The use of passive sampling as a

potential compliance tool for the WFD

Andy Sweetman, Lancaster University

What's new in the analysis of complex environmental matrices?

Royal Society of Chemistry

Environmental Chemistry Group, Water Science Forum and the

Separation Science Group Joint Meeting

Friday 3rd March 2017

EU - Water Framework Directive

• Prevent deterioration and enhance status of

aquatic ecosystems & associated wetlands

• Promote sustainable water use

• Prevent deterioration/reduce pollution of

groundwater

• Contribute to mitigating effects of floods/droughts

• Reduce pollution from priority substances

The WFD, adopted in 2000, based on river basins and designed to

ensure all European waters in good condition.

Ecological and Chemical status

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.

..

...

...

Hospital

Industry

Landfill

AquacultureFarm

STP

Domestic

Agriculture

Complexity of contaminant

sources, fate and behaviour

in a typical catchment

Policy decisions - Annex X of WFD.List of Priority Substances

Reduce to ‘zero’ Reduce to below EQS

Priority Hazardous

Substances Priority Substances Other specific pollutants

Anthracene 1,2-Dichloroethane DDT / p,p‘-DDT

Brominated diphenylethers Aclonifen Aldrin

C10-C13-Chloroalkanes Alachlor Dieldrin

Cadmium and its compounds Atrazine Endrin

Di(2-ethylhexyl)phthalate

(DEHP) Benzene Isodrin

Dicofol Bifenox Carbontetrachloride

Endosulfan Chlorfenvinphos Tetrachloroethylene

HCBDD Chlorpyrifos (ethyl) Trichloroethylene

Heptachlor and

heptachlorepoxide Cybutryne

Hexachlorobenzene (HCB) Cypermethrin

Hexachlorobutadiene (HCBD) Dichloromethane

Hexachlorocyclohexane Dichlorvos

Mercury and its compounds Diuron

Nonylphenols Fluoranthene

PCDD/Fs Isoproturon

Pentachlorobenzene Lead and its compounds

PFOS Naphthalene

Polyaromatic Hydrocarbons

(PAHs) Nickel and its compounds

Quinoxyfen Octylphenols

Tributyltin compounds Pentachlorophenol

Trifluralin Simazine

Terbutryn

Trichlorobenzenes

Trichloromethane

Watch list (monitored for up to 4 years)

diclofenac

17-Beta-estradiol (E2)

17-Alpha-ethinylestradiol (EE2)

Under discussion

Acetamiprid

Azithromycin

Clothianidin

Thiacloprid

Thiamethoxam

2-Ethylhexyl 4-methoxycinnamate

2,6-ditert-butyl-4-methylphenol

Erythromycin Clarithromycin

Imidacloprid

Methiocarb

Tri-allate

EU Survey: Frequency of detection of

selected substances in rivers and

groundwater – emerging contaminants

Wide range of contaminant groups

Industrial chemicals

Surfactants

Pharmaceuticals

Pesticides

Personal/household care ingredients

Sets out environmental quality standards (EQS) of certain

pollutants identified as priority on account of the substantial

risk they pose to or via the aquatic environment

• AA-EQS - the average value or concentration of the

substance concerned calculated over a one-year period.

• MAC-EQS the maximum allowable concentration of the

substance.

Environmental Quality Standards

(EQS) Directive 2008/105/EC

Member States must ensure compliance with these standards.

Difficult and expensive!

EQS setting for fluorinated surfactant in

European waters

PFOS added to Annex B of the Stockholm Convention (restriction on production

and use) in 2009 by the Conference of Parties

In 2010 the European Union has added PFOS to the POPs regulation (EC)

850/2004 (ensures compatibility with SC)

Selection of the protection goals is challenging.

Approach 1. Maximum Permissible Concentration for humans based on fish

consumption and Tolerable Daily Intake is 0.65 ng/L

Approach 2. The PNEC for the aquatic ecosystem was suggested by a UK report to

be 25 μg/L, (based on the mysid shrimp Americamysis bahia NOEC)

In-stream fate modelling for

persistent fluorinated surfactant PFOS

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Distance Downstream (km) and STPs

PFOS 2010

PFOS 2013

GLRM Pop @27µg/day ÷ 3

GLRM STP Adj @27ug/day

Predicted PFOS concentrations per EVnBETR box in European fresh (ng/L) and salt water (pg/L) environments. In freshwater, predicted concentrations were allocated to major rivers for demonstration purposes.

*EQS based on protection of human health via fish consumption

European Scale PFOS Modelling

– 90% exceeds 0.65 ng/l*

(even more challenging in

coastal waters 0.13 ng/l)

Review of priority substances under the WFD –monitoring and modelling based approaches

Andrew Johnson – Centre for Ecology and Hydrology

A comparison of a low protective value for a chemical (such as predicted no effect concentration –PNEC) with high measured environmental concentrations such as used in the 2016 EU –JRC monitoring based approach to chemical prioritisation

3-point scoring system that involves the 95%ile

of measured concentrations (MEC95) vs PNEC

This system picked out deltamethrin as

the number 1 new priority chemical

So why was this insecticide selected

as being of the highest risk?

Why was deltamethrin ranked as the highest risk by EU/JRC?1) A very low toxicity threshold PNEC 0.0031 ng/L

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Deltamethrin ecotoxicity data (ug/L) and PNEC

PNEC set at a staggering 0.0031 ng/L!

Akerblom et al (2008) Chironomus riparius LC50 0.016 ng/L

But how often was deltamethrin quantified across 7 countries and 28,757 samples?

% deltamethrin above LOQ

% <LOQ % quantified

Answer = only 0.6%

Why was deltamethrin ranked as the highest

risk by EU/JRC?

2) A high exposure (MEC95) of 50 ng/L

How to demonstrate compliance?

Guidance on sampling strategy: location, frequencies and methods

Establishment of EQS values has been limited for the majority of priority

substances to water only. The principle matrix is whole water, or for metals,

the liquid fraction obtained by filtration of the whole water sample.

For most water bodies spot samples are likely to be appropriate. However,

situations, where pollutant concentrations are heavily influenced by flow

conditions and temporal variation flow-proportional or time-proportional

maybe preferable

Sampling frequency once-a-month for priority substances and once-per-three-

months for other pollutants

However, the guidance acknowledges that available analytical

methods are not sufficiently sensitive.

LOQ should be <30% of the EQS

• PFOS (AA EQS 0.65 ngL-1) this would be <0.2 ngL-1

• BaP (AA EQS 0.17 ngL-1) this would be <0.05 ngL-1

• Cypermethrin (AA EQS 0.08 ngL-1) this would be <0.02 ngL-1

How to demonstrate compliance?

Passive samplers (e.g., Semi-Permeable Membrane Devices

(SPMD), Polar Organic Chemical Integrative Samplers (POCIS),

Diffusion Gradient Thin Films (DGTs), Chemcatcher) are

exposed in the aquatic environment for several days or up to

weeks to yield time-integrated average concentrations for

organic contaminants and heavy metals.

PS are less influenced by short-term fluctuations in

concentrations than spot sampling.

PS sampling rates are in the range of litres per day for various

contaminants (e.g., organic compounds of medium

hydrophobicity, heavy metals), allowing analysis of trace

contaminant levels

What about passive sampling?

Importantly PS sample the freely-dissolved bioavailable water concentrations

which reflects the biologically available fraction but doesn’t provide total

water concentrations as required by the WFD.

However, if DOC, SPM and TOC content of the SPM are known, then

partitioning theory can be used to estimate the total concentrations.

TWO main types:

Hydrophobic chemicals: Can be biphasic e.g. SPMD or commonly monophasic

polymer strips e.g. silicone rubber, Low Density PolyEthylene (LDPE) strips

Requires knowledge of polymer-water partition coefficients and use of

performance reference compounds (PRCs)

What about passive sampling?

What about passive sampling?

Hydrophilic chemicals: Mostly adsorption based adsorption to a coated

disc protected by a membrane

POCIS A sorbent layer covered either side by porous polyethersulfone

membranes

Chemcatcher comprises a 47 mm 3M Empore disk as the receiving phase.

A range are available for different classes of chemicals class (e.g., non-

polar organic, polar organic, metals, radionuclides). A thin diffusion

limiting membrane can be placed over the receiving phase to restrict the

rate of uptake of pollutants.

PRCs can be used to account for variations in sampling rate.

Diffusion Gradients in thin-films (DGT) – two layers initially developed for

metals

19

Metals (Al, Cr, Cd, Cu, Co, Ni, Zn, Pb, Fe, Mn, Ca, Mg, Mo, As,

Se,W, V, Sb, Au, Hg)

Radionuclides (Cs, Sr, Tc, U)

Nutrients (SO42-

, NH4+)

Others (Ra, Pu)

Organics (current and in development)

• Wide range of antibiotics

• Personal/household product ingredients

• Pharmaceuticals

• Non-brominated flame retardants

• Pesticides

What Can DGT Measure?

Diffusion Gradients in Thin-films (DGT)

Davison W. and Zhang H., Nature, 1994.

Zhang H. and Davison W., Anal. Chem. 1995.

Passive sampling in rivers

and effluents

Agarose gel XAD or HLB

Diffusion Coefficient (D) Measurement

Cross-section through a diaphragm diffusion cell

Initially 50ml MQ

water containing

NaCl & Antibiotics

Initially 50ml MQ

water with NaCl

• Temperature: 20°C

• pH: 6.5

• Source part: 2ppm SMX

• Sampling: 0.4mL/15min

----HPLC-UV analysis

• De = k∆g/(CbA)

Cb = M∆g/(DAt)

DGT Development – diffusion rates

Measured masses (M, μg) of selected test chemicals in HLB-DGT deployed in well

stirred solution

bisphenol-A Propylparaben

DGT Development – effect of pH, IS, DOM

IS: 0.001-0.5 M

DOM: 0-20 mg L-1

pH: 3.5-9.5

• DGT accumulation with deployment time

• Most substances detected in INF, fewer in EFF

• 7-18 days accumulation (1-2 weeks recommended)

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TCS-EFF

WWTP Field testing

• DGT (HLB) compared to auto-sampling & grab sampling)

• Comparable with auto-sample (TWA concentrations)

• 7 day sampling period (7 grabs, 7 24 hour composites from autosampler)

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WWTP Field testing

Field testing – Liuxi river, Guangdong province

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SDZ SPD TMP SMZ SMM SMX SQX NFX OFX CIP EFX LFX LIM LEM CLM ROM SAM FLO CHL

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Passive & grab sampling in Liuxi River S2

S2-Grab

S2-DGT

Focussed on wide range of antibiotics

Chinese WWTP Fate Study - Wuhan & Dalian

INF1st

Treatment EFF2nd

Treatment

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D: FE

� All 20 target chemicals detected in raw influent, 18 in final effluent

Chinese WWTP Fate Study

• Removal rates found to be very variable

Fate Study in Chinese WWTPs

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Chemicals

-184% -183% -125% -466%

� Parabens: 81-100 %

� Estrogens: >50 % (not DES)

� BPA, OPP, TCS: > 50 %

� Antioxidants: < 50 %

� Alkyl-phenols: < 50 %

� DES and TCC: < 50 %

� PHBA: < 0 %

� DGT has been successfully applied for a wide range of organic

chemicals – most common configuration HLB resin as binding

agent

� Passive sampling has a wide range of applications - pre-

concentration and ‘clean-up’, sensitive, TWA concentrations,

provides bioavailable fraction.

� Needs further research and calibration/validation to define

sampling rates, operating range.

� Need to assess ability to predict ‘total concentrations’ for EQS

compliance for a wide range of chemicals

DGT and passive sampling