Comparative food chain behaviour and distribution of actinide elements in and around a contaminated fresh-water pond
1982
Garten, C.T. | Trabalka, J.R. Jr. | Bogle, M.A. (Oak Ridge National Lab., TN (USA))
The bioaccumulation of sup(233,234)U, 238U, 238Pu, sup(239,240)Pu, 241Am, and 244Cm in both native and introduced biota was studied at Pond 3513, a former low-level radioactive waste settling basin (0.4 ha surface area) at Oak Ridge National Laboratory. This system, which was decommissioned in 1976 after more than 30 years' use, contains approximately 5 Ci of sup(239,240)Pu; inventories of other actinide isotopes are considerably less. Significantly higher concentrations of actinides in fish that were allowed access to sediments indicated that sedimentary particulates may be the primary source of transuranics to biota in shallow fresh-water ecosystems. The study determined habitat, in particular the degree of association of an organism with the sediment/water interface, to be the primary factor in controlling transuranic concentrations in aquatic biota. In most of the biological samples analysed, excluding samples suspected of being contaminated by sediment, 241Am/239Pu, 244Cm/239Pu, and 238U/239Pu ratios were greater than the respective ratios in sediment while sup(233,234)U/238U, and sup(239,240)Pu/238Pu (aquatic biota only) ratios were not different from the respective ratios in sediment. The relative uptake of actinides from contaminated sediment by aquatic and terrestrial biota at this site was UCm=AmPu. The relative extractability of actinides from shoreline sediment (using 1 M HNO3 and 0.01 M HO1) was UCm approximately equal to AmPu. Concentrations of transuranics in water, terrestrial vegetation, and vertebrate carcasses were less than 10% of the recommended public exposure maximum permissible concentration (MPC) of the ICRP, even in this highly contaminated system, which has radioactive inventories atypical of any other fresh-water site now in use or planned for future use in association with nuclear power technologies. (author)
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