In the present state of the art in nuclear operations, environmental monitoring is as fundamental as film badges, neutrons, or uranium. Presumably there will come a time when one is sufficiently confident of the ability to design a reactor, a chemical processing plant, or other nuclear facility, that the question of environmental contamination will never arise; that time has not yet come. Preoperational monitoring to date has chiefly consisted of measurements of gross activity; it is the purpose of the paper to show the usefulness of analysis for specific nuclides in this type of measurement. (Author)