This project will investigate reactions that could potentially reduce Disinfection By-Products (DBPs) in distribution systems. The researchers hypothesize that the dominant abiotic loss pathways involve reactions with pipe deposit material and with nascent cast iron, especially under reduced conditions. The objective of this research is to characterize the reactivity of selected DBPs with model and collected pipe deposit material, and with cast iron. A special emphasis will be on reactions with unidentified organic halide containing compounds, referred to as unidentified Total Organic Halogen uTOX. This material generally accounts for over 75% of the total halogen incorporated into organic matter.