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TECHNETIUM-99M: FROM NUCLEAR MEDICINE APPLICATIONS
TO FINE SEDIMENT TRANSPORT STUDIES
Jefferson V. Bandeira1 & Lécio H. Salim1
International Conference on Applications of Radiation Science and Technology (ICARST-2017)
Vienna 24-28 April 2017
1 Nuclear Technology Development Center
(CNEN/CDTN) – Belo Horizonte, Brazil
Objective
To rescue the history of the development of the application
of 99mTc, widely used in Nuclear Medicine, to its use as a
tracer for studying the transport of fine sediment in
suspension, in water environment.
Background
IAEA TC Project URU/8/009 – 1997
Study of the environmental quality of Montevideo Bay -
Sedimentological studies with the application of nuclear
techniques.
Background
IAEA TC Project URU/8/009 – 1997
• It was scheduled to label mud with 198Au imported from Brazil
• 198Au did not arrive and was substituted by 99mTc (T1/2 = 6.02h),
eluted from Mo/Tc generator as pertechnetate (TcO4-), obtained
from the Center of Nuclear Medicine - University of the Republic of
Uruguay (UdelaR).
• Quick labeling tests for the reduction of TcO4- with
the reductants:
stannous chloride (SnCl2.2H2O)
sodium thiosulfate (Na2S203.5H2O)
Montevideo Harbour
IAEA – URU/8/009 (1997)
Sub-superficial injection of
mud labelled with 99mTc
Background
After this first use, and considering the favourable
characteristics of 99mTc:
• Convenient half-life = 6.02 h for studies of transport of fine
sediment in suspension;
• Low gamma ray energy (140 keV) moderate shielding and
ease of manipulation in field conditions;
• Availability even in places where there are no nuclear facilities
widespread application in Nuclear Medicine;
• Convenient half-life of the 99Mo parent nuclide (66 h)
possible to obtain 99mTc for one week or more in field studies.
the feasibility of its use for labeling mud was studied:
IAEA Research Contract BRA-10891.
Lab labeling results – CDTN/Brazil
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
5 10 15 20
Reductant mass (mg)
Eff
icie
nc
y o
f s
orp
tio
n
SnCl2.2H2O Na2S2O3 NH2.OH.HCl
Effect of reducing agent nature for the
sorption of 99mTc in fine sediments.
0.0
0.2
0.4
0.6
0.8
1.0
0 25 50 75 100 125 150 175 200 225
Reductant mass (mg)
Eff
icie
nc
y o
f so
rpti
on
Variation of sorption of 99mTc in 100 mg of
sediment with mass of SnCl2.2H2O
Labeling yield as function of
different factors
Lab labeling results – CDTN/Brazil
Effect of pH in the sorption of 99mTc
Influence of the concentration in the
sorption of 99mTc by fine sediment
0,0
0,2
0,4
0,6
0,8
1,0
0 2 4 6 8 10 12
pH
Efi
cie
nc
y o
f s
orp
tio
n
0,90
0,92
0,94
0,96
0,98
1,00
0 5 10 15 20 25 30 35
Concentration (g/L)
Efi
cie
nc
y o
f s
orp
tio
n
Labeling yield as function of
different factors
Lab labeling results – CDTN/Brazil
Influence of contact time in the sorption
of 99mTc by fine sediment
Desorption of 99mTc in river water for
different sediment concentrations
Labeling yield as function of
different factors
0,70
0,75
0,80
0,85
0,90
0,95
1,00
0 2 4 6 8 10 12 14 16
Contact time (min.)
Efi
cie
nc
y o
f s
orp
tio
n
0,7
0,8
0,9
1,0
0 20 40 60 80 100 120 140
Shaking time (min.)
Fra
cti
on
of
init
ial
ac
tiv
ity
re
ma
inin
g in
the
la
be
lle
d s
ed
ime
nt
50mg/l 200 mg/l 1000 mg/l
Lab labeling results – CDTN/Brazil
Hydrodynamic behavior of labeled and
not labeled sediment.
Sedimentation tests – Stokes law.
(1)
(2)
Andreasen pipette (1) & test tube (2)
Natural sediment in distilled water
0,0
20,0
40,0
60,0
80,0
100,0
0,0001 0,001 0,01 0,1 1
Fall velocity (mm/s)
(%
) M
as
s
Tube 1 Tube 2
Labelled (but not floculated) sediment using minimum
quantities of SnCl2 and HCl to reduce the Tc (VII)
0,0
20,0
40,0
60,0
80,0
100,0
0,0001 0,001 0,01 0,1 1
Fall velocity (mm/s)
% M
as
s
Tube 7 Tube 8
Pampulha reservoir dredging – Belo Horizonte, Minas Gerais State,
Brazil (1999-2004)
Pampulha
Reservoir
1964
1981
2001
Pampulha reservoir accretion
Santa
Luzia Santa
Luzia
Pampulha studies: Injection points (PI) & detection points (D)
Pampulha tracer studies: injection of mud with 99mTc
Onça Creek
Double labelling: sediment with 99mTc & water with Rhodamine WT
Injection
Point: PI-2
Detection
station: D3
Upstream view Downstream view ISCO Sampler
Onça Creek
Pampulha tracer studies: Eulerian Detection
Station D4
Hora
da inje
ção 1
0:3
6:0
0
0,0E+00
2,0E-04
4,0E-04
6,0E-04
8,0E-04
1,0E-03
1,2E-03
10:00:00 12:00:00 14:00:00 16:00:00 18:00:00 20:00:00 22:00:00 00:00:00
Hora
Ati
vid
ad
es
norm
ali
zad
as
Estaçao D3 - sedimento
Estaçao D3 - água
Estaçao D4 - sedimento
Estaçao D5 - sedimento
Estaçao D5 - água
Estaçao D6 - sedimento
Estaçao D6 - água
D6D5D4D3
Onça creek (Jul./03/2001)
Rhodamine WT stretch (D3-D5) v = 0.282m/s; D = 9.4m2/s
0,0E+00
5,0E+00
1,0E+01
1,5E+01
2,0E+01
200 300 400 500 600
Tem po (m in.)
Ati
vid
ad
e n
orm
aliz
ad
a
medido calcu lado
99mTc stretch (D3-D5) v = 0.290m/s; D = 11.4m2/s
0,0E+00
5,0E+00
1,0E+01
1,5E+01
2,0E+01
100 200 300 400 500 600
T empo (min.)
Ati
vid
ad
e n
orm
aliza
da
medido calcu lado
Detection & mathematical model curves
Pampulha studies: Some results
Mathematical model used – (Sing & Beck, 2003)
Dt
vtxerfc
c
c
22
1
0
x
cv
x
cD
t
c
2
2
One-dimensional dispersion equation (1)
Dt
vtx
tDA
Mtxc
4
)(exp
4),(
2
A solution of (1) for point and instantaneous
injection Taylor equation (2)
Equation (3) corresponds to equation (2) for large values of vx / D and a
point and instantaneous injection (SINGH & Beck, 2003), as is the case of
the experiments performed in the studied creeks and rivers, in the region
downstream of Pampulha reservoir.
Sing & Beck equation (3)
Pampulha studies: Some results
Pampulha
tracer
studies
Results
Ribeirões Pampulha e
Onça 27/09/2000
Trecho
D1-D2
Trecho
D1-D3
Trecho
D2-D3
Água
(Rodamina WT)
v = 0,441m/s
D = 9,2m2/s
v = 0,741m/s
D = 15,1m2/s
v = 0,936m/s
D = 5,5m2/s
Sedimento fino
(99mTc)
v = 0,714 m/s
D = 8,8m2/s
Ribeirão da Onça
03/10/2000
Trecho
D3-D4
Trecho
D4-D6
Água
(Rodamina WT)
v = 0,379m/s
D = 11,2m2/s
v = 0,344m/s
D = 10,2m2/s
Sedimento fino
(99mTc)
v = 0,386m/s
D = 11,9m2/s
v = 0,326m/s
D = 54,0m2/s
Rio das Velhas
26/06/2001
Trecho
D7-D8
Trecho
D8-D9
Água
(Rodamina WT)
v = 0,550m/s
D = 16,2m2/s
v = 0,480m/s
D = 14,6 m2/s
Sedimento fino
(99mTc)
v = 0,541m/s
D = 13,9m2/s
v = 0,525m/s
D = 24,8m2/s
Ribeirão da Onça
03/07/2001
Trecho
D3-D4
Trecho
D3-D5
Trecho
D4-D5
Trecho
D4-D6
Trecho
D5-D6
Água
(Rodamina WT)
v = 0,282m/s
D = 9,4m2/s
v = 0,327m/s
D = 7,2m2/s
Sedimento fino
(99mTc)
v = 0,314m/s
D = 12,8m2/s
v = 0,290m/s
D = 11,4m2/s
v = 0,264m/s
D = 7,3m2/s
v = 0,300m/s
D = 21,5m2/s
v = 0,320m/s
D = 30,6m2/s
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
1,00
0 100 200 300 400 500 600 700
Time interval (10 min.)
Co
ncen
trati
on
att
en
uati
on
D1
D3
D4
D5
D6
FOZ
D7
D8
D9
DP
DPRS
DJEQ
Temporal variation of sediment concentration, downstream Pampulha dam, as a function of dredging dumping at D1, with 9 hours duration, obtained with a convolution model calibrated with the results of experiments of fine sediment labelled with 99mTc
Pampulha studies: Some results
Pampulha studies
The above studies made it possible to calculate physical environmental
impacts:
• increase of sediment concentration in the watercourses due to the
dumping of dredged sediment downstream the Pampulha reservoir dam;
• the possibility of deposition of the dumped sediment.
The measurement of physical-chemical parameters of the water (DO;
pH; Eh; conductivity & temperature) allowed to evaluate the possibility
of desorption of the metals adsorbed in the sediment to be dredged, and
dumped downstream.
As for the impacts studied, it was concluded that there was no impediment
to the dumping of fine material in the water courses downstream from
Pampulha reservoir (Bandeira, 2004).
Orinoco River – Venezuela (2005-2006)- VEN/8/019
Labelling & injection boat
Orinoco River – Venezuela (2005-2006) - VEN/8/019
Detection boat
Orinoco River - Labelling & injection of mud with 99mTc
Injection tube
Lead shielding (3 mm)
Detection orientation floats together with injection
Orinoco River - Lagrangean detection (suspension)
2.5 Orinoco River – Venezuela (2005-2006)- VEN/8/019
1st injection: sediment in suspension with 99mTc
Detection lines
Orinoco River – Venezuela (2005-2006)- VEN/8/019
2st injection: sediment in suspension with 99mTc
Detection lines
Orinoco River – Venezuela (2005-2006) - VEN/8/019
Synthesis
Results of suspended sediment studies
Injection
Probe SR
(g/ton/s)
DL
(m2/s)
DT
(m2/s)
D
U
(m/s)
Thalf
(min)
Lhalf
(m)
1 1 (1.5 m) 520 1.373 0.495 500 0.723 22.2 963
1 2 (0.5 m) 532 1.081 0.450 0.720 21.7 937
2 1 (1.5 m) 372 - 0.278 30 0.609 31.1 1136
2 2 (0.5 m) 421 - 0.265 0.609 27.4 1001
SR - Sedimentation rate
DL - longitudinal dispersion coefficients for time Thalf.
DT - transversal dispersion coefficients for time Thalf.
D - Dilution
U - Advection velocity
Thalf - the necessary time for half of the suspended sediment dumped to settle
Lhalf - distance travelled from the dumping site
Orinoco River studies
The results obtained for the behavior of the natural sediment in suspension,
in the end of the low water season of the Orinoco River (April), could be
used for preliminary designs of outfalls for industrial effluents which
discharge particulate material with the density of fine sediment or for
pollutant material that could be adsorbed by the fine sediment.
A- Evaluating, using tracers and related techniques, the physical
environmental impact: advection, dispersion and sedimentation rate of
the dumping in downstream waterways, of the material removed from
the reservoir through bottom discharge and / or dredging;
B- Assess the environmental impact on its biological aspects, using as
bioindicator the zoobenthos aquatic community existing in the
Paraibuna River, downstream the reservoir;
C- Perform the physical and chemical characterization of sediments
deposited in the reservoir, which is periodically removed through
bottom discharge;
Study goals
Environmental impact due to fine sediment originated from
bottom discharge of Small Hydroelectric Power Plant (SHP)
Paciência SHP – Paraibuna River, MG - Brazil
D- Establish a basic methodology considering hydrosedimentological,
chemical and biological aspects together, to be applied, adapted to
each case, for other SHP.
Key Map
Area under study: EMF (physical) and EMB (biological) monitoring stations.
Site characterization
Paciencia SHP dam
Upstream view from the dam during
bottom discharge
• Sampling of bottom sediments from the reservoir and downstream region,
just before and just after bottom discharge, to evaluate the influence of
bottom discharge in the sediment distribution.
• Two bathymetric surveys were performed in the backwater region of the
dam, just before and just after bottom discharge, to quantify: the accreted
volume and the sediment transferred downstream due to bottom discharge.
Hydro sedimentological work
• Mathematical modeling, with the above parameters measured, to simulate
the bottom discharge and assess physical environmental impacts arising
from it.
• Experiments with tracers to assess the parameters of transport of fine
sediment in suspension: advection, dispersion and sedimentation rate,
arising from dredging / bottom discharge;
Hydro sedimentological work
Equipment for tracer injection Tracers injection
Scintillation detectors operating Analog and digital meters
Tracer studies
Rio Paraibuna, MG - Experimento 21/08/2012
0,0E+00
5,0E+00
1,0E+01
1,5E+01
2,0E+01
2,5E+01
3,0E+01
3,5E+01
4,0E+01
10:00:00 12:00:00 14:00:00 16:00:00 18:00:00
Tempo
Ati
vid
ad
es
no
rma
liza
da
s
T2 MEDIDO T3 MEDIDO T3 MODELO
T2 T3
Hora
do lançam
ento
: 11:1
1:0
0
Rio Paraibuna, MG - Experimento de 23/08/2012
0,0E+00
1,0E+01
2,0E+01
3,0E+01
4,0E+01
5,0E+01
6,0E+01
7,0E+01
10:00:00 12:00:00 14:00:00 16:00:00 18:00:00
Tempo
Ati
vid
ad
es
no
rma
liza
da
s
T2 MEDIDO T3 MEDIDO T3 MODELO
Hora
do lançam
ento
: 10:4
5:3
0
Tracer studies Paraibuna River, MG - Experiment on 08/22/2012
0.0E+00
1.0E+01
2.0E+01
3.0E+01
4.0E+01
5.0E+01
6.0E+01
7.0E+01
10:00:00 12:00:00 14:00:00 16:00:00 18:00:00
Time
No
rma
lize
d a
cti
vit
ies
EMB2 MEASURED EMB4 MEASURED EMB4 MODEL
Rele
ase t
ime:
11:1
5:3
0
EMB2 EMB4
Examples of measured and modelled results (Field experiments – August 2012)
Tracer studies
Paciência SHP and the
study region downstream,
with monitoring stations.
Values of advection velocity (v) and dispersion coefficient (D) obtained with
the adjustment of Singh & Beck model (2003) to field data
Tracer studies
Stretch/Day 08/21/2012 08/22/2012 08/23/2012
EMB2 –
EMB4
v = 0.39 m/s
D = 9.40 m2/s
v = 0.38 m/s
D = 9.85 m2/s
v = 0.38 m/s
D = 9.00 m2/s
Stretch/Day 24/10/2012 25/10/2012
Power house – EMB1 v = 0.21 m/s
D = 5.7 m2/s
--
EMB1 – EMB4 v = 0.36 m/s
D = 13.3 m2/s
--
Power house – EMB2 -- v = 0.33 m/s
D = 5.7 m2/s
EMB2 – EMB4 -- v = 0.33 m/s
D = 13.0 m2/s
Experiments of October 2012
Experiments of August 2012
Temporal representation of the concentration of sediment in suspension
due to bottom discharge lasting for 4.5 days, considering a unit
concentration in the release point. It is the simulation, obtained by
convolution, of the continuous bottom discharge, using average values of v
and D from the experiments.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 200 400 600 800 1000
Time interval (10 minutes)
Te
mp
ora
l c
on
ce
ntr
ati
on
pro
file
s
Release point
EMB1
EMB2
EMB3
EMB4
EMB5
Peixe River
Preto River
Tracer studies - Paciência SHP
Main results - Paciência SHP
This information can be used by CEMIG (Electric Utility Company) as a
tool in the management of bottom discharge, associated with
the currently employed controls, based on the level of DO <3.
The attenuation of the concentration of fine sediment in suspension, arising
from a bottom discharge, in the Paciencia SHP, was calculated up to the
mouth of Preto river (18% of the initial concentration), about 34 km
downstream. A mathematical model calibrated with the results of tracer
studies was used for this calculation.
Main conclusions
• The above mentioned case studies confirm that labeling of fine sediment
with 99mTc can be successfully accomplished and that the labelled
sediment has the same hydrodynamic behavior as the natural one.
• The application of this radioactive tracer, widely used in Nuclear
Medicine, became available in the field of Sedimentology for which fine
sediments are instrumental in the transportation of heavy metals and
other pollutants in the water environment.
• The work performed in the laboratory research and in some field
applications used second week generators obtained, at no cost, from
Nuclear Medicine laboratories. The reason is that the 99mTc detector for
environmental applications is placed into the water, in 4π geometry and for
medical applications it is situated externally to the patient. So, the necessary
activity concentrations for environmental use (Bq/mL of water) are much
lower (10-7) than in Nuclear Medicine utilization (Bq/mL of blood).
Acknowledgements
• IAEA (Research Contract Nr. 10891) and CDTN/CNEN-Brazil;
• Edmundo Garcia Agudo (IAEA-Retired), Technical Officer of TC Project
URU/8/009;
• Authors would like to thank their colleagues of CDTN involved in the
development of the technique and in the field works performed;
• ECOGRAF and ECOAR Nuclear Medicine laboratories (Dr. Ivana Sena
Nascimento), from Belo Horizonte, Brazil, for supplying the 99mTc used in
the laboratory research and for part of the field work performed in
Pampulha studies (second week generators);
• Special thanks to Dr. Patrick Brisset (IAEA), for his ever-present role in
disseminating the use of tracers and nuclear techniques in the study of
sediment transport and dispersion of pollutants in water environment.
• The researchers and collaborators from Uruguay, who participated in the
IAEA TC Project URU/8/009, outstandingly the Pharmaceutical Chemist
Beatriz Souto Ameigenda, for her original idea of trying to replace the
scheduled labelling of fine sediment with 198Au, by the labeling with 99mTc;
Thanks for your attention
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