23 rd Annual NARPM Training Program Passive Sampling Case Study: United Heckathorn Superfund Site...

23rd Annual NARPM Training Program

Passive SamplingCase Study: United

Heckathorn Superfund SiteRachelle S. Thompson, MS, PE

US EPA Region 9

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Presentation Outline

Site location and background Past remedial actions Current conditions Feasibility study Passive sampler deployments Preliminary results Next steps

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United Heckathorn Superfund Site

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Site Location

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Cleanup History

Initial response (1990-1998) 3,300 cubic yards of DDT-contaminated

soil removed from upland area Dredged 107,000 cubic yards of

contaminated sediment (3 tons DDT) from Lauritzen Channel and Parr Canal

Capped upland area with concrete to prevent erosion

Monitoring and additional investigations Sampling of fish, mussels, sediment, and

water Five Year Reviews in 2001, 2006, and

2011

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Current Status The upland cap remains intact

and protective. DDT levels in the Inner

Richmond Harbor, Santa Fe Channel and Parr Canal have decreased significantly.

DDT levels in Lauritzen Channel pose a potential long-term risk to human health through consumption of fish.

DDT levels in Lauritzen Channel pose a potential ecological risk to fish-eating birds and mammals.

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Mussel Trends

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Feasibility Study

Tier 1 Sediment Study

Tier 2 Sediment Study

Source Identification Study

DDT Fate & Transport Study

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Tier 1 Sediment Study

Multi-beam and side-scan sonar create images of the channel bottom

Areas of deposition and erosion of sediment

Natural and anthropogenic forces

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Tier 2 Sediment Study Current and turbidity

monitoring Particle tracking Sediment erosion

analysis Sediment transport

modeling

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Source Identification Study

Groundwater Embankments and seeps Pilings Undredged sediments Other sources

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DDT Fate & Transport Study

Passive samplers Sediment cores Trends Sources and sinks

Approximately 66,000 yd3 of contaminated sediment in Lauritzen Channel

Approximately 350 kg of DDT in those sediments

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Passive Sampling Goals Evaluate spatial distribution of contamination Evaluate contaminant fate & transport and

potential sources Evaluate long-term monitoring options

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Types of Passive Samplers

Sediment: Polyethylene mounted in metal frame

Surface water: Polyethylene strips in mesh bag, co-deployed with mussels

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Sampling Locations Sediment locations: 2012

(purple) and 2013 (green) Water locations (additional

background point not shown)

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Deployment and Recovery September-October

2013 ERT dive team support

for sediment samplers Surface water samplers

deployed from boat

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PE

target

PRC

co

ncen

tra

tion

sediment porous medium

sediment porous medium

DPE DSED DSED

PE

target

PRC

co

ncen

tra

tion

0

position

sediment porous medium

sediment porous medium

KPESED

target PRCs target

at time = 0

Cpe = 0 for targets

at some later time, t measure PRC losses and Cpe(t) use results to find Cpe(t = ∞)

D

D D

D

D

D

DD

D

D

D

D D

D

D

D

DD

D

D

Performance Reference Compounds

Laboratory method: Gshwend, P. et al, Passive PE Sampling in Support of In Situ Remediation of Contaminated Sediments: Standard Operating Procedure for PED Preparation, December 2012.

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Field Challenges Shutdown Boat logistics Poor visibility Channel depth Active channel

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4,4’-DDD, 4,4’-DDT, and 4,4’-DDE with depth into bed (ng/g PE)DDD dominant

4,4’-DDD 4,4’-DDE

4,4’-DDT

Vertical Chemical Profiles

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Spatial Distribution

Bottom water and pore water concentrations (ng/L 4,4’-DDD)

Strong gradient down channel

Every channel station has porewater > bottomwater

Bed-to-water column fluxes

Gschwend

2013 modelingporewater conc’s

section 4 >1000 ng/L

section 3100 to 1000 ng/L

section 210 to 100 ng/L

section 1~ 10 ng/L

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Simple Mass Balance Estimate

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Site Monitoring- 2012

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Site Monitoring- 2013

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Surface Water

Filtered water PE-inferred

water concentration

Mussel- inferred water concentration

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Preliminary Conclusions

Porewater DDx concentrations are highest in the northern reach of the channel

There is a high degree of uncertainty in the mass balance modeling, but there appears to be an ongoing source mid-channel

Water-column passive samplers could potentially be used for long-term monitoring at the site

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Next Steps

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Acknowledgements

CH2MHILL- Brenda McConathy, Patricia White E2- Tamara Frank EPA Region 9 Lab- Andy Lincoff ERT Dive Team – Steve Blaze, Alan Humphrey,

Scott Grossman, Chris Gallo, John McBurney Massachusetts Institute of Technology- Phil

Gshwend, Patricia Tcaciuc Sea Engineering Inc.- Craig Jones US Army Corps of Engineers- Karl Gustavson,

Earl Hayter

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Questions?

Additional information epa.gov/region09/unitedheckathorn

Contact information Rachelle S. Thompson, MS, PE

Superfund Division US EPA Region 9 75 Hawthorne Street, SFD-7-3 San Francisco, CA 94105 415-972-3962 thompson.rachelle@epa.gov