand River Watershed: What are waterborne pathogens? What are the sources and effects of pathogens? What are some methods of monitoring pathogens? How can the pathogen load in a stream or river be reduced?
A pathogen is any disease-producing agent, especially a virus, bacterium, or other microorganism. Examples of pathogens that are associated with waterborne disease outbreaks are: bacteria (Legionella, Shigella, Vibrio cholerae, Salmonella, Yersimia, E. coli 0157:H7, Campylobacter), protozoans (Cryptosporidium, Giardia, Toxoplasma), and viruses (hepatitis, coxsackie, Norwalk). Pathogenic organisms are generally present in surface waters in very low numbers, but typically pose relatively little risk to human health at such small amounts. Major sources of pathogens that pose a higher risk to human health are human waste (feces), agriculture practices (livestock operations and using manure as fertilizer), and animals (wildlife and pets).
Analytical tests to determine the presence, quantity, and type of pathogens in our water bodies are both expensive and difficult to conduct. Consequentially, levels of fecal coliform bacteria and Escherichia coli (E. coli) bacteria are often used as indicators of the presence of pathogens instead of monitoring for each individual disease-causing organism. The presence of fecal coliform bacteria and E. coli bacteria in water samples indicates human waste might be present in the water. This means human waste potentially has contaminated the water with a variety of pathogens that could make people sick.
The U.S. Environmental Protection Agency (EPA) “develops criteria to protect people from microbial organisms such as bacteria and viruses in water bodies (e.g., lakes, rivers, beaches). State and tribal governments can use the criteria as guidance when setting their own water quality standards to protect human health.” Water quality standards for pathogens are based on indicator bacteria since it is not feasible to test for each individual pathogenic organism. Rule 62 of the Michigan Water Quality Standards (Part 4 of Act 451) limits the concentration of microorganisms in surface waters of the state and surface water discharges, such as treated wastewater.
MDEQ estimates that about half of Michigan’s river miles are impaired by E. coli, and about 22% of beaches had closures due to E. coli contamination in 2014. MDEQ’s BeachGuard site can be consulted to view current beach closings and supporting monitoring data (http://www.deq.state.mi.us/beach/). Elevated E. coli levels are a reason to close beaches and limit recreational activities.
Monitoring for indicator bacteria in the Lower Grand River Watershed has been conducted for decades by the Grand Rapids Water Resource Recovery Facility. The Facility’s long-term datasets are valuable for assessing the variations in bacterial load from tributaries of the Grand River, as well as monitoring the efficacy of the operations of the Facility. The city has implemented several improvements to reduce the bacterial load coming from the Facility, such as construction of a retention basin, separating the sanitary sewer system from the storm sewer system, limiting discharges, evaluating and repairing sewer systems, and passing local ordinances. These improvements have largely eliminated combined sewer overflow events in Grand Rapids.
The Lower Grand River Watershed Management Plan (LGRWMP) identifies subwatersheds affected by pathogen pollution. Nonpoint sources of pathogen contamination appear to be more prevalent than point sources of contamination in the watershed. The main sources are cropland, livestock, septic tanks, ducks and geese, and the sanitary sewer.
For more detailed background information and references, click on Lesson 3: Managing Pathogens, in the For Teachers section below.
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The Michigan Department of Environmental Quality’s Nonpoint Source Program assists numerous non-profit entities and other local, state, and federal partners to reduce nonpoint source pollution (NPS) statewide. NPS pollution comes from all over the watershed – anywhere rain falls. There is no specific source like a pipe or smoke stack. As such, the basis for this program is watershed management.
The Lower Grand River Watershed Management Plan (LGRWMP) is a document developed to provide a description of the watershed, identification of impairments, and goals and objectives for management and improvement of the watershed. The WMP’s Information and Education (I&E) Strategy calls for educating stakeholders about the watershed and the impacts that stakeholders have on the watershed. The strategy has three steps: (1) awareness, (2) education, and (3) action.
With funding from the Michigan Department of Environmental Quality (MDEQ) Nonpoint Source Program, four lessons that draw upon information from the Lower Grand River Watershed Management Plan (WMP) have been developed for teachers. The purpose of these lessons is to further the I&E objectives that reach students as outlined in the WMP.
The three main nonpoint source pollutants of concern in the Lower Grand River Watershed Management Plan include sediment, pathogens, and nutrients. The lesson titles, which reflect this, are: