Nutrient Loading and Associated Anitibiotic Resistant E. coli in Water and Air Samples Neart Large Livestock Facilities in MI

Nutrient loading in streams due to large livestock operations and associated manure application has been well documented.  Fecal coliform bacteria, including E. coli in streams also has been identified and linked to these operations.  Arguments have been made that it is impossible to separate farm inputs from similar nutrient loading from septic fields in rural areas or defective wastewater treatment plants.  Past research has suggested that the comparison of soluble reactive phosphorus (SRP) and ammonia (NH₃) over time is an accurate indicator of direct discharge of animal waste and can separate point source from non-point source discharges.  This study attempted to confirm the use of SRP and NH₃ as a predictive tool for identifying direct discharge into surface water.  In addition, occurrence of fecal coliform bacteria including E. coli was measured in air and water samples and tested for antibiotic resistance to Tetracycline Hydrochloride, an antibiotic commonly added prophylactically to animal feed and rarely used in the human population.  Results show that correlations of SRP and NH₃ were significantly higher downstream from known inputs as compared with upstream samples even though both sample locations were highly influenced by non-point source inputs.  Also, these findings were associated with Tetracycline Hydrochloride antibiotic resistance in fecal coliform bacteria in both water and air samples.  This research further confirms that correlating SRP and NH₃ is an effective and relatively simple way to identify direct discharge of animal waste into streams.  Additionally, this study highlights the impact of the potential proliferation of antibiotic resistant E. coli specifically due to these large livestock operations.