Passive sampling in the regulatory context (WFD)

Transcription

1 Passive sampling in the regulatory context (WFD) Ian J. Allan, Christopher Harman & Norman W. Green IJ Allan, C Harman & NW Green 1

2 Message Provide reasons for the incorporation of passive sampling into regulatory monitoring Identify some of the challenges regarding its implementation in the WFD regulatory context IJ Allan, C Harman & NW Green 2

3 Recent steps forward 2006 BSI PAS 61:2006 Passive sampling for priority pollutants in surface waters 2007 ISO 17402:2008 Measurement of contaminant bioavailability in soils and sediments* 2009 WFD CMA Guidance WFD CMA Guidance Norman Network position paper PSDs mentioned as «complementary» tools for chemical quality monitoring of water Listed in the guidance for sediment and biota monitoring PSDs for screening for emerging substances and contaminants 2011 ISO :2011 Passive sampling in surface waters *Harmsen et al. (2007) IJ Allan, C Harman & NW Green 3

4 Passive sampling 20 years of research and developments Passive sampling measures a concentration of contaminant Dissolved or labile in water Based on diffusive processes In/ex situ measurements of trace contaminants: Dissolved/labile in water Dissolved/labile in sediment/soil pore waters That are bioaccessible Passive sampling-prc vs. biomonitoring Standardised method Integrative monitoring over periods of days to months Improved limits of detections and simplified matrix composition IJ Allan, C Harman & NW Green 4

5 Passive sampling Focus on surface waters, but should consider other matrices (air, sediments etc) Applicable to: Nonpolar organic substances (e.g. PAHs, PCBs & PBDEs) Polar compounds (e.g. pharmaceuticals and pesticides) Metals, metalloid and radionuclides Organo-metallics (e.g. TBT) IJ Allan, C Harman & NW Green 5

6 Advantages of passive sampling 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 IJ Allan, C Harman & NW Green 6

7 Sampler selection Passive sampling Sampler deployment Exposure for days-months Sampler Retrieval Calculation of concentration, C W Modelling Sampler Extraction and analysis IJ Allan, C Harman & NW Green 7

8 Sampler deployment & retrieval -Clean cage! -Standard equipment -Contamination -Site survey -Deployment technique Sampler storage & transport -Stability -Temperature -PRC/analyte stability -Contamination (cross-) Environmental variability -Biofouling -Temperature -Salinity Uptake rates (reproducibility, bias) -Calibration rig set-up (tank, carousel, analyte delivery) -Control over temperature/turbulences -Water sample collection, prep., analysis -DOC/TOC/biofouling -Sampler prep., deployment, extraction & analysis TRUE TWA Concentration Passive sampler-measured TWA Concentration Sampler preparation -Membrane thickness -Surface -Vs -PRC concentration -Contamination Sampler extraction -Contamination -Recoveries Extract analysis for analytes and PRCs -Calibration, linearity -LOD/LOQ etc Modelling of TWA concentrations (e.g. for NP) -Sampler characteristic (Vs, Surface area ) -Contaminant characteristics (Log Kow, etc) -Rs estimation procedure -Model selection -Ksw IJ Allan, C Harman & NW Green 8

9 QA/QC for PSDs for nonpolar substances At equilibrium: Required time to equilibrium Level of fluctuations in analyte concentrations K sw values Integrative mode: K sw for analytes of interest and PRCs Method for R s estimation from PRC (e.g. nonlinear least square method*) Model to calculate R s for nonpolar substances within a wide range of hydrophobicity *Booij and Smedes (2010) IJ Allan, C Harman & NW Green 9

10 QA/QC for PSDs for nonpolar substances K sw values Mostly available for LDPE or PDMS Uncertainty of log units Effect of temperature can be modelled but impact is generally minor Effect of salinity can be modelled using the Setschenow constant* *Jonker and Nuijs (2010) IJ Allan, C Harman & NW Green 10

11 Application to regulatory monitoring EU Water Framework Directive monitoring: - Surveillance monitoring - Operational and investigative monitoring More specifically: Testing for compliance with EQS Monitoring long-term trends in contaminant levels Measurements of transboundary fluxes Sources tracking/spatial distribution Linking exposure and effects Contaminant speciation Support to more common monitoring methods (bottle sampling and biomonitoring) IJ Allan, C Harman & NW Green 11

12 Compliance checking with PSDs? EQS are set for the «whole water» i.e. substances dissolved as well as fractions sorbed to dissolved/particulate matter PSDs measure only the dissolved concentration! Nonpolar substances cannot be measured practically and reliably in the water column by other means! Which alternatives exist? Suspended particulate matter (SPM) monitoring, Biomonitoring (e.g. Musselwatch), Freshly deposited bed-sediment monitoring? How do we reconcile «whole water»-based EQS with dissolved phase PSD data? IJ Allan, C Harman & NW Green 12

13 Compliance checking with PSDs? 1. From the Deltares report: Calculate Cw EQS from «whole water» EQS and: 1. Equilibrium partioning theory (EqP) 2. Pre-set DOC/SPM levels 2. Calculate «whole water» concentrations from PSD data and: 1. Measured DOC and SPM levels and EqP 2. Site/water-body specific partitioning data 3. Combine PSD data with SPM data? How do we reconcile «whole water»-based EQS with dissolved phase PSD data? IJ Allan, C Harman & NW Green 13

14 Compliance checking when C w are low SPMD/Sil measurement near Bear Island > 100d exposures Integrative sampling for compounds with logk ow > 6 Sampling at Andøya, Bear Island & Jan Mayen K sw values not corrected for salinity or temperature IJ Allan, C Harman & NW Green 14

15 SPMD/Sil measurement near Bear Island PAHs PCBs/OCs 1 C PS /C "whole water" C PS /C "whole water" mg L -1 OC 1.0 mg L -1 OC 10 mg L -1 OC 0.1 mg L -1 OC 1.0 mg L -1 OC 10 mg L -1 OC LogK ow LogK ow Partitioning to OC (Schwarzenbach et al. 2003) Most PAHs present in the dissolved phase IJ Allan, C Harman & NW Green 15

16 SPMD/Sil measurement near Bear Island Priority substances AA-EQS (ng L -1 ) Bjørnøya Period 1 (ng L -1 ) Anthracene Bjørnøya Period 2 (ng L -1 ) Pentabromodiphenylether Fluoranthene Hexachlorobenzene Pentachlorobenzene Benzo[a]pyrene 50 <0.02 <0.009 Benzo[b+k]fluoranthene* Benzo[ghi]perylene & indeno[1,2,3-cd]pyrene** 2 <0.04 a p,p -DDT 10 <0.012 <0.008 *Sum of benzo[b]fluoranthene and benzo[k]fluoranthene **Sum of Benzo[ghi]perylene and indeno[1,2,3-cd]pyrene a Both values were below LODs IJ Allan, C Harman & NW Green 16

17 Compliance checking with PSDs? For most PAHs, estimated «whole water» concentrations << EQS values What is the risk of false negative? How do we reduce it? How do we build in safety factors? How do we reconcile «whole water»-based EQS with dissolved phase PSD data? IJ Allan, C Harman & NW Green 17

18 Compliance checking with PSDs? Contaminant partitioning in Norwegian rivers Sandvikselva, Alna and Akerselva Drammenselva and Glomma PAHs, PCBs, OCs and PBDEs Passive samplers: LDPE, silicone and SPMDs SPM monitoring: Centrifuge, in-situ samplers What about DOC? (How) Can we combine passive sampling and SPM monitoring? IJ Allan, C Harman & NW Green 18

19 The tools Continuous flow centrifuge In situ samplers (SPM) LDPE membranes, silicone strips and SPMDs IJ Allan, C Harman & NW Green 19

20 Monitoring on the Glomma River IJ Allan, C Harman & NW Green 20

21 SPM-water partitioning for PAHs 9 8 PAH partitioning in the Glomma river logk POC 7 6 For 2009: LogK poc = 0.97logK ow (R 2 =0.958, se = 0.08) logk OW Exposure 1, 2010 Exposure 2, 2010 Exposure in 2009 K poc C C SPM PAH wpah f oc IJ Allan, C Harman & NW Green 21

22 Evaluation of PSDs through intercomparisons 2005 SWIFT-WFD project Tank calibration and field exposure of 7 types of PSDs for polar/nonpolar substances and metals PSTS water/sed (ICES) 12 laboratories Eclipse project Tank calibration and field exposure of 5 types of PSDs for nonpolar substances 2010 Aquaref intercomparison 2011 Norman Network intercomparison Field exposures involving 25 laboratories, polar and nonpolar substances Intercomparison of PSDs for emerging substances IJ Allan, C Harman & NW Green 22

23 SWIFT-WFD: intercomparison First intercomparison of passive samplers* Meuse river (NL), 2005 Overlapping exposures of 7, 14 and 28 days Evaluation of 7 types of passive samplers: - Chemcatcher - MESCO I (m), MESCO II - LDPE membrane - Silicone rods and strips - SPMDs Analysis performed in three laboratories - PAHs - PCBs and some organochlorines (Too?) many dimensions *Allan et al. (2009) IJ Allan, C Harman & NW Green

24 SWIFT-WFD intercomparison (N/A)/(N/A) LDPE membrane (A) Comparison of: Contaminant masses accumulated C W Standard deviations C TWA / Mean C TWA (B) Chemcatcher LDPE membrane MESCO I (m) MESCO II 1 X Data Silicone rod Silicone strip 99 SPMD 262 Variation in C W caused by: PRC data Sampler-water partition coefficient, K SW Use of C W estimator models Analysis in three different labs Standard Deviation (C) 2.5 Chemcatcher LDPE membrane MESCO I (m) MESCO II Silicone rod Silicone strip X Data SPMD 87 IJ Allan, C Harman & NW Green 1.0 Chemcatcher LDPE membrane MESCO I (m) MESCO II Silicone rod X Data Silicone strip SPMD

25 ECLIPSE: Intercomparison IJ Allan, C Harman & NW Green 25

26 ECLIPSE: Intercomparison IJ Allan, C Harman & NW Green 26

27 AQUAREF: Intercomparison Metals, PAHs and polar pesticides 3 sites in France Charente River (Pest) Ternay/Rhone River (PAHs/metals) Thau Lagoon (Pest/PAHs/Metals) IJ Allan, C Harman & NW Green 27

28 Norman Network: Intercomparison IJ Allan, C Harman & NW Green 28

29 Interlaboratory calibration study in 2011 present variability in data by comparing results from various passive samplers sent by participating laboratories exposed to water at a single (reference) site Target substances: polar pesticides - 19 participants Pharmaceuticals 17 participants steroid hormones 14 participants Triclosan - 8 participants bisphenol A - 11 participants PFOA, PFOS - 8 participants PBDE -16 participants 28 participants from commercial, academic and regulatory laboratories Silicone strips CONTACT: branovrana@gmail.com

30 Intercomparisons A wide range of field-based intercomparisons/tank calibrations ( ) Much work already undertaken Increasing level of testing and complexity of the trials QC solutions PSDs by participants and organisers Trials have yet to include deployment/exposure procedures Should we focus our effort on a restricted number of samplers? IJ Allan, C Harman & NW Green 30

31 Reference material/matrix spikes Reference to the ISO standard (2011) A need for reference materials/matrix spikes Straightforward production Relative standard deviation on PRC spikes in LDPE/Sil/SPMDs: < 10% for sampler batches ~ 100 What about scaling up? A challenge is the many types of passive sampling devices available today! Should we aim to reduce the number of passive sampling devices on the market? IJ Allan, C Harman & NW Green 31

32 Costs of passive sampling Two field trips are needed Deployment equipment is needed Replication Need for enough preparation and trip control samplers For a similar level of information, are passive sampling costs higher than for conventional bottle sampling? IJ Allan, C Harman & NW Green 32

33 Moving forward How do we reconcile «whole water»-based EQS and dissolved phase passive sampling data? Will water-based EQS translated into sediment EQS? How will this be done? and can this be of benefit to us? Have other fields attempted such a move towards regulatory use? Can we benefit from the experience of others? Who can/will undertake regulatory passive sampling? Can we simplify passive sampling? Can we demonstrate that passive sampling costs are lower than for other monitoring methods for a similar level of information? Is this level of information needed, wanted? IJ Allan, C Harman & NW Green 33

34 Moving forward Should we establish «PSDbanks»? AQUA-GAPS?* What about setting up sampling networks using ferry routes? Should we be interested in highly hydrophobic substances in the dissolved phase (e.g. BDE209)? *Lohmann & Muir (2010) IJ Allan, C Harman & NW Green 34

35 Acknowledgement Sissel Ranneklev (NIVA) Guttorm Christensen (Akvaplan-NIVA) Klif: Norwegian Climate and Pollution Agency *Lohmann & Muir (2010) IJ Allan, C Harman & NW Green 35