Sampling the Little Wildcat Creek
Author: Logan Jennings | Major: Biological Engineering | Semester: Spring 2022
Hello, my name is Logan Jennings, and I am a recently graduated Biological Engineering major. Over the course of Fall 2021 and Spring 2022, I had the pleasure of working with Dr. Brian Haggard and the Water Quality Lab with the Arkansas Water Resources Center (AWRC) to determine the impact that varying land usage has on elemental concentrations within Northwest Arkansas streams. In this project, we looked into three types of land use- urban, including both residential and industrial development, agricultural, and forested. The breakdowns of each land use type were provided by the Model My Watershed tool (https://modelmywatershed.org/), using the Land Use/Cover 2019 data.
In order to have enough data to establish correlations, I initially chose 21 different stream sites around Northwest Arkansas to collect three sets of samples from. The sampling proved to be the most difficult part of the entire project, for many reasons. For one, I had to drive out to each of the streams to personally collect samples. It is best to collect the entire set of samples within one or two days of each, so that meant around 10 hours of driving each time. Fortunately, one of my roommates was able to come along for the ride, so it wasn’t nearly as bad as it could have been. Driving time aside, however, there were a few other issues that we ran into during sample collection. Two of the sites had no water flowing through at any point, so I only ended up with 19 samples each time. On top of that, I went out and collected samples from early January through late March, as that is the time of year with highest average flow rates. This meant that I was getting my hands wet in sub-20-degree weather. Not a fun experience, let me tell you.
Once I collected the samples, I delivered them to the AWRC’s Water Quality Lab, where Dr. Haggard and his team analyzed them for elemental concentrations. I wasn’t personally involved with running the machine, but the analysis was done using inductively coupled plasma optical emissions spectrometry (ICP OES). In this process, the samples are run through a high-energy argon flame, which excites the atoms within the sample and causes them to release an emission spectrum. This spectrum is then analyzed to determine the concentration of elements within the sample. Dr. Haggard helped a great deal with this stage of the project, both in ensuring the ICP OES analyses were performed accurately and on time, and in guiding me through the process of translating the data to useful results.
Once the ICP OES results came back, I performed various statistical analyses to determine what elements were correlated with the changing land use categories. Overall, I found that increasing urban land use corresponded to increasing concentrations of boron, copper, calcium, magnesium, and sodium. Increased agricultural land use corresponded to increased barium and potassium, but also decreased magnesium and zinc concentrations. No positive correlations were found between forested land use and any elemental concentrations, which was in line with initial expectations. What was surprising was the negative correlation between agricultural land and magnesium and zinc, as we did not expect human development to reduce any elemental concentrations. More research into this topic may be worthwhile.
This Honors College Research Grant allowed me to further pursue my interests in academia. While I do not plan on making a career of this exact topic, many of the skills I picked up will be of use later in life. Writing in a professional manner, for example, will be a valuable skill no matter where I end up. On top of that, my research has led to further questions, and may be the groundwork for future research. I am proud to have performed something that can be built upon in the future.