Coupled Impacts of Agricultural runoff and ethanol pollution

Abstract

Ethanol losses to surface water bodies are widely recognized to deplete dissolved oxygen due to rapid biodegradation.  Notably, this has resulted in fish kills in downstream receiving waters following acute spillage events, as evidenced by recent warehouse collapses in central Kentucky distilleries.  While such events are rare, chronic releases of low levels of ethanol to surface waters are inevitable from distilleries and these acute spills may also lead to chronic contamination of groundwater resources. Oxygen depletion issues are confounded in agroecosystems by the high nutrient concentrations in runoff and subsurface drainage from agriculture landscapes that promote high rates of in-stream primary production (Ford and Fox, 2014).  Sustainable management solutions require consideration of these complex biochemical processes as well as consideration of future climate and production predictions.  For instance, precipitation and temperature changes for the midwestern region of the US may alter stream hydrology, algal biomass dynamics, and nutrient loadings from agricultural runoff (e.g., Sinha et al., 2017).   Likewise, expansion of the bourbon industry will likely simultaneously increase losses of ethanol to surface waters.  A need exists to evaluate how sensitive stream dissolved oxygen levels are to ethanol pollution and to determine potential sensitivity under future conditions.