SOURCE-TRACKING OF FECAL CONTAMINATION IN A TIDAL CREEK IN COASTAL SOUTH CAROLINA

In South Carolina, there are 504 water bodies identified as impaired for recreation or shellfishing activities. 78% of those impairments are due to pathogen levels above regulatory limits. Upper Inlet Creek, a tidal creek located along the Atlantic Intracoastal Waterway in Mount Pleasant, SC, is an important habitat for a variety of estuarine life and supports local shellfish operations. According to the South Carolina 303(d) list for impaired waterways, Upper Inlet Creek is impaired for shellfishing activities due to high levels of fecal coliform, a type of bacteria indicator. However, it is unknown whether this impairment is due to human fecal contamination (i.e. sewage or septic) or due to non-point sources such as stormwater runoff, pets and wildlife. The goal of this study was to determine possible causes and sources of fecal contamination by using various inexpensive source-tracking methods. Methods included the use of fecal indicator bacteria fecal coliform and enterococci, optical brightener measurements, targeted sampling, and water quality monitoring and analysis for pH, temperature, turbidity and conductivity. Objectives of this study were to (1) provide monthly water quality and bacteria monitoring for the impaired waterway for a 12 month period, and (2) identify potential bacterial sources and best management practices (BMPs) that could be implemented to reduce bacteria loading in coastal streams similar to Upper Inlet Creek. Results from the source tracking study indicate that the measurement of bacterial indicators in conjunction with optical brightener analyses was effective in determining a probable sources of fecal contamination in Upper Inlet Creek. Fecal contamination at this site is likely due to a combination of non-point sources such as wildlife, pets, and stormwater runoff. By providing methodology for inexpensive water quality and pathogen source assessment, this study will assist in future mitigation efforts in tidal creeks of coastal South Carolina and the Southeast.