Use of Bromide to Trace Infiltration of Rainfall through Sandy Soil in Northeast Thailand

Abstract

Bromide (Br -) was used to successfully trace the infiltration of rainfall through a sandy soil in northeast Thailand. A method was developed to measure the Br -concentration in extracted water from soil samples in order to determine the vertical distribution of the Br -concentration in soil water. Our experimental results revealed that Br -moved downward with a piston flow and that the increase in the amount of water in the soil above the depth of the peak Br -concentration equaled the increase in soil moisture caused by the infiltration. Using our method, we found that the largest amount of rainfall infiltration occurred during September. The amount of soil water above the peak Br -concentration was calculated to be about 0 mm during the period between

pH Dependence and Unsuitability of Fluorescein Dye as a Tracer for Pesticide Mobility Studies in Acid Soil

“…Several inorganic ions may be used as tracers, with bromide being the most common (for example van Staden 1987;Ndongo et al 2000;Ammann et al 2003;Flury and Wai 2003;Clay et al 2004;Petersen et al 2004;Hamada et al 2005), although chloride (Kissel et al 1973) and chromium (Watson 1969) are sometimes used. It is believed that anions make ideal tracers due to their repulsion by negatively charged soil particles, a phenomenon known as ion exclusion (Flury and Wai 2003).…”