| Autor: |
Kathy Kawtaluk, Joy J. Bell, Peter H. Santschi, R. M. Trier, Yuan-Hui Li |
| Rok vydání: |
1980 |
| Předmět: |
|
| Zdroj: |
Earth and Planetary Science Letters. 51:248-265 |
| ISSN: |
0012-821X |
| DOI: |
10.1016/0012-821x(80)90208-3 |
| Popis: |
Analysis of water samples from the New York Bight area and Narragansett Bay reveals that a small fraction of the total Pu (probably Pu (III + IV) species) is continuously removed to the sediments at a rate similar to that of the particle-reactive isotope 228 Th. A more “soluble” Pu species appears to be released at times from the sediments to the water column in these nearshore regions. Sediments in shallow areas of the New York Bight south of Rhode Island and Narragansett Bay have high Pu inventories and relatively deep penetration of this element, although the net sediment accumulation rate is generally low ( 2 yr). The high Pu inventories can be explained if both sediment resuspension and sediment mixing are assumed to be the major controlling factors for the effective transfer of Pu from the water column to the sediments. By simultaneous modelling of the depth distribution of three tracers which operate on vastly different time scales: 234 Th (half-life 24 days), 210 Pb (half-life 22 years) and 239,240 Pu (introduced into the environment during the past 30 years), bioturbation rates ranging from 4 to 32 cm 2 /yr in the surface mixed layer (5–10 cm thick) and from 0.3 to 2.5 cm 2 /yr in the layer below (up to 40 cm thick) and net sediment accumulation rates of approximately zero to 0.14 g/cm 2 yr were calculated for these areas. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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