Fecal Microbe Contamination in Otter Creek, Madison County, Kentucky
Environmental Health Science
We measured the concentration of fecal microbes in the Otter Creek watershed to determine possible contaminant sources. Otter Creek is one of the principal watersheds in Madison County and drains into the Kentucky River. Land use determines the type and intensity of contaminants. The watersheds drains mainly rural lands mostly devoted to raising cattle, but also drains a portion of the town of Richmond. Cattle farming, septic tanks, and sewage lines are possible sources of fecal contamination.
We comprehensively sampled the entire drainage basin but focused sampling at key locations such as major stream confluences and proximal to likely fecal microbe sources. We used IDEXX materials to quantify E. coli counts. 100-mL samples were taken in the field, immediately put on ice, and transported to the laboratory. Each sample was spiked with growth media specific to E. coli containing tags that fluoresce under UV light.
The EPA has created guidelines for fecal contamination based on E. coli counts. 25% of samples show waters fit for human bathing (/100 mL) whereas 20% are fit for recreation only and 55% are designated as human contact not recommended (>575 cfu/100 mL). High E. coli counts consistently occur in Dreaming Creek, which drains mostly Richmond. High counts also occur associated with pastures. We sampled the watershed immediately before and after a significant rainfall event and found that E. coli counts increased significantly afterward. We could not demonstrate any donation of fecal microbes from septic tanks situated in rural areas.
Robin, Jacob L., W.S. Borowski, Elijah D. Wolfe, 2015. Fecal microbe contamination in Otter Creek, Madison County, Kentucky. Kentucky Academy of Science, 101st Annual Meeting, Northern Kentucky University, November 13-14 2015, pg. 35.
Kentucky Academy of Science, Northern Kentucky University