Application of cesium-137 in a study of soil erosion and deposition in Southeastern Brazil

A study using Cs-137, a component of radioactive fallout, was carried out to estimate soil erosion and deposition on a small watershed in Piracicaba District, Sao Paulo State, Southeastern Brazil. Soil samples were collected along three transects employing different land uses and conservation practices on different slopes. Cs-137 concentration was measured with a high-resolution germanium semiconductor detector coupled to a multi-channel analyzer. The Cs-137 estimates of soil movement and redistribution were related to slope, land use, and conservation practices, allowing the identification of sites with soil loss and accumulation. This study shows that the application of the Cs-137 technique is viable for Brazil. A relationship between Cs-137 concentration in soil profiles and soil losses or accumulations for Brazilian conditions needs to be established to avoid the use of equations developed for the Northern hemisphere.