Appendix E. Key Quantities for Radioecology and Monitoring

Activity concentration also: surface activity concentration (for surface/ area), activity density, activity per mass, activity per volume, activity per area, surface activity Am (for mass) Av (for volume) Aa (for area) Bq kg Bq m Bq m The activity of a specified radionuclide per mass (Am), volume (Av) or area (Aa) of a specified substance. Substance or environmental compartment; mass, volume or area basis; wet or dry mass basis; averaging method. The names “activity per mass”, “activity per volume” and “activity per area” are unequivocal and therefore also recommended. The activity density depends on input and output rates to the specified substance or compartment, and thus on various processes as well as time. This quantity, when applied to transfer from air to soil or water to sediment on a per area basis (Aa) has also been called “deposition density” or “deposition”. For this usage, it is very important to specify whether the measurement reflects initial deposition following a discrete event, or whether it is a measurement made sometime following an event or series of events. For deposition measurement purposes, it is also important to specify the sampling depth because the depth profile can vary greatly. Activity content (for an object, sample, environmental compartment, etc.) also: organ, tissue or wholebody burden A Bq The activity of a specified radionuclide in a specified object Object, substance, environmental compartment, organ or tissue.