Order number 940330-160606-96 -001-001 page 18 set 11 with 111 of 111 items western Pacific Ocean, with the Te and Tf zqgnes of the previously established Tertiary Far East Letter Zonation. Correlation using these two benthic groups is critical because calcareous nannofossils and planktic foraminifers are absent in the lower Miocene strata. Biostratigraphic data from these boreholes delineate a thick (greater than 700 feet) sequence of upper Oligocene and lower Miocene strata corresponding to lower and upper Te zone. These strata document a major period of carbonate accumulation at Enewetak during the Late Oligocene and early Miocene ago). KEYWORDS (26 to 18 million years ENIWETOK/geologic formations ;GEOLOGIC FORMATIONS/paleontology ;STRATIGRAPHY; FORAMINIFERA; BOREHOLES;MARSHALL ISLANDS; THICKNESS ; CARBONATES ; ENIWETOK; TERTIARY PERIOD; CORRELATIONS; EXPLORATION; AGE ESTIMATION; PALEONTOLOGY; NUCLEAR EXPLOSIONS EDB Item 25 ANALYTIC TITLE ENGLISH Comparative study of plutonium and americium bioaccumulation from two marine sediments contaminated ANALYTIC AUTHOR/AFFIL in the natural environment Hamilton, T.F.; (Australia). LaRosa, J.; Smith, PAGE RANGE DATE [Melbourne Univ., Fowler, Holm, E. Energy [International (Monaco). Lab. Atomic LIMITATION CODE ABSTRACT S.W.; of Marine Radioactivity]; Aarkrog, A.; Dahlgaard, National Lab., Roskilde (Denmark) J (YYMMDD) Parkville of Inorganic Chemistry]; Agency, Monaco-Ville PUB. J.D. Dept. H. [Risoe 211-223 910000 UNL Plutonium and americium sediment-animal transfer was studied under controlled laboratory conditions by exposure of the benthic polychaete Nereis diversicolor (O. F. Mueller) to marine sediments contaminated by a nuclear bomb accident (near Thule, Greenland) and nuclear weapons testing (Enewetak Atoll). In both sediment regimes, the bioavailability of plutonium and {sup 241}Am was low, with specific activity in the tissues <1% (dry wt) than in the sediments. Over the first three months, a slight preference in transfer of plutonium over {sup 241}Am occurred and {sup 241}Am uptake from the Thule sediment was enhancedwcompared to that from lagoon sediments of Enewetak Atoll. Autoradiography studies indicated the presence of hot particles of plutonium in the sediments. The results highlight the importance of purging animals of their gut contents in order to obtain accurate estimates of transuranic transfer from ingested sediments into 9003452