Sheen Characterization

2009 Data and Observations

July 2010 Progress Meeting

McCormick & Baxter Superfund Site

Portland, Oregon

Sheen Characterization Presentation

• Objectives – Identify Nature of Sheen• Previous Investigations Summary• 2009 Sheen Characterization Activities and Results

– Chemical– Biological (Dr. Anne Camper)

• Conclusions and Recommendations

– Shallow contour maps– Hydrographs– Gradients

2007 Sheen Investigations

• Focused on area surrounding large Reactive Core Mat and shoreline in the TFA – June

• Time-series sampling in September

2008 Sheen Investigations• Sheen with water, adjacent surface

water, and sediment with sheen were collected from 4 locations along the shoreline

• Concentrations of low molecular weight similar to those in surface water were detected in the sheen with water

• Sheen appeared blocky and iridescent in appearance; did not re-coalesce upon probing

2008 Investigation Tasks• SPME, sediment cores, and porewater samples

• 10 co-located flux chamber samples

• Biodegradation study on cores

• Survey of locations and rates of ebullition through tidal cycle and season

• Continued shoreline documentation of sheen

• Sampling of sheen (July 2008)

Sampling Locations

Overall Conclusions 2008

• Organoclay retains its full sorption capacity – both OC mats and granular

• Permeability remains near fresh organoclay (similar to sand)

• HEM fraction higher in ET-1 – likely reason for enhanced microbial activity in bulk granular organoclay

• Porewater concentrations generally below comparison criteria

• No evidence that sheens are caused by creosote migrating from beneath the cap

Overall Conclusions 2008 (cont.)

• Sediment concentrations in cap below cleanup goals

• Sheen concentrations comparable to ambient surface water

• Ebullition is a pathway for contamination – however, below comparison criteria with exception of low level cPAHs thought to be particulate matter

• Sheen origin remains unknown

2010 Characterization Activities

• Shoreline Sheen Observations

• Sheen Simulation with Site Product

• Sheen Sampling– Chemistry– Biological

Sheen Simulation

• Method with pipette and pan• Sheen was sampled similarly to the field sampling – by passing a

Teflon® net and pad through the sheen (ASTM D4489)

More Photos

Sheen Sampling

Methods• Sheen

– Teflon nets and pads (ASTM 4489)- used to collect sheen samples from surface water. Each pad/net used daily at same location for four days to obtain sufficient sheen on pad/net.

– C-18 cartridges – know volume of sheen with water was pumped through C-18 cartridge.

• Ambient Water – peristaltic pump

Samples sent to Pace for Analytical and Dr. Anne Camper/MSU for biological analysis

Sampling Locations

Chromatograms

25,000 g Total PAHs

<0.59g Total PAHs

0.918g Total PAHs

Simulated Sheen

Actual Site Sheen - TFA

Blank Net

Analytical Results

Teflon® Net/Pad• Iron/Mg was concentrated in sheen (54X - sheen/9X -

water)• PAHs were not detected in sheen (exception: fluorene

was estimated in 2 samples)

C-18 Method• Method comparable for water and sheen• PAHs (acenaphthene, acenaphthylene, fluorene, and

naphthalene) detected at slightly higher concentrations in water than in sheen samples.

Chemistry Conclusions

• Collection method robust

• Chromatograms demonstrate sheen is very different from a site product sheen

• Iron concentration in sheen (in creosote sheen – chromium is the highest concentration metal -0.11XMg)

• PAH concentrations detected with C-18 cartridge reflective of water concentrations (nets and pads will not sorb dissolved PAHs from water)

Microbiology Methods

• Samples of parallel water and mesh

• Heterotrophic plate counts

• Extracted DNA and population analysis

• Microscopy

Heterotrophic Plate Counts

• Water counts from 10^4 to 10^5/ml

• Mesh counts from 10^6 to 10^8/meshSheen had associated bacteria

• No major difference between two samplings

• No differences in colony morphologies

Denaturing Gradient Gel Electrophoresis

• Targeted 16S rDNA

• Each band ~ one species

• No substantial differences

TFA28-13-09

Water Mesh

Microscopy

• Staining methods to determine if sheen was created/stabilized by bacteria

• Emphasis on morphologies typical of iron oxidizing bacteria

• Mesh samples inconclusive for bacteria; sheen not formed by bacterial biofilms or iron bacteria

Overall Conclusions-Sheen Characterization

• 2009 characterization work support the previous sheen sampling results, porewater sampling results, and core sampling results from 2007 and 2008

• General shoreline sheen in late summer/early fall are not due to sheen migrating through the sediment cap

• Sheen appears to be a non-biological iron concentration