Study on the Variation of Hydrogen and Oxygen Isotopes in Soil Water

Understanding the movement of soil water is important for water resource management and for analyzing pollutant transport in the vadose zone. The information about transfer and transformation in soil water could be provided by isotope tracing technology. The stable isotopic composition of soil water may be affected by many factors, e.g. precipitation, surface evaporation and movement of soil water. In this paper, basic principle of isotope transformation, main influence factor and the variation process of stable isotope concentration are studied. An experiment of isotope exchange in soil columns is carried out, and the exchange and mixing processes between input water and soil water are analyzed. The results show that the isotope concentration variation of mixed water in soil columns may reach more than 20% compared to the initial input water while the mass proportion of soil water and input water is about 3:10, which indicate that the isotope exchange degree is considerable. Therefore, the mixing action between precipitation and soil water may be an important way for the isotopic variation of soil water in the basins.