1. Philippe Quevauviller - Metrology in environmental chimistry 1 METROLOGY IN ENVIRONMENTAL CHEMISTRY Philippe QUEVAUVILLER Centre of Excellence on Environmental Analysis and Monitoring Gdansk, 21st April 2005

2. Philippe Quevauviller - Metrology in environmental chimistry 2 CONTENT OF THE COURSE GENERALITIES - Chemical Metrology - - Quality assurance - - Environment monitoring - - Regulations - SCIENTIFIC AND TECHNICAL FRAMEWORK - Methods: selection and validation - - Tools for quality: Reference materials - - Interlaboratory studies - - Examples of European projects - PERSPECTIVES - Monitoring - - Data quality - - Research - - Training -

3. Philippe Quevauviller - Metrology in environmental chimistry 3 METROLOGY - Generalities - The metrology is the science of measurements System covering basic concepts such as traceability, uncertainty, calibration, validation, etc. of measurements - It must guarantee that analytical data are: (1) expressed according to recognised units, in principle units of the “Système International” (SI) (2) comparable between laboratories and over time (3) provided to the user(s) with clear information regarding their significance (uncertainty)

4. Philippe Quevauviller - Metrology in environmental chimistry 4 METROLOGY - Units of the “Système international (SI)” - Metric system established in France during the French revolution (standard metre conserved at BIPM in Sèvres since 1889) At the Conférence Générale des Poids et Mesures (CGPM) in 1901: the kilogramme is declared mass unit, sorting out the the ambiguity between « weight » and « mass » Time: The SI unit is the atomic second (since 1968), corresponding to the radiation between two levels of the basic state of the 133 cesium atom Temperature: centigrade or Celsius scale (freezing or boiling points of pure water established at 0 and 100 °C - Kelvin scale (absolute zero at approx. -273 °C) Mole: mass of substance, measured in reference to the kilogramme (mass of 12 g of 12 carbon = one mole of carbon) - This unit links the atomic/molecular entity of the matter to a macroscopic scale, through classical chemical reactions Derived units: for example, surface, density, pressure, viscosity, etc., the most used being the volume (defining the litre as « a volume occupied by the mass of 1 kg pure water at its maximal density, at a standard atmospheric pressured »)

5. Philippe Quevauviller - Metrology in environmental chimistry 5 METROLOGY - Some definitions (1) - Trueness: « closeness of agreement between the result of a measurement and the true value of the measured value. The true value is the value that would be obtained by the measurement if the amount could be perfectly determined and all the errors eliminated » Precision : « closeness of agreement between the results of a series of repetitions of analyses of a substance in a single sample. This term is usually separated into repeatability (same instrument, analyst, location, conditions of utilisation, and short-term period of time) and reproducibility (variations of conditions, methods, analyst, location). The data related to precision are generally expressed in the form of standard deviations or, more often, of coefficients of variation of the mean of results of the measurement series. This should be distinguished from the robustness, which corresponds to the capacity of the method to remain unaffected by minor changes of the procedure (e.g. reagents or environment) »

6. Philippe Quevauviller - Metrology in environmental chimistry 6 METROLOGY - Some definitions (2) - Specificity: « response of a single analyte, not affected by possible interferences » Sensitivity: « minimal significant variation of a measurement result » Linearity: « capacity of obtaining, in a given interval, results that are directly proportional to the analyte concentration » Limit of detection : « smallest quantity of analyte that may be detected but not quantified (the detection limit is closely linked to sensitivity and to the stability of the analytical system » Limit of determination : « expression of the smallest amount of analyte which may be quantified - This limit is generally taken as being equivalent to 5 to 10 times the detection limit »

7. Philippe Quevauviller - Metrology in environmental chimistry 7 METROLOGY - Some definitions (3) - Traceability : « property of a measurement result or the value of a standard to be linked to established references, generally national or international standards, through an unbroken chain of comparisons, each having an established uncertainty » The comparabilitu of the results is the primary condition - The traceability is a tool, which should permit to achieve this comparability. The references may be SI units, calibrants, reference materials, (written) standards, reference methods - The unbroken chain of comparisons implies that links are established between the various analytical steps of the method used - The uncertainty should in principle be calculated at each step and combined (total uncertainty), which is not always achievable in practice. Possible « hierarchy » of links: SI Units (e.g. kg, mole) - international transfer standards (ex. kg) - atomic masses - pure calibrants of chemical substances - primary methods - Primary (matrix) reference materials - Secondary reference materials - Routine methods and Laboratory reference materials

8. Philippe Quevauviller - Metrology in environmental chimistry 8 CHEMICAL METROLOGY - Specific aspects -  Influence of sample matrix  Variety of analytical problems in relation to the millions of substances and thousands of sample types  Need of preliminary operations before the analysis (sampling, storage etc.) and related problems (e.g. stability, homogeneity of samples)  Needs of tools for the quality control of measurements (e.g. « matrix » reference materials)  Specific needs for the validation of methods including various steps  Difficulties for demonstrating the traceability of results and calculating the total uncertainty

9. Philippe Quevauviller - Metrology in environmental chimistry 9 QUALITY ASSURANCE - Chemical analyses - DEFINITIONS Quality: « Characteristics of a product or a service which confer the aptitude to satisfy the implicit or expressed needs » Quality assurance : « Preestablished and systematic actions necessary to provide the appropriate confidence that a product or service will satisfy given requirements related to quality » Quality Control : « Techniques and operational activities that are used to respond to respond to quality requirements. It implies activities that both aim to follow a process and to eliminate the causes of failure with the view of achieving the best economic efficiency » Quality system: « Organisational structure, covering the responsibilities, procedures and processes, to implement the quality activities (determining the quality policy of an enterprise) »

10. Philippe Quevauviller - Metrology in environmental chimistry 10 QUALITY ASSURANCE - User’s needs - The results have to be fit to the purpose for the study, as well as the means that are used (the highest level of accuracy is not systematically required) Example: Considering the guide value of arsenic in contaminated soils = 40 mg.kg -1 A soil will be considered as contaminated is an analytical result exceeds this guide value. If the As content is below 10 mg.kg -1, an absolute trueness is not necessary, and it is only necessary to define the confidence level of the results. The problem will be different if the content is 39 mg.kg -1 or 41 mg.kg -1 A well informed customer will ask (1) if the method is appropriate, (2) if it has been validated, (3) what are the sources of uncertainty and (4) what is the confidence level that can be expected from the results. The quality/price ratio of the analyses will also be considered.

11. Philippe Quevauviller - Metrology in environmental chimistry 11 QUALITY ASSURANCE - Implications - FOOSTUFFS - Detection of toxic risks - - Nutrition - ENVIRONMENT - Evaluation of environmental risks - - Detection of pollution - - Biogeochemical studies - BIOMEDICAL ANALYSES - Diagnosis - - Biochemical research - - Forensic science - INDUSTRY - Product quality -

12. Philippe Quevauviller - Metrology in environmental chimistry 12 CONSEQUENCES OF ANALYTICAL ERRORS DECISIONS Food toxicity (e.g.. dioxins) Environmental pollution (e.g. drinking water) Medical diagnosis, forensic science Industrial products (e.g. impact on trade)

13. Philippe Quevauviller - Metrology in environmental chimistry 13 ANALYTICAL ERRORS - Example - Dioxins in fly ashes « There is no democracy in science » A statistical analysis enables one to study the distribution of a population of data but it cannot explain the differences between results

14. Philippe Quevauviller - Metrology in environmental chimistry 14 Dioxins in fly ashes Mean  standard deviation Time F118 F119 F121 F130 45 : 0050 : 0055 : 00 Lab. 5 (a) Column used for the first time (lab. 5) F118 (+F119) F121 F130 ( b) Other columns or old DB Dioxin The majority of the laboratories (b) found a value for F118 (hexaclorodibenzofuran) which was 20 % too high. Only the laboratory 5 was right.

15. Philippe Quevauviller - Metrology in environmental chimistry 15 ANALYTICAL ERRORS - Example - Heavy metals in lichen BCR (1992) Element Lowest value (mg/kg) [Method] Highest value (mg/kg) [Method] Ratio Zn Cu Hg 9.7 [AAS] 0.8 [AAS] 0.005 [CVAAS] 283 [ICP] 39 [ICP] 0.551 [CVAAS] 29 48 110 Within the two years preceeding this study, around 2000 papers had been published in lichenology. The results of these studies have been used to evaluate the atmospheric contamination and to take “appropriate” decisions …...

16. Philippe Quevauviller - Metrology in environmental chimistry 16 ENVIRONMENT MONITORING - General principles - PRINCIPLES - Definition of the problem (regulations, research?) - - Choice of a strategy - - Chemical and/or biological analyses - - Interpretation and decision - PARAMETERS - Media, types of samples analysed - (e.g.. Contaminated soils, sediments, waters, biological samples, etc.) - Substances (regulated or not) - (e.g. heavy metals, nutrients, chemical species of element, organic compounds) OPERATIONS - Sampling - - Treatment / Storage of samples - - Analysis - - Presentation of the data -

17. Philippe Quevauviller - Metrology in environmental chimistry 17 ENVIRONMENT MONITORING - Matrix types (1) - WATERS groundwater, lake waters, rivers, estuaries, seawater, rainwater, wastewater - direct analyses, pretreatment in some cases (e.g. for waters rich in organic matters) SEDIMENTS Contaminants « sinks » (contamination history). Matrices of variable compositions, numerous interfering substances, difficulties to obtain a complete recovery of the analytes. Analyses requiring pretreatment steps, followed by various steps (e.g. separation) SOILS, SLUDGES, COMPOSTS Agronomy studies, risk assessment, monitoring of treatment efficiencies, etc. Similar difficulties in comparison to sediments, but more acute owing to a greater heterogeneity.

18. Philippe Quevauviller - Metrology in environmental chimistry 18 ENVIRONMENT MONITORING - Matrix types (2) - BIOLOGICAL SAMPLES Plants, biological organisms (e.g. molluscs) analysed for bioaccumulation capacity and used as « indicators » (trend studies, indicators of the quality of an ecosystem, nutritional studies, etc.). Complex matrices that include various types of components (carbon, fat mineral particles, dusts). ATMOSPHERIC SAMPLES Air, dusts, fly ashes, etc. Direct analyses using sensors (air) or indirect (e.g. sampling on filters, leaching and « classical » analysis). Some bioindicators are used for the indirect monitoring of atmospheric contamination (e.g. lichens) VARIOUS WASTES Of domestic or industrial origin. Analyses often based on leaching tests to determine the « mobile » fraction of contaminants

19. Philippe Quevauviller - Metrology in environmental chimistry 19 ENVIRONMENT MONITORING - Parameters (1) - PHYSICO-CHEMICAL pH, turbidity, conductivity, redox potential, etc. MAJOR ELEMENTS Matrix elements, contents above 0.1% in the environment Examples: Si, Ca, K, P, Mg, Mn, N, Na, Fe TRACE ELEMENTS Contents at the mg/kg or µg/kg level - Ultratraces levels being less than µg/kg Toxic and/or essential elements Examples: As, Ba, B, Br, Cd, Cr, Co, Cu, F, I, Hg, Mo, Ni, Pb, Sb, Se, V, Zn

20. Philippe Quevauviller - Metrology in environmental chimistry 20 ENVIRONMENT MONITORING - Parameters (2) - CHEMICAL FORMS OF ELEMENTS Specific forms of elements (e.g. different oxidation states, organometallic compounds, oxides or hydroxides, complexed forms) Examples: As(III), Cr(VI), methylmercury, tributyltin « EXTRACTABLES » CHEMICAL FORMS Chemical forms of elements that are operationally defined (single or sequential extraction) They are qualified, e.g. as « mobile », « bioavailable », etc. forms ORGANIC COMPOUNDS Of anthropogenic origin or products of organic decompositions Examples: chlorophenols, dioxins, hydrocarbons, pesticides, herbicides, polychlorobiphenyls

21. Philippe Quevauviller - Metrology in environmental chimistry 21 ENVIRONMENT MONITORING - Types of methods (1) - CALCULABLE METHODS Result which may be foreseen from a calculation made on the basis of physical or chemical measurements such as, e.g., sample weighing, volume of titrating reagent, etc. (e.g. titrimetry, gravimetry,etc.) PRIMARY (OR DEFINITIVE) METHOD Method with the highest metrological quality, having few random errors (and no systematic errors), and for which a complete estimate of the uncertainty may be obtained in terms of SI units (e.g. titrimetry, IDMS) RELATIVE METHODS Comparison of the analysed sample with calibrants of known concentrations. The result is established through interpolation with the response curve of the calibrants (e.g. spectrometric techniques) COMPARATIVE METHODS Comparison of the analysed sample with calibrating samples which have not been subject to any chemical treatment. The calibration is performed using certified reference materials with a matrix similar to that of the sample (e.g. X-ray Fluorescence spectrometry)

22. Philippe Quevauviller - Metrology in environmental chimistry 22 ENVIRONMENT MONITORING - Critical points (1) - GENERAL FRAMEWORK Selection of suitable method(s) (sampling, analysis, storage) Quality assurance (validation, quality control) Long-term storage (specimen banking)

23. Philippe Quevauviller - Metrology in environmental chimistry 23 ENVIRONMENT MONITORING - Critical points (2) - SOME SELECTION CRITERIA SAMPLING Representativeness of the environment, type of sample, (selective, random of composed), sampling strategy (site, frequency, procedure, etc.) CONSERVATION / STORAGE Preservation of the integrity (transport conditions and conservation / storage, types of containers, temperature, etc.) ANALYTICAL METHODS Equipment (e.g. glassware), and consumables (e.g. reagents of known purity), maintenance, costs and adaptation to the aim of the analyses

24. Philippe Quevauviller - Metrology in environmental chimistry 24 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (1) Criteria - Selectivity, sensitivity, trueness - - Repeatability, reproducibility - - Detector linearity - - Robustness - - Costs (purchase, maintenance) - - Facility and speed of utilisation - “COUPLED” METHODS Extraction (acids, organic solvents) Derivatisation (hydride generation, Grignard reactions) Separation (GC, HPLC) Detection (AAS, ICP-MS, ECD, MS, etc.)

25. Philippe Quevauviller - Metrology in environmental chimistry 25 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (2) Sampling « avoiding any risk of contamination or losses » WATERS - PTFE, polyethylene, polypropylene, borosilicate glass, etc. - SEDIMENTS / SOILS, BIOTA - Plastic tools or PTFE - Pre-treatment WATERS - Acidification, filtration - SEDIMENTS - Sieving (wet, using water from the site) -

26. Philippe Quevauviller - Metrology in environmental chimistry 26 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (3) Stabilisation / Long-term storage (examples) « Preserve the initial geo- and biochemical status » STABILISATION - Acidification (waters) - - Lyophilisation (biota, sediments, etc.) - - Oven-drying (sediments) - - Pasteurisation (sediments) - - Gamma irradiation (biota, sediments, waters) - STORAGE - Freezing for “sensitive” compounds (biota, sediments) - - Storage at ambient temperature or at 4 °C (in the dark) -

27. Philippe Quevauviller - Metrology in environmental chimistry 27 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (4) Extraction / Digestion (examples) ACIDS Acetic acid, sulphuric acid, nitric acid (e.g. with microwave), hydrofluoric acid (total digestion), etc. MIXTURE ACID / ORGANIC SOLVENT Hydrochloric acid/toluene, sulphuric acid/toluene, etc. ORGANIC SOLVENTS Toluene, methanol, tropolone pentane, etc. RECOVERY TEST: Spiking (three levels) OTHERS CO 2 / methanol, supercritical fluid enzymatic digestion (protease/lipase), etc.

28. Philippe Quevauviller - Metrology in environmental chimistry 28 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (5) Derivatisation (examples) « Transformation of a given compound for a better separation » Hydride generation (NaBH 4 ) Ethylation (NaBEt 4 ) Grignard reactions VERIFICATION OF YIELDS (secondary calibrants)

29. Philippe Quevauviller - Metrology in environmental chimistry 29 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (6a) Separation (examples) « required owing to the fact the determination of different compounds of a same ‘family’ cannot, in general, be carried out with a sufficient selectivity (e.g. selective detection by AAS) » GAZ CHROMATOGRAPHY - with packed column - - with capillary column - HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) OTHERS - Cryogenic trapping - - Capillary electrophoresis - - Ion exchange microcolumns -

30. Philippe Quevauviller - Metrology in environmental chimistry 30 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (6b) Examples of chromatograms 1 2 3 4 1 2 3 4 Retention time (minutes) 13.9 16.911.2 11.412.0 AB Peak height A - Megabore column B - Capillary column 1. Ph 2 SnPe 2 ; 2. Cy 2 SnPe 2 ; 3. Ph 3 SnPe; 4. Cy 3 SnPe

31. Philippe Quevauviller - Metrology in environmental chimistry 31 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (7) Detection (examples) SPECIFIC OF A GIVEN ELEMENT - Atomic absorption spectrometry - (electrothermal, flame, quartz furnace) MULTI-ELEMENT - Inductively coupled plasma atomic emission spectrometry (ICP-AES) - - ICP mass spectrometry (ICP-MS) - SPECIFIC OF A GIVEN ELEMENT SPECIES - Voltametry - SPECIFIC OF A GIVEN COMPOUND - Flame ionisation detection (FID) - - Flame photometric detection (FPD) - - Electron capture detection (ECD) -

32. Philippe Quevauviller - Metrology in environmental chimistry 32 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (8) Calibration AVAILABILITY OF CALIBRANTS - Primary calibrants (calibration) - - Internal standards (*) - (correction of matrix interférences, with associated risks, e.g. different response, linearity) - Stoichiometry, purity - CALIBRATION METHODS - External - - Matrix matching - - Bracketing calibration - - Standard additions - (*) The term « standard » is often prone to confusion (calibrants, RM, written standards)

33. Philippe Quevauviller - Metrology in environmental chimistry 33 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (9) Uncertainty « Parameter associated to the result of an analysis, characterising the dispersion of the values which may be attributed to the measurement » : Range of values in which the measured amount should be found The uncertainty defines the degree of confidence which may be attributed to a measurement. It includes both systematic effects (errors that are constant or varying in a foreseable way, which may be corrected, e.g. blanks, incomplete extraction, etc.) and random effects (not controlled, e.g. background noise). IMPLICATIONS FOR ENVIRONMENTAL ANALYSES The “total” uncertainty should in principle combine the uncertainties of each analytical step - Sampling - - Pre-treatment (extraction, derivatisation) - - Separation and detection - - Calibration -

34. Philippe Quevauviller - Metrology in environmental chimistry 34 SELECTION OF METHODS FOR ENVIRONMENTAL MONITORING (10) Example : Tributyltin (TBT) in coastal waters PRESENT AT THE ULTRA-TRACE LEVEL (ng.L -1 ) Hence need of a sensitive method OCCURRENCE NUMEROUS ORGANOTIN COMPOUNDS Hence need for a selective method RISKS OF DEGRADATION OF TBT Particular care at the sampling and storage steps. Need to determine degradation products (DBT, MBT) ANALYTICAL PROCEDURE Obviously a sophisticated technique, combining an efficient extraction (but not destructive), a good separation and a sensitive detection. Alternative: Bioindicators (e.g. Nucella lapilus)

35. Philippe Quevauviller - Metrology in environmental chimistry 35 PERFORMING ANALYTICAL WORK General aspects Obtaining samples and conserve them in the best conditions Selecting the method and ensuring that it is in good functioning order Planning the work and identifying critical steps (including risks) Ensuring that a suitable working space is available Verifying glassware, consumables, calibrants and RMs Foreseeing procedures related to wastes (e.g. used solvents) Cleaning of the laboratory NOTE: The analytical report and data archiving is considered as being an integral part of the metrological system. The report should contain a detailed description of the objective of the study, of the procedures used, quality control, performances of the method, the interpretation of the data, questions and unsolved problems. The archiving should in principle be in electronic form (e.g. use of LIMS software).

36. Philippe Quevauviller - Metrology in environmental chimistry 36 QUALITY CONTROL (1) Validation (principles) « Demonstrating that the results obtained with a given method are reliable, reproducible and that the method is adapted to the foreseen application » Apparatus, computers Analytical method (following slides) Control charts S1 S2 M Synthetic solutions (known calibrants) Solutions with known analyte concentrations and unknown matrix (e.g. spiked extract) “Matrix” material similar to the sample (natural or spiked) Signal calibration Purification separation Extraction digestion

37. Philippe Quevauviller - Metrology in environmental chimistry 37 QUALITY CONTROL (2) Verification of trueness « Closeness of agreement between the result of a measurement and the true value of the measured value (the true value is known only is the measured amount may be perfectly determined and if all the measurement errors have been eliminated » Verification of precision « Closeness of agreement between results of measurement of a same substance, applying the same experimental procedure several times in the same conditions (repeteability; the reproducibility is the closeness of agreement in time, taking into consideration variations of conditions (location, analyst); it has to be distinguished from robustness (capacity of the method to remain unaffected by minor changes of the procedure (e.g. reagents or environment) » * * * * * * * * ** * * * * * * * * * * * * * * * * * * * *

38. Philippe Quevauviller - Metrology in environmental chimistry 38 QUALITY CONTROL (3) Reference Material « Material or substance one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials (ISO, guide 30) » Certified Reference Material « Reference material, accompanied by a certificate, one or more of whose property values are certified by a procedure which establishes traceability to an accurate realisation of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence (ISO, guide 30) »

39. Philippe Quevauviller - Metrology in environmental chimistry 39 QUALITY CONTROL (4) Control charts « Graphical mean to evaluate the reproducibility of a method » SIMPLE CHARTS The value reported on the chart is the result obtained each time a measurement is carried out. (see following example) CUMULATIVE CHART (CUSUM The value reported on the chart is the sum of the absolute value of the differences between the measured value and a reference value. This type of chart enables to detect more rapidly possible method drifts.

40. Philippe Quevauviller - Metrology in environmental chimistry 40 QUALITY CONTROL (4 ’) Example of control chart Measured concentration mean 2 s 3 s Warning (2 s) and action (3 s) limits correspond, respectively, to a risk of 1 and 5 % that the result does not belong to the population of other results. The values of the mean and standard deviation (s) are determined by several measurements (at least 10 repetitions) carried out at the start of the analytical work, but on several days.

41. Philippe Quevauviller - Metrology in environmental chimistry 41 QUALITY CONTROL (5) Interlaboratory testing « Study in the framework of which several laboratories analyse one or several identical and homogeneous material(s), in specified conditions and for which the results are collected in a single report »

42. Philippe Quevauviller - Metrology in environmental chimistry 42 INTERLABORATORY TESTING (1) Generalities TYPES OF STUDIES Method performance studies Proficiency testing schemes (several methods) Certification of reference materials (attribution of « true values ») REQUIREMENTS Co-ordination Motivation of laboratories (and competence) Availability of testing materials Technical evaluation of the results Statistical evaluation

43. Philippe Quevauviller - Metrology in environmental chimistry 43 INTERLABORATORY TESTING (2) Improving schemes (method performance studies) The followed principle is similar to a method validation, i.e. analyses of increasingly complex matrices to detect errors that may occur at various analytical steps. These schemes have a pedagogical aim and imply the organisation of technical meetings in the framework of which participants exchange their experience and discuss weak points of the methods and the error sources. S1 S2 M1 M2 Simple solutions (pure substances or mixtures of substances) Matrix-matching solutions or extracts (spiked or not) Reference material (« matrix ») similar to the sample, spiked with a known analyte concentration Matrix material similar to the sample DETECTION DERIVATISATION PURIFICATION SEPARATION EXTRACTION MINERALISATION OVERALL METHOD

44. Philippe Quevauviller - Metrology in environmental chimistry 44 REFERENCE MATERIALS Conditions Representativeness It implies a similarity of composition between the material and the sample that is routinely analysed (similar sources of errors): Matrix composition Contents of substances Binding status of the substances in the matrix Physical status of the material Homogeneity / stability - Intra- and inter-vial homogeneity - - Long-term stability - Setting reference values - « Definitive » method in a specialised laboratory - - Several independent methods in an expert laboratory - - Several methods applied by several laboratories -

45. Philippe Quevauviller - Metrology in environmental chimistry 45 EXAMPLE OF IMPROVEMENT SCHEME (Methylmercury) WORK PROGRAMME Improvement scheme (series of 3 rounds): 1988-90 Certification of fish reference materials: 1991-94 Certification of sediment reference material: 1994-96 RESULTS Withdrawal of packed columns Detection of sources of errors (e.g. distillation) Two fish CRMs One sediment CRM Enriched extract Raw extract YOUDEN PLOT mg/kg MeHgMean of means

46. Philippe Quevauviller - Metrology in environmental chimistry 46 EXAMPLE OF CERTIFICATION RESULTS (Methylmercury) CONCLUSIONS Creation of a network of laboratories Enhanced knowledge on methods and validation needs Tools for quality control PERSPECTIVES - Development of new methods - (more rapid and easy to use) - Studies of analytical artefacts - - Laboratory reference materials - M 75.085.065.0 GC-CVAFS GC-CVAAS GC-QFAAS GC-ECD SFEGC-MIP HPLC-CVAAS HPLC-CVAFS HPLC-ICPMS MeHg (sediment) in µg/kg

47. Philippe Quevauviller - Metrology in environmental chimistry 47 PERSPECTIVES (1) - Monitoring - - Quality (and metrology)- - Research - - Training -

48. Philippe Quevauviller - Metrology in environmental chimistry 48 PERSPECTIVES (2) Environment monitoring Towards a global approach HARMONISATION - of strategies - - of methods (from sampling to analysis) - - of “target” parameters and matrices - - Selection de reference sites (at national / international level) - “MEMORY” - Storage of environmental specimens - (specimen banking) - Warning system at the international level -

49. Philippe Quevauviller - Metrology in environmental chimistry 49 PERSPECTIVES (3) Quality assurance STANDARDISATION? - Necessary for monitoring strategies - - Not systematic for analytical methods (risk of “progress fossilisation”) - ACCREDITATION? - Necessary for control laboratories - - Necessary for RM producers - REFERENCE MATERIALS - Establishment of a producer network in Europe - - Feasibility studies and CRM production - - Structure production of control MRs - PROFICIENCY TESTING - Organisation of targeted ring tests at international level - - Support to the accreditation of control laboratories -

50. Philippe Quevauviller - Metrology in environmental chimistry 50 PERSPECTIVES (4) Metrology TRACEABILITY Avoiding “fundamentalism” - The demonstration of traceability of a measurement should remain accessible to routine laboratories - Systematic studies of risks of error related to sampling - - “Matrix” materials enriched with isotopically-labelled compounds - - “Secondary” standards - - Recovery studies on extraction and derivatisation - UNCERTAINTY - Systematic study on “total uncertainty budgets” - (uncertainty calculated at each step and combined) - Studies of simplified alternatives for routine uncertainty calculations -

51. Philippe Quevauviller - Metrology in environmental chimistry 51 EXAMPLE OF TRACEABILITY CHAIN (Trace elements in seawater) RESULTS CHEMICAL TREATMENT PRETREATMENT, STORAGE SAMPLING IDMS DETECTION ANALYTICAL STEPS Addition of spike of known purity and stoichiometry Internationally recognised procedures Internationally recognised procedures Measurements of spike ratios REFERENCES A B C D

52. Philippe Quevauviller - Metrology in environmental chimistry 52 EXAMPLE OF TRACEABILITY CHAIN (Tribultin in harbour dredges) RESULTS EXTRACTION STORAGE, PROCESSING SAMPLING DERIVATISATION (if necessary) ANALYTICAL STEPS No standards, available CRMs No standards, literature-based No standards, literature-based Secondary standards REFERENCES SEPARATIONInternal standards FINAL DETECTION Primary calibrants A B C D E F

53. 53 Extraction, digestion etc. Written standards, matrix CRMs Chemical reactions (e.g. derivatisation) Secondary standards Separation Internal standards Detection Primary calibrants Control charts, proficiency testing Routinely operated method(s) RESULTS LRMs (freeze-dried) STORAGE, PROCESSING SAMPLING REFERENCE SITES IRMs (fresh) Validated written standards Harmonised written standards SPECIMENSBANKING FOLLOW-UP OF ENVIRONMENT QUALITY INTERNATIONALNETWORKINTERNATIONALNETWORK VALIDATED METHOD Method optimisation Development of new methods Research/testing to improve field methods and sampling procedures A BC D1D2 D3E F GH I J

54. Philippe Quevauviller - Metrology in environmental chimistry 54 PERSPECTIVES (5) Research ENVIRONMENTAL STUDIES - Biogeochemical cycle of elements and compounds - - Toxicity and bioavailability studies - - Development of new methods - (in particular rapid methods, low cost, applicable to the field) FEASABILITY STUDIES - Research on reference materials - (e.g. wet materials) - Stability studies of materials / substances - APPLICABILITY - Interface “science-policy” - - Public awareness -

55. Philippe Quevauviller - Metrology in environmental chimistry 55 PERSPECTIVES (6) Training ENVIRONMENTAL SCIENCES Mulidisciplinary training - Geochemistry, biology - - Analytical chemistry - - Metrology (including quality assurance) - - Regulations (“science-policy” interface) - QUALITY ASSURANCE Theoretical and applied training - Quality of environmental measurements - (from sampling to decision-making) - Practical training on site -

56. Philippe Quevauviller - Metrology in environmental chimistry 56 CONCLUSIONS EUROPEAN NETWORKS - Networked site monitoring (harmonised strategies) - - International meetings held at regular intervals - (involving scientists, industrialists, regulators) EXCHANGES / TRAINING - Transfer of knowledge and technologies - - Exchanges of students and technicians - - International hosting institutions - CENTRES OF COMPETENCE (National / Regional) - Multidisciplinary expertise in the environmental field - - Site monitoring - - Environmental specimen banking -

57. Philippe Quevauviller - Metrology in environmental chimistry 57 FURTHER INFORMATION REFERENCE MATERIALS - CRMs and interlaboratory studies for environmental analysis (1999) - (Quevauviller & Maier, Elsevier, ISBN 0-444-82389-1) - ISO/REMCO (Laboratoire National d ’Essais) - - Matériaux de référence pour l ’environnement (Tec&Doc, 2002) - ACTIVITIES OF THE EUROPEAN COMMISSION - Institute for Reference Materials and Measurements (IRMM) - (http://www.irmm.jrc.be/mrm.html) - Various general and targeted publications - (contact: philippe.quevauviller@cec.eu.int) ENVIRONMENTAL METROLOGY - Métrologie en chimie de l ’environnement (Tec&Doc, 2000) - - Metrology in chemistry - A practical approach (Valcárcel et al., 1998) -