Downstream Survival of Total Bacteria, Escherichia coli and Salmonella spp. in Sinking Creek and Evaluation of the Effectiveness of the Implemented Constructed Wetland

• Main Author: Brooks, Blaire
• Format: Others
• Published: Digital Commons @ East Tennessee State University 2020
• Subjects: Escherichia coli; Salmonella; Bacteria; Survival; Sinking Creek; Environmental Health and Protection
• Online Access: https://dc.etsu.edu/honors/572; https://dc.etsu.edu/cgi/viewcontent.cgi?article=1683&context=honors

Access to good quality, pathogen-free water is a necessity for human life. Pathogencontaminated water poses a threat to human health, and steps must be taken to minimize that risk using remediation techniques, such as constructed wetlands. Sinking Creek is a tributary of the Watauga River that was placed on the 2016 303(d) list published by the Tennessee Department of Environment and Conservation due to the presence of Escherichia coli. Because of this impairment, a constructed wetland was placed in Sinking Creek to decrease the downstream transport of pathogens. Knowing this, three primary goals were made for this experiment. The first goal was to establish the seasonal presence of E. coli, Salmonella spp., and other culturable bacteria in Sinking Creek. The second goal was to determine the concentration patterns of E. coli, Salmonella, and other culturable bacteria as water in Sinking Creek flows downstream. The third goal was to use the data to analyze the effectiveness of the constructed wetland in Sinking Creek and its ability to decrease bacterial concentrations downstream. To achieve these goals, water samples were collected every Wednesday from January 29th to March 11th from four sites on Sinking Creek: two upstream from the constructed wetland and two downstream from the constructed wetland. The samples were plated on mFC, XLD, and R2A agar using the micro drop technique to establish the presence of E. coli, Salmonella, and other culturable bacteria, respectively. It was hypothesized that, because of the placement of the wetland, concentrations of E. coli, Salmonella, and other culturable bacteria would be lower at Sites 3 and 4 than at Sites 1 and 2, but this hypothesis was disproved. Data analysis and statistical tests displayed that all bacterial concentrations were higher at Sites 3 and 4 than at Sites 1 and 2. From this, it was concluded that the constructed wetland is not functioning as it was intended, and the increase in bacterial concentrations at Sites 3 and 4 suggest that there is most likely a source of fecal contamination below the wetland.