1
Directeurs de Thèse :
Dr. S. MOUNIER Université du Sud Toulon Var – PROTEE(PROcessus de Transferts et d'Echanges dans l'Environnement)
Dr. D. OMANOVIĆ Institut Ruđer Bošković – LPCT(Laboratory for Physical Chemistry of Traces)
« Mise au point d’une systématique de caractérisation des interactions Matière Organique Naturelle Dissoute
(MOND) – Contaminants métalliques »
Université du Sud Toulon Var 21 novembre 2008
Thèse de Doctorat soutenue par:
M. Yoann LOUIS
En vue d’obtenir le titre de Docteur de l’Université du Sud Toulon-Var
Subvention N° 03/1214910/TMatière Organique NAturelle en miLIeu SAlé
2
1.Introduction
2.Analytical protocol improvements
3.Concentrated Marine DNOM study
4.Natural Estuarine ecosystem study
5.Conclusions & perspectives
SUMMARY
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
3
I. Introduction
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
4
• Trace metals in the environment
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Metals
Metals
Metals
Natural origin
Anthropogenic origin
MetalsAQUATIC ENVIRONMENT
(Coastal and estuarine system)SOILS
WATER
ATMOSPHERE
SEDIMENTS
5
Metals
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
“Oligoelements”:necessary for metabolismCu, Fe, F, Mg, Mn, Zn, …
Toxic metals:not neededPb, Hg, Cd, …
Concentra
tion in
crease
Toxicity ≠ Total concentration
When metal became toxic ? depend on its speciation
• Trace metals in the environment
6
Generally toxic for biota
MM
M
Micro-organisms (bacteria, virus,…)
Organic and Inorganic Particules
M n+
Inorganic Ligands
Cl-, NO3-, SO4
2- …
OH-
Filtration (0.45µm)
Particulate > 0.45 µm Dissolved < 0.45 µm
M
MM
M
Water column
Dissolved metal speciation
Organic Ligands
EDTA, DNOM …
Metal trap: Less toxic
• Trace metals speciation in the water column
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
MétalMétal
“Not” or lessbioavailable
bioavailable
[MTOTAL] ≠ [MTOXIC]
“Not” or less bioavailable
Could be bioavailable
7
• DNOM Origin?
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Anthropogenic activities
PhotosynthesisBacterial activitydegradation
Phytoplankton activity
Humification&Polymerization DNOM modifications
Heterogeneous origins heterogeneous and complex structure
Plants, animals, µorganisms decomposition River input
Representation of a simplified NOM
8
• DNOM speciation
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
“Analytical speciation” “Mechanistical speciation”
“structural” determination
separation and analysis
Dialysis, UF GFAASCFFFF, HPSEC ICP-MSHPLC, GC CV-AFSC18, Chelex Voltammetry… ...
Specific components determination
Less usable for metal behavior prediction
Interactions characterization
ISEVoltammetry
Fluorescence Quenching…
Results usable in speciation codes for prediction
(for example MOCO from IFREMER)
No Functional characterization
9
KHthermo
KMthermo
kM1
kM-1
• DNOM speciation
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
DNOM-Metal interaction study
•Continuous model: NICA-Donnan•Discrete model: WHAM
M+
Used to describe the DNOM reactivity
Assuming a kinetic of 1st order
LDNOM
M
H++
H+
+ Comp KCompthermo
Comp
LDNOM
For 1 DNOM: All K and [LiT] determined = “Chimiotype”
For Metal-DNOM interaction study: Need a technique to measure only M
orM
LDNOMMM
LDNOM LLDNOM
10
3 electrodes system:Counter electrode (Pt)Reference electrode (Ag/AgCl/KClsat)Working electrode (Hg)
StirrerPurging (N2)
Metal additionOxydation step
Escan (V)
-0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1
Inte
nsi
ty (
A)
0.0
2.0e-9
4.0e-9
6.0e-9
8.0e-9
1.0e-8
1.2e-8
1.4e-8
1.6e-8
• Analytical tool used to measure trace metal: DPASV
M
DNOM
L Metal-Ligand Complex
DNOM
L
DNOM
L
M
DNOM
L
DNOM
L
DNOM
L
DNOM
L
DNOM
L
DNOM
L
M
M
M
M
Reduction Step
Edep
e-
MM
M
M
M
MM
M
MM
Edep
After tdep = 5 minEscan
Voltamogram
I=f([M])
Escan
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Direct measurement of free & inoganic copper fraction
= electrolabile fraction
(= bioavailable fraction)
11
-9.50
-9.00
-8.50
-8.00
-7.50
-7.00
-6.50
-6.00
-5.50
-5.00
-9.50 -9.00 -8.50 -8.00 -7.50 -7.00 -6.50 -6.00 -5.50 -5.00
pCuT
pCu
Lab
[Metal added]: From nM to µM
5.8
6.2
6.6
7.0
7.4
7.8
8.2
8.6
5.86.26.67.07.47.88.2pCuT
pCul
ab
1:1Sal11 expSal11 calc
Metal complexed by DNOM
Data at equilibrium Kequilibrium, [LT]
0.0E+00
2.0E-09
4.0E-09
6.0E-09
8.0E-09
1.0E-08
1.2E-08
1.4E-08
1.6E-08
0 50 100 150t (mn)
Cu
(M)
CuT
Culabile
Kinetic k1, k-1, [LT]
For each point:2h of equilibriumMeasurements every 6 min.
Discrete fitting of experimental data with
PROSECE program(Speciation calculus + optimization)
Determination of Kequilibrium, [LT]
Determination of k1, k-1, [LT] New characterization of the DNOM: reactivity
• Metal logarithmic scale titration (Garnier et al., 2004, Env. Technol. 25, 589-599)
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
12
0
2
4
6
8
10
12
14
16
-0.65-0.60
-0.55-0.50
-0.45-1.2
-1.0-0.8
-0.6-0.4
stru
ja /
A
potencijal / Vpotencijal akumulacije / V
potencijal akumulacije / V
-1.4 -1.3 -1.2 -1.1 -1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4
stru
ja /
A
0
2
4
6
8
10
12
14
16
0
2
4
6
8
10
12
14
16
-0.65-0.60
-0.55-0.50
-0.45-1.2
-1.0-0.8
-0.6-0.4
stru
ja /
A
potencijal / Vpotencijal akumulacije / V
potencijal akumulacije / V
-1.4 -1.3 -1.2 -1.1 -1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4
stru
ja /
A
0
2
4
6
8
10
12
14
16
0
2
4
6
8
10
12
14
16
-0.65-0.60
-0.55-0.50
-0.45-1.2
-1.0-0.8
-0.6-0.4
stru
ja /
A
potencijal / Vpotencijal akumulacije / V
potencijal akumulacije / V
-1.4 -1.3 -1.2 -1.1 -1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4
stru
ja /
A
0
2
4
6
8
10
12
14
16
0
2
4
6
8
10
12
14
16
-0.65-0.60
-0.55-0.50
-0.45-1.2
-1.0-0.8
-0.6-0.4
stru
ja /
A
potencijal / Vpotencijal akumulacije / V
potencijal akumulacije / V
-1.4 -1.3 -1.2 -1.1 -1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4
stru
ja /
A
0
2
4
6
8
10
12
14
16
0
2
4
6
8
10
12
14
16
-0.65-0.60
-0.55-0.50
-0.45-1.2
-1.0-0.8
-0.6-0.4
stru
ja /
A
potencijal / Vpotencijal akumulacije / V
potencijal akumulacije / V
-1.4 -1.3 -1.2 -1.1 -1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4
stru
ja /
A
0
2
4
6
8
10
12
14
16
0
2
4
6
8
10
12
14
16
-0.65-0.60
-0.55-0.50
-0.45-1.2
-1.0-0.8
-0.6-0.4
stru
ja /
A
potencijal / Vpotencijal akumulacije / V
potencijal akumulacije / V
-1.4 -1.3 -1.2 -1.1 -1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4
stru
ja /
A
0
2
4
6
8
10
12
14
16
Voltammograms Pseudopolarogram
• Pseudopolarography measurements (Nicolau et al., 2008, ACA 618, 35-42)
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Deposition potential (V)Deposition potential (V)Scanning potential (V)
Inte
nsi
ty (
nA
)
Inte
nsi
ty (
nA
)
Edep for CC measurements
Labile fraction
Direct ML complex reduction
Labile fraction = Free + inorganic fraction : bioavailableDissociable organic fraction: Probably not bioavailableNot measured fraction = electroinactive in the Edep range used
Measured if: UV, pH=2,
Edep << Edep for CC
13
8. Goals of the study
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Analytical protocol determinationadapted to low [DOC] and [Metal]
Improvements:
•Technical •Analytical •Mathematical “Model DNOM” definition
Based on the concentrated sample from GDR MONALISA
Real complex natural ecosystem study
14
II. Analytical Protocol determination
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
15Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
• Technical and mathematical improvements
pCuT6.06.57.07.58.0
pC
ula
bile
6.0
6.5
7.0
7.5
8.0
8.5
9.0
E (V)-0.5 -0.4 -0.3 -0.2 -0.1 0.0
i (A
)
0
1e-9
2e-9
3e-9
4e-9
5e-9 experimentals pointsfitted curvepeak 1 peak 2baseline
•Limit adsorption (Teflon use)•Precise metal additions (automatic pumps 500µl)•Avoid pollution with additions (tubing separation)•Avoid evaporation (N2 wet purging)•Mathematical baseline and peak definition •Multi-PROSECE (more optimization loop & confidence interval calculus)
16
• Analytical improvement: Surface Active Substances (SAS) interferences (Louis et al., 2008, ACA 606, 37-44)
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
M M
M
e-
Edep
SAS
Escan
e-
Escan
SAS
M M
M
I [Cu]meas [LT]
-0.45V without SAS
-0.45V with SAS
Distorded shape
17
Analytical process to get rid of SAS interferences during the stripping step
Additional experiment A.C Voltametry (Phase angle: 90° measure of capacitive current)
Max. Ads.At pzc
Only 1% of the total deposition time (297s)
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Edep = -0.6V
Edep = -1.6V
Edep = -0.6V + 3s at -1.6V
Classical used tdep
Classical Edep used for Cu
ΔI ↑ = Itcap- It0
cap = SAS quantity ↑
High influence of SAS at tdep = 300 s and Edep ≈ - 0.5 V
- +Eacc= -0.45 V + 3sec at -1.6V Eacc= -1.6 V
Eacc= -0.45 V
Full circles Edep=60 sDotted circles Edep=60 s + 1s at -1.6VTriangles Edep =60s (After UV)
18
Influence of these SAS on the apparent [LT]
Without 3sec
[LT]= 335 nM
logK=6.17
With 3sec
[LT]= 160 nM
logK=6.47
[LT] change from 335 nM to 160 nM Artificially « Hidden Metal » by SAS bad speciation determination toxicity
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Ruzić linearization
19
Filtration at 0.45µm
DOC
Total Metal
UV at pH2
Salinity or majors ions by Ionic
Chromatography
Log addition window determination :
Add1= 10% MiniFinal conc.:
1mgC/L 1µM10 mgC/L 10µM
Pseudo Edep
(Optional)
H+ , Ca2+ competition(After Chelex)
Log additions at Edep, Kinetic experiment
PROSECE
Raw sample Potentiometry(Chelex)
(1)
(2)
(4)
(3)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
• Analytical protocol for DNOM study
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
For concentrated samples
“Chimiotype”
20
III. Study of a natural seawater sample (MONALISA project)
(Article submitted to Marine Environmental Research)
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
21
Military port
1. Sampling site: Balaguier Bay
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
1000L seawater sampling (online filtration and nanofiltration and reverse osmosis concentration by GDR MONALISA, ISM-LPTC: E. Parlanti, PhD of Arnaud Huguet). Concentrated from 1000 L to ~10 L, [DOC]final= 30.4 mg/L
Site interest: Coastal Semi-Closed Area under
anthropogenic influencesGoal: Give standard DNOM usable in metal
speciation/transport program
> 100 nM
~ 15 nM
~ 5 nM
22
2
4
6
8
10
12
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14nOH
-ajouté (mmol)
pH
-5
-4
-3
-2
-1
0
1
2
3
4
5
Err
eur
(%)
PROSECE Fitting for 4 types of acidic sites (DOC=1.2mmolC.L-1).
LH1 LH2 LH3 LH4Carboxylic
like Phenolic
like
Total acidic Sites
LHiT
(meq/molC)210 ± 10.8 54 ± 2.4 80.4 ± 1.2 100.8 ± 1.2 265.2 181.2 446.4
pKa 3.6 ± 0.1 4.8 ± 0.1 8.6 ± 0.1 12.0 ± 0.4
60% 40%
Lu and Allen (2002) : Suwanee River(also concentrated by RO)
30%70%
Carboxylic-like Phenolic-like
165.3
/2.7
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
• Potentiometry on Concentrated DNOM (Garnier et al., 2004, Water Research, 38, 3685-3692)
(Letizia and Gnudi, 1999)
23
pCuT
45678
Cu
T (
%)
0
20
40
60
80
100
5,6 4,6
1st site saturation
2nd site saturationEdep = -0.5V
Estimation of a [1st site]: 90% x 2.5µM = 2.25 µM (= 1.87 meq/molC)
Estimation of a [2nd site]: 50% x 25µM - [1st site]: = 10.25 µM (= 8.54 meq/molC)
• Exploratory experiment: Pseudopolarography coupled with logarithmic addition
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
24
• Log addition and Cu2+ competition with H+ and Ca2+
[Cu]T = 12.5µM, pH = 8.2 [Cu]T = 4µM.
LM1 LM2
LMiT (meq/molC) 1.72 ±0.13 10.25 ±2.7
logKCuL 9.9 ±0.1 6.9 ±0.1
logKCaL 2.5 ±0.4 5.5 ±0.6
pKa 8.6 ±0.1 8.2 ±0.3
Complexing parameters determined after simultaneous fitting by PROSECE of the 3 experiments
Strong affinity of copper for the studied DNOM
Total metal binding site density LMT
12
Ca additions
% Cu lab
≈ 2µM of Cu bound to specific sites
% Cu lab
pH
Strong affinity toward proton phenolic-like sites
Phenolic-like sites
Total acidic sites density
446
~3% of
(= Buffle, 1988)
Strong complexing site specific to copperHight calcium competition effect
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Edep = -0.5V, pH = 8.2, DOC = 1.2mmolC.L-1.
[L M1] =
0.03 meq/mol C
Comparison of 2 different Edep (-0.5V and -1.5V).
Closed to values estimated with pseudo coupled with log add.
Model Marine DNOM complexing parameters = DNOM “Chimiotype”(Comparable to standards OM used in NICA-Donnan /WHAM models, obtained for soil/river extracted OM)
LH1 LH2 LH3 LH4
LHiT
(meq/molC)210 ± 10.8 54 ± 2.4 80.4 ± 1.2 100.8 ± 1.2
pKa 3.6 ± 0.1 4.8 ± 0.1 8.6 ± 0.1 12.0 ± 0.4
25
seawater sample treated with Chelex (DOC = 0.09 mmolC.L-1); pH = 8.2, Salinity 37.
Experimental pointsDNOM simulated by Mineql adjusting only [DOC]Difference between modeled DNOM and experimental points
<<5%
• Correct simulation validating the characterization protocol• DNOM reactivity is not strongly modified by concentration stepModel DNOM determined usable
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
• MINEQL simulation of natural DNOM according to determined model marine DNOM
26
7.5 8.3N
atur
al m
arin
e w
ater
cond
itio
ns
80% of total copper complexed as organic forms >90% found in several paper: Influence of SAS ? specific behavior of the studied DNOM and high copper content
Condition: Majors ions for salinity of 38, DOC = 0.09 mmolC.L-1, Cutot = 14.8nM
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
• Simulation of copper speciation for the studied marine environment
27
IV. Estuarine DNOM Study (Article submitted to Marine Chemistry)
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
28
• Sampling in the water column: gradient of salinity
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
0 10 20 30 40
Salinity
Dep
th (
m)
FSI layerBrackish
Seawater
1. Sampling site: Krka, Croatia (2007&2008)
•Pristine watershed•Potential anthropogenic inputs in estuary•On site measurements in nearby laboratory
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
•Low tide on Adriatic sea stratified estuary
•Challenge is to give data on speciation and kinetic in this natural area
29
Filtration at 0.45µm
DOC
Total Metal
UV at pH2
Salinity or majors ions by Ionic
Chromatography
Log addition window determination :
Add1= 10% MiniFinal conc.:
1mgC/L 1µM10 mgC/L 10µM
Pseudo Edep
(Optional)
H+ , Ca2+ competition(After Chelex)
Log additions at Edep, Kinetic experiment
PROSECE
Raw sample Potentiometry(Chelex)
(1)
(2)
(4)
(3)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
• Simplified protocol used
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
No concentration step and no use of Chelex
30
Salinity
0 10 20 30 40
Dep
th (
m)
-8
-6
-4
-2
0
DOC (µMC)
40 50 60 70 80
CuT (nM)2 4 6 8 10 12
Salinity0 10 20 30 40
Cu
T
2
4
6
8
10
12
Salinity0 10 20 30 40
DO
C
40
50
60
70
80
A B C
• Same curve shape for 2007 & 2008 • Oligotrophic freshwater Very few carbon content, DOC est. < DOC sea low anthrop. inputs• Non conservative behavior: Bigger amount of metal & DOC in the FSI “special layer”• Additional source of DOC in the FSI: can be due to an exacerbated biological activity (Svensen et al, 2006)
• Increase of copper in the FSI: particulate/dissolved metal exchange due to salinity increase
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
• Salinity, DOC and Copper profiles(Elbaz-Poulichet F. et al., 1991) 1.78 in may 1988
31
0.0E+00
2.0E-08
4.0E-08
6.0E-08
8.0E-08
1.0E-07
1.2E-07
1.4E-07
6.97.17.37.57.77.9pCuT
LT
(mol
/L)
2
4
6
8
10
logk
1 &
logK
th
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
5.56.06.57.07.58.0 pCuT
pCul
ab
-10
-5
0
5
10
erre
ur (
%)
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
5.56.06.57.07.58.0 pCuT
pCul
ab
-10
-5
0
5
10
erre
ur (
%)
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
5.56.06.57.07.58.0 pCuT
pC
ula
b
-10
-5
0
5
10
erre
ur
(%)
Fitting at EquilibriumData at Equilibrium
0.0E+00
5.0E-09
1.0E-08
1.5E-08
2.0E-08
2.5E-08
3.0E-08
3.5E-08
4.0E-08
4.5E-08
5.0E-08
0 1000 2000 3000 4000 5000 6000 7000 8000t (s)
Cul
abil
e (M
)
0.0E+00
5.0E-09
1.0E-08
1.5E-08
2.0E-08
2.5E-08
3.0E-08
3.5E-08
4.0E-08
4.5E-08
5.0E-08
0 1000 2000 3000 4000 5000 6000 7000 8000t (s)
Cul
abil
e (M
)
Kinetic dataFitted Kinetic data
Log K kinetic
LT kinetic
Log k1 kinetic
0.0E+00
2.0E-08
4.0E-08
6.0E-08
8.0E-08
1.0E-07
1.2E-07
1.4E-07
6.97.17.37.57.77.9pCuT
LT
(mol
/L)
2
4
6
8
10
logk
1 &
logK
th
0.0E+00
2.0E-08
4.0E-08
6.0E-08
8.0E-08
1.0E-07
1.2E-07
1.4E-07
6.97.17.37.57.77.9pCuT
LT
(mol
/L)
2
4
6
8
10
logk
1 &
logK
th
Log K at Equilibrium
LT at Equilibrium
Average of Log K kinetic
Average of Log k1 kinetic
Average of LT kinetic
Good agreement between the constants obtained at equilibrium
and with the kinetic approach
Data obtained for only 1 sample: Example from Salinity 11, April 2007
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
4. Comparison of the kinetic and at Equilibrium approach
32
Time (s)0 2000 4000 6000 8000
Cu
lab
ile (
M)
0
1e-8
2e-8
3e-8
4e-8
pCuT6.06.57.07.58.0
pC
ula
bile
6.0
6.5
7.0
7.5
8.0
8.5
9.0
A B
k1
logKM Li at equilibrium9 10 11 12 13 14
log
KM
Li K
inet
ic9
10
11
12
13
14
LiT at equilibrium (nM)5 6 7 8 60 90 120 150
LiT
Kin
etic
(n
M)
5
6
7
8
60
90
120
150 A B
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Good agreement between constants determined at equilibrium or kinetic
Apparent overestimation of Kinetically determined logK (or underestimation of the at equ. approach) due to:
• kinetic first point estimation of Culab at t0
• Is the solution at equilibrium with the at equ. Approach•Both approaches are complementary
At equ: Higher M/L ratio better [L] determination
Kinet.: more points after each addition less equilibrium dependent, kinetic parameters determined
4. Comparison of the kinetic and at Equilibrium approach
k-1
2007 (,) and 2008 (,).
33
Cu (%)0 10 20 80 90 100
LiT (nM)
5 20 50 20010 100D
epth
(m
)
-10
-8
-6
-4
-2
0
Salinity0 10 20 30 40
log Kiequ
8.5 9.5 10.5 11.5 12.5 13.5
A B C
Cu2+(M)1e-12 1e-11 1e-10
Dep
th (
m)
-10
-8
-6
-4
-2
0
strong (,) and weak (,) ligands, 2007 (,) and 2008 (,), In dotted line in inset: toxicity limit of 10 pM (Sunda et al., 1987).
• Complexing parameters results
Expected variation with salinity
Observed variation
Difference Autochthonous DNOM production in the estuaryHigher affinity for ligands from seawater originIn the FSI: Higher inorganic and free copper content (up to 20pM) in spite of [ligands] increase
Organic Cu
90 to 99%
83%
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
& In MINEQL:
34
CuT (nM)
0 2 4 6 8 10 12 14
Dep
th (
m)
-8
-6
-4
-2
0
Cu2+ (M)1e-12 1e-11 1e-10
Reaction time (min)0 20 40 100 200 300
A B C
2008 2008 2006 t50% t99%
2006
Omanović et al., 2006
• Simulation of DNOM reactivity under a Cu contamination
Used for prediction
•Higher [Metal] in summer due to traffic of touristic boats•Calculated free copper concentration potentially toxic for µorganisms at the surface in summer•Lower reactivity of the FSI DNOM•Compared to hydrodynamics variations tequ. are quite long system probably not at equilibrium in the estuary
≈ 2h30
≈ 4h30
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
time
35
• Comparison of the measured DNOM vs. the model DNOM
dep
th (
m)
dep
th (
m)
simulated from model marine DNOM
Determined with the simplified protocol
Higher free [Cu] with the use of model DNOM > toxicity limitBigger difference for marine sample ≠ DNOM behavior between Toulon & ŠibenikModel DNOM not sufficient, even if DNOM is from same origin This ≠ show the necessity to study samples representatives of the studied system
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
36
V. Conclusion
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
37
• NEW use of “3sec” for DNOM analysis remove SAS interferences
•Determined protocol NEW direct analysis of coastal natural samples at low [DOC] and [M] complexing parameters determination + NEW Kinetic parameters (reactivity prediction) model DNOM usable in environmental contaminant speciation/transport programs
•Standard DNOM hardly usable to model DNOM behavior of a complex environmentUse of the determined protocol for specific ecosystem understanding
•Main improvement needed: Voltammograms automatic fitting
•Deeper analysis of pseudopolarograms,
•On site measurements (DGT) and comparison of data
•Actually protocol applied on a depth profile from Dycomed (Dyfamed site) …
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Conclusions and perspectives
38
[Cu]Free
1e-12 1e-11 1e-9 1e-8
Dep
th
-2000
-1500
-1000
-500
0
[Cu]Tot
Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion
Application of the method to an “oceanic” depth profile
First results shows:
•At natural [Cu]: Cufree under toxicity limit until simulated total [Cu] up to 5nM•Surface DNOM is less complexant•Still analyzing samples (Dycomed 15) and need to treat all kinetics data…• Need to make a connection with on site measurments (Chlorophyll, COT, fluorescence … )
5 nM
39
Martinska (Šibenik, Croatia)Balaguier Bay (Toulon, France)
Merci à tous de votre attention !Special thanks to my Directors:
Dr. Mounier S.Dr. Omanović D.
To the Jury’s members: Prof. Marmier N. Prof. Riso R.
D.R. Elbaz-Poulichet F. D.R. Cossa D. Dr. Garnier C.
And members from PROTEE (USTV) and LPCT (RBI) labs