www.sciencemag.org/cgi/content/full/314/5799/638/DC1
Supporting Online Material for
Colloid Transport of Plutonium in the Far-Field of the Mayak Production Association, Russia
Alexander P. Novikov, Stepan N. Kalmykov, Satoshi Utsunomiya, Rodney C. Ewing,* François Horreard, Susan B. Clark, Vladimir V. Tkachev, Boris F. Myasoedov
*To whom correspondence should be addressed. E-mail: [email protected]
Published 27 October, Science 314, 638 (2006)
DOI: 10.1126/science.1131307
This PDF file includes:
Materials and Methods Figs. S1 to S3 Table S1 References
Supporting Online Material
“Colloid Transport of Plutonium in the Far-field of the Mayak Production
Association, Russia” by Alexander P. Novikov, Stepan N. Kalmykov,
Satoshi Utsunomiya, Rodney C. Ewing, François Horreard, Susan B. Clark,
Vladimir V. Tkachev, Boris F. Myasoedov
METHODS
Groundwater samples were extracted from the well by an in-situ pump at the rate of
2-2.5 m3/hour. The samples were collected in glass bottles previously purified by
washing with nitric acid (high purity) and deionized water. The equipment was purged by
nitrogen before taking samples. Conductivity, pH and Eh were measured immediately
after the sampling, and samples were taken after the measured values became constant.
Samples were transported to the laboratory immediately after sampling in order to
conduct micro- and ultrafiltration and further measurements. The aliquots of solutions
were taken from each sample for the analysis of major and trace elements and
radionuclides.
Successive micro- and ultrafiltrations were performed in nitrogen atmosphere to
avoid changes in Eh values and carbonate concentration. The samples were filtered
through 200 nm, 50 nm (nucleopore filters, Dubna, Russia), 15 nm (Vladipor, Russia), 10
kD (~1.5nm) and 3 kD (1 nm) (Millipore) micro- and ultrafilters. Aliquots of each filtrate
and filters were used for further analysis.
Major and trace elements and radionuclide analysis
A piece of each filter (about 50 % of the total filter mass) was dissolved in
concentrated nitric acid upon boiling. The concentrations of major and trace elements
were determined using atomic absorption spectroscopy, ion chromatography and
inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of actinides
were determined using gamma-spectrometry with HPGe-detector, liquid scintillation
spectrometry, alpha spectrometry with passivated ion planar silicon detectors (PIPS) and
ICP-MS after appropriate chemical separation procedures (S1).
Actinide redox speciation
The total concentration of actinides in the groundwater samples was too low to use
spectroscopic methods, such as X-ray absorption spectroscopy for actinide redox
speciation. Therefore the solvent extraction method with tenoyl-trifluoroacetone (TTA)
as an extractant (S2) and extraction with supported liquid membrane with di-2-ethylhehyl
phosphoric acid (HDEHP) (S3) were used. In order to achieve the complete extraction of
actinides and to desorb the actinides from colloids, the samples were acidified to pH of 1.
SEM and TEM analysis
Filters were placed in high purity acetone and ultasonicated for a minute in order to
remove the colloidal matter from the filter. The colloid suspension was placed onto
holey-carbon film supported by a copper grid. Transmission electron microscopy (TEM)
was conducted using JEOL JEM2010F field emission gun TEM. High resolution (HR)
TEM, selected area electron diffraction (SAED), HAADF-STEM (high-angle annular
dark-field scanning TEM) and energy dispersive X-ray analysis (EDX) were conducted
using 200 keV electron beam to characterize the sample (S4). The beam diameter of 0.5
nm was used for EDX analysis. The copper signal is from the supporting Cu-grid.
SIMS analysis
The colloidal material was taken from the filters in the same manner as for TEM. For
SIMS measurements an aliquot of suspension was dropped on silicon chips and air-dried.
All analyses were performed by a Nano-SIMS50 (Cameca, France) using 16keV O-
primary ions, and detecting positive secondary ions. Mass resolution was set at M/dM
=2000 for all data. The images were acquired by scanning the primary beam over the
samples and detecting the emitted secondary ions in parallel. Uranium was detected in the
form of UO+ ions in order to get a relatively intense signal without any isobaric
interferences. Iron was followed as 54Fe+, as the 56Fe+ signal was too intense. For the
same reason, 44Ca+ was measured instead of 40Ca+. Manganese and aluminum were
measured as 55Mn+ and 27Al+.
2 4 6 8 10 12-20
-15
-10
-5
0
pH
log
a N
p4+
NpO2+
NpO2(CO3)23-
NpO2(CO3)35-
NpO2CO3-
NpO2
10oC
Near source
2 4 6 8 10 12-20
-15
-10
-5
0
pH
log
a N
p4+
Np3+
NpO2+
3-
NpO2(CO3)35-
NpO2CO3
NpO2(CO3)2-
NpO2
10oC
Well 1/69
Fig. S1. Stability diagrams of Np species in the solution calculated using the conditions at well #41/77 (near source) and well 1/69 (3.9 km). The calculation was carried out using Geochemist's Workbench incorporating thermodynamic database of "thermo.com.v8.r6+". Thespecies in plain and italic text represent the solid and the aqueous species, respsectively.
44Ca
238U16O
54Fe
10 micron 10 micron
10 micron
238U16O 55Mn
20 micron 20 micron
Fig. S2. Nano-SIMS elemental maps of colloids from well 1/69. The contrast is enhanced for the trace elements. (A), Uranium adsorped onto an aggregate of amorphous hydrous Fe oxides. (B),Uranium adsorbed onto rancieite, (Ca,Mn)Mn4O93H2O.
A
B
0 2 4 6 8 10 12–20
–15
–10
–5
0
pH
log
a P
u4+
Pu(CO3)2+
Pu(OH)4(aq)
PuO 2
Pu(CO3)2 PuO2
Well# 1/69Near source
25 Co
Figure S3. Stability diagram for Pu carbonate species. The thermodynamic data were based on (26). In the case of calculations that include other carbonate species; Pu(CO3)32-, Pu(CO3)44-, and Pu(CO3)56- , these species were dominant over the species indicated in this diagram.
Table S1. Oxidation state of actinides in the groundwaters from Mayak region, as percentage.
* Am(III) was analyzed to control performance of liquid membranes
Well index
Distance (km)
Depth (m) U(IV) U(VI) Np(IV) Np(V) Pu(III) Pu(IV) Pu(V) Pu(VI) Am(III)*
63/68 1.10 20 0 100 0 100 0 100 0 0 100 65/68 1.75 60 0 100 0 100 0 54 37 9 100 9/68 2.15 60 0 100 0 100 0 90 10 0 100
176/94 2.50 63 0 100 0 100 0 100 0 0 100 1/69 3.2 44 0 100 0 100 0 79 21 0 100
14/68 3.9 100 0 100 8 92 0 72 28 0 100
References cited in supporting material
S1. B. F. Mayasoedov, A. P. Novikov, F. I. Pavlotskaya, Radiochemistry 40, 461
(1998).
S2. A. Saito, G. R. Choppin, Anal. Chem. 55, 2454 (1983).
S3. B. F. Myasoedov, A. P. Novikov, Evaluation of speciation technology.
Workshop Proc. Tokai-mura, Japan, p25–37 (1999).
S4. S. Utsunomiya, R. C. Ewing, Environ. Sci. Technol. 37, 786 (2003).
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