Weatherill, J.J., S. Atashgahi, U. Schneidewind, S. Krause, S. Ullah, N. Cassidy, and M.O. Rivett. Water Research 128:362-382(2018)
Filed Under: Research
Filed Under: Research
The aquifer-river interface (i.e., hyporheic zone) is a critical pathway for chlorinated ethane (CE) discharge to surface water bodies in groundwater baseflow. The pore water system may represent a natural bioreactor where anoxic and oxic biotransformation process act in synergy to reduce or even eliminate contaminant fluxes to surface water. This review encompasses current process understanding of anaerobic CE respiration in the competitive framework of hyporheic zone biogeochemical cycling fuelled by in situ fermentation of natural organic matter. Anoxic-oxic interface development for metabolic and cometabolic mineralization by a range of aerobic bacteria is conceptualized with a focus on vinyl chloride degradation pathways. The superimposition of microbial metabolic processes occurring in sediment biofilms and bulk solute transport delivering reactants produces scale-dependent contaminant transformation rates. Insights from recent field experience of CE plumes discharging to surface water are discussed and a range of practical monitoring technologies is introduced to address the inherent complexity at different spatial scales.