Chemistry of Natural Waters: A Partnership Between Northland College and the Bad River Watershed Alliancepublished Jan 18, 2011
Northland College is an environmental liberal arts college located in Ashland, Wisconsin. In addition to two, fifteen week semesters, Northland has a May term — a four-week semester where students and faculty focus solely on one course. The Chemistry of Natural Waters is a field and laboratory intensive May-term course taken primarily by chemistry, biology, environmental studies, and geoscience majors. Students learn water quality field techniques as well as analytical skills for laboratory analysis of water samples. This course employed service learning, which has been shown to have a positive impact on students' academic learning (Driscoll et al., 1996), improve student satisfaction with college (Astin and Sax 1998), and improve students' abilities to apply their learning to "the real world" (Eyler and Giles 1999).
During May 2010 the Chemistry of Natural Waters partnered with the Bad River Watershed Association (BRWA) to assess water quality on seven tributaries flowing into the Marengo River, about fifteen miles south of Ashland (see maps in Figures 1 and 2). These tributaries were chosen because BRWA citizen volunteers and last year's Chemistry of Natural Waters class found levels of Escherichia coli (E. coli) that exceed the EPA limit of 235 CFU (colony forming units) (USEPA 1986) downstream of these tributaries on the Marengo River. Our hope was to discover which tributaries contribute to these high levels of E. coli. Additionally, we measured pH, dissolved oxygen, chloride, turbidity, and phosphate in order to better characterize the overall water quality in these tributaries. In addition to assessing water quality in the field, another goal of our course was to help the BRWA characterize the reliability of the data gathered by their citizen volunteers with LaMotte chemical test kits. For the sake of brevity, only our field measurements of E.coli and phosphate will be described in this article.
Figure 1. Map of the Bad River watershed, with the Marengo River watershed highlighted in white. The river flows through sparsely populated and highly agricultural lands.
Figure 2. Chemistry of Natural Waters 2010 Sampling Sites. The Chemistry of Natural Waters students sampled seven tributaries of the Marengo River, all accessed by County Highway C. Sampling sites are marked by black circles.
Sixteen students enrolled in the course Chemistry of Natural Waters in May 2010. The class met formally for eighteen hours a week (see Table 1). On Mondays and Wednesdays students learned some theory but focused mainly on analytical techniques in the lab. On Tuesdays and Thursdays, students met with BRWA representatives, learned field techniques, collected samples, and then analyzed them in the lab. Student evaluation consisted of homework assignments, lab practical exams focusing on accuracy and precision, lab notebooks, and a final group project. Students chose from four group projects: (1) an oral presentation geared to representatives of the BRWA and the Marengo Valley community, (2) a written report for the BRWA detailing our methods and results, (3) a scientific poster that hangs in Northland's science building, and (4) an article that the BRWA published in their quarterly newsletter.
Table 1. Course Schedule for the Chemistry of Natural Waters, 2010.
We collected grab samples of water in the field and brought them back to the laboratory for analysis. These samples were transported on ice and were analyzed within two hours of sampling. In the laboratory, we measured E.coli by combining either 5 mL (for typical conditions) or 2 mL (for turbid samples) of water sample with Easygel Coliscan bacterial growth medium. The resultant solution was evenly distributed in a pretreated petri dish sold by Micrology Labs. The samples were incubated for approximately forty eight hours at 35°C. We used Hach ascorbic acid method 490 and a Hach 2800 spectrometer to measure orthophosphate.
Water Quality Field Samples
Phosphate. Phosphorus is recognized as an important water quality indicator because it is often the limiting nutrient responsible for eutrophication, a situation in which excessive algae growth occurs and ultimately causes water quality degradation (Litke 1999). In rural areas such as the Marengo River Valley, the main sources of phosphorus are non-point sources such as fertilizer, manure, and failing septic systems (Klienman and Sharpley 2003; Carpenter et al. 1998). The benchmark maximum phosphate concentration recommended by the United States Geological Survey (USGS) is 0.1 mg/L4. Phosphate in the seven tributaries sampled was often higher than 0.1 mg/L (of the 32 samples taken from the seven tributaries over six days, 25 had a phosphate concentration greater than 0.1 mg/L). Also, as seen in Figure 3, on May 13, the day of a substantial rain event, phosphate levels exceeded the 0.1 mg/L USGS benchmark at each the five sites sampled.
Figure 3. Phosphate Concentrations during a Rain Event. Phosphate concentrations were higher than the USGS benchmark of 0.1 mg/L at all of the five sampling sites sampled during a rain event on May 13th, 2010.
E Coli. E. coli indicates the presence of fecal matter in a water body and possibly the presence of disease causing bacteria and viruses. The EPA limit for E. coli is 235 CFU/100 mL (EPA 1986). As seen in Figure 4 for Billy Creek, on sampling days when it did not rain, the E coli counts were consistently under the EPA limit. However as depicted in Figure 5, on May 13, 2010, the day of the rain event, E. coli exceeded the EPA limit at all sites but NC-1. These results are in line with other studies that have shown that E. coli counts rise during rain events due to fecal material from humans, wildlife, and farm animals washing into streams (Kleinheinz et al. 2009).
Figure 4. E. coli at Billy Creek During May, 2010. E. coli measurements at Billy Creek were typically below the EPA's limit of 235 CFU throughout the month of May, 2010. However, E. coli counts spiked during a rain event on May 13.
Figure 5. E. Coli at the Seven Sampling Sites During a Rain Event. E. coli counts were higher than the EPA limit of 235 CFU at six of the seven sampling sites during the May 13th rain event.
The partnership between the Chemistry of Natural Waters class and the BRWA was mutually beneficial. The data the class collected will be incorporated into the Marengo Watershed Action Plan to be compiled by the BRWA and submitted to the U.S. Environmental Protection Agency. The BRWA also benefited from the partnership because the time students and faculty spent collecting water quality data was translated into matching funds for a National Fish and Wildlife Foundation grant awarded to the BRWA. Because their data were going to be used by the BRWA, students took their work very seriously, carefully learning the analytical skills necessary to gather reliable water quality data. Moreover, the active role taken by the BRWA helped students understand the relevance of their work. The BRWA worked with the faculty member to design the field and quality control projects, trained our students in the LaMotte chemical test kits, attended the final oral presentation, and asked students what they believed the next steps should be. They also published a student-written article about the course in their quarterly newsletter, disseminating our work to the larger community.
Student learning from the project was summarized well in their final poster:
Phosphate and E. coli were well above the EPA suggested guidelines for the rain event on May 13, 2010.
Continued sampling of the Marengo River Watershed tributaries with multiple rain events is needed for further analysis.
The work of the class is being continued throughout the summer and 2010/2011 school year with funds from a GLISTEN (Great Lakes Innovative Stewardship through Education Network) grant. Two students from the Chemistry of Natural Waters class are continuing to monitor the water quality on the seven tributaries sampled by the class. Depending on their results, next year's Chemistry of Natural Waters students will likely sample the water quality at several points along the most problematic tributaries in an effort to pinpoint the sources of the high phosphate and E. coli measured this spring.
About the Authors
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Carpenter, S., N.F. Caraco, D.L. Correll, R.W. Howarth, A.N. Sharpley, and V.H. Smith. 1998. "Nonpoint Pollution of Surface Waters with Phosphorus and Nitrogen," Issues in Ecology 3: 600–601.
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Kleinman, P.J.A., and A.N. Sharpley. 2003. "Effect of Broadcast Manure on Runoff Phosphorus Concentrations over Successive Rainfall Events." Journal of Environmental Quality 32: 1072–1081.
Litke, D.W. 1999. "Review of Phosphorous Control Measures in the United States and Their Effects on Water Quality." U.S. Geological Survey Water-Resources Investigations Report 99-4007.
U.S. Environmental Protection Agency (EPA). 1986. "Ambient Water Quality Criteria for Bacteria." Report Number EPA440/5-84-002. United States Environmental Protection Agency, Office of Water Regulations and Standards, Washington, D.C.
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