The April 1986 accident at the Chernobyl nuclear power reactor resulted in the pulse-like delivery to the Black Sea of a variety of fallout radionuclides. By studying a number of Chernobyl tracers with differing chemistries, both scavenging and removal processes have been able to be followed for particle-reactive species as well as the rates of physical mixing between the oxic and anoxic waters. A surprising element in all these studies is the rapid vertical and horizontal rates of particle and water transport which are important for all elements. This proposal allows for follow up on the earlier work and adds an important scientific component which is missing from all of the 1988 KNORR- based studies, namely an examination of the northern Black Sea. Specifically, access was gained to the Danube fan region aboard a Soviet research vessel in April 1989. On this cruise the only recent samples from this study area were obtained, which are crucial for completing studies of this basin's geochemistry.
