Dust, sand and fish: neutron activation analysis of rare-earth tags

This paper discusses the advantages of stable-element tags over radioactive ones in studying complex systems outside the laboratory, and illustrates three applications. These are collaborative investigations of atmospheric transport of dust, seabed movement of sand, and long-term survival rates of freshwater fish. All use lanthanide tags, with analysis by instrumental neutron activation. The importance of a high-throughput, inexpensive analytical method is stressed. (author) 7 refs.; 5 figs