Critical pathways of radionuclides to man from agro-ecosystems. Annual progress report, October 1980-September 1981

The research program has as its objectives the description of the fate and behavior of radionuclides released to the environment from nuclear fuel chemical separations facilities. The greenhouse uptake studies designed to examine factors which possibly can alter phytoavailability of radionuclides have shown only slight differences among crop species or soil treatment (lime or lime plus chelate) in Pu or Cm uptake. The temporal effect on Pu and Cm uptake, observed from a partial data set, is inconclusive, with variable effects from different crop species, radionuclides, and soil treatments. Cesium uptake shows variable response with different crop species but generally decreases with time. Broadleaf crops grown in the field hve differing Pu concentrations which appear to be associated with plant morphology, with some species exceeding those concentrations observed for wheat and soybean crops. In crops that tend to trap aerially deposited Pu, washing the leaves removed > 50% of the Pu. Uranium contamination of a wheat crop grown near the F-Area separations facility appears to be strongly affected by root uptake. This is in distinct contrast to the behavior of Pu in agro-ecosystems, where surficial pathways are the dominant modes of contamination, and is probably related to: (1) the ubiquitous presence of naturally occurring U isotopes; and (2) a greater concentration ratio for U than for Pu