Workshop Minutes. Passive Sampling Workshop, 1 Chairman's welcome. 2 Presentation Philipp Mayer (Aarhus University, Denmark) Wednesday morning session

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1 Workshop Minutes Wednesday morning session Utrecht, 9-10 November 2011 Passive Sampling Workshop, 1 Chairman's welcome Chairman Gert-Jan de Maagd of the Dutch Ministry of Infrastructure and Environment welcomes all participants. He explains that passive sampling has been called 'a promising approach' for a long time already and that a step forward is needed now. A next step could be that passive sampling is not only done parallel to conventional spot sampling but that it really replaces this. The question to be answered is then 'what is needed to make this step forward possible?'. Gert-Jan explains further that the outcome of this workshop is used to write a position paper on the possible use of passive sampling in regulatory monitoring. This position paper can be used to inform other member states and to address the EC. 2 Presentation Philipp Mayer (Aarhus University, Denmark) Phillips presentation is titled 'Equilibrium Sampling of Hydrophobic Organic Pollutants' and addresses three aspects: 1 Equilibrium sampling of hydrophobic organic chemicals in sediment and water 2 Validation and QA/QC considerations for equilibrium sampling with silicone rubber 3 Relating equilibrium sampling to conventional monitoring Ad 1. The concentration in an equilibrium sampling device passes through three stages: the kinetic stage, the intermediate stage and the (near) equilibrium stage at which C medium = C sampler / K sampler-medium. The change of the concentration in the sampler in time can be described by a first order, one-compartment model and from that a result can be derived that is representative for the freely dissolved concentration in the medium. At equilibrium, the chemical activity of the compound to be measured is equal in both the sampler and the medium. Reasons to use passive sampling in sediments include: - The concentration in sediment is often higher and more stable than in water; - Benthic bioconcentration is crucial for both benthic and pelagic bioaccumulation; - Historically polluted sediment might give rise to a diffusive pollutant flux to the water; - Sediment samples can be brought to the laboratory and - Organic matter can enhance the sampling kinetics. Silicon rubber (PDMS) can act as an equilibrium sampler material which can be used in different ways, including SPME (Soil Phase Micro Extraction) fibers end coated vials. SPME fibers can be used to sample both liquids and the headspace above liquids. Small PDMS discs can be used to sample organic compounds directly in fish. Equilibrium is reached slower in water than in sediment. A short equilibration time requires micrometer thin polymers, which are best coated on inert support (glass fiber fabric, glass or metal).

2 Ad 2 Equilibrium passive sampling requires the following assumptions/validity criteria: - Equilibrium; - Negligible depletion; - Absence of surface fouling artifacts; - Constant K polymer,water (confirmed from GC columns, SPME), linear isotherms, no competition; - K polymer,water is not affected by matrix. Sampling tests with multiple thicknesses have confirmed equilibrium, negligible depletion and the absence of surface fouling artifacts. Research has further shown that the influence of complex matrices on PDMS sorption properties is limited: in lipid-rich matrices sorption constant K for PCB52 is slightly (ca 10%) elevated with respect to non-lipid matrices. Ad 3 Equilibrium sampling measurements can well be related to lipid normalized concentrations in biota (through the K lipid,pdms ) and to total aqueous concentrations (through the free fraction or the enhancement factor) Remark: Relating the measured freely concentration to the total concentration seems difficult to apply in monitoring programs: It gives a lot of extra work. Answer: Yes, we should not do this for every single sample. Remark: Sampling with variable thicknesses to confirm equilibrium may fail when the concentrations changed in time. A thinner sampler has forgotten (released) an earlier peak concentration while a thicker still remembers it, and vica versa. Isn't that a problem? Answer: That s true but then anyway more information on the system is obtained than with a single sampler. Remark: Not always reaching equilibrium. Is that a problem? Answer: It depends on what you want to know but it can indeed be a draw-back of the method. Remark: Is passive sampling actually implemented in monitoring programs in Denmark? Answer: It is not yet implemented. 3 Presentation Gerrit Niebeek (Centre for Water Management, The Netherlands) Gerrits presentation is titled 'Passive sampling a policy perspective'. Gerrit starts his presentation by sketching the legal background of regulatory monitoring: - Water Framework Directive (2000/60/EC); - EQS-Directive (2008/105/EC); - Commission Directive on QA/QC (2009/90/EC); - Marine Strategy Framework Directive (2008/56/EC). Related to these Directives, several Guidance documents have been written: - Guidance on monitoring; - Guidance on biota and sediment monitoring; - Guidance on the derivation of EQS. The Water Framework Directive and the EQS directive require monitoring (programs) to check compliance with EQSs and to determine trends in the chemical and ecological status of water bodies. For this WFD monitoring priority substances have been selected and EQSs have been derived. Quality criteria for methods have been set for WFD monitoring.

3 For MSFD much work is still under construction: by July 2014 a monitoring program for ongoing assessment and regular updating of targets has to be established and implemented. Chemical monitoring (in water, suspended matter, biota and sediment) in The Netherlands takes place at two levels: at the national level and at the regional water board level. Passive sampling is not mandatory nor forbidden. The policy questions Gerrit poses with respect to passive sampling are however: - For which problem is passive sampling a solution? For compliance checking (AA and MAC)? For trend analysis for biota or sediment? For screening?; - Is passive sampling a solution or do we encounter new problems?; - Is it an extra matrix or an alternative for water, biota, sediment?; - What are the costs of passive sampling (is it cheaper or more efficient)?; - Is passive sampling ready for implementation or should we focus on RBMP 3?; - Does passive sampling fulfill QA/QC (extraction or compartment?)?; - Do we need to change derivation of EQS?; - What do we need to implement passive sampling in EU water monitoring (WFD or MSFD) or do we need more research and validation? Remark: Is biota monitoring allowed and can EQSs be self-derived? Answer: Biota monitoring is allowed for 3 substances (Hg, HCB and HCBD). For new priority substances more biota monitoring will be possible. It is allowed to derived your own national biota EQS. Remark: One EQS for all compartments (i.e. for silicon rubber) would be the best. Remark: Is there a chance that 'policy' will agree with this? Answer: Then you will have to change the Directives! This is not impossible but will be a long way! Remark: Setting the target on total concentration makes it difficult to assess risks. Answer: yes but this is how it is described in the Directives; Remark: Passive sampling of sediment is most promising for trend monitoring because you have no problems with differences in sediment characteristics; Remark: Maybe pointing out the pro's and con's of passive sampling helps implementing it in monitoring programs; Remark: In a trial within the UK we are now comparing measurements in water, sediment, biota and passive samplers. Remark: Use results/learn from 'effect-based monitoring' which we did in the past. Remark: We need agreement between member states how to use passive sampling for trend monitoring under MSFD.

4 4 Presentation Ian Allan (NIVA, Norway) Ian's presentation is titled 'Passive sampling in the regulatory context (WFD)'. The message Ian wants to give with this presentation is: - Provide reasons for the incorporation of passive sampling into regulatory monitoring; - Identify some of the challenges regarding its implementation in the WFD regulatory context. Advantages of passive sampling that are identified, are: - Continuous sampling; - Low variability (particularly when compared with biomonitoring); - No need for normalisation such as for sediments; - Control over blanks; - Ability to standardise uptake (e.g. with PRCs); - Extremely low limits of detection (low pg/l level); - Measurement of a relevant fraction of contaminants in water; - Simplified matrix composition. One of the main questions that is associated with using passive sampling in WFD-monitoring is: 'Can passive sampling be used for compliance checking, knowing that EQSs are based on whole water concentrations and passive sampling measures freely dissolved concentrations?'. Possible solutions are: - Calculate a dissolved EQS from the whole water EQS; - Calculate the whole water concentration from passive sampling data; - Combine passive sampling data with suspended matter measurements. Passive sampling with SPMD/Silicon rubber near Bear Island showed that here most PAHs were present in the dissolved phase and that estimated whole water concentrations were much lower than the EQSs. The questions that rise from these results are: Can we use this data for compliance checking? Can we build in safety factors? What is the risk of false negative? How do we reduce it? Since 2005 several intercomparison programs have been carried out. These include SWIFT- WFD, ICES, ECLIPSE, AQUAREF and NORMAN. One of the challenges identified is the fact that there are today so many types of passive sampling devices. This gives rise to the question whether one should aim to reduce the number of devices on the market and whether one should focus ones efforts to a restricted number of samplers. In order to be able to move forward Ian indentifies the following questions to be answered: - How do we reconcile 'whole water' based EQS and dissolved phase passive sampling data? - Will water-based EQS be translated into sediment EQS? How will this be done? Can this be of benefit to us? - Have other fields attempted such a move towards regulatory use? Can we benefit from the experinece of others? - Who can/will undertake regulatory passive sampling? - Is it just too compliated or are we making it too complicated? Why is the QA/QC information not wanted? Can we simplify passive sampling? - Can we demonstrate that passive sampling costs are lower than the other monitoring methods for a similar level of iformation> Is this the level of information needed, wanted? - Should we establish 'PSD-banks'? - AQUA-GAPS? (Lohmann& Muir, 2010)

5 - What about setting up sampling networks using ferry routes? - Should we be interested in highly hydrophobic substanes in the dissolved phase? (e.g. BDE209) Remark: What tell the intercalibration us about the accuracy of kinetic sampling? Answer: less than a factor 2; Remark: A modelled (calculated whole water) concentration is not the same as a measured concentration. Answer: collect suspended matter; Remark: It will never happen that everyone uses the same passive sampler. A better idea would possible be a 'reference area' where one could compare different samplers.