Integrating Chemical Measures of Hydrocarbon Bioavailabilty ......and Toxicity in MGP Site Sediments Sediment Total PAH Concentration (mg/kg dry wt.) Percent Survival (%) 0 20 40 60

Integrating Chemical Measures of Hydrocarbon Bioavailabilty into Risk-Based Management Strategies for Sediments

Joe Kreitinger and David Nakles The RETEC GroupNovember 10th, 2005

Can We Improve Technical Framework for Sediment Management?

Generic Site Specific

Look-Up Sediment Screening

Value

Chemical Tests to Predict Bioavailability

and Toxicity

Directly Measure

Bioavailability & Toxicity

Quality of Information

Uncertainty Confidence

Value of Improving Chemical Predictors of Sediment Toxicity

• Better information for remedial decision-making• Prioritize where resources are spent• Expedite site closures• Reduce costs

• More focused monitoring methods• Residuals following dredging• Long-term monitoring of caps • MNA evaluation

Assessing the Bioavailability of PAHsin Soils and Sediments

How did we get here? • Gas Research Institute: bioavailability research initiated in

1993• Published “Red Book”• Petroleum Environmental Research Forum study

followed• Conclusion: Bioavailability is important concept but

more carefully integrated studies were needed

• Two follow-on industry supported research programs initiated in 1997:• CA human health study: Lampblack-impacted soils

($1MM)• NY ecological study: PAH-impacted soils/sediments

(~ $3 MM)

Significant Collaborative Research with Academic and National Laboratories

Characterizing bioavailability and toxicity of PAHsin MGP site soils/sediments since 1993

• The RETEC Group (Ithaca, NY; Pittsburgh, PA)

• Gas Research Institute (Chicago, IL)

• Lawrence Berkeley National Laboratory (Berkeley, CA)

• Cornell University (Ithaca, NY)

• Stanford University (Palo Alto, CA)

• University of Texas (Austin, TX)

• University of North Dakota (Grand Forks, ND)

• Ohio State University (Columbus, OH)

• University of Maryland, (Baltimore, MD)

• US Army Engineering Research & Development Center

Approaches for Assessing Bioavailability

• Characterize carbon-types and assign carbon-specific partitioning coefficients?

• Determine sediment pore water chemical concentrations

• Use direct measurements of chemical release to predict bioavailability

• Directly measure uptake and toxicity to organisms directly

Survey of Hudson River Sediments Demonstrated Presence of Natural and Anthropogenic Carbon

wood lignite bituminous anthracite coal oxidized coalcoal

charcoal coke soot carbon coal tar pitch cenosphere

PAH binding (Koc) is very different for different types of carbon

(U. Ghosh et al. , 2003)

Two Chemical Methods have been Developed and Evaluated

• Solid Phase Micro Extraction (SPME)• Measures the dissolved concentration of PAHs in sediment pore water

• Supercritical Fluid Extraction (SFE)• Measures the release of PAHs in sediment samples

Do these measurements correlate to bioavailability?

Site Specific Information

• TOCNatural carbonAnthropogenic

• Correct KOC?• SPME Porewater Conc• SFE Rapidly Released Conc

Soil/Sediment Concentration

Equilibrium Partitioning Model

Biota Exposure

Hydrocarbon Narcosis Model

Toxicity Endpoint

Procedures for the

Derivation of

(EPA 2003)

Sediment Benchmarks: PAH Mixtures

Site Specific Measures Of Chemical Availability Reduce Uncertainty In Predicting Exposure

Solid Phase Microextraction (SPME) of Pore Water

• Uses sorbent microfiber• Accurately measures PAHs in pore water• Rapid – 30 minutes• Small sample size required

~ 20 ml of sediment~ 1.5 ml of pore water

• Very low detection limit~ pg/mL (ppt)

(Hawthorne et al., 2005b)

SPME Fiber Injection into GC/MS

Conventional EPA water analysis methods would require liter(s) of sediment pore water to achieve similar sensitivity

Detection limits for representative PAHs

EPA 8270 EQL

1 liter water

10 µg/l

10

10

10

10

SPME

1.5 ml water

0.5 µg/l

0.2

0.01

0.005

0.002

Naphthalene (2-ring)

Phenanthrene (3-ring)

Chrysene (4-ring)

Benzo(a)pyrene (5-ring)

Benzo(g,h,i)perylene (6-ring)

Why is SPME so much more sensitive for larger PAHs?All molecules collected by SPME are transferred to the GC

For 8270 only ca. 0.1% are injected

(Hawthorne et al. , 2005b)

Supercritical Fluid Extraction (SFE) of Sediments

• Extraction Conditions• Liquid CO2,200 atmos, 50◦C•40 minutes extraction

• Advantages• CO2 polarity is similar to lipids• Release rates correlate to water desorption• Solubility of PAHs in CO2 is proportional to their solubility in water• Little effect on OM matrix• Can be easily calibrated to biological uptake

(Hawthorne, 2002)

Illustrative SFE Release Curve for PAHs

0 30 60 90 120 150 180Time (Minutes)

0

0.2

0.4

0.6

0.8

1.0

F = Fraction of Chemical Rapidly Released at 40

minutes

Frac

tion

Of P

AH

Rel

ease

dD

urin

g SF

E Ex

trac

tion

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80 100 120

Rapidly Released Fraction (F) can Vary Significantly Between Samples

SFE Extraction Time (min)

Total PAH Release Using SFE

Perc

ent E

xtra

cted

(%)

F = 0.75F = 0.75

F = 0.12F = 0.12

Soil HP3 (3,970 mg/kg)Soil HP3 (3,970 mg/kg)

Soil HP12 (3,030 mg/kg)Soil HP12 (3,030 mg/kg)

(Kreitinger et al. 2005)

Field Surveys and Case Studies to Assess Tools for Predict Bioavailability

Hyalella azteca28-day chronic toxicity

Chironomus tentans10-day acute toxicity

Cooperative Research and Development Agreement (CRADA) U.S. Army Corps of Engineers

Center for Contaminated Sediments

Generic Assessment Protocol Using Amphipods as Standard Sensitive Test Organisms

(EPA 2003)

1

10

100

1000

0 20 40 60 80 100

Test

Org

anis

m M

ean

Acu

te V

alue

(µ

mol

e PA

H /

g lip

id)

% Rank of Tested Organisms

Hyalella Chironomus

Leptocheirus19.0 µmole/g lipid is toxic to Leptocheirus – Marine test species13.9 µmole/g lipid is toxic to Hyalella –Freshwater test species

There is No Relationship Between [PAH] and Toxicity in MGP Site Sediments

Sediment Total PAH Concentration (mg/kg dry wt.)

Perc

ent S

urvi

val (

%)

0

20

40

60

80

100

120

1 10 100 1000 10000

Nontoxic Sediment

Toxic Sediment

EPA Hyalella azteca 28-day Test

0

20

40

60

80

100

120

1 10 100 1000 10000

BL Control - H. azteca BL - H. aztecaBL Control - C. tentans BL - C. tentansNY Control - H. azteca NY - H. azteca

High total PAHs did not exhibit toxicity to H. azteca or C. tentans at an Aluminum Smelter Site

Perc

ent S

urvi

val (

%)

Sediment Total PAH Concentration (mg/kg)

H. H. aztecaaztecaPitchPitch--spiked Control spiked Control

(51 mg/kg)(51 mg/kg)

C. C. tentanstentansPitchPitch--spiked Controlspiked Control

(~60 mg/kg)(~60 mg/kg)

Toxicity to H. azteca Can be Predicted by Estimating PAHs in Porewater

0

20

40

60

80

100

120

0.001 0.01 0.1 1 10 100

Nontoxic Sediment

Toxic Sediment

SPME Pore Water PAH Conc. (µmoles/L)

Surv

ival

(%

)

NONTOXIC TOXIC

EPA Hyalella azteca 28-day Test

Toxicity to H. azteca Can be Predicted by Estimating SFE Rapidly Released PAHs

SFE Rapidly Released PAHs (mmoles/kg TOC)

Surv

ival

(%

)

0

20

40

60

80

100

120

0.01 0.1 1 10 100 1000 10000

Nontoxic Sediment

Toxic Sediment

NONTOXIC TOXIC

EPA Hyalella azteca 28-day Test

Integration Within Risk-Based Decision Making

• Use Simple Screening Tools:• To focus toxicity testing• Appropriate for the size of the problem

• Implement Case-Studies:• Assure appropriate toxicity endpoints• Gain regulatory acceptance

1. Anticipated Approach Using Sediment Contaminant Bioavailability Assessment (SCBA)

No Further Action

Predict Nontoxic

No Further Action

Predict Toxic

Address

Predict Toxic

Address

No Further Action

No

Yes Uncertain Toxicity

> Background PAH

YesChemistry Screen

Fails for Total PAHs

No

SPME/SFEChemistry

Screen

Amphipod Toxicity Test

Predict Nontoxic

No Further Action

2. Anticipated Approach Using Sediment Contaminant Bioavailability Assessment (SCBA)

Predict Toxic

Address

Predict Nontoxic

No Further Action

Uncertain Toxicity

SPME/SFEChemistry

Screen

Four case studies are on-going to answer the

question:

“How well does the SPME/SFE chemistry screen predict toxicity

to amphipods?”

3. Anticipated Approach Using Sediment Contaminant Bioavailability Assessment (SCBA)

Predict Toxic

Address

Amphipod Toxicity Test

Predict Nontoxic

No Further Action

Additional studies will be required to answer:

“How well does the amphipod toxicity testing predict toxicity to other

aquatic life?”

Soil/Sediment Bioavailability Program

Interaction with regulatory agencies is key

• Conduct technical workshops to key State Regulatory Agencies and EPA

• New York DEC and DOH• New Jersey DEP• California EPA

• Developed Five-Year to Support Integration of Bioavailability Concepts into Federal and State Regulatory Guidance

Sediment Bioavailability Program

Major Program Tasks• Task 1 - Conduct Case Studies• Task 2 - ASTM/EPA Approval of Analytical Methods• Task 3 - Technology Transfer

• Conferences• Peer-Review Publications

• Task 4 – Support Regulatory Guidance Development by EPA and ITRC• Task 5 - Communication and Coordination

Proposed Alliance Sediment Contaminant Bioavailability Program

Industry Alliance

Case Studies(Task 1)

• Utility Industry• Aluminum Industry• Steel Industry?• Others …..?

Program Support(Tasks 2-5)

2. Analytical Methods3. Technology Transfer4. Regulatory Guidance Support5. Alliance Communication & Coordination

Program Advisory Board (PAB)

Project ManagerRETEC

Science Advisory Board (SAB)

Current Members

Interested Parties

Sediment Contaminant Bioavailability Alliance

Multi-Industry Approach to Move Forward

CASE STUDIES/ State Regulatory

Participation

Utility Aluminum Petroleum Navy Industry Industry Industry Industry DOD Support

COMMUNICATIONPeer Reviewed Technical Publications

Synthesis Report for ITRC

IMPLEMENTATION

ITRC Industry/Gov’tAnalysis Support

EPA and/or ASTM Standard Method

Development

Presentation Summary

• Simple screening tools are needed whichare appropriate for small “everyday” projects• Interaction with state regulatory agenciesis required to define “risk endpoints” requiring protection• Case studies are necessary for gainingacceptance and to evaluate the effect of bioavailability data on sediment management