Survival, mobilization, and transport of Escherichia coli from sheep faeces

Aims: This study looked at the survival, mobilization, and transport of Escherichia coli from sheep faeces over an extended period, which was then repeated for all four seasons. Methods and Results: Rain simulation was used to measure E. coli mobilization directly from faecal pats and subsequent transport across a soil surface. The rain simulation experiments were conducted over the same 90-day period and for the four seasons as per the survival experiments conducted to determine E. coli survival in faecal pats. The survival experiments demonstrated up to three orders of magnitude increase of E. coli in sheep faeces. Peak E. coli concentrations in the faeces were observed on Day 2 through to Day 30, with no significant effect of seasons or weather patterns. The E. coli concentrations in the runoff followed the survival pattern of E. coli concentrations in the faeces. Conclusions: There was a statistically significant relationship between the E. coli concentrations in the faeces and the runoff. Significance and impact of study: The data generated on the relationship between Escherichia coli concentrations in the faeces and in the runoff can support the development of runoff risk models for sheep grazing pastureland to support catchment modelling, land use decisions, and public health.