Particle-solution behaviour of plutonium in an estuarine environment, Esk Estuary, UK

Conference · Thu Jul 01 04:00:00 EDT 1993 · Geochimica et Cosmochimica Acta; (United States)

OSTI ID:5852966

Hamilton-Taylor, J; Kelly, M; Titley, J G ^[1]; Turner, D R ^[2]

---

1. Lancaster Univ. (United Kingdom)
2. Plymouth Marine Laboratory, West Hoe (United Kingdom)

The particle-solution (K[sub d]) relationships of Pu(III,IV) in the Esk Estuary are investigated, using new experimental data together with a synthesis of earlier work. Adsorption of [sup 236]Pu(IV) by a suspension of intertidal mud (40 mg L[sup [minus]1]) from the Esk Estuary was determined after 1 h, as a function of salinity and pH, in a series of controlled laboratory experiments. Desorption of [sup 239,240]Pu(III,IV) from this environmentally contaminated sediment was determined concurrently. The short term (i.e., within a tidal cycle) non-conservative behaviour of Pu(III,IV) in both the laboratory experiments and the estuary appears to be dominated by a rapid, reversible surface complexation reaction, although only a small fraction (<5%) of the [sup 239,240]Pu(II,IV) activity of the environmentally contaminated sediment is able to participate in the reaction. The existence of this exchangeable or labile fraction can explain the apparent dependence of Pu(III,IV) K[sub d] on sediment concentration. Thus, a single K[sub d] value is able to describe both the observed adsorption and desorption behaviour and the effect of sediment concentration, when desorption is expressed with respect to the labile [sup 239,240]Pu(III,IV) fraction. For example, in R. Esk water, the adsorption of [sup 236]Pu(III,IV) and the desorption of [sup 239,240]Pu(III,IV), over a two order of magnitude concentration range of unwashed Esk Estuary sediment, can be accounted for by a single K[sub d] of [approximately]3 [times] 10[sup 3] L kg[sup [minus]1]. The K[sub d] for the labile Pu(III,IV) fraction varies mainly as a function of salinity. pH is not an important factor over the pH range 4-9, although H[sup +] ion exchange does occur, probably through a similar surface complexation reaction. The kinetic and equilibrium characteristics of the Pu(III,IV) sorption behaviour conform to the pattern observed by JANNASCH et al. (1988) and other workers for a range of trace elements.

• OSTI ID: 5852966
• Report Number(s): CONF-911017--; CNN: PECD 7/9/429
• Conference Information: Journal Name: Geochimica et Cosmochimica Acta; (United States) Journal Volume: 57:14
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540330* -- Environment
Aquatic-- Radioactive Materials Monitoring &amp; Transport-- (1990-)
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ACTINIDES
ALPHA DECAY RADIOISOTOPES
ELEMENTS
ENVIRONMENTAL TRANSPORT
ESTUARIES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FUNCTIONS
HEAVY NUCLEI
INTERFACES
ISOTOPES
MASS TRANSFER
METALS
NUCLEI
PARTITION FUNCTIONS
PLUTONIUM
PLUTONIUM 236
PLUTONIUM 239
PLUTONIUM 240
PLUTONIUM ISOTOPES
RADIOISOTOPES
SEDIMENT-WATER INTERFACES
SEDIMENTS
SORPTIVE PROPERTIES
SPONTANEOUS FISSION RADIOISOTOPES
SURFACE PROPERTIES
SURFACE WATERS
TRANSURANIUM ELEMENTS
YEARS LIVING RADIOISOTOPES