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Remediation Strategies for Pine Street Barge Superfund Burlington, VT

Remediation Strategies for Pine Street Barge Superfund Burlington, VT. Review of Human and Ecological Risk Related to Contaminants, Containment Measures and Potential Remediation Strategies. Meghan Montgomery, Lisa Fredette, and Noelle Bramer. History of Pine Street Barge.

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Remediation Strategies for Pine Street Barge Superfund Burlington, VT

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  1. Remediation Strategies for Pine Street Barge SuperfundBurlington, VT Review of Human and Ecological Risk Related to Contaminants, Containment Measures and Potential Remediation Strategies Meghan Montgomery, Lisa Fredette, and Noelle Bramer

  2. History of Pine Street Barge 1906-1966: Coal Gasification Plant 1960-1970: Landfill construction debris, manufacturing wastes 1983: EPA listed site Superfund National Priorities 1985: 500 cubic yards excavated, solidified, disposed Clay lining/sand cap applied on top and underwater 2006: First five year review of remedial actions (EPA, 2010) (EPA, 2006).

  3. Problem Statement • Five Year Review of the Pine Street Barge Canal • Despite capping of contaminated sediment in canal and wetlands - coal tar leaks • EPA concluded that capping of coal tar is not effective for long term management • Long term solution evaluated • Eliminate releases of coal tar into surface waters of canal and adjacent areas • Prevent spread to Lake Champlain • Prevent completion of exposure pathways • Remove threat to ecological and human health (EPA, 2006)

  4. Goals/Objectives • Assess conditions at Pine Street Barge Canal at present • Consider the nature of the contaminants • Local geology • Current control strategies • Review potential remediation strategies • No action option • Soil Washing • Bioremediation • Provide recommendations for action • Effective in removing pollutants • Minimize risk • Restore land for community use

  5. Approach • Research using search engines: • Science Direct • Academic Search Premier • Web of Science • GoogleScholar • Literature Reviewed • Abstract • Credibility • Tables/graphs • Geological survey presented at the New England Intercollegiate Conference

  6. Findings • Contaminants • Hydrocarbons: Benzene, Toluene, Ethylbenzene, Xylene • PAH compounds – Naphthalene • Cyanide • Exposure pathways • Ecological receptors on site • Receptors in Lake Champlain • Risk to human health

  7. Hydrocarbons: BTEX • Benzene • Toluene • Ethylbenzene • Xylene • Non-aqueous phase liquid • Surface water, groundwater , soil layers (EPA ROD, 1998)

  8. Benzene Toluene • Carcinogenic • Effects bone marrow • Hematological issues reported at 1ppm airborne • Lower evaporation rate • Mobility into groundwater (ASTDR, 2007) (Johnson et al., 2007) • Nervous System • Brain, liver and kidney damage • Volatilization to air • Sorption to organic matter (DEFRA, 2004) (NHDES, 2005) (ASTDR, 2006)

  9. Ethylbenzene Xylene • High ability to break down in air and surface water • Chronically affects blood • Possible human carcinogen (ASTDR, 2006) • Easily Evaporate • Inhalation and Skin contact • Central nervous system depression • Blood and liver damage (Clayton& Clayton, 1981) (MDSD, 2008) (TTNAT, 2007)

  10. Polycyclic Aromatic Hydrocarbons • Toxic for immune system and development • Complete carcinogens mutations in DNA proliferative capacity of mutated cells • Skin and eye irritants (Flowers et al., 2003) • Persist in environment for long periods of time • Natural and man-made sources • Naphthalene (University of Wisconsin, 2010)

  11. Cyanide • Contact: inhalation, absorption, ingestion • Effects: • Forms cytochrome oxidase in bloodstream • cannot use oxygen – hypoxia • Fish/aquatic invertebrates • Very sensitive to exposure: 5.0 – 7.2 micrograms/L • Reduces swimming performace • Inhibits reproduction (NYS, 2004) (CMC, 2006)

  12. Exposure Pathways (Menzie & Coleman, 2007)

  13. Danger: Foodchain • PAH in water, sediment • Benthic organisms: algae, mollusks, invertebrates • Do not metabolize = accumulate • Fish consume = health risks + biomagnification • People consume = health risks (Menzie & Coleman, 2007) (UKMSAC, 2001)

  14. Options for Remediation “No Action” Soil Washing Bioremediation

  15. “No Action Option” • Hydrogeology of Pine Street Barge • Site 70 acres between Lake Champlain and Pine Street • Boundaries - East by Pine Street, West by Vermont Railroad Track, North by Burlington Street Dept., South by Lakeside Avenue • Natural geology and hydrology protects lake and bedrock aquifer (Maynard, 1999)

  16. Geology • Surface: Protective Sand Cap • 20 feet peat saturated with coal tar waste • Center: • 45- 110 feet laminated silt/clay from Champlain Sea deposits and Glacial Lake Vermont • Base: • Coarse silty gravel from Wisconsin Ice Sheet • Quartzite bedrock • Structural faults (fractures) – aquifer (Maynard, 1999)

  17. Geological Protection • Base: structural faults form “steplike” benches of vertical walls and bedding planes slope 10-20o away from lake • Center: layered silt/clay deposits from Champlain Sea and Glacial Lake Vermont • Continuous over site • Very low hydraulic conductivity • 1,000’s years to infiltrate through • Hydrology: • Gradient (direction of water flow) is upwards • Limits migration (Maynard, 1999)

  18. Current Protection • Coal tar waste within 15-20 feet peat • Carbon matrix of soil on site binding capacity – limits bioavailability • plant’s cannot access PAH compounds • Buried beneath fill prevent bioaccessibility • Unlikely to come into direct contact with compounds • In canal • Buried in 5 feet sediment • Further restricted by submerged sand cap, land barrier between it and lake (Maynard, 1999)

  19. PAH Contamination Spread (EPA, 2006)

  20. Monitoring • Remedial Investigation 1994 • 100 monitoring wells, piezometers, 600 boring logs • Water quality testing – maximum contamination level reached one well on perimeter, none west/towards lake • Level of contamination in well stable – groundwater equilibrium • Public drinking supply – classified as Class IV (not suitable as potable) (Maynard, 1999)

  21. Sampling Wells (EPA, 2006)

  22. Despite Protective Measures • Capping Failures • Subaqueous caps Area 1 and 2 exceed EPA benchmarks for protection of on-site ecological communities • Spread to adjacent area 2003, canal in 2005 • Extension of capping, absorbent booms (EPA, 2006) • Research • Long-term caps undergo consolidation (sinking and compression) • Pore-water advection (migration) of pollutants outwards and upwards (Kim et al., 2009)

  23. From “No Action” Option • Pollutants appear in a static state, not moving towards the aquifer nor out to the lake. (Maynard, 1999) • BUT……… • Presence of contaminants represents long term risk • Potential for completion of exposure pathways • Hazardous substance above health-based levels – require 5 year reviews by EPA • Capping Failures • Canal hydrologically connected to Lake Champlain and subject to flooding • Consider effects have on human/ecological health • Long term remediation must be evaluated (EPA, 2006)

  24. Soil Washing • Why are PAHs hard to treat? • Low aqueous solubility • Bind to carbon matrix of soil • Not accessible to plants/bacteria for degradation (Menzie & Coleman, 2007) • How can soil washing help? • Surfactants – counteract these traits make PAH soluble and removable! • Widely available technology (Maturi & Reddy, 2008)

  25. Surfactants • Amphiphilic: hydrophobic tail, hydrophilic head • “Like attracts like.” • Hydrophobic tail attracts water-insoluble PAH • Brings compound into ring of tails – micelle • Hydrophilic head “sticks out” around perimeter • Water can interact with head, flush ring away • Process for removing compounds environmental priority (Gan et al., 2009)

  26. Steps for Soil Washing • Two step process • Desorption/removal of compound from binding site • Elution/flushing from fluid • Waste product captured in slurry mixture/bound to activated carbon for disposal • Other steps within • Screening, mixing, scrubbing, sieving • Role of Surfactants – increase effectiveness of system (Gan et al., 2009)

  27. Basics of Soil Washing (Diels & Gemoets, 1997)

  28. Surfactant Options • Combinations • 5% 1-pentanol - 10% water – 85% ethanol • 1g/100ml, extraction time 24 hours = 95% removal • Single compounds • Organic solvents: Acetone/ethanol – safe, available • Cyclodextrins: high removal efficiency solution:soil 6:1 • Vegetable Oil: least expensive, most effective, biodegradable option (Lee et al., 2001)(Gan et al., 2009)

  29. Vegetable Oil? • Strong sorption medium for PAHs • Free fatty acid chains act like chemical surfactants • Sunflower oil - 1kg:4L 81-100% removal • Paired with activated carbon 90% removal consistent • Other benefits • Increase biodegradation by acting as medium/substrate for microorganisms (Gan et al., 2009)

  30. Soil Washing Shortcomings • Ineffective at removing heavy metals • Processing involves excavation of contaminated soil • Vapor emissions: release volatile organic carbons into air • Minneapolis Gas Works - strong community reaction • Complaint calls, demonstrations, property damage • Processing produces waste products • Residual sludge/activated carbon processed by incineration or co-combustion in coal-powered plants/cement kilns • Waste water treat with chemicals to recycle it for use (Maturi & Reddy, 2008)(Muserait, 2001) ((Symonik et al., 1999) (Diels & Gameots, 1997)

  31. Bioremediation • Process: biodegradation • Organisms break down waste products (organic/inorganic) into nutrients • Anaerobic/aerobic • Organisms • Specialized and adaptable native fungi and bacteria • Techniques promoting function • Land farming • Composting (Gan et al., 2009)

  32. Landfarming • Indigenous microorganisms • Increase effectiveness • Periodic tilling of location – provide homogeneity of soil, aeration • Monitoring soil moisture and nutrients • Add bulking agents, nutrients improves degradation/oxidation (Gan et al., 2009)

  33. Previous Studies • 1st: Soil amendments + weekly tilling (15cm) – 100% reduction in 12 weeks • 2nd: Using soil from MGP • Several hundred ft3 in prepared plot 30cm deep • 6- 12 months 90% of low molecular weight PAHs removed (Gan et al., 2009)

  34. Benefits of Landfarming • Simple • Low maintenance • Requires scheduled tilling and monitoring (Gan et al., 2009)

  35. Limitations of Landfarming • Only applicable in top 10-35 cm of soil • Effectiveness may be limited in highly contaminated sites • Native communities may not be effective in degrading compounds – may add white button mushrooms, white rot fungus, and specialized bacteria to complement (Gan et al., 2009)

  36. Composting • Viable option effective at treating soils with PAHs • Scientists studied use of composting mixture • White button mushrooms • Wheat straw • Chicken manure • Gypsum • Soil from MGP • Maintained optimal temperatures/aeration • 54 days later • PAH concentration reduced 20-60% • Additional removal 37- 80% after 100 days (Gan et al., 2009)

  37. White Rot Fungus: One Key to Composting • Ability to degrade wide variety of heavy aromatic hydrocarbons (persistent compounds) • Ability stems from specialized enzymes – extracellular lignin degrading enzymes • Irpex lacteus and Pleurotus ostreatus • Degrade 58-73% 4-ring PAHs • Effective at treating cyanide (Gan et al., 2009)

  38. Chart (Gan et al., 2009)

  39. Bacteria in Composting • Attach to surface of sediments • Produce biosurfactants release PAHs from soil • Combination of bacteria and fungi • Study: degrade 16 types PAHs • Combination of bacteria • Study: combining Mycobacterium and Spingomonas reduced PAH concentration by 30% • Complement the degradative actions of each other • “co-metabolism” • Increases tolerance for mixed contaminants (Gan et al, 2009) (Hughes et al., 1997)

  40. +Bioremediation + • Naturally occurring microorganisms • Metabolically driven breakdown • Specialized strains efficient in removal • Lowest environmental impact • Neither bacteria nor fungi pose significant environmental threat • Capable of spreading across location remove PAH may have migrated (Diels & Gemoets, 1997)

  41. -Bioremediation- • Aeration required for respiration: electron acceptor for hydrocarbon breakdown • Mixtures of contaminants inhibit degradation • Limited effectiveness compared to surfactants • Requires excavation: release of VOC’s • Potential release into lake is released into canal waters (Gan et al., 2009) (Hughes et al., 1997)

  42. VOC Controls • VOC release main concern • Reduce size of excavation area • Dig in winter – cold temps limit release/human exposure • Cover work area – water, surface foams, tents • Monitoring stations perimeter – safe working environment, protect residents (within 1 mile) (Muserait, 2001) (Diels & Gameots, 1997)

  43. Other Considerations: Stakeholders • Minneapolis, MN • Minnegasco + Pollution Control Agency + citizens + business owners+ interest groups = advisory board • MN State Office of Dispute Resolution • Stakeholders: ID, informed, involved in remediation options • Diffused tensions, educated public (Symonik et al., 1999)

  44. Minnesota Results • West River Parkway – returned for community use • Bike trails • Hiking • Picnic area • Success story • Remediation of similar site • Urban setting • Sensitive to environmental health issues, community involvement (Symonik, 1999)

  45. Recommendations • Remediation of Pine Street Barge Canal in Burlington, VT • Chemical nature of pollutants • Continued human/ecological health risks • Potential mobilization to adjacent land/Lake Champlain • Lost potential land use • Formation of city-wide council identify stakeholders, educate, approval for remediation, recommendations for site use

  46. Recommendations • Use of both soil washing and bioremediation • PAH tightly bound over time, multiple compounds • Surfactants make bioaccessible/available • Pretreatment allows bioremediation to occur 2 -6x faster • Vegetable oil as solvent • Bioremediation remove additional PAH compounds & cyanide • Adding PAH degrading bacteria & white rot fungus • Landfarming – only requires tilling (possibly fertilization) • Excavation – sequentially, winter, tent, air monitoring perimeter, protective equipment for workers

  47. Sources:

  48. Sources:

  49. Sources: University of Wisconsin. (2010). Image of Polycyclic Aromatic Hydrocarbon Molecules. Retrieved from fti.neep.wisc.edu.

  50. Summary Problem: Present control measures to prevent spread of coal tar contaminated sediment from Pine Street Barge to adjacent land and Lake Champlain ineffective for long term management. Goals/Objectives: • Assess conditions at Pine Street Barge Canal at present (nature of the contaminants, geology, current control strategies) • Review potential remediation strategies (no action, soil washing, bioremediation • Provide recommendations for action (effective, minimize risk, restore) Findings: • Contaminants: hydrocarbons - BTEX , PAHs (carcinogens damage body systems) • Contaminants: cyanide (damage nervous system) • Treatment • Soil washing: use surfactants, high removal efficiency, can be used as pretreatment • Bioremediation: use bacteria/fungi, remove additional PAHs and cyanide Recommendations: combine soil washing and bioremediation, form council of stakeholders education/approval, safely remove contamination, return site to community use

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