Passive sampling in the regulatory context (WFD)

IJ Allan, C Harman & NW Green 1

Passive sampling in the regulatory context (WFD)

Ian J. Allan, Christopher Harman & Norman W. Green


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


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 19

PSDs mentioned as «complementary» tools for chemical quality monitoring of water

2010 WFD CMA Guidance 25

Listed in the guidance for sediment and biota monitoring

2010 Norman Network position paper

PSDs for screening for emerging substances and contaminants

2011 ISO 5667-23:2011 Passive sampling in surface waters

*Harmsen et al. (2007)

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



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)

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



Sampler deployment

Sampler Retrieval

Sampler Extraction

and analysis Calculation of

concentration, CW

Exposure for days-months

Modelling…

Sampler selection

Passive sampling

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


Passive sampler-measured

TWA

Concentration

Sampler extraction

-Contamination

-Recoveries

Extract analysis

for analytes and PRCs

-Calibration, linearity

-LOD/LOQ … etc

TRUE TWA

Concentration

Modelling of TWA concentrations (e.g. for NP)

-Sampler characteristic (Vs, Surface area…)

-Contaminant characteristics (Log Kow, …etc)

-Rs estimation procedure

-Model selection

-Ksw

Sampler storage &

transport

-Stability

-Temperature

-PRC/analyte stability

-Contamination (cross-)

Sampler preparation

-Membrane thickness

-Surface

-Vs

-PRC concentration

-Contamination

Sampler deployment & retrieval

-Clean cage!

-Standard equipment

-Contamination

-Site survey

-Deployment technique


QA/QC for PSDs for nonpolar substances

At equilibrium:

• Required time to equilibrium

• Level of fluctuations in analyte concentrations

• Ksw values

Integrative mode:

• Ksw for analytes of interest and PRCs

• Method for Rs estimation from PRC (e.g. nonlinear least square method*)

• Model to calculate Rs for nonpolar substances within a wide range of hydrophobicity

*Booij and Smedes (2010)


QA/QC for PSDs for nonpolar substances

Ksw values

• Mostly available for LDPE or PDMS

• Uncertainty of 0.2-0.5 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)

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)



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?



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?


PSD data?


Compliance checking when Cw are low

• SPMD/Sil measurement near Bear Island

• > 100d exposures

• Integrative sampling for compounds with logKow > 6

• Sampling at Andøya, Bear Island & Jan Mayen

• Ksw values not corrected for salinity or temperature


SPMD/Sil measurement near Bear Island

PAHs

LogKow

3 4 5 6

CP

S/C

"wh

ole

wa

ter"

0.01

0.1

1

10

0.1 mg L-1

OC

1.0 mg L-1

OC

10 mg L-1

OC

PCBs/OCs

LogKow

4 6 8 10

CP

S/C

"wh

ole

wa

ter"0.001

0.01

0.1

1

10

0.1 mg L-1

OC

1.0 mg L-1

OC

10 mg L-1

OC

• Partitioning to OC (Schwarzenbach et al. 2003)

• Most PAHs present in the dissolved phase


SPMD/Sil measurement near Bear Island

Priority substances

AA-EQS

(ng L-1)

Bjørnøya Period 1

(ng L-1)

Bjørnøya Period 2

(ng L-1)

Anthracene 100 0.043 0.053

Pentabromodiphenylether 0.2 0.001-0.008 0.0002-0.007

Fluoranthene 100 0.95 0.60

Hexachlorobenzene 10 0.12 0.078

Pentachlorobenzene 7 0.029 0.016

Benzo[a]pyrene 50 <0.02 <0.009

Benzo[b+k]fluoranthene* 30 0.12 0.088

Benzo[ghi]perylene & indeno[1,2,3-cd]pyrene**

2 <0.04 a 0.025

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 aBoth values were below LODs




PSD data?

• 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) Can we combine passive sampling and SPM monitoring?

• 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?


The tools

• Continuous flow centrifuge

• In situ samplers (SPM)

• LDPE membranes, silicone strips and SPMDs


Monitoring on the Glomma River


SPM-water partitioning for PAHs

logKOW

4 5 6 7 8 9

logK

PO

C

4

5

6

7

8

9

Exposure 1, 2010

Exposure 2, 2010

Exposure in 2009

PAH partitioning in the Glomma river

For 2009:

LogKpoc= 0.97logKow+1.11

(R2=0.958, se = 0.08)

ocPAHw

PAHSPMpoc

fC

CK


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

2006-2007

PSTS water/sed (ICES)

12 laboratories

2009-2011

Eclipse project Tank calibration and field exposure of 5 types of PSDs for nonpolar substances

2010 Aquaref intercomparison

Field exposures involving 25 laboratories, polar and nonpolar substances

2011 Norman Network intercomparison

Intercomparison of PSDs for emerging substances

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…

IJ Allan, C Harman & NW Green

*Allan et al. (2009)

SWIFT-WFD intercomparison

X Data

Che

mca

tche

r

LDPE m

embr

ane

MESC

O I

(m)

MESC

O II

Silico

ne ro

d

Silico

ne stri

p

SPM

D

(N/A

)/(N

/A) L

DP

E m

em

bra

ne

0.0

1.0

2.0

3.0

4.0

7.0(A)

8

6

1623

70

63

X Data

Che

mca

tche

r

LDPE m

embr

ane

MESC

O I

(m)

MESC

O II

Silico

ne ro

d

Silico

ne stri

p

SPMD

CT

WA / M

ean C

TW

A

0.1

1

10(B)

84

262

200

99

101

50

264

X Data

Che

mca

tche

r

LDPE m

embr

ane

MESCO I

(m)

MESCO II

Silic

one

rod

Silic

one

strip

SPM

D

10

Sta

ndard

Devia

tion

1.0

1.5

2.0

2.5

3.3 (C)

27

87

88

36

3817

88

Comparison of: Contaminant masses accumulated

CW

Standard deviations

Variation in CW caused by: PRC data

Sampler-water partition coefficient, KSW

Use of CW estimator models

Analysis in three different labs

IJ Allan, C Harman & NW Green


ECLIPSE: Intercomparison


ECLIPSE: Intercomparison


AQUAREF: Intercomparison

• Metals, PAHs and polar pesticides

• 3 sites in France – Charente River (Pest)

– Ternay/Rhone River (PAHs/metals)

– Thau Lagoon (Pest/PAHs/Metals)


Norman Network: Intercomparison

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: [email protected]


Intercomparisons

• A wide range of field-based intercomparisons/tank calibrations (2005-2011)

• 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?


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?


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?


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?


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)


Acknowledgement

Sissel Ranneklev (NIVA)

Guttorm Christensen (Akvaplan-NIVA)

Klif: Norwegian Climate and Pollution Agency

*Lohmann & Muir (2010)

Documents

Passive sampling in the regulatory context (WFD)