Boron isotope ratio measurements with a double-focusing magnetic sector ICP mass spectrometer for tracing anthropogenic input into surface and ground water

Double-focusing magnetic sector inductively coupled plasma mass spectrometry (ICP-MS) is used for precise boron isotope ratio measurements in surface and ground water. The precision is in the range of 1–2‰. Boron in detergents has a characteristic isotope ratio that can be used to identify the boron source. Anthropogenic input of boron into surface and ground water has been successfully identified by analysing the boron isotope ratios in an area north of the Harz Mountains in Germany. The method was validated by comparing the results of the boron isotope ratio measurements with the lithium concentration. Lithium is anthropogenically released in the study area and is used as a second independent tracer. The conclusions from the boron isotope ratio measurements agree exactly with those from analysis of Li concentrations in the study area.