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1 Directeurs de Thèse : Dr. S. MOUNIERUniversité du Sud Toulon Var – PROTEE (PROcessus de Transferts et d'Echanges dans l'Environnement) Dr. D. OMANOVIĆ

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Presentation on theme: "1 Directeurs de Thèse : Dr. S. MOUNIERUniversité du Sud Toulon Var – PROTEE (PROcessus de Transferts et d'Echanges dans l'Environnement) Dr. D. OMANOVIĆ"— Presentation transcript:

1 1 Directeurs de Thèse : Dr. S. MOUNIERUniversité 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 dune 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 dobtenir le titre de Docteur de lUniversité du Sud Toulon-Var Subvention N° 03/ /T Matière Organique NAturelle en miLIeu SAlé

2 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 3 I.Introduction Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion

4 4 1.Trace metals in the environment Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Metals Natural origin Anthropogenic origin Metals AQUATIC ENVIRONMENT (Coastal and estuarine system) SOILS WATER ATMOSPHERE SEDIMENTS

5 5 Metals Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Oligoelements: necessary for metabolism Cu, Fe, F, Mg, Mn, Zn, … Toxic metals: not needed Pb, Hg, Cd, … Concentration increase Toxicity Total concentration When metal became toxic ? depend on its speciation 1.Trace metals in the environment

6 6 Generally toxic for biota M M M Micro-organisms (bacteria, virus,…) Organic and Inorganic Particules M n+ Inorganic Ligands Cl -, NO 3 -, SO 4 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 2.Trace metals speciation in the water column Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Not or less bioavailable [M TOTAL ] [M TOXIC ] Not or less bioavailable Could be bioavailable

7 7 3.DNOM Origin? Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Anthropogenic activities Photosynthesis Bacterial activity degradation Phytoplankton activity Humification& Polymerization DNOM modifications Heterogeneous origins heterogeneous and complex structure Plants, animals, µorganisms decomposition River input Representation of a simplified NOM

8 8 4.DNOM speciation Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Analytical speciation Mechanistical speciation structural determination separation and analysis Dialysis, UFGFAAS CFFFF, HPSEC ICP-MS HPLC, GC CV-AFS C18, ChelexVoltammetry …... Specific components determination Less usable for metal behavior prediction Interactions characterization ISE Voltammetry Fluorescence Quenching … Results usable in speciation codes for prediction (for example MOCO from IFREMER) No Functional characterization

9 9 K H thermo K M thermo kM1kM1 k M -1 4.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 L DNOM M H+H+ + H+H+ + Comp K Comp thermo Comp L DNOM For 1 DNOM: All K and [L iT ] determined = Chimiotype For Metal-DNOM interaction study: Need a technique to measure only M or

10 10 3 electrodes system: Counter electrode (Pt) Reference electrode (Ag/AgCl/KClsat) Working electrode (Hg) Stirrer Purging (N 2 ) Metal addition Oxydation step 5.Analytical tool used to measure trace metal: DPASV M DNOM L Metal-Ligand Complex MMMM M Reduction Step E dep e-e- M M M M M M M M M M After t dep = 5 min E scan Voltamogram I=f([M]) E scan Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Direct measurement of free & inoganic copper fraction = electrolabile fraction (= bioavailable fraction)

11 11 pCu T pCu Lab [Metal added]: From nM to µM Metal complexed by DNOM Data at equilibrium K equilibrium, [L T ] Kinetic k 1, k -1, [L T ] For each point: 2h of equilibrium Measurements every 6 min. Discrete fitting of experimental data with PROSECE program (Speciation calculus + optimization) Determination of K equilibrium, [L T ] Determination of k 1, k -1, [L T ] New characterization of the DNOM: reactivity 6.Metal logarithmic scale titration (Garnier et al., 2004, Env. Technol. 25, ) Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion

12 12 VoltammogramsPseudopolarogram 7.Pseudopolarography measurements (Nicolau et al., 2008, ACA 618, 35-42) Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Deposition potential (V) Scanning potential (V) Intensity (nA) E dep for CC measurements Labile fraction Direct ML complex reduction Labile fraction = Free + inorganic fraction : bioavailable Dissociable organic fraction: Probably not bioavailable Not measured fraction = electroinactive in the Edep range used Measured if: UV, pH=2, E dep << E dep for CC

13 13 8.Goals of the study Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Analytical protocol determination adapted 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 14 II.Analytical Protocol determination Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion

15 15 Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion 1.Technical and mathematical improvements Limit adsorption (Teflon use) Precise metal additions (automatic pumps 500µl) Avoid pollution with additions (tubing separation) Avoid evaporation (N 2 wet purging) Mathematical baseline and peak definition Multi-PROSECE (more optimization loop & confidence interval calculus)

16 16 2.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- E dep SAS E scan e- E scan SAS M M M I [Cu] meas [L T ] -0.45V without SAS -0.45V with SAS Distorded shape

17 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 E dep = -0.6V E dep = -1.6V E dep = -0.6V + 3s at -1.6V Classical used t dep Classical E dep used for Cu ΔI = I t cap - I t0 cap = SAS quantity High influence of SAS at t dep = 300 s and E dep V -+ E acc = V + 3sec at -1.6V E acc = -1.6 V E acc = V Full circles E dep =60 s Dotted circles E dep =60 s + 1s at -1.6V Triangles E dep =60s (After UV)

18 18 Influence of these SAS on the apparent [L T ] Without 3sec [L T ]= 335 nM logK=6.17 With 3sec [L T ]= 160 nM logK=6.47 [L T ] 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 19 Filtration at 0.45µm DOC Total Metal UV at pH2 Salinity or majors ions by Ionic Chromatography Log addition window determination : Add1= 10% Mini Final conc.: 1mg C /L 1µM 10 mg C /L 10µM Pseudo E dep (Optional) H +, Ca 2+ competition (After Chelex) Log additions at E dep, Kinetic experiment PROSECE Raw sample Potentiometry (Chelex) (1) (2) (4) (3) (5) (6) (7) (8) (9) (10) (11) 3.Analytical protocol for DNOM study Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion For concentrated samples Chimiotype

20 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 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 influences Goal: Give standard DNOM usable in metal speciation/transport program > 100 nM ~ 15 nM ~ 5 nM

22 22 PROSECE Fitting for 4 types of acidic sites (DOC=1.2mmol C.L -1 ). L H1 L H2 L H3 L H4 Carboxylic like Phenolic like Total acidic Sites L HiT (meq/mol C ) 210 ± ± ± ± pKa3.6 ± ± ± ± %40% Lu and Allen (2002) : Suwanee River (also concentrated by RO) 30% 70% Carboxylic-likePhenolic-like /2.7 Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion 2.Potentiometry on Concentrated DNOM (Garnier et al., 2004, Water Research, 38, ) (Letizia and Gnudi, 1999)

23 23 1 st site saturation 2 nd site saturation E dep = -0.5V Estimation of a [1 st site]: 90% x 2.5µM = 2.25 µM (= 1.87 meq/mol C ) Estimation of a [2 nd site]: 50% x 25µM - [1st site]: = µM (= 8.54 meq/mol C ) 3.Exploratory experiment: Pseudopolarography coupled with logarithmic addition Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion

24 24 4.Log addition and Cu 2+ competition with H + and Ca 2+ [Cu] T = 12.5µM, pH = 8.2 [Cu] T = 4µM. L M1 L M2 L MiT (meq/mol C )1.72± ±2.7 logK CuL 9.9±0.16.9±0.1 logK CaL 2.5±0.45.5±0.6 pKa8.6±0.18.2±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 L MT 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 copper Hight calcium competition effect Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion Edep = -0.5V, pH = 8.2, DOC = 1.2mmol C.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) L H1 L H2 L H3 L H4 L HiT (meq/mol C ) 210 ± ± ± ± 1.2 pKa3.6 ± ± ± ± 0.4

25 25 seawater sample treated with Chelex (DOC = 0.09 mmol C.L -1 ); pH = 8.2, Salinity 37. Experimental points DNOM 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 step Model DNOM determined usable Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion 5.MINEQL simulation of natural DNOM according to determined model marine DNOM

26 Natural marine water conditions 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 mmol C.L -1, Cu tot = 14.8nM Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion 6.Simulation of copper speciation for the studied marine environment

27 27 IV.Estuarine DNOM Study (Article submitted to Marine Chemistry) Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion

28 28 Sampling in the water column: gradient of salinity FSI layer Brackish 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 29 Filtration at 0.45µm DOC Total Metal UV at pH2 Salinity or majors ions by Ionic Chromatography Log addition window determination : Add1= 10% Mini Final conc.: 1mg C /L 1µM 10 mg C /L 10µM Pseudo E dep (Optional) H +, Ca 2+ competition (After Chelex) Log additions at E dep, Kinetic experiment PROSECE Raw sample Potentiometry (Chelex) (1) (2) (4) (3) (5) (6) (7) (8) (9) (10) (11) 2.Simplified protocol used Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion No concentration step and no use of Chelex

30 30 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 3.Salinity, DOC and Copper profiles (Elbaz-Poulichet F. et al., 1991) 1.78 in may 1988

31 31 Fitting at EquilibriumData at Equilibrium Kinetic dataFitted Kinetic data Log K kinetic L T kinetic Log k 1 kinetic Log K at Equilibrium L T at Equilibrium Average of Log K kinetic Average of Log k 1 kinetic Average of L T 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 32 k1k1 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 Cu lab at t 0 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 (, ) and 2008 (, ).

33 33 strong (, ) and weak (, ) ligands, 2007 (, ) and 2008 (, ), In dotted line in inset: toxicity limit of 10 pM (Sunda et al., 1987). 5.Complexing parameters results Expected variation with salinity Observed variation Difference Autochthonous DNOM production in the estuary Higher affinity for ligands from seawater origin In 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 t 50% t 99% 2006 Omanović et al., 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 t equ. 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 35 7.Comparison of the measured DNOM vs. the model DNOM simulated from model marine DNOM Determined with the simplified protocol Higher free [Cu] with the use of model DNOM > toxicity limit Bigger difference for marine sample DNOM behavior between Toulon & Šibenik Model 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 36 V.Conclusion Introduction – Analytical protocol – Marine DNOM study – Estuarine DNOM Study - Conclusion

37 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 environment Use 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 38 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]: Cu free 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 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 Jurys 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

40 40

41 41 Representation of baseline determination problem

42 42 Sensitivity Intensity peak or Area peak = Sensitivity x [Metal] labile

43 43 π/2 = 90° Capacitive current Faradic current A.C. Voltammetry at 90°

44 44 Kinetic at (to) low and (to) high metal content To much noise at low [M]/[L]Not enough curvature at high [M]/[L]

45 45 Thermodynamic and Conditional stability constants

46 46 Algorithm of optimisation use of a modified simplex parameters values (complexation, acidic, fluorescence …) adjustment to simulate the experimental titrations General principle of PROSECE (« PRogramme dOptimisation et de SpEciation Chimique en Environnement ») Garnier et al., Analytica Chimica Acta, 2004, 2005 Algorithm of chemical speciation. equilibrium resolution by a Newton-Raphson algorithm. minimisation of the mass-balance deviation Composed of two modules:

47 47 Quasi-particles (Sposito, 1983) parameters. Initial values Speciation calculation Comparison to experimental results (pH and/or pM) Bias test YES Optimised values NO modified Simplex evolution of ALL quasi-particles parameters iteration Determination of the parameters which better depict the analysed DNOM properties chemical speciation algorithm optimisation algorithm Modified with multi-PROSECE Principle of (multi-)PROSECE (« PRogramme dOptimisation et de SpEciation Chimique en Environnement ») Garnier et al., Analytica Chimica Acta, 2004, 2005 SD calculus

48 48 PARAFAC results C1: Humic like (peak A) C2: Protein like (Tryptophane) C3: Marine Humic like (peak M)


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