Upload
others
View
35
Download
0
Embed Size (px)
Citation preview
24th Annual NARPM Training Program
Passive
Sampling
for Measuring Freely
Dissolved Contaminants
in Sediments: Basics, Principles &
Applications
Robert M Burgess
U.S. EPA ORD NHEERL
Atlantic Ecology Division
Narragansett, RI, USA
25th
24th Annual NARPM Training Program 1
OUTLINE
Why use passive sampling methods (PSM) and what they tell us
Why do we care about the freely dissolved concentration (Cfree)
Types of PSM and how they work
Preparing, deploying, recovering, and storing PSM
Analyzing PSM data
Evaluating PSM applications
Summary
Focus on nonionic organic contaminants (no metals)
PCBs DDTs
Dioxins
PAHs Furans
25th
24th Annual NARPM Training Program 2
(1) Freely dissolved concentrations (Cfree) of contaminants of concern (COC) in water around passive sampler • Surrogate for bioavailable concentrations of COC
• Media
– Porewater (Interstitial Water)
– Water column
• Compare to Water Quality Criteria (WQC), other water quality standards, sediment guidelines or water-only toxicity data
(2) Concentration of COCs in passive sampler
• Evidence of correlation with bioaccumulation by aquatic organisms
• Serve as surrogates for biomonitoring organisms
– Benthic and water column organisms
– Especially in situations where mussels or fish cannot be used (e.g., low dissolved oxygen, toxicity, low/high temperature constraints (ice))
√
√
WHY USE PASSIVE SAMPLING METHODS
(PSM) AND WHAT THEY TELL US
25th
24th Annual NARPM Training Program 3
WHY DO WE CARE ABOUT THE FREELY
DISSOLVED CONCENTRATION (CFREE)?
For benthic organisms: What media is an effective surrogate for
exposure to bioavailable chemicals?
Sediment?
Food?
Water column?
Pore Water = Freely dissolved?
Adams et al. (1985) addressed this question
Two Kepone-amended sediments (same levels)
• 1.5% and 12.3% Sediment organic carbon
Freshwater midge (Chironomus tentans)
Flow-through and static 14 day exposures
Acute and chronic (growth) endpoints
Exposure-response relationships
• Survival and growth versus exposure
Chironomus tentans
=
Kepone
√
√
25th
24th Annual NARPM Training Program 4
WHY DO WE CARE ABOUT THE FREELY
DISSOLVED CONCENTRATION (CFREE)?
Sediment Concentration
(mg Kepone/Kg sediment (dry))
Mid
ge S
urv
ival (%
)
1.5% Organic
carbon/Kg
sediment (dry)
12.3 % Organic
carbon/Kg
sediment (dry)
25
75
Water Column
Food
What media is an effective
surrogate for exposure to
bioavailable chemicals?
Sediment
50
0
100
20 40 80 60
25th
24th Annual NARPM Training Program 5
WHY DO WE CARE ABOUT THE FREELY
DISSOLVED CONCENTRATION (CFREE)?
Freely Dissolved Concentration (Cfree)
(µg Kepone/L Pore water)
Mid
ge S
urv
ival (%
)
1.5% Organic
carbon/Kg
sediment (dry)
12.3 % Organic
carbon/Kg
sediment (dry)
50
0
100
12.5 25 50 37.5
25
75
Water Column
Food
What media is an effective
surrogate for exposure
to bioavailable chemicals?
Sediment
Pore Water √
Pore Water Concentration
(µg Kepone/L Pore water)
Freely Dissolved
25th
24th Annual NARPM Training Program 6
Is there another sampling method for measuring the freely dissolved concentrations (Cfree) of
contaminants?
Measuring freely dissolved concentrations (Cfree) in the pore waters and water column Why not continue to use conventional sampling methods? Some problems:
Pore Water
• Centrifugation or squeezing pore water results in limited volumes
• Several artifacts including losses to filters and surfaces and contamination by colloids and small particles reduce accuracy of analysis
• Collecting large volumes of pore waters is logistically challenging, scientifically dodgy and generally expensive
Water Column
• Logistically and technically difficult to collect and extract large volumes of surface water
• Same artifacts as pore water collection
• Analytical detection limits are often not sufficiently low
√
√
WHY USE PASSIVE SAMPLING METHODS
(PSM) AND WHAT THEY TELL US
25th
24th Annual NARPM Training Program 7
Atmosphere
Water
Contaminated Sediments
Freely Dissolved Concentration (Cfree)
Diffusion/Advection
Freely Dissolved Concentration (Cfree)
WHY USE PSM AND WHAT THEY TELL US
25th
24th Annual NARPM Training Program 8
WHY USE PSM AND WHAT THEY TELL US
Diffusion with replacement to maintain equilibrium Bioaccumulation with replacement to maintain equilibrium Passive sampling with replacement to maintain equilibrium
In equilibrium systems… there is equilibrium partitioning
and there are partition coefficients
25th
24th Annual NARPM Training Program 9
Time (days)
Fre
ely
Dis
solv
ed
Pore
wate
r C
oncentr
ation (
Cfr
ee)
(ng/L
)
0 30
Resuspension Event (water column intrusion)
Actual
Cfree
“Time-averaged” or
“time-integrated”
measurement
WHY USE PSM AND WHAT THEY TELL US
Passive sampler-based
Cfree
For your average contaminated sediment –
How does pore water Cfree behave?
25th
24th Annual NARPM Training Program 10
Atmosphere
Water
Contaminated Sediments
Freely Dissolved Concentration (Cfree)
Atmosphere
Water
Contaminated Sediments
TYPES OF PSM AND HOW THEY WORK
(Cfree)
25th
24th Annual NARPM Training Program 11
Polyethylene (PE) Polyoxymethylene (POM)
PE 25 - 50 µm thick
POM
75 µm thick
TYPES OF PSM AND HOW THEY WORK
25th
24th Annual NARPM Training Program 12
0.2
5 m
2.5 cm
SPME
fiber-optic cable
2.5 cm
50 - 95 um thick polyethylene shell
containing synthetic lipid triolien
cross-section SPMD
triolien layer
Solid Phase
Microextraction (SPME) Semi-Permeable
Membrane Device (SPMD)
TYPES OF PSM AND HOW THEY WORK
25th
24th Annual NARPM Training Program 13
HI
CI
H
HI
CI
H
HI
CI
H
HI
CI
H
HI
CI
H
HI
CI
H
(a)
(c)
(b)
H
I
H - C - HI
SiI
H - C - H
I
H
O
H
I
H - C - HI
SiI
H - C - H
I
H
O
H
I
H - C - HI
SiI
H - C - H
I
H
O
H
I
H - C - HI
SiI
H - C - H
I
H
HI
CI
H
HI
CI
H
HI
CI
H
HI
CI
H OO O
Polyethylene
Polydimethylsiloxane
Polyoxymethylene
Atom Key:
White = Hydrogen
Black = Carbon
Red = Oxygen
Grey = Silicon
Green = Chlorine
TYPES OF PSM AND HOW THEY WORK
“Like Dissolves Like”
(i.e., contaminants
dissolve into the polymers)
PCB molecule
25th
24th Annual NARPM Training Program 14
Pore water
Passive Sampler
(e.g., PE, POM, SPME) Initial concentration of PCBs in
passive sampler = 0 ng/g
PCB molecule (Cfree form)
TYPES OF PSM AND HOW THEY WORK
25th
24th Annual NARPM Training Program 15
Deployment Time (days)
Concentr
ation
(ng/g
Passiv
e S
am
ple
r)
Equilibrium Sampling
TYPES OF PSM AND HOW THEY WORK
0 30
25th
24th Annual NARPM Training Program 16
Deployment Time (days)
Concentr
ation
(ng/g
Passiv
e S
am
ple
r) = Equilibrium *
√
√
√
Equilibrium Sampling
TYPES OF PSM AND HOW THEY WORK
Cfree is the freely dissolved concentration
of a contaminant (ng/mL),
CSampler is the passive sampler
concentration (ng/g),
KSampler-free is the passive sampler-
dissolved partition coefficient (mL/g)
Freely Dissolved
Concentration (Cfree)
freeSampler
Sampler
free K
CC
0 30
25th
24th Annual NARPM Training Program 17
TYPES OF PSM AND HOW THEY WORK
Number of peer-reviewed publications by PSM
25th
0
5
10
15
20
25
Nu
mb
er
of P
ub
lica
tio
ns
Year
Polydimethylsiloxane
Polyoxymethylene
Polyethylene
0
5
10
15
20
25
Nu
mb
er
of P
ub
lica
tio
ns
Year
DGT
Polydimethylsiloxane
Polyoxymethylene
Polyethylene
24th Annual NARPM Training Program 18
Superfund sites where PSMs have been used (Updated 2 November 2017):
Allegany Ballistics Laboratory (Region 3)
Aniston PCB (Region 4)
Berry’s Creek (Region 2)
Brodhead Creek (Region 3)
Columbia Slough (Region 10)
Dover Gas Light (Region 3)
Diamond Alkali (Region 2)
Grand Calumet (GLNPO-Region 5)
Grasse River (Region 2)
Lake Hartwell (Region 4)
Lower Duwamish Waterway (Region 10)
Manistique River (Region 5)
McCormick and Baxter (Region 10)
TYPES OF PSM AND HOW THEY WORK
√
25th
Metal Bank (Region 3)
MW Manufacturing (Region 3)
Naval Station Newport (Region 1)
New Bedford Harbor (Region 1)
Ordot Landfill (Region 9)
Pacific Sound Resources (Region 10)
Palos Verdes Shelf (Region 9)
Portland Harbor (Region 10)
San Jacinto Waste Pits (Region 6)
Tennessee Products (Region 4)
United Heckathorn (Region 9)
Whitmoyer Laboratories (Region 3)
Wyckoff (Region 10)
24th Annual NARPM Training Program 19
Passive
Sampler
(PE or POM)
(1) Solvent Cleaning
(~24 hours)
(2) Deployment and
Recovery (~ 30 days)
(4) Solvent Extraction (48 hours) (6) GC/MS Analysis and
Data Interpretation (5) Volume reduction (~ 1 hour)
(3) Storage
(-4 ˚C wrapped
in foil)
PREPARING, DEPLOYING,
RECOVERING, AND STORING PSM
25th
24th Annual NARPM Training Program 20
Water Column Deployment
(NHEERL & MIT)
PE
Stainless steel ring
SPME (in copper
mesh envelope)
PE POM
(NHEERL & Brown U)
Fish trap
PREPARING, DEPLOYING,
RECOVERING, AND STORING PSM
25th
24th Annual NARPM Training Program 21
Water Column Deployment
PREPARING, DEPLOYING,
RECOVERING, AND STORING PSM
25th
24th Annual NARPM Training Program 22
Pore water Deployment
(SCCWRP)
Copper tubing
housing SPME (in
protective syringe)
SPME (in protective syringe) (Texas Tech U)
SPME (inside
stainless steel tube)
(Technical U Denmark)
PREPARING, DEPLOYING,
RECOVERING, AND STORING PSM
25th
24th Annual NARPM Training Program 23
PE or POM (in aluminum frame)
Pore water Deployment
(MIT)
PE or POM (in aluminum frame)
(MIT)
PREPARING, DEPLOYING,
RECOVERING, AND STORING PSM
25th
24th Annual NARPM Training Program 24
PREPARING, DEPLOYING,
RECOVERING, AND STORING PSM
(U Maryland Baltimore County)
Pore water Deployment
POM
(in wire mesh
enclosure)
25th
24th Annual NARPM Training Program 25
Pore water Deployment
PREPARING, DEPLOYING,
RECOVERING, AND STORING PSM
25th
24th Annual NARPM Training Program 26
OSRTI’s Environmental Response Team Dive Team & Region 10’s Dive Team
have extensive experience deploying and recovering passive samplers – cost-
effective resource
(MIT
& R
egio
n 9
)
Diver-assisted
sediment deployment
(United Heckathorn
Superfund Site)
Pore water
Deployment
PREPARING, DEPLOYING,
RECOVERING, AND STORING PASSIVE
SAMPLERS
25th
24th Annual NARPM Training Program 27
(NHEERL )
(NH
EE
RL )
PE and POM
(in aluminum frames)
SPME in copper tubing Porewater Deployment (Palos Verdes Shelf Superfund Site)
PREPARING, DEPLOYING,
RECOVERING, AND STORING PSM
25th
24th Annual NARPM Training Program 28
Raw data (from the analytical laboratory)
Measured concentration of contaminants in the passive sampler (CSampler)
• Units
– ng/g sampler
– ng/mL sampler (convert to µg/g sampler by dividing by the passive sampler density (e.g., PE = 0.92 g/mL))
Calculate contaminant freely dissolved concentration (Cfree) (ng/mL):
ANALYZING PSM DATA
freeSampler
Sampler
free K
CC
25th
24th Annual NARPM Training Program 29
Establishing when equilibrium between the contaminants and passive sampler occurs
Challenge in all monitoring (including biomonitoring)
Potentially expensive to determine (i.e., extra samples = $$$) • Perform time series (e.g., collect PSM weekly for 30 days)
• Compare different thicknesses of PSM
One approach: Performance Reference Compounds (PRCs) loaded into the passive sampler to predict equilibrium
• PRC is a chemical that behaves like the target COC
Deployment Time (days)
Co
nce
ntr
atio
n
(ng
/g P
assiv
e S
am
ple
r)
* = Equilibrium
ANALYZING PSM DATA
25th
24th Annual NARPM Training Program 30
Pore water
Passive Sampler
(PE, POM or SPME) Initial concentration of 13C-PCBs in
passive samplers is known
PCB (Cfree form)
13C-PCB
(used as
the PRC)
ANALYZING PSM DATA
25th
24th Annual NARPM Training Program 31
Deployment Time (days)
Concentr
ation
(ng/g
Passiv
e S
am
ple
r)
0 30
ANALYZING PSM DATA
25th
24th Annual NARPM Training Program 32
PCB
PRC
Magnitude of adjustment for
non-equilibrium conditions
Step 1
Step 2
First Order Method: Two Step Process
t
C
C
kf
i
PRC
PRC
e
ln
where, ke is the
exchange rate coefficient
for a given PRC, PRCi and PRCf
are the initial and final PRC
concentrations, and t is the
deployment duration
freeSampler
Sampler
free K
CC
tk
freeSampler
Sampler
free eeK
CC
1*
Deployment Time (d)
Concentr
ation
(ng/g
passiv
e s
am
ple
r)
ANALYZING PSM DATA
Two other methods:
- Diffusion-based
- Rate of PRC diffusion through polymer is used to determine
magnitude of disequilibrium correction for target contaminants
- Exchange rate-based
- PRC data used to calculate disequilibrium-corrected exchange rates
for target contaminants
- Both methods are very calculation intensive and are available on
computer-based graphical-user interfaces (GUIs) or spreadsheets
- GUIs available on-line
- Superfund website
- SERDP/ESTCP websites
25th
24th Annual NARPM Training Program 33
Measuring COC bioavailability
Using PSM as surrogates for organism bioaccumulation
Bioavailability assessments:
Passive Sampler (e.g., POM,
PE or SPME)
?
= Blue Mussels Benthic Worms
EVALUATING PSM APPLICATIONS
Friedman et al. (2009)
Bioaccumulation = 0.948*PSM Uptake + 1615
r2 = 0.88
n = 48
New Bedford Harbor Superfund Site
(Laboratory deployment)
Burgess et al. (2015) Joyce et al. (2016)
► When applied properly, passive sampling based
estimates of bioaccumulation may provide useful
information for making informed decisions about the
bioavailability of COCs in aquatic environments
25th
24th Annual NARPM Training Program 34
Determining COC Flux
Using PSM to measure transport of COCs between sediments and water column
EVALUATING PSM APPLICATIONS
Sediment & Pore water
Water Column
De
pth
(cm
)
20
15
10
5
-5
-10
-15
-20
Sediment & Pore water
Water Column
Magnitude of transfer
to water column
Cap effectiveness Cap
25th
24th Annual NARPM Training Program 35
Recover passive sampler
EVALUATING PSM APPLICATIONS
1
3
2
25th
24th Annual NARPM Training Program 36
(NHEERL )
(NH
EE
RL )
Platform when deployed
EVALUATING PSM APPLICATIONS
Flux = 260 ng
p,p’-DDE/cm2 y
Superfund Sites:
Palos Verdes Shelf (Region 9)*
Lower Duwamish Waterway
(Region 10)
Grasse River (Region 2)
Dover Gas Light (Region 3)
Palos Verdes Shelf Superfund Site
25th
24th Annual NARPM Training Program 37
EVALUATING PSM APPLICATIONS
Derived from
Passive Sampling
25th
24th Annual NARPM Training Program 38
Passive sampling provides data on: Freely dissolved concentrations (Cfree) of COCs
- Effective surrogate for bioavailable contaminant concentrations
Concentration of COCs in the passive sampler Approach operates based on the well-understood principles of equilibrium
partitioning and sampling
Preparation, deployment, recovery and storage are no more complicated than current contaminant sampling methods Possibly greater scientifically-robustness, logistically simpler, and more
cost-effective
Applications Assessing COC bioavailability Measuring COC fluxes Developing Pore Water Remedial Goals (PWRGs)
√
SUMMARY
√
√
25th
24th Annual NARPM Training Program 39
Useful documents https://semspub.epa.gov/work/HQ/175405.pdf (2012)
http://www.epa.gov/nheerl/download_files/publications/
RB%20ESB%202012final_2.pdf (2012)
Society of Environmental Toxicology and Chemistry journal:
Integrated Environmental Assessment and Management
2014 Series (Six papers on passive sampling) (2014)
https://semspub.epa.gov/work/HQ/100000146.pdf (2017)
https://semspub.epa.gov/work/HQ/100000539.pdf (2017)df
SUMMARY
EPA/600/R-16/357
Laboratory, Field, and Analytical Procedures for Using Passive Sampling in the Evaluation of Contaminated Sediments: User’s Manual
February 2017 Final Web Version (1.0)
25th