Tracing sources of ammonium in reducing groundwater in a well field in Hanoi (Vietnam) by means of stable nitrogen isotope (d15N) values
In the Southern part of Hanoi, high ammonium (NH4 + ) concentrations in reducing groundwater have been an issue over the last 25 years. Elevated NH4 + concentrations in groundwater, in general, are an indicator of influences from anthropogenic sources, but the buried peat layers in the Red River delta formation are also hypothesized to contribute to the high NH4 + levels (up to 100 mg/l). We trace
