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Lecture 9: Case Studies in Marine Lecture 9: Case Studies in Marine Pollution Pollution
Distribution of Anthropogenic Distribution of Anthropogenic radionuclides in the Moroccan coastal radionuclides in the Moroccan coastal
waters and sedimentswaters and sediments
Moncef BenmansourMoncef Benmansour
CNESTEN, Rabat, MoroccoCNESTEN, Rabat, Morocco
IAEA Regional Training Course
Sediment Core Dating Techniques - RAF/7/008 Project
CNESTEN, Rabat, 05-09 July 2010IAEA CNESTEN
22
ContentsContents
IntroductionIntroduction
Material and MethodsMaterial and Methods
Results and DiscussionResults and Discussion
ConclusionConclusion
33
IntroductionIntroduction
Long coast (~ 3500 km), Long coast (~ 3500 km),
Development of National Development of National and Mediterranean and Mediterranean industrial activitiesindustrial activities
Marine trafficsMarine traffics
Characteristics of the Characteristics of the Mediterranean seaMediterranean sea
44
IntroductionIntroduction
IAEA regional project ( North of Africa): RAF7/004IAEA regional project ( North of Africa): RAF7/004– «Contamination assessment of the south Mediterranean sea»«Contamination assessment of the south Mediterranean sea»
Specific objectivesSpecific objectives
– Obtaining data on R.N contaminants Obtaining data on R.N contaminants 137137Cs, Cs, 239,240239,240Pu, Pu, 238238Pu, Pu, 241241Am, Am, 9090Sr, Sr, natural natural ( ( 210210Pb, Pb, 210210Po, Po, 226226Ra…), but also heavy metals and organicsRa…), but also heavy metals and organics
– Understanding the behaviour and the fate of contaminantsUnderstanding the behaviour and the fate of contaminants
– Modelling the dispersion of contaminantsModelling the dispersion of contaminants
– Development of national databases Development of national databases
55
Explored StationsExplored Stations
Morocco
AtlanticOcean
MediterraneanSea
St. 1
St. 2
St. 3St. 4
Morocco
AtlanticOcean
MediterraneanSea
St. 1
St. 2
St. 3St. 4
66
Material and MethodsMaterial and Methods
R.V: Charif El Idrissi -INRH- Technical Staff: CNESTEN (2), IAEA (2) INRH (3)
77
Material and MethodsMaterial and Methods
N° Name &Position
Maximal depth (m) Samplescollected
St.1 Mohammedia33°46'N; 7°28'W
300 Surface water
St.2 M'Diq35°47'N; 04°48'W
800 Water column,Sediment core
Biota
St.3 M'Diq35°47'N; 05°15'W
270 Surface water
St.4 Tangier35°52'N; 05°51'W
200 Surface water
88
99
1010
Material and MethodsMaterial and Methods
Pre-treatmentPre-treatment– Sea waterSea water ( ( 239,240239,240Pu, Pu, 241241Am, Am, 137137Cs, Cs, 9090Sr)Sr)
filtered (0.45 filtered (0.45 m) addition of tracers and carriers (addition of tracers and carriers (242242Pu, Pu, 243243Am, Am, 8585Sr, Cs, Sr…)Sr, Cs, Sr…)
sequential concentrationssequential concentrations – 239,240239,240Pu and Pu and 241241Am with MnOAm with MnO2 2 ,,137137Cs with AMP, Cs with AMP, 9090Sr with oxalic Sr with oxalic
acidacid
– Sediment cores ( depth profilesSediment cores ( depth profiles: : 239,240239,240Pu, Pu, 137137Cs Cs 210210Pb, Pb, 226226Ra)Ra)
sectioned ( 0.5 – 2 cm)sectioned ( 0.5 – 2 cm)
1111
Material and MethodsMaterial and Methods
Physical preparation Physical preparation – Freeze-dryingFreeze-drying– Homogenisation Homogenisation
Radiochemical separation Radiochemical separation ( Pu-Am)( Pu-Am)– Digestion ( HNODigestion ( HNO33))– Separation of transuranics : Pu and AmSeparation of transuranics : Pu and Am– Electrodeposition on stainless steel discsElectrodeposition on stainless steel discs
1212
•
8M HNO3/ NaNO2
Fraction Pu, Th
HCl conc. Th
HCl conc./NH4I Pu
Am, Cm, R.E, Fe, U, Po, Bi
AG1 X 8
Ppt. Oxalate Ca
9 M HCl
Pu, Fe, U, Po, Bi
AG1X 8
AG50W X 8
Pre treatement..
Pu, Fe, U, Po, Bi
Th
12 M HNO3
DDCPCa, Pb, Ra
AG1X 4
1M HNO3/93% CH3OH
Fe
NH4SCN/HCl/CH3OHTerres Rares
AmCH3OH/HCl
1313
Material and MethodsMaterial and Methods
Other R.NOther R.N– 137137Cs in sea waterCs in sea water
Dilution of AMP precipitate in NaOH 10MDilution of AMP precipitate in NaOH 10M
– 210210Pb and Pb and 210210Po in sedimentPo in sediment Total digestion ( HNOTotal digestion ( HNO33, HCl, HF, HClO, HCl, HF, HClO44)) Spontaneous deposition in silver discs Spontaneous deposition in silver discs
RR.N Mesurements.N Mesurements– spectrometryspectrometry
HPGe detector (Canberra) – n-type, 45% - HPGe detector (Canberra) – n-type, 45% - – spectrometryspectrometry: :
Semi-conductor detectors (Si) EG&G OrtecSemi-conductor detectors (Si) EG&G Ortec
1414
Preparation and Radiochemical Laboratories
1515
Analysis Laboratories
1616
242Pu239,240Pu
238Pu
243Am
241Am
Alpha Spectrometry: 239,249Pu & 241Am
1717
Alpha spectrometry: 210Po
1818
Gamma spectrumGamma spectrum
1919
Quality ControlQuality Control
Activité (Bq/kg)IAEA 385sédiment
Radioélément
V.D V.R137Cs 33.9 1.9 33.5
239,240Pu 2.92 0.13 2.90241Am 3.60 0.20 3.78210Pb 35.2 2.7 35.4
40K 612 34.1 612238U 25.7 1.8 29.6234U 25.8 1.8 27.2235U 1.22 1.4 1.24
230Th 30.5 2.9 30.5232Th 31.9 3.0 33.9
2020
Heavy Metal Analyses in Sediment
Preparation of sediment: - dry-freezing- ground - sieving (63mm)- digestion: teflon reactors, HNO3 H2SO4,
Aqua-Regal, HF
Measurements: – Atomic Absorption System – hydrure system for Hg, graphite oven
2121
Petroleum HC Analyses
Sediment – extraction by soxhlet extractors and
hexane/dichloromethane– Purification– dosage CPG « HP plus-Agilent 6890 »,
Spectrofluometer (P.E)
Water– extraction by carbon tetrachloride– separation from O.M– Measurements by IR
2222
RESULTSRESULTS
2323
WatersWatersTable 1: 137Cs, 239+240Pu and 241Am activity concentrations in surface sea water and in the water column.
Station 137Cs (mBq L-1)
239,240Pu
(Bq L-1)
241Am
(Bq L-1)
241Am/239,240Pu 239,240Pu/137Cs
St. 1 (Tangier) (35°52’N, 5°51’W)
3.110.23
8.290.94
N.D.
N.D.
0.00270.0003
St. 2 (Mdiq) (35°47’N, 4°48’W)
0m 2.320.18 8.290.87 1.50.0.20 0.180.03 0.00350.0004
250m 2.460.18 23.22.3 N.D. N.D. 0.00890.0010
500m 2.500.19 32.75.4 7.61.2 0.230.05 0.01140.0020
900m 2.290.16 27.12.4 N.D. N.D. 0.01180.0013
St. 3 (Mdiq) (35°47’N, 5°15’W)
2.370.14
8.821.39
1.560.50
0.170.02
0.00370.0006
Reported uncertainties are 1; N.D. means not determined
2424
800
600
400
200
0
0.00 0.01 0.02 0.03 0.04 0.05 1 2 3 4
Pu/ Cs ratios
Cs
Pu800
600
400
200
0
1 2 3 4
Pu/ Cs ratios
Cs
Pu
Specific activities (mBq/L)
Dep
thin
wa
ter
(m)
800
600
400
200
0
0.00 0.01 0.02 0.03 0.04 0.05 1 2 3 4
Pu/ Cs ratios
Cs
Pu800
600
400
200
0
1 2 3 4
Pu/ Cs ratios
Cs
Pu
Specific activities (mBq/L)
Dep
thin
wa
ter
(m)
Waters Waters
2170 Bq.m-2
23 Bq.m-
2
2525
Data in Bibliography Data in Bibliography
2626
Data in BibliographyData in Bibliography
2727
Data in bibilographyData in bibilography
2828
Data in bibilographyData in bibilography
2929
Data in bibilographyData in bibilography
3030
Data in bibilographyData in bibilography
3131
Sediment: Sediment: 137137Cs and Cs and 239,240239,240PuPu
0
2
4
6
8
10
0 0,2 0,4 0,6 0,8 10
2
4
6
8
10
0 0,2 0,4 0,6 0,8 10
2
4
6
8
10
0 0,2 0,4 0,6 0,8 1
239+240Pu (Bq/kg)
Dep
th(c
m)
0
2
4
6
8
10
12
0 2 4 6 86 8
137Cs (Bq/kg)
Dep
th(c
m)
0
2
4
6
8
10
0 0,2 0,4 0,6 0,8 10
2
4
6
8
10
0 0,2 0,4 0,6 0,8 10
2
4
6
8
10
0 0,2 0,4 0,6 0,8 1
239+240Pu (Bq/kg)
Dep
th(c
m)
0
2
4
6
8
10
0 0,2 0,4 0,6 0,8 10
2
4
6
8
10
0 0,2 0,4 0,6 0,8 10
2
4
6
8
10
0 0,2 0,4 0,6 0,8 1
239+240Pu (Bq/kg)
Dep
th(c
m)
0
2
4
6
8
10
12
0 2 4 6 86 8
137Cs (Bq/kg)
Dep
th(c
m)
0
2
4
6
8
10
12
0 2 4 6 86 8
137Cs (Bq/kg)
Dep
th(c
m)
Peaks 1963: Global Fallout ?
284 Bq/m2 32 Bq/m2
3232
Sediment: Sediment: 210210PbPb
Table 2. Vertical distribution of 210Pb, 226Ra and bulk density in the sediment core from the southwest Mediterranean Sea sampled in December 1999 (35°47’N, 04°48' W; depth 800m).
Depth (cm)
Bulk density (g/cm3)
Total 210Pb (Bq/kg)
226Ra (Bq/kg)
Excess 210Pb (Bq/kg)
0 – 0.5 0.321 680 40 28 5 650 40
0.5 - 1 0.313 690 40 28 5 660 40
1 - 2 0.454 600 30 25 4 580 30
2 - 3 0.645 620 30 23 4 600 30
3 - 4 0.577 435 16 30 4 405 16
4 - 5 0.684 316 16 21 3 295 16
5 - 6 0.716 264 12 24 3 240 12
6 - 7 0.697 237 15 34 4 203 16
7 - 8 0.639 219 11 33 4 186 12
8 - 9 0.604 210 40 24 3 190 40
10 - 12 0.609 121 15 28 5 93 16
3333
Dating of Sediment Core: Dating of Sediment Core: 210210PbPb
y = 716,38e-0,32x
R2 = 0,98
0
100
200
300
400
500
600
700
800
0 2 4 6 8 10 12
Mass depth [g/cm2]
Uns
uppo
rted
21
0P
b [B
q/kg
]
Dashed line is the best fit corresponding to the CIC-CSR model while the continuous line corresponds to the CM-CSR model
3434
Dating of Sediment Core: Dating of Sediment Core: 210210PbPb
CIC-CSR Model: CIC-CSR Model: – Initial Concentration and Initial Concentration and
sedimentation rate constantsedimentation rate constant
)()0()( m
wExpAmA
w = 0.10 ± 0.02 g cm-2 y-1
F = A(0) w, 720 ± 150 Bq m-2 y-1.
3535
Dating of Sediment Core: Dating of Sediment Core: 210210PbPb
CRS Model: Constant Rate of supply is CRS Model: Constant Rate of supply is Constant butConstant but Sedimentation rate Sedimentation rate varyvary
0
0.05
0.1
0.15
0.2
0 2 4 6 8 10 12 14
Se
dim
en
tatio
n r
ate
[g
/(cm
^2
y)]
Depth [cm]
0
20
40
60
80
100
120
0 2 4 6 8 10 12 14
CR
S a
ge
s [
y]
Depth [cm]
0
0.05
0.1
0.15
0.2
0 2 4 6 8 10 12 14
Se
dim
en
tatio
n r
ate
[g
/(cm
^2
y)]
Depth [cm]
0
20
40
60
80
100
120
0 2 4 6 8 10 12 14
CR
S a
ge
s [
y]
Depth [cm]
Mean value: w = 0.10 g.cm-2 y-1
F = I, 712 ± 25 Bq m-2 y-1.
mm AIw /
m
m dmmAI ')'(
3636
Dating of Sediment Core: Dating of Sediment Core: 210210PbPb
CM-CSR Model: Constant Mixing and CM-CSR Model: Constant Mixing and constant Sedimentation Rateconstant Sedimentation Rate
2
2
;2
4;)()(
Dk
k
kwwxmxExp
xkw
FmA m
m
m
m
km is an effective mixing coefficient given in terms of the diffusion coefficient D and the bulk density (Abril 2003b)
w= 0.092 ± 0.003 g cm-2 y-1
F = 670 ± 25 Bq m-2 y-1.
y = 716,38e-0,32x
R2 = 0,98
0
100
200
300
400
500
600
700
800
0 2 4 6 8 10 12
Mass depth [g/cm2]
Uns
uppo
rted
21
0P
b [B
q/kg
]
3737
Reconstruction of Reconstruction of 137137Cs, Cs, 239,240239,240Pu Pu ProfilesProfiles
)()( wA
mm
Ak
mA
t
Am
with boundary conditions
0)(
),0()(0
mA
twAm
AktF
mm
dtwCkFdt wd Cw : radionuclide concentration in overlying water
dt
dF
hZCkCwk
dt
Cd atwhwd
w 1
3838
Historical records of Historical records of 137137Cs, Cs, 239,240239,240Pu in Pu in water water
0
1
2
3
4
5
6
7
1950 1975 2000
137-
Cs
[mB
q/L]
Date
0
0.01
0.02
0.03
0.04
0.05
0.06
1950 1975 2000
(239
+240
)Pu
[mB
q/L]
Date
3939
Reconstruction of Reconstruction of 137137Cs, Cs, 239,240239,240Pu Pu profiles in sedimentprofiles in sediment
0
1
2
3
4
5
6
7
8
0 1 2 3 4 5 6 7 8 9 10
13
7-C
s [
Bq
/kg
]
Mass depth [g/cm^2]
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 1 2 3 4 5 6 7 8 9 10
(23
9+
24
0)P
u [
Bq
/kg
]
Mass depth [g/cm^2]
0
1
2
3
4
5
6
7
8
0 1 2 3 4 5 6 7 8 9 10
13
7-C
s [
Bq
/kg
]
Mass depth [g/cm^2]
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 1 2 3 4 5 6 7 8 9 10
(23
9+
24
0)P
u [
Bq
/kg
]
Mass depth [g/cm^2]
4040
Laissaoui, M. Benmansour N. Ziad, M. Ibn Laissaoui, M. Benmansour N. Ziad, M. Ibn Majah J. M. Abril and S. MulsowMajah J. M. Abril and S. Mulsow. Anthropogenic . Anthropogenic radionuclides in the water column and a sediment radionuclides in the water column and a sediment core from the Alboran Sea: application to core from the Alboran Sea: application to radiometric dating and reconstruction of historical radiometric dating and reconstruction of historical water column radionuclide concentrations.water column radionuclide concentrations. Journal of Journal of Paleolimnology 40 (2008) 823-833Paleolimnology 40 (2008) 823-833
M. Benmansour, A. Laissaoui, S. Benbrahim, M. M. Benmansour, A. Laissaoui, S. Benbrahim, M. Ibn Majah, A.Chafik and P.PovinecIbn Majah, A.Chafik and P.Povinec. Distribution . Distribution of anthropogenic radionuclides in Moroccan coastal of anthropogenic radionuclides in Moroccan coastal waters and sediments. waters and sediments. Radioactivity in the Radioactivity in the Environment. Book Series. 8 ( 2006) 145-150Environment. Book Series. 8 ( 2006) 145-150
4141
Heavy metalsHeavy metals
4242
Cr (mg/kg)
60,00
70,00
80,00
90,00
100,00
110,00
120,00
130,00
tranches en cm
Cu (mg/kg)
0,005,00
10,0015,0020,0025,0030,0035,0040,00
tranches en cm
Cd (mg/kg)
0,000
0,100
0,200
0,300
0,400
0,500
tranches en cm
Mn (mg/kg)
0
500
1000
1500
2000
2500
tranches en cm
Fe (mg/kg)
23600
23800
24000
24200
24400
24600
Tranches en cm
Hg (mg/kg)
00,020,040,060,080,1
0,120,14
tranches en cm
4343
Total hydrocarbonsTotal hydrocarbons
4444
Mdiq (St2) 10m
Mdiq (St2) 100 m
Mdiq (St2) 250 m
Mdiq (St2) 500 m
Mdiq (St2) 900 m
Mdiq (St3) surface
Tanger (St.4)
8.30 55 11 12 72 9.3 3.5 Table 3.: HC concentrations ( mg/l) in water .
Section (cm) HC concentration 0-0.5 1.8 0.5-1 1.2 1-2 2.5 2-3 3.6 3-4 3 4-5 3 5-6 3 6-7 2 7-8 2.2 8-9 2 9-10 1
10-12 1 12-14 0.4 14-16 0.4 16-18 0.2 18-20 0.2 20-22 0.2 22-24 0.2 24-26 0.2 26-30 0.2 30-34 0.2 34-38 0.2
Table 4 : HC concentrations (ppm/dry weight) in sediment core Mdiq St.2
4545
SummarySummary
Levels of Anthropogenic R.N ( Levels of Anthropogenic R.N ( 137137Cs , Cs , 239,240239,240Pu, Pu, 241241Am) in Am) in surface sea water and sediment - Morocco coast –surface sea water and sediment - Morocco coast –
Vertical distributions of R.N in water column and sediment Vertical distributions of R.N in water column and sediment corecore
Use of Use of 210210PbPb exex , , 137137Cs, Cs, 239,240239,240Pu: sedimentation rate, chronology Pu: sedimentation rate, chronology
of contaminantsof contaminants
Main source of R.N : Global falloutMain source of R.N : Global fallout
Heavy metals (Mn, Hg) important in the sediment surface
Cr high / Cd, Hg, and / previous studies
No significant contamination by HC