[PPT] - Passive Sampling for Measuring Freely Dissolved Contaminants in PowerPoint Presentation

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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

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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

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(1) Freely dissolved concentrations (Cfree) of contaminants

f 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

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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

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WHY DO WE CARE ABOUT THE FREELY DISSOLVED CONCENTRATION (CFREE)?

Sediment Concentration (mg Kepone/Kg sediment (dry)) Midge Survival (%)

1.5% Organic carbon/Kg sediment (dry) 12.3 % Organic carbon/Kg sediment (dry)

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Water Column Food What media is an effective surrogate for exposure to bioavailable chemicals? Sediment

50 100 20 40 80 60

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WHY DO WE CARE ABOUT THE FREELY DISSOLVED CONCENTRATION (CFREE)?

Freely Dissolved Concentration (Cfree) (µg Kepone/L Pore water) Midge Survival (%)

1.5% Organic carbon/Kg sediment (dry) 12.3 % Organic carbon/Kg sediment (dry)

50 100 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

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Pore Water Concentration (µg Kepone/L Pore water) Freely Dissolved 25th

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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

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Atmosphere Water Contaminated Sediments Freely Dissolved Concentration (Cfree)

Diffusion/Advection

Freely Dissolved Concentration (Cfree)

WHY USE PSM AND WHAT THEY TELL US

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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

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24th Annual NARPM Training Program 9 Time (days) Freely Dissolved Pore water Concentration (Cfree) (ng/L)

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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?

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Atmosphere Water Contaminated Sediments Freely Dissolved Concentration (Cfree) Atmosphere Water Contaminated Sediments

TYPES OF PSM AND HOW THEY WORK

(Cfree)

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Polyethylene (PE) Polyoxymethylene (POM)

PE

25 - 50 µm thick

POM

75 µm thick

TYPES OF PSM AND HOW THEY WORK

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0.25 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

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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

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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

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24th Annual NARPM Training Program 15 Deployment Time (days) Concentration (ng/g Passive Sampler)

Equilibrium Sampling

TYPES OF PSM AND HOW THEY WORK

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24th Annual NARPM Training Program 16 Deployment Time (days) Concentration (ng/g Passive Sampler) = Equilibrium

*

√ √ √ Equilibrium Sampling

TYPES OF PSM AND HOW THEY WORK

Cfree is the freely dissolved concentration

f 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)

free Sampler Sampler free

K C C





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TYPES OF PSM AND HOW THEY WORK

 Number of peer-reviewed publications by PSM

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5 10 15 20 25 Number of Publications Year Polydimethylsiloxane Polyoxymethylene Polyethylene 5 10 15 20 25 Number of Publications Year DGT Polydimethylsiloxane Polyoxymethylene Polyethylene

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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

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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)

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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

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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

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Water Column Deployment

PREPARING, DEPLOYING, RECOVERING, AND STORING PSM

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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

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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

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PREPARING, DEPLOYING, RECOVERING, AND STORING PSM

(U Maryland Baltimore County)

Pore water Deployment

POM (in wire mesh enclosure) 25th

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Pore water Deployment

PREPARING, DEPLOYING, RECOVERING, AND STORING PSM

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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 & Region 9)

Diver-assisted sediment deployment (United Heckathorn Superfund Site)

Pore water Deployment

PREPARING, DEPLOYING, RECOVERING, AND STORING PASSIVE SAMPLERS

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(NHEERL ) (NHEERL )

PE and POM (in aluminum frames) SPME in copper tubing

Porewater Deployment

(Palos Verdes Shelf Superfund Site)

PREPARING, DEPLOYING, RECOVERING, AND STORING PSM

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 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

free Sampler Sampler free

K C C





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 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) Concentration (ng/g Passive Sampler)

* = Equilibrium

ANALYZING PSM DATA

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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

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24th Annual NARPM Training Program 31 Deployment Time (days) Concentration (ng/g Passive Sampler) 30

ANALYZING PSM DATA

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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 k

f 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

free Sampler Sampler free

K C C





 

t k free Sampler Sampler free

e

e K C C

 

  1 *

Deployment Time (d) Concentration (ng/g passive sampler)

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

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 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

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 Determining COC Flux

Using PSM to measure transport of COCs between

sediments and water column

EVALUATING PSM APPLICATIONS

Sediment & Pore water Water Column

Depth (cm)

20 15 10 5

5
10
15
20

Sediment & Pore water Water Column Magnitude of transfer to water column Cap effectiveness Cap

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Recover passive sampler

EVALUATING PSM APPLICATIONS

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(NHEERL ) (NHEERL )

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

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

EVALUATING PSM APPLICATIONS

Derived from Passive Sampling 25th

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 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)

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SUMMARY

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 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

f Contaminated Sediments:

User’s Manual

February 2017 Final Web Version (1.0)

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