sheen characterization 2009 data and observations july 2010 progress meeting mccormick & baxter...
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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
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