Fate and transport of N-nitrosamines under conditions simulating full-scale groundwater recharge operations.

The key objective of this study was to investigate the attenuation mechanisms of seven N-nitrosamine compounds at environmental concentrations and under conditions relevant to groundwater recharge operations. The study used a combination of controlled laboratory-scale soil-column experiments and groundwater monitoring at a full-scale river-bank filtration facility. Findings of the controlled column experiments suggest that N-nitrosodimethylamine and six other N-nitrosamines (N-nitrosodiethylamine, N-nitrosomethylethylamine, N-nitroso-n-propylamine, N-nitrosodi-n-butylamine, N-nitrosopiperidine, and N-nitrosopyrrolidine) are biodegradable under oxic and anoxic oxidation-reduction conditions. Half lives determined in this study for the targeted compounds varied between 1.3 and 7 days, which will ensure a removal to below detection limits (< 2 ng/L) within short travel times in groundwater recharge systems. Findings of this study suggest that complete removal of N-nitrosamines requires the presence of an adapted biocommunity, which will be established over several weeks to months.