Redistribution of Cesium-137 as an example of a chemical indicator of environmental stress.

The use of the artificially-produced radioactive isotope Cesium-137 for the measurement of soil erosion is examined in this article as an example of the development of a chemical indicator of a specific environmental stress. The theoretical and methodological bases of the technique ar examined in the context of seven criteria developed to assess the suitability of a technique as a chemical indicator. The type of results available from the application of the technique are demonstrated for research in agricultural ecosystems in Saskatchewan, Canada. The research indicates that mean soil losses within agricultural fields are 2 to 3 times higher than the tolerable soil losses for the area and that net soil export from fields is a poor indicator of the intensity of erosion within the field. The major remaining constraint to the use of the technique is the lack of a standardized sampling and analytical framework for researchers using the procedure.