E. coli in the Ohio River and its Tributaries

Abstract

Escherichia coli(E. coli)is a bacterium found in the lower intestines of warm-blooded animals. The presence of E. coli in streams indicates that feces of warm-blooded animals are present and causes water to become cloudy with an unpleasant odor. High concentrations of E. coli are a health concern because it is an indicator that pathogenic bacteria and viruses may also be existing. The US Environmental Protection Agency sets a maximum safe limit of 235 colony forming units (cfu) for recreational water usage, but concentrations of E. coli can change rapidly with environmental conditions. We sought to investigate trends of E. coli concentrations in the Ohio River and Wheeling Creek, a tributary to the Ohio River because both are increasingly being utilized for recreational activities. We collected water samples weekly at two sites on the Ohio River, five sites on Wheeling Creek, and three sites on tributaries of Wheeling Creek between September 27, 2018, and December 27, 2018. In total, we collected 128 samples that were analyzed for E. coli using the IDEXX Colilert System. We have found that the concentrations ranged from 25 to 2,400 colonies of E. coli, and only 43 readings (32.8%) were below the EPA safe standard for recreational usage. The Ohio River and tributaries of Wheeling Creek tended to have lower concentrations of E. coli than Wheeling Creek itself. As the temperature declined in December E. coli concentrations decreased likely driven by the bacteria only being able to survive in waters 4°C and warmer.