Sediment movement on beaches is an important consideration in sedimentologic research. The source, history of movement, and ultimate fate of beach sand are essential factors in the planning of modern coastal facilities and the reconstruction of sedimentary patterns in the past. Long-term studies based on models or surveys of erosion or accretion are traditional approaches but they tend to be awkward and expensive. Studies of sediment movement using radioactive, fluorescent, or mineralogic tracers are proving to be a most useful source of both theoretical and empirical information. Fluorescent dyes commonly are preferred because they are safe, inexpensive, easy to apply, and readily identifiable. A surface film of anthracene, a common fluorescent organic chemical, proved s tisfactory for short-term studies. The technique was tested in the intertidal zone of a beach in New York Harbor, where direction and rate of sediment movement was clearly demonstrated.

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