Passive Samplers for Monitoring VOCs in Groundwater and the Prospects Related to Mass Flux...

114 Ground Water Monitoring & Remediation Spring 2010/pages 114–126 NGWA.org

Copyright © 2010 The Author(s)Journal compilation © 2010 National Ground Water Association.doi: 10.1111/j1745–6592.2010.001281.x

Passive Samplers for Monitoring VOCs in Groundwater and the Prospects Related

to Mass Flux Measurementsby Goedele Verreydt, Jan Bronders, Ilse Van Keer, Ludo Diels, and Paul Vanderauwera

AbstractMeasurement and interpretation of mass fluxes in favor of concentrations is gaining more and more interest, especially

within the framework of the characterization and management of large-scale volatile organic carbon (VOC) groundwater contamination (source zones and plumes). Traditional methods of estimating contaminant fluxes and discharges involve indi-vidual measurements/calculations of the Darcy water flux and the contaminant concentrations. However, taken into account the spatially and temporally varying hydrologic conditions in complex, heterogeneous aquifers, higher uncertainty arises from such indirect estimation of contaminant fluxes. Therefore, the potential use of passive sampling devices for the direct mea-surement of groundwater-related VOC mass fluxes is examined. A review of current passive samplers for the measurement of organic contaminants in water yielded the selection of 18 samplers that were screened for a number of criteria. These criteria are related to the possible application of the sampler for the measurement of VOC mass fluxes in groundwater. This screen-ing study indicates that direct measurement of VOC mass fluxes in groundwater is possible with very few passive samplers. Currently, the passive flux meter (PFM) is the only passive sampler which has proven to effectively measure mass fluxes in near source groundwater. A passive sampler for mass flux measurement in plume zones with regard to long-term monitoring (several months to a year) still needs to be developed or optimized. A passive sampler for long-term monitoring of contaminant mass fluxes in groundwater would be of considerable value in the development of risk-based assessment and management of soil and groundwater pollutions.

IntroductionThe monitoring of organic contaminants in water (ground-

water and surface water) represents an ongoing challenge. Contaminant concentrations can vary substantially because of the spatial and temporal variability of the source mass and the pathway patterns of its degradation, sorption, desorp-tion, and dissolution. Natural gradients and biogeochemical processes as well as human activities can influence pollutant point concentrations. Concentration measurements through active sampling are like snapshots. As a consequence, peak concentrations can pass the monitoring well without being noticed, because monitoring is not continuous.

An alternative for concentration measurements by active sampling is the application of the passive samplers. Because of their longer-term application, they can produce more reliable results when it comes to variable field conditions and they offer opportunities for the direct measurement of

contaminant mass fluxes (Goltz et al. 2009). The concept of a passive sampler, a device that is capable of “sampling groundwater” at a specific depth, without providing active transport by pumping or suction, is shown in Figure 1. Since the first applications conducted three decades ago, passive samplers have been widely used for environmental monitoring throughout the world (Namiesnik et al. 2005). In this paper, the prospects and limitations of direct flux measurement of organic compounds in groundwater with passive samplers currently available are discussed.

Passive Samplers for Monitoring Organic Contaminants in Water

The most important driving processes in passive sam-plers are adsorption, diffusion, and advection (Greenwood et al. 2007). A passive sampler is placed in the screened part of a monitoring well. Generally, a passive sampler consists of a receiving phase that is contained within a permeable housing, usually a porous wall (Hatfield et al. 2004; Martin et al. 2001). The receiving phase can be a solvent, distilled water, a chemical reagent, or a porous adsorbent.

NGWA.org G. Verreydt et al./ Ground Water Monitoring & Remediation 30, no. 2: 114–126 115

Many passive sampling devices have been developed for the monitoring of organic contaminants in water. Based on the differences in transport processes through the housing and the receiving phase, two types of passive samplers can be differentiated: diffusion-based passive samplers and permeation-based passive sampler (Kot-Wasik et al. 2007).

Diffusion-Based Passive SamplersThe transport of the contaminants through the porous

housing of a diffusion-based passive sampler is diffusion-limited. This means that advective transport through the housing is inhibited. This can be achieved by selecting a sufficiently low permeable housing or even a housing with a selective permeability for the contaminant(s) of interest.

The diffusion process follows Fick’s first law (Bear 1988):

UDA

LC C� �.

Rs W (1)

where U is the diffusion rate (g/m2/s), D the diffusion coef-ficient (through the membrane and the aqueous boundary layer) (1/s), A the effective area (m2), C

Rs and C

w the con-

centrations of the contaminant in, respectively, the receiving phase (Rs) and in the surrounding water (w) (g/m3), and L the diffusion length (thickness of the membrane including the aqueous boundary layer) (m). With this, D/L is defined as the mass transfer coefficient k

0. The diffusion constant

K = D.A/L is determined in laboratory conditions, compa-rable with the field conditions. When applying this type of passive samplers, a limited exposure time is recommended because of the possibility of variations in the environmental conditions. Variations in water level and groundwater flow rate can on the one hand result in another K-value, and on the other hand result in the sensitivity to biofouling and/or degradation of the membrane or housing. Note that the vari-ations in groundwater flow rate only become problematic if the influence of the thickness of the boundary layer on the diffusion rate is significant and it is not possible to separate

CW.v (where v is the groundwater flux [m³/m2/s]) from the

regression equation when calculating mass fluxes.

Permeation-Based Passive SamplersWith respect to this type of samplers, the groundwater

flow is the driving force that acts out the advective transport of the contaminant through the housing and also through the receiving phase. The contaminant uptake rate U (g/m2/s) is directly proportional to the groundwater flow rate. An impor-tant requirement with this type of samplers is that diffusive transport must be negligible compared with advective trans-port. Peclet numbers are evaluated to determine the domina-tion of advective flux (Bear 1988; Hatfield et al. 2004). In order to calculate back to mass fluxes, the sampler needs to be applied in the kinetic time range of the sampler.

Samplers applied in the kinetic time range are also referred to as kinetic passive samplers, samplers applied in the equilibrium time range are called equilibrium pas-sive samplers. Furthermore, samplers for measuring trace or microconcentrations can be differentiated from samplers with higher detection limits. Table 1 provides a brief over-view of current passive samplers suitable for the measure-ment of organic contaminants in water and some of their characteristics.

Measuring Mass Flux with a Passive Sampler

Mass Flux PrinciplesContaminant mass flux (Equation 2) can be defined as

the total amount of contaminant, expressed as mass, passing per unit area per unit time through a well-defined control plane or plane of compliance that is orthogonal to the mean groundwater flow direction (Basmadijan 2004; Bear 1988; Newman et al. 2005). Figure 2 shows the concepts of a con-taminant flux at a plane of compliance between source and receptor.

J Cvm

Atc� � (2)

Figure 1. Schematic view of active vs. passive sampling of groundwater.

-

- snapshot - in combination with Darcy

water flux measurement - higher costs

+

- more representative- long-term monitoring- lower costs

active sampling

passive sampling

~ t

sampled zone

ground level

water level

groundwater flow direction

ground level

water level

monitoring well

monitoring well with passive sampler

Δ

116 G. Verreydt et al./ Ground Water Monitoring & Remediation 30, no. 2: 114–126 NGWA.org

Tabl

e 1

Ove

rvie

w o

f P

assi

ve S

ampl

ers

Suit

able

for

the

Mea

sure

men

t of

Org

anic

Con

tam

inan

ts in

Wat

er

Tech

nolo

gyM

easu

rem

ent

Tra

nspo

rt

Pro

cess

esC

onta

min

ants

Surface Water

Groundwater

App

licat

ion

Tim

e

Quantitative

Adv

anta

ges

Lim

itat

ions

Development Stage

Ref

eren

ces

Diff

usio

n-ba

sed

pass

ive

sam

pler

s

Poly

ethy

lene

di

ffus

ion

bag

sam

pler

s (P

DB

s)

Equ

ilibr

ium

co

ncen

trat

ion

Dif

fusi

onM

ost V

OC

s—

X14

day

s to

1

year

Yes

For

long

-ter

m

mon

itori

ngL

ong

equi

libra

tion

time

1A

rchf

ield

and

LeB

lanc

(2

002)

, Int

erst

ate

Tech

nolo

gy

& R

egul

ator

y C

ounc

il (I

TR

C)

(200

4, 2

005)

, St

icht

ing

Ken

niso

ntw

ikke

ling

Ken

niso

verd

rach

t Bod

em (

SKB

) et

al.

(200

5), a

nd V

robl

esky

and

C

ampb

ell (

2000

)

Reg

ener

ated

-ce

llulo

se

dial

ysis

mem

-br

ane

sam

pler

s (R

CD

Ms)

Equ

ilibr

ium

co

ncen

trat

ion

Dif

fusi

onV

OC

s, m

ost m

etal

s,

all a

nion

s, m

ethy

l te

rtia

ry b

utyl

eth

er

(MT

BE

)

—X

1 da

y to

sev

-er

al w

eeks

No

Shor

ter

equi

li-br

atio

n tim

eD

egra

datio

n of

th

e m

embr

ane,

bi

ofou

ling

2E

hlke

et a

l. (2

004)

, Har

ter

and

Talo

zi (

2004

), I

TR

C (

2005

, 20

07),

Nam

iesn

ik e

t al.

(200

5),

and

Vro

bles

ky e

t al.

(200

3)

ME

SCO

sa

mpl

erA

ccum

ulat

ed

mas

s—tim

e-av

erag

ed

conc

entr

atio

n

Dif

fusi

on,

adso

rptio

nM

icro

conc

entr

atio

ns

of P

AH

s, p

olyc

hlo-

rina

ted

biph

enyl

s (P

CB

s), s

ome

VO

Cs

XX

20 d

ays

No

—D

egra

datio

n of

the

mem

bran

e, b

iofo

ul-

ing,

lim

ited

upta

ke

capa

city

3N

amie

snik

et a

l. (2

005)

, Pa

schk

e et

al.

(200

3) a

nd V

rana

et

al.

(200

1, 2

006a

, 200

6b)

Sem

i-pe

rme-

able

mem

-br

ane

devi

ces

(SPM

Ds)

Acc

umul

ated

m

ass—

time-

aver

aged

co

ncen

trat

ion

Dif

fusi

on,

adso

rptio

nM

icro

conc

entr

atio

ns

of h

ydro

phob

ic s

emi

vola

tile

orga

nic

carb

ons

(sV

OC

s),

som

e V

OC

’s

(log

KO

W >

3)

XX

1 m

onth

Yes

, w

ith

PRC

s

Hig

h-sa

mpl

ing

rate

Low

upt

ake

capa

c-ity

, onl

y fo

r ve

ry

low

con

cent

ratio

ns,

biof

oulin

g

1B

ooij

et a

l. (1

998,

200

2, 2

006)

, H

ucki

ns e

t al.

(199

9, 2

002)

, IT

RC

(20

05),

Ke

et a

l. (2

006)

, L

ee e

t al.

(200

7), L

uelle

n an

d Sh

ea (

2002

), N

amie

snik

et a

l. (2

005)

, Vra

na a

nd S

chüü

rman

(2

002)

, Vra

na e

t al.

(200

5),

and

Wen

zel e

t al.

(200

4)

Cer

amic

do

sim

eter

Acc

umul

ated

m

ass—

time-

aver

aged

co

ncen

trat

ion

Dif

fusi

on,

adso

rptio

nPA

Hs,

BT

EX

, chl

ori-

nate

d hy

droc

arbo

nsX

X14

day

s to

sev

eral

m

onth

s

Yes

Rob

ust

mem

bran

eL

ow s

ensi

tivity

3B

örke

(20

07),

Mar

tin e

t al.

(200

1, 2

003)

, Vra

na e

t al.

(200

5), a

nd W

eiss

et a

l. (2

007)

Rig

id p

orou

s po

lyet

hyl-

ene

sam

pler

s (R

PPS)

Equ

ilibr

ium

co

ncen

trat

ion

Dif

fusi

onM

ost V

OC

s, s

ome

sVO

Cs,

mos

t met

als,

m

ost a

nion

s

—X

14 d

ays

to

1 m

onth

No

—B

ette

r fo

r m

etal

s th

an f

or V

OC

s2

Col

umbi

a A

naly

tical

Ser

vice

s In

c. (

2007

), I

TR

C (

2005

), a

nd

Mar

tin e

t al.

(200

1)


Tabl

e 1

Con

tinu

ed

Tech

nolo

gyM

easu

rem

ent

Tra

nspo

rt

Pro

cess

esC

onta

min

ants

Surface Water

Groundwater

App

licat

ion

Tim

e

Quantitative

Adv

anta

ges

Lim

itat

ions

Development Stage

Ref

eren

ces

Peep

er s

ampl

ers

Equ

ilibr

ium

co

ncen

trat

ion

Dif

fusi

onM

ost V

OC

s, s

ome

met

als,

mos

t ani

ons

XX

14 d

ays

to

1 m

onth

No

—M

inim

um d

iam

eter

of

mon

itori

ng w

ell:

10 c

m

1IT

RC

(20

05)

and

Web

ster

et a

l. (1

998)

Nyl

on-s

cree

n pa

ssiv

e di

ffu-

sion

sam

pler

s (N

SPD

S)

Equ

ilibr

ium

co

ncen

trat

ion

Dif

fusi

onM

ost V

OC

s, m

ost

met

als,

mos

t ani

ons

—X

A f

ew w

eeks

No

—M

inim

um d

iam

eter

of

mon

itori

ng w

ell:

10 c

m, l

imite

d ex

peri

ence

1IT

RC

(20

05)

and

Web

ster

et a

l. (1

998)

Pass

ive

vapo

r di

ffus

ion

sam

-pl

ers

(PV

Ds)

Acc

umul

ated

m

ass—

time-

aver

aged

co

ncen

trat

ion

Dif

fusi

on

as v

olat

ile,

adso

rptio

n

Mos

t VO

Cs

XX

1–3

wee

ksN

oFa

st e

quili

bra-

tion,

for

qui

ck

scre

enin

g

Ana

lyze

PV

Ds

with

in 5

day

s, n

ot

deep

er th

an 1

.25

m

belo

w w

ater

leve

l

1IT

RC

(20

05),

Chu

rch

et a

l. (2

002)

, and

Vro

bles

ky (

2001

, 20

02)

GO

RE

™ S

orbe

r M

odul

eA

ccum

ulat

ed

mas

s—tim

e-av

erag

ed

conc

entr

atio

n

Dif

fusi

on

as v

olat

ile,

adso

rptio

n

All

VO

Cs,

mos

t sV

OC

sX

X48

hou

rsN

oV

ery

shor

t eq

uili

brat

ion

tim

e (1

5 m

in-

utes

to

4 ho

urs)

Not

for

long

-ter

m

mon

itori

ng1

ITR

C (

2005

, 200

7) a

nd V

rana

et

al.

(200

5)

Che

mca

tche

r—em

pore

dis

kA

ccum

ulat

ed

mas

s—tim

e-av

erag

ed

conc

entr

atio

n

Dif

fusi

on,

adso

rptio

nM

icro

conc

entr

atio

ns

of h

ydro

phob

ic (

KO

W

> 4

) an

d hy

drop

hilic

(2

< K

OW

< 4

) or

gani

c co

mpo

nent

s

X—

14 d

ays

to

1 m

onth

No

Hig

h-up

take

ra

te, s

hort

eq

uilib

ratio

n

Low

upt

ake

capa

c-ity

, tur

bule

nce,

and

bi

ofou

ling

infl

u-en

ce th

e up

take

rat

e

3K

ings

ton

et a

l. (2

000)

, Mat

tice

et a

l. (1

998)

, Mor

riso

n (2

006)

, an

d V

rana

et a

l. (2

005,

200

6b,

2007

)

Pass

ive

in s

itu

conc

entr

atio

n ex

trac

tion

sam

-pl

er (

PISC

ES)

Acc

umul

ated

m

ass—

time-

aver

aged

co

ncen

trat

ion

Dif

fusi

on,

adso

rptio

nM

icro

conc

entr

atio

ns

of V

OC

s, m

ost

sVO

Cs

(hyd

roph

obic

)

X—

14 d

ays

Yes

Not

sen

sitiv

e fo

r bi

ofou

ling

due

to th

e so

l-ve

nt-s

atur

ated

m

embr

ane

A s

olve

nt in

side

th

e sa

mpl

er is

not

al

low

ed in

man

y co

untr

ies

3IT

RC

(20

05)

and

Vra

na e

t al.

(200

5, 2

006b

)

Mem

bran

e as

sist

ed p

as-

sive

sam

pler

(M

APS

)

Acc

umul

ated

m

ass—

time-

aver

aged

co

ncen

trat

ion

Dif

fusi

on,

ioni

zatio

nIo

niza

ble

orga

nic

com

pone

nts

X—

Not

kno

wn

No

Hig

h se

lect

ivity

Lim

ited

expe

ri-

ence

, lim

ited

targ

et

com

pone

nts

3C

him

uca

and

Cuk

row

ska

(200

6)

Pola

r or

gani

c ch

emic

al in

te-

grat

ive

sam

pler

s (P

OC

IS)

Acc

umul

ated

m

ass—

time-

aver

aged

co

ncen

trat

ion

Dif

fusi

on,

adso

rptio

nM

icro

conc

entr

atio

ns

of V

OC

s, m

ost

sVO

Cs

(pol

ar)

X—

14–3

0 da

ysY

esSi

mul

ates

the

resp

irat

oric

ex

posu

re

of a

quat

ic

orga

nism

s

Bio

foul

ing

of th

e m

embr

ane

1IT

RC

(20

05)

and

Vra

na e

t al.

(200

5)


where Jc is the contaminant mass flux (g/m2/day), C the

mean concentration of the contaminant in the groundwater (g/m3), v the Darcy groundwater flux (m3/m2/day), m the mass of contaminant (g), A a well-defined plane of compli-ance (AA’B’B), orthogonal to the groundwater flow direc-tion (m2), and t the time (day).

The total mass flux of an organic contaminant through a saturated porous medium is achieved by the simultane-ous action of the processes advection, dispersion, and diffu-sion (Bear and Verruijt 1998). Other processes that can have considerable impact as well on the contaminant mass flux through a porous medium are adsorption, ion exchange, and degradation processes.

The contaminant mass flux, determined at a plane located between a source and receptor, is a measure for the linear transport of the contaminant in the direction of the groundwater flow, orthogonal to the control plane. It mainly gives an indication of the resulting advective transport of the contaminant.

Mass Flux MeasurementThe measurement of mass fluxes with passive samplers

can be achieved theoretically in three different ways (pre-sented in Figure 3):

• direct measurement with permeation-based samplers• indirect measurement with diffusion-based samplers• indirect estimation with diffusion-based samplers in

combination with a cumulative water flux measurement.

Only a permeation-based passive sampler allows a direct flux measurement because of the direct influence of the groundwater flux. When using a diffusion sampler, the interpretation is more complex. If a linear influence of the groundwater flow rate on the uptake rate of the contami-nant can be validated for the existing field conditions, the mass flux J

c can be derived from a calibration curve. If

the process is nonlinear you might be able to calibrate the sampler for given conditions as it comes to time-averaged concentration measurements (Greenwood et al. 2007). This conditions, however, are very specific and limited in time. Therefore, this samplers can never be used for longer-term monitoring and combined with water flux measurements to calculate the mass fluxes. Direct or indirect calibrating for mass fluxes is not possible. If the passive sampler can

Tabl

e 1

Con

tinu

ed

Eco

scop

eA

ccum

ulat

ed

mas

sD

iffu

sion

, ad

sorp

tion

Non

pola

r or

gani

c co

ntam

inan

tsX

—H

ours

to

days

No

Cos

t pri

ce, e

asy

Onl

y qu

alita

tive

mea

sure

men

t3

Kot

-Was

ik e

t al.

(200

7)

Perm

eati

on-b

ased

pas

sive

sam

pler

s

Env

irof

lux

PFM

Acc

umul

ated

m

ass—

con-

tam

inan

t mas

s fl

ux

Adv

ectio

n,

adso

rptio

nW

ide

rang

e, d

epen

-da

nt o

n so

rben

t (V

OC

s, s

VO

Cs,

met

-al

s an

d an

ions

)

—X

Few

day

s to

sev

eral

m

onth

s

Yes

Cum

ulat

ive

mas

s fl

ux a

nd

wat

er f

lux

mea

sure

men

t

Big

siz

e, lo

ts o

f so

rben

t nee

ded

1A

nnab

le e

t al

. (2

005)

, B

asu

et a

l. (

2006

), H

atfi

eld

et a

l. (2

002,

200

4, 2

006,

200

7),

Kla

mm

ler

et a

l. (

2007

a),

Lee

et

al.

(20

07),

and

Yan

cus

(200

5)

Gai

asaf

e Pa

ssiv

e Sa

mpl

erA

ccum

ulat

ed

mas

s—tim

e-av

erag

ed

conc

entr

atio

n

Adv

ectio

n,

adso

rptio

nW

ide

rang

e, d

epen

-da

nt o

n so

rben

t (V

OC

s, s

VO

Cs,

met

-al

s an

d an

ions

)

XX

14 d

ays

No

Cos

t pri

ceU

ncer

tain

ties

abou

t ca

libra

tion

1B

örke

(20

07)

and

Haa

s an

d O

este

(20

01)

Sorb

i sam

pler

Acc

umul

ated

m

ass—

time-

aver

aged

co

ncen

trat

ion

Pres

sure

gr

adie

nt,

adso

rptio

n

Wid

e ra

nge,

dep

en-

dant

on

sorb

ent

(VO

Cs,

sV

OC

s, m

et-

als

and

anio

ns)

XX

1–2

wee

ks

to 6

mon

ths

Yes

No

infl

u-en

ces

of m

ost

envi

ronm

enta

l pa

ram

eter

s

—1

De

Jong

e an

d R

othe

nber

gh

(200

5), D

e Jo

nge

et a

l. (2

005)

, an

d SK

B (

2005

, 200

6)

Figure 2. Concept of a contaminant mass flux at a plane of compliance (figure redrawn after EPA 2003).


measure a time-integrating concentration (i.e., no influence of the groundwater flow rate), the sampler can be combined with a time-averaged water flux measurement to estimate a time-averaged mass flux. However, spatial correlations between Darcy water flux and concentration can complicate the ability to quantify mass fluxes. The criteria to evaluate the applicability of passive samplers to measure contaminant mass fluxes are summarized in the section on Screening of Existing Passive Samplers for Measuring VOCs in Water.

Note that the impact of the passive sampler and the monitoring well including the surrounding filter pack on the flow field always needs to be taken into account (Klammler et al. 2007a, 2007b). The flow velocity (v

D) in the monitor-

ing well or in the passive sampler is directly proportional to the flow velocity (v

0) in the aquifer. This can be expressed

in Equation 3:

v vD

� �0

(3)

The flow convergence/divergence factor α can be calcu-lated from the potential theory (Drost et al. 1968).

Passive Samplers for the Measurement of Volatile Organic Carbon (VOC) Mass Fluxes in GroundwaterScreening of Existing Passive Samplers for Measuring VOCs in Water

A selection of existing passive samplers for the mea-surement of VOCs in water were screened for their capac-ity in measuring VOC mass fluxes in groundwater in the frame of a long-term monitoring approach (several months to a year). For this purpose, a number of criteria have been defined (Table 2). Subsequently, weighting factors (WF) based on expert judgment were assigned to each criterion as a function of the importance of each factor (WF = 5: most important; WF = 1: less important).

Based on the results reported in literature scores rang-ing from −1 (not suitable) to 2 (very suitable) were given to each characteristic of the passive samplers distinguished (Table 3).

According to Table 3, 6 out of the 18 screened passive samplers get the maximum score (2) with respect to the cri-teria “contaminant specificity.” The duration of the kinetic phase is only long enough and thus suitable for a long-term time-integrating measurement for 5 out of the 18 screened samplers.

When a “−1” score is given to one of the so-called master criteria (i.e., criteria having a WF ≥ 4: “contaminant speci-ficity,” “kinetic aspect,” “applicable in monitoring well,” and “physical strength”) the particular passive sampler is rejected for further application as passive flux sampler. As a result, the passive flux meter™, the ceramic dosimeter, the Sorbi sampler, the Membrane-enclosed sorptive coat-ing sampler (MESCO), the Gaiasafe passive sampler, the Gore™Sorber Module, and the RCDM sampler remain as potentially applicable for the measurement of VOC mass fluxes in groundwater. Because of their general lower score, the Gore Sorber Module and the RCDM sampler were not considered further. Both samplers are not eligible for a quantitative measurement and have a rather short kinetic uptake time range.

A brief description of the passive samplers indicated as being suitable for the measurement of VOCs is given in the next section.

Potentially Suitable Passive Samplers for the Measurement of VOC Mass FluxesPassive Flux Meter

The passive flux meter (PFM) is a permeation-based kinetic passive sampler that is placed in the monitoring well or borehole. It intercepts the groundwater flow and captures the contaminants from it (Hatfield et al. 2002, 2004, 2007). The PFM consists of a permeable sock which is packed with a permeable receiving phase (cf. Figure 4a).

The receiving phase of the flux meter is a matrix of hydrophobic and hydrophilic permeable sorbents that cap-tures the organic and inorganic solutes from the groundwa-ter flow. The sorbent matrix is also pre-equilibrated with a known amount of one or more water soluble tracers, usually alcohols. These tracers are eluted from the matrix with an elution rate that is directly proportional to the water flux

FLUX MEASUREMENT

DIRECT INDIRECT

output: - cumulative mass flux - cumulative water flux

Linear influence of the groundwater flow rate

No influence of the groundwater flow rate

Diffusion-based sampler

output: - fraction of the cumulative mass flux Combined with a

cumulative water flux measurement

output: - time integrating conc.

Permeation-based sampler

Figure 3. Overview diagram for the measurement of contaminant mass fluxes with passive samplers.


passing through. A widely used sorbent for the capture of VOCs in the PFM is active carbon.

After a fixed exposure time, the PFM is retrieved from the monitoring well or borehole. The exposure time typi-cally ranges from 3 days to 1 month. Analysis of the PFM involves extracting the sorbents in order to determine the present contaminant masses and the residual tracer amounts. The measured contaminant masses are used to calculate the cumulative and time-integrating mass fluxes for each con-taminant. The residual tracer amounts are a measure of the cumulative or time-integrating water flux.

The PFM can allow monitoring time-integrating water and contaminant mass fluxes in the long term, depending on the contaminant concentration, groundwater flow, and loading capacity of the PFM (Annable et al. 2005; Basu et al. 2006). Temporal fluctuations in contaminant mass con-centrations and groundwater flows during the measurement

period do not influence the accuracy of the measurement, as is the case when using the classical monitoring methods (Hatfield et al. 2004).

The PFM is patented (U.S. patent no. 6.401.547) and presently has only been used commercially in the United States, Canada, and Australia by Enviroflux, LLC. The PFM has been used for monitoring of contaminant plumes in groundwater and characterization of source zones.

Ceramic DosimeterThe ceramic dosimeter is a diffusion-based kinetic pas-

sive sampler. It consists of a ceramic tube filled with water-saturated adsorbent and closed at either end with caps made of, for example, polytetrafluoroethylene (PTFE) (Bopp 2004) (Figure 4b). The adsorbent matrix needs to have a high affinity as well as a high capacity for the uptake of the chemicals to be sampled (Weiss et al. 2007). A very

Table 2 Criteria and WF for the Measurement of Organic Mass Fluxes with Passive Samplers

Criterion Description WF Motivation

Contaminant specificity: VOCs

Because the target contaminants are VOCs, the passive sampler must be applicable for measuring these parameters

5 The maximum WF is assigned because the criterion is a requirement

Kinetic aspect Passive samplers are called kinetic if the equilibrium with the surrounding water is only achieved after a certain time period. During this period, the passive sampler is continuous enriched with contaminants. To make a long-term mass flux measurement possible, the passive sampler must be characterized over longer durations to overcome kinetics

5 The maximum WF is assigned because the criterion is a requirement. No mass flux can be derived from equilibrium conditions

Physical strength Physical strength means robustness, resistance to degradation or (bio)fouling

4 This property is also extremely important regarding to a long-term application in the field. It is not an absolute requirement; therefore, a weighting of 4 has been assigned

Applicable in monitoring well

The passive sampler must fit in the most widely used monitoring wells (e.g., 1 or 2 inch wells)

4 This criterion is highly appropriate, but not absolutely required

Direct flux measurement

Is direct flux measurement possible? This also implies: is this a permeation-based sampler?

3 It is a very important criterion which is not con-sidered as a master criterion (WF ≥ 4) because of the possibilities of an indirect flux measurement with a diffusion-based sampler

Quantitative data This characteristic indicates the possibility to obtain accurate quantitative analytical results

3 It is a very important criterion which is not considered as master criterion because a passive sampler that provides qualitative flux data is also of interest

Reliability With respect to characterization of contaminated sites and risk assessment reliability, the sampling equipment applied is a very important parameter

3 Reliability is very important, but not considered as master criterion. It is not always possible for a highly innovative sampler to provide enough data to substantiate the reliability

Standard analysis This criterion indicates if the VOCs in the receiving phase of the passive sampler can be measured by using a standard procedure and standard analysis

2 This criterion is another important factor, however, less decisive than the factors above

Simplicity The more simple the sampler is constructed, the more desirable and the higher the score will be

1 Additional criterion

Availability This indicates the extent of availability of the passive sampler on the market

1 Additional criterion

Cost price A low cost price is more desirable than a higher one 1 Additional criterion


suitable matrix for VOCs is the DOWEX Optipore L-493. Analysis of the ceramic dosimeter also involves extraction of the adsorbent and analysis of the extract. One of the main advantages of the ceramic dosimeter is its robustness and its suitability for a long-term monitoring (Martin et al. 2003). The ceramic housing can easily be saturated with water and is less sensitive to adsorption of organic substances as well as degradation or biofouling. The thickness of the ceramic wall reduces the influence of the thickness of the aqueous boundary layer; and consequently, the flow rate and turbu-lence of the associated groundwater. The application time of the ceramic dosimeter varies from several months to even 1 year (Bopp et al. 2005). A disadvantage of the thicker housing is the lower diffusion rate whereby rapid passing contaminant peaks can be missed. This is mainly a prob-lem in surface water where flow rates are higher compared with groundwater. The ceramic dosimeter measures a time average concentration. Direct determination of a mass flux is not possible. Contaminant mass flux data over long-time periods can only be achieved in combination with measure-ment of the cumulative groundwater flux.

The ceramic dosimeter is patented (German Patent DE 198.30.413.A1) and available on the European market by Innovative Messtechnik Dr. Weiss.

Sorbi SamplerThe Sorbi sampler is a forced permeation-based kinetic

sampler (De Jonge and Rothenberg 2005). The driving force is not the groundwater flow, but a pressure gradient that is created inside the sampler. The sampler consists of a hous-ing that contains one or more sampling cartridges that are permeable to water (Figure 4c). The cartridges are connected to a hollow tube through a capillary. A pressure gradient is created by lowering the hollow tube below the groundwater level. The hollow tube, in turn, is in connection with the atmosphere. The flow through the cartridges is regulated by the capillaries between the hollow tube and the cartridges. The diameter and length of the capillary are important as well as the depth of the sampler below the water level, which also influences the pressure gradient and hence the flow-through. Poiseulle’s law allows calculating in advance the flow-through to cartridges (Sutera and Skalak 1993).

Table 3 Screening Table for the Measurement of Organic Mass Fluxes with Passive Samplers

Kin

etic

Asp

ect

Con

tam

inan

t:

VO

Cs

App

licab

le in

M

onit

orin

g W

ell

Phy

sica

l Str

engt

h

Dir

ect

Flu

x M

easu

rem

ent

Qua

ntit

ativ

e

Rel

iabi

lity

Stan

dard

Ana

lysi

s

Sim

plic

ity

Ava

ilabi

lity

Cos

t P

rice

Quo

tati

on

WF 5 5 4 4 3 3 3 2 1 1 1

Enviroflux PFM 1 2 2 2 2 2 2 1 2 1 0 54

Ceramic dosimeter 1 2 2 2 −1 2 2 1 2 2 1 47

Sorbi sampler 1 2 2 2 −1 2 2 1 1 2 1 46

MESCO sampler 1 2 2 0 −1 2 1 1 1 1 1 34

Gaiasafe passive sampler

1 1 2 1 0 0 1 1 2 2 2 33

PDBs −1 2 2 0 −1 1 1 2 2 2 2 26

RCDMs 0 2 2 0 −1 0 0 1 2 0 1 20

GORE sorber module

0 2 2 1 −1 −1 1 1 1 2 −1 23

PVDs −1 1 2 0 −1 0 1 2 2 2 2 18

SPMDs −1 −1 2 0 −1 2 2 2 2 2 2 17

RPPS −1 1 2 0 −1 1 0 2 1 2 2 17

Peeper samplers −1 1 2 0 −1 1 1 2 0 2 0 17

NSPDS −1 1 1 0 −1 1 1 2 2 1 2 16

Chemcatcher—empore disk

−1 −1 1 0 −1 1 1 1 1 1 0 1

Ecoscope −1 1 0 0 −1 −1 −1 2 2 1 0 −2

POCIS −1 −1 −1 0 −1 1 0 1 1 2 1 −8

MAPS −1 −1 0 0 −1 0 0 1 0 −1 0 −12

PISCES −1 −1 −1 0 −1 1 0 1 0 −1 0 −13

Note: −1 = not suitable, 0 = maybe suitable, 1 = suitable, 2 = very suitable ; WF = weighting factor; WF ≥ 4 = master criterion.


The type of sorbent in the cartridges depends on the target contaminant. Popular sorbents are silica gel, car-bon-based resins, zeolites, and activated carbon (De Jonge and Rothenberg 2005). After retrievement, the exact flow through the cartridges can be calculated based on the water volume in the hollow collection tube and the release of tracer salt from the sampling cartridge. The cartridges are chemically extracted, and the adsorbed solute mass and tracer loss are quantified using standard laboratory methods. The Sorbi sampler measures a time-integrating contaminant concentration. Note that the water flux through the cartridge is different from the groundwater flux. The flux through the cartridge is a function of the pressure gradient, related to the provided capillary and the head in the well.

A great advantage of this sampler is its robustness. Concentration and environment-specific factors such as temperature and flow rate do not influence the sampling rate. This means that no complex and influenced kinet-ics need to be considered during back calculation as with other passive samplers. However, attention needs to be paid to variations in the water level, because these cause variations in the pressure gradient and therefore variations in the flux through the cartridges. The Sorbi sampler has a high resistance to biodegradation because it consists of a nano material through which bacteria cannot pass. Also, the adsorption coefficient K

d is so high that no diffusion from

the sampler takes place (De Jonge et al. 2005). The sam-pler can be applied for medium- and long-term monitoring (1 week till 6 months).

Like the ceramic dosimeter, the Sorbi sampler can be a solution for the determination of contaminant mass fluxes in the long term, if combined with a measurement of the cumulative groundwater flux.

The Sorbi sampler is patented (U.S. patent no. 7.325.443 B2) and supplied by the Danish company Sorbisense S/A.

Membrane-Enclosed Sorptive Coating SamplerA MESCO sampler is a diffusion-based kinetic sampler.

It consists of a membrane tubing or bag made of regenerated celluloses (dialysis membrane) or a low-density polyethyl-ene (LDPE). The tubing or bag is filled with distilled water containing a Twister stir bar, coated with polydimethylsi-loxane (PDMS) as receiving phase (Vrana et al. 2001). The Twister stir bar comes from the stir bar sorptive extraction (SBSE) technology (Tienpont et al. 2003). Figure 4d pres-ents a picture of a MESCO sampler.

The organic solutes from the surrounding water will be adsorbed on the silicone coating of the Twister stir bar during the exposure. After retrievement, the Twister bar is thermally desorbed in an online system whereupon the absorbed solute mass is directly quantified using standard analytical methods.

The main advantage of this system is the solvent-free desorption of the contaminants. A full silicone rod or a sili-cone tubing is often used as an alternative to the coated stir bar in order to enlarge the capacity of the receiving phase (Wennrich et al. 2003).

The typical application time of a MESCO is rather short, taking several hours to 1 week. The sampler is applied to the measurement of time-integrating concentrations, not to a mass flux measurement.

Quantitative measurements with the sampler are only possible when using performance release compounds (PRCs). The desorption behavior of the PRCs is similar to the adsorption behavior of the contaminants in the receiving phase (Huckins et al. 2005; Vrana et al. 2006a and 2006b; Paschke et al. 2006).

Figure 4. Picture of the (a) PFM, (b) Ceramic dosimeter, (c) Sorbi sampler, (d) MESCO sampler, and (e) Gaiasafe passive sampler.


The MESCO sampler is not patented and therefore not available as a complete sampler on the market. Because of its simplicity, it is easy to construct (Paschke 2005).

Gaiasafe Passive SamplerThe Gaiasafe passive sampler consists of a paper-based

active fiber membrane (Figure 4e). Depending on the type of active fiber material, the Gaiasafe sampler can be used for capturing metals, metalloids, anions, and organic com-pounds (Haas and Oeste 2001). The paper-based active fiber membrane is a porous structure and allows advective water flow through the sampler. The contaminants from the sur-rounding water will be adsorbed during exposure on acti-vated carbon and iron(III)oxide fixed on cellulose fibers. After retrievement, the absorbed contaminant mass on the Gaiasafe membrane is desorbed and is directly quantified using standard analytical methods.

The Gaiasafe passive sampler can be used for surface water as well as for groundwater. It fits in 2 inch monitor-ing wells.

The sampler gives a time-integrating concentration (Haas and Oeste 2001) and possibly also a flux measure-ment. The latter has not been proven yet. The average expo-sure time is about 4 weeks.

A great advantage of the Gaiasafe sampler is its simplic-ity. It only consists of paper. A disadvantage is the influ-ence of environmental-specific factors, especially reducing conditions, which will destroy the cellulose fibers due to microbial activity. The Gaiasafe sampler has no internal tracers or PRCs to correct for this. This implicates that only qualitative or semi-quantitative measurements are possible. Calibration in the field is often performed to correct for the average field conditions.

The Gaiasafe paper-based active fiber membranes are patented (EU Patent No. 1115469 v.15.10.03), and the sam-pler is available on the market by the German company Gaiasafe GmbH.

ConclusionsCurrently, the PFM is the only passive sampler which

has proven to effectively measure mass fluxes. To date, the Gaiasafe Passive Sampler, also a permeation-

based sampler, is used for time-integrating measurements only. Because of its porous structure, it theoretically offers also the potential to a direct cumulative mass flux measure-ment. The latter has not been proven yet.

The MESCO sampler is a diffusion-based sampler of which the impact of the groundwater flow rate should be precisely investigated. In case of a linear influence within the natural variations of the groundwater flow rate, a mass flux can possibly be derived.

The ceramic dosimeter and the Sorbi sampler which are not subjected to the influence of groundwater flow rate seem to offer more opportunities as time-integrating sam-plers. Cumulative mass fluxes can then be determined by combining the measured time-integrating concentrations with a measured cumulative water flux. The great advan-tage of both samplers is their physical robustness and their

attendant limited number of influencing factors, which allows for very long-term monitoring.

Recommendations and PerspectivesThis screening study indicates that direct measurement

of VOC mass fluxes in groundwater is possible with pas-sive samplers. It is recommended that the selected passive samplers that have a potential concerning the measurement of mass fluxes in groundwater be investigated in high-quality laboratory and field experiments. PFMs have been extensively applied in near source zones and the higher concentration zones of groundwater plumes, nevertheless, information about the application of PFMs in plume zones with very low concentrations that vary around the maximum contaminant level (MCL) is still missing. There is no detec-tion limit stated yet for the use of PFMs. The possibilities on long-term monitoring with a PFM in the lower concentra-tion plume zones should still be investigated as well as the possibilities and the methods concerning the other selected passive samplers. An implementation of this monitoring approach in the developing risk-based assessment and man-agement of ground and groundwater pollutions would offer a great added value.

AcknowledgmentsThis study is part of the PhD research of Goedele Verreydt

and funded through the Flemish Institute for Technological Research (VITO NV). Mr. Andrew J. Victor is gratefully acknowledged for the linguistic improvements. Also many thanks to three anonymous reviewers who helped improve the paper.

ReferencesAnnable, L.D., K. Hatfield, J. Cho, H. Klammler, B.L. Parker, J.A.

Cherry, and P.S.C. Rao. 2005. Field-scale evaluation of the pas-sive flux meter for simultaneous measurement of groundwater and contaminant fluxes. Environmental Science & Technology 39, no. 18: 7194–7201.

Archfield, S.A., and D.R. LeBlanc. 2002. Comparison of diffu-sion- and pumped-sampling methods for monitoring volatile organic compounds in ground water. July 1999–December 2002, USGS Scientific Investigations Report 2005-5010. Cape God, Massachusetts: Massachusetts Military Reservation.

Basmadjian, D. 2004. Mass Transfer: Principles and Applications. Boca Raton, Florida: CRC Press LLC.

Basu, N.B., P.S.C. Rao, I.C. Poyer, M.D. Annable, and K. Hatfield. 2006. Flux-based assessment at a manufacturing site con-taminated with trichloroethylene. Journal of Contaminant Hydrology 86: 105–127.

Bear, J. 1988. Dynamics of Fluids in Porous Media, Dover edi-tion. Originally published: New York: American Elsevier Pub. Co., 1972. Reprint with corrections: New York: Dover Publications Inc.

Bear, J., and A.Verruijt. 1998. Modeling Groundwater Flow and Pollution. First published 1987. Reprinted with corrections. Dordrecht: D. Reidel Publishing Company.

Booij, K., F. Smedes, E.M. Van Weerlee, and P.J. Honkoop. 2006. Environmental monitoring of hydrofobic organic con-taminants: The case of mussels versus semipermeable devices. Environmental Science and Technology 40: 3893–3900.


Booij, K., F. Smedes, and E.M. van Weerlee. 2002. Spiking of performance reference compounds in low density polyethyl-ene and silicone passive water samplers. Chemosphere 46: 1157–1162.

Booij, K., H.M. Sleiderink, and F. Smedes. 1998. Calibrating the uptake kinetics of semi permeable membrane devices using exposure standards. Environmental Toxicology and Chemistry 17: 1236–1245.

Bopp, S. 2004. Development of a passive sampling device for combined chemical and toxicological long-term monitoring of groundwater. Ph.D. diss., Mathematisch-Naturwissenschaftlichen Fakultät der Universität Rostock. Leipzig, Germany.

Bopp, S., H. Weiß, and K. Schirmer. 2005. Time-integrated moni-toring of polycyclic hydrocarbons (PAHs) in groundwater using the Ceramic Dosimeter passive sampling device. Journal of Chromatography A 1072: 137–147.

Börke, P. 2007. Untersuchungen zur quanifizierun der Grund wasserimmison vor Polyzyklischen Aromatischen Kohlenwasserstoffen mithilfe von Passiven probennahmesys-temen. Ph.D. diss., Technische Universität Dresden, Dresden, Germany.

Chimuca, L., and E. Cukrowska. 2006. The role of passive sam-plers in the monitoring of aquatic ecosystems and occupational hygiene pollution. LCGC solutions for separation scientists, North America. www.lcgcmag.com.

Church, P.E., D.A. Vroblesky, F.P. Lyford, and R.E. Willey. 2002. Guidance on the use of passive-vapor-diffusion samplers to detect volatile organic compounds in ground water-discharge areas, and example applications in New England. USGS Water-Resources Investigations Report 02-4186. Reston, Virginia: USGS.

Columbia Analytical Services Inc. 2007. Rigid porous polyeth-ylene passive diffusion samplers. Paper presented at the 7th Passive Sampling Workshop and Symposium, April 24–26, Reston, Virginia.

De Jonge, H., and G. Rothenbergh. 2005. New device and method for flux-proportional sampling of mobile solutes in soil and groundwater. Environmental Science and Technology 39: 274–282.

De Jonge, H., G. Rothenberg, J. Metselaar, M. van den Berg, T. Grotenhuis, K. Groen, and A. Peekel. 2005. Sorbisampler. Interne workshop SKB-project PT5408. June 29, Rotterdam, The Netherlands.

Drost, W., D. Klotz, A. Koch, J. Moser, F. Neumaier, and W. Rauert. 1968. Point dilution method measuring groundwater flow by means of radioisotopes. Water Resources Research 4: 125–146.

Ehlke, T.A., T.E. Imbrigiotta, and J.M. Dale. 2004. Laboratory comparison of polyethylene and dialysis membrane diffusion samplers. Ground Water Monitoring and Remediation 24, no. 1: 53–59.

U.S. Environmental Protection Agency (EPA). 2003. The DNAPL remediation challenge: Is there a case for source depletion? Expert Panel on DNAPL Remediation. EPA 600-R-03-143.

Goltz, M.N., M.E. Close, H. Yoon, H. Junqi, M.J. Flintoft, S. Kim, and C. Enfield. 2009. Validation of two innovative methods to measure contaminant mass flux in groundwater. Journal of Contaminant Hydrology 106, nos. 1–2: 51–61.

Greenwood, R., G. Mills, and B. Vrana. 2007. Passive sam-pling techniques in environmental monitoring, 1st ed. In Comprehensive Analytical Chemistry, ed. D. Barcelo. Vol. 48. Amsterdam, The Netherlands: Elsevier.

Haas, R., and F.D. Oeste. 2001. Passivsammler zur Wasserun-tersuchung. UWSF-S. Umweltchem. Ökotoxikologie 13: 2–4.

Harter, T., and S. Talozi. 2004. Evaluation of a simple inexpensive dialysis sampler for small diameter monitoring wells. Ground Water Monitoring and Remediation 24, no. 4: 97–105.

Hatfield, K., M.D. Annable, and P.S. Rao. 2006. Field demonstra-tion and validation of a new device of measuring water and solute fluxes at CFB Borden. ESTCP Report ER-0114.

Hatfield, K., M. Annable, J. Cho, P.S.C. Rao, and H. Klammler. 2004. A direct passive method for measuring water and con-taminant fluxes in porous media. Journal of Contaminant Hydrology 75: 155–181.

Hatfield, K., P.S.C. Rao, M.D. Annable, and T.J. Campbell. 2002. Device and method for measuring fluid and solute fluxes in flow systems. U.S. Patent No. 6.401.547.

Huckins, J.N., K. Booij, W.L. Cranor, D.A. Alvarez, R.W. Gale, M.E. Bartkow, G.L. Robertson, R.C. Clark, and R.E. Stewart. 2005. Fundamentals of the use of performance reference compounds (PRCs) in passive samplers. In Proceedings of SETAC North America 26th Annual Meeting, November 13–17, 2005, 1–24. Pensacola: SETAC.

Huckins, J.N., J.D. Petty, J.A. Lebo, F.V. Almeida, K. Booij, D.A. Alvarez, W.L. Cranor, R.C. Clark, and B.B. Mogenson. 2002. Development of the permeability/performance reference compound approach for in situ calibration of semipermeable membrane devices. Environmental Science and Technology 36: 85–91.

Huckins, J.N., J.D. Petty, C.E. Orazio, J.A. Lebo, R.C. Clark, V.L. Gibson, W.R. Gala, and K.R. Echols. 1999. Determinations of uptake kinetics (sampling rates) by lipid-containing semi-permeable membrane devices (SPMDs) for polyclic aromatic hydrocarbons (PAHs) in water. Environmental Science and Technology 33: 3918–3923.

Interstate Technology & Regulatory Council (ITRC). 2007. Protocol for the Use of Five Passive Samplers to Sample for a Variety of Contaminants in Groundwater. DSP-5. Washington, D.C.: Interstate Technology & Regulatory Council, Diffusion/Passive Sampler Team. www.itrcweb.org.

Interstate Technology & Regulatory Council (ITRC). 2005. Technology Overview of Passive Sampler Technologies. DSP-4. Washington, D.C.: Interstate Technology & Regulatory Council, Diffusion/Passive Sampler Team. www.itrcweb.org.

Interstate Technology & Regulatory Council (ITRC). 2004. Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers to Monitor Volatile Organic Compounds in Groundwater. Washington, D.C.: Interstate Technology & Regulatory Council, Diffusion/Passive Sampler Team. www.itrcweb.org.

Ke, R., Y. Xu, Z. Wang, and S.U. Khan. 2006. Estimations of the uptake rate constants for polycyclic aromatic hydrocarbons accumulated by semipermeable membrane devices and triolein-embedded cellulose acetate membranes. Environmental Science and Technology 40: 3906–3911.

Kingston, J.K., R. Greenwood, G.A. Mills, G.M. Morrison, and L.B. Persson. 2000. Development of a novel passive sampling system for the time-averaged measurement of a range of organic pollutants in aquatic environments. Journal of Environmental Monitoring 2: 487–495.

Klammler, H., K. Hatfield, and M.D. Annable. 2007a. Concepts for measuring horizontal groundwater flow directions using the passive fluxmeter. Advances in Water Resources 30: 984–997.

Klammler, H., K. Hatfield, M.D. Annable, E. Agyei, B.L. Parker, J.A. Cherry, and P.S.C. Rao. 2007b. General analytical treatment of the flow field relevant to the interpretation of passive fluxmeter measurements. Water Resources Research 43, W04407, doi:10.1029/2005WR004718.


Kot-Wasik, A., B. Zabiegala, M. Urbanowicz, E. Dominiak, A. Wasik, and J. Namiesnik. 2007. Advances in passive sampling in environmental studies. Analytica Chimica Acta 602: 141–163.

Lee, J., P.S.C. Rao, I.C. Poyer, R.M. Toole, M.D. Annable, and K. Hatfield. 2007. Oxyanion flux characterization using pas-sive flux meters: Development and field testing of surfactant-modified granular activated carbon. Journal of Contaminant Hydrology 92, 209–229.

Luellen, D.R., and D. Shea. 2002. Calibration and field verification of semipermeable membrane devices for measuring polycyclic aromatic hydrocarbons in water. Environmental Science and Technology 36: 1791–1797.

Martin, H., B.M. Patterson, G.B. Davis, and P. Grathwohl. 2003. Field trial of contaminant groundwater monitoring: Comparing time-integrating ceramic dosimeters and conventional water sampling. Environmental Science and Technology 37: 1360–1364.

Martin, H., M. Piepenbrink, and P. Grathwohl. 2001. Ceramic dosimeters for time-integrated contaminant monitoring. Journal of Process Analytical Chemistry 6, no. 2: 68–73.

Mattice, J.D., S.K. Park, and T.L. Lavy. 1998. Potential pas-sive empore C18 disk extraction for analysis of water sam-ples containing fine particulates. Bulletin of Environmental Contamination and Toxicology 60: 202–208.

Morrison, G. 2006. Principles of passive sampling, development of Chemcatcher and comparison with other devices. In STAMPS Satellite Dissemination Workshop, January 16, 2006, Prague.

Namiesnik, J., B. Zabiegala, A. Kot-Wasik, M. Partyka, and A. Wasik. 2005. Passive sampling and/or extraction tech-niques in environmental analysis: A review. Analytical and Bioanalytical Chemistry 381: 279–301.

Newman, M., K. Hatfield, J. Hayworth, P.S.C. Rao, and T. Stauffer. 2005. A hybrid method for inverse characterization of subsur-face contaminant flux. Journal of Contaminant Hydrology 81: 34–62.

Paschke, A. 2005. Existierende und neue Methoden für chemische und ökologische Gewässerüberwachung nach der WRRL. Präsentation SWIFT-WFD 2005. http://www.swift-wfd.com/.

Paschke, A., K. Schwab, J. Brümmer, G. Schüürmann, H. Paschke, and P. Popp. 2006. Rapid semi-continuous calibration and field test of membrane enclosed silicone collector as passive water sampler. Journal of Chromatography A, 1124: 187–195.

Paschke, A., V. Branislav, P. Popp, L. Wennrich, W. Lorenz, and G. Schüürmann. 2003. Novel passive samplers for monitor-ing organic pollutants in surface and ground water based on membrane-enclosed silicone material. In New Horizons and Challenges in Environmental Analysis and Monitoring, August 18–31, 2003, CEEAM, Gdansk University of Technology, Gdansk Wrzeszcz, Poland.

Stichting Kennisontwikkeling Kennisoverdracht Bodem (SKB). 2006. Toepassing van de Sorbisamplers bij grondwatermonitoring in het kader van grondwatersanering. SKB Demonstratieproject. Deelresultaat 2. 9R1336/R00007/AFP/Rott1.

Stichting Kennisontwikkeling Kennisoverdracht Bodem (SKB). 2005. Toepassing van de Sorbisampler bij grondwatermonitoring in het kader van grondwatersanering. SKB Demonstratieproject. Deelresultaat 1. 9R1336/R00006/APF/Rott1.

Stichting Kennisontwikkeling Kennisoverdracht Bodem (SKB), C.J.M.M. Mels, and T.M. Prins. 2005. Toepassingsmogelijkheden van diffusiesamplers bij een VOCl-grondwater-verontreiniging. CUR/SKB, Gouda.

Sutera, S.P., and R. Skalak. 1993. The history of Poiseuille’s law. Annual Review of Fluid Mechanics 25: 1–20.

Tienpont, B., F. David, T. Benijts, and P. Sandra. 2003. Stir bar sorptive extraction-thermal desorption-capillary GC-MS for

profiling and target component analysis of pharmaceutical drugs in urine. Journal of Pharmaceutical and Biomedical Analysis 32: 569–579.

Vrana, B., G.A. Mills, M. Kotterman, P. Leonards, K. Booij, and R. Greenwood. 2007. Modeling and field application of the chemcatcher passive sampler calibration data for the monitor-ing of hydrophobic organic pollutants in water. Environmental Pollution 145: 895–904.

Vrana, B., A. Paschke, and P. Popp. 2006a. Calibration and field performance of membrane-enclosed sorptive coating for inte-grative passive sampling of persistent organic pollutants in water. Environmental Pollution 144: 296–307.

Vrana, B., G.A. Mills, E. Dominiak, and R. Greenwood. 2006b. Calibration of the chemcatcher passive sampler for the moni-toring of priority organic pollutants in water. Environmental Pollution 142: 333–343.

Vrana, B., G.A. Mills, I.J. Allan, E. Dominiak, K. Svensson, J. Knutsson, G. Morrison, and R. Greenwood. 2005. Passive sam-pling techniques for monitoring pollutants in water. Trends in Analytical Chemistry 24, no. 10: 845–868.

Vrana, B., and G. Schüürman. 2002. Calibrating the uptake kinet-ics of semipermeable membrane devices in water: Impact of hydrodynamics. Environmental Science and Technology 36: 290–296.

Vrana, B., P. Popp, A. Paschke, and G. Schüürmann. 2001. Membrane-enclosed sorptive coating. An integrative pas-sive sampler for monitoring organic contaminants in water. Analytical Chemistry 73: 5191–5200.

Vroblesky, D.A. 2002. Appendix 1: Laboratory and field test-ing of passive-vapor-diffusion sampler equilibration times, temperature effects, and sample stability. In Guidance on the Use of Passive-Vapor-Diffusion Samplers to Detect Volatile Organic Compounds in Ground Water-Discharge Areas, and Example Applications in New England. eds. P.E. Church, D.A. Vroblesky, F.P. Lyford, R.E. Willey United States Geological Survey Water-Resources Investigations Report 02-4186. http://water.usgs.gov/pubs/wri/wrir024186/.

Vroblesky, D.A. 2001. User’s guide for polyethylene-based pas-sive diffusion bag samplers to obtain volatile organic com-pounds concentrations in wells, Part 1—Deployment, recovery, data interpretation, and quality control and assurance and Part 2—Field tests. U.S. Geological Survey Water Resources Investigation Reports 01-4060 and 01-4061. Available as DSP-1, Interstate Technology & Regulatory Council, Diffusion/Passive Sampler Team. www.itrcweb.org.

Vroblesky, D.A., J. Manish, J. Morrell, and J.E. Peterson. 2003. Evaluation of passive diffusion bag samplers, dialysis samplers, and nylon-screen samplers in selected wells at Andersen Air Force Base, Guam, March–April 2002. USGS Water-Resources Investigations Report 03-4157. Reston, Virginia: USGS.

Vroblesky, D.A., and T.R. Campbell. 2000. Equilibration times, compound selectivity, and stability of diffusion samplers for collection of ground-water VOC concentrations. Advances in Environmental Research 5: 1–12.

Webster, I., P. Teasdale, and N. Grigg. 1998. Theoretical and experimental analysis of peeper equilibration dynamics. Environmental Science and Technology 32: 1727–1733.

Weiss, H., K. Schirmer, S. Bopp, and P. Grathwohl. 2007. Use of ceramic dosimeters in water monitoring, 1st ed. In Comprehensive Analytical Chemistry, ed. D. Barcelo. Vol. 48, Amsterdam, The Netherlands: Elsevier.

Wennrich, L., B. Vrana, P. Popp, and W. Lorenz. 2003. Development of an integrative passive samplers for the monitoring of organic water pollutants. Journal of Environmental Monitoring 5: 813–822.


Wenzel, K.D., B. Vrana, A. Hubert, and G. Schuurman. 2004. Dialysis of persistent organic pollutants and polycyclic aro-matic hydrocarbons form semi-permeable membranes. A proce-dure using an accelerated solvent extraction device. Analytical Chemistry 76: 5503–5509.

Yancus, W. 2005. A method for determining groundwater fluxes and uncertainties in measurement. Journal of Undergraduate Research 7, no. 1: 1–5.

Biographical SketchesGoedele Verreydt, corresponding author, is a Ph.D. candidate in

the Department of Biology at the University of Antwerp. She is a doc-toral researcher in the research group Land and Water Management at the Flemish Institute for Technological Research (VITO), Boeretang 200, B-2400 Mol, Belgium; (32) 14-33-69-69; fax: (32) 14-33-69-88; [email protected].

Jan Bronders, Ph.D., from the University of Leuven, is a senior hydrogeologist currently Programme Manager of the research group Land and Water Management at the Flemish Institute for Technological Research (VITO), Boeretang 200, B-2400 Mol, Belgium, [email protected].

Ilse Van Keer, Ph.D., from the University of Leuven, researcher in the research group Land and Water Management at the Flemish Institute for Technological Research (VITO), Boeretang 200, B-2400 Mol, Belgium, [email protected].

Ludo Diels, Ph.D., from the University of Antwerp, professor in the Departments of Environmental Sciences and Biology at the University of Antwerp, Research Manager Sustainable Chemistry at the Flemish Institute for Technological Research (VITO), Boeretang 200, B-2400 Mol, Belgium, [email protected].

Paul Vanderauwera, Ph.D., from the University of Leuven, professor in the Department of Industrial Sciences of the Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp, Belgium, [email protected].

NGWREF aids programs such as:

The Len Assante Scholarship Fund, benefiting the young people who are the future of our industry

The 21st Century Fund, providing for projects that reach the general public with information about wells and groundwater

The Ground Water Research Fund, providing grants for cutting-edge projects of importance to water well technology and groundwater science

The Developing World Projects Fund, affording those who are in need in the developing world with potable drinking water from water well systems

The Darcy Distinguished Lecture Series in Ground Water Science

The McEllhiney Distinguished Lecture Series in Water Well Technology.

Investing in education, in NGWREF, is vital to the future of the groundwater industry. Make your commitment known with a donation to NGWREF today.

How to donate:Phone

800 551.7379 (614 898.7791)

Write NGWREF 601 Dempsey Rd. Westerville, OH 43081

Visit www.ngwa.org/ngwref

With your contribution, the possibilities are endless . . .With your contribution, the possibilities are endless . . .

Passive Samplers for Monitoring VOCs in Groundwater and the Prospects Related to Mass Flux...

Documents

Transcript of Passive Samplers for Monitoring VOCs in Groundwater and the Prospects Related to Mass Flux...