Pathways and mean residence times of dissolved pollutants in the ocean derived from transient tracers and stable isotopes

During the past decades, a variety of transient tracers have been used to d erive information on pathways and mean residence times of oceanic water mas ses. Here, we discuss how information obtained in such studies can be appli ed to studying the spreading of dissolved pollutants in the ocean. The disc ussion focuses on the transient tracers tritium/He-3 and the (H2O)-O-18/(H2 O)-O-16 ratio of water. These tracers are used in combination with CFCs and C-14 in a case study of Arctic Ocean contaminant transport to: (1) separat e the freshwater components contained in the near-surface waters; (2) infer mean pathways of freshwater and associated contaminants from the (H2O)-O-1 8/(H2O)-O-16 distribution in the surface waters; and (3) determine mean res idence times of the surface, intermediate, deep and bottom waters. (C) 1999 Elsevier Science B.V. All rights reserved.