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Creosote Treated Timber in the Alaskan Marine Environment: a Report to the Alaska Department of Transportation and Public Facilities. 19 November 2009 Dr. Robert A. Perkins, PE. Report. Summarize Findings and Discuss Background Alternatives Other Creosote Disposal Economic Impacts

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Creosote Treated Timber in the Alaskan Marine Environment: a Report to the Alaska Department of Transportation and Public Facilities

19 November 2009

Dr. Robert A. Perkins, PE

  • Summarize Findings and Discuss
    • Background
    • Alternatives
    • Other Creosote
    • Disposal
    • Economic Impacts
    • Consultations
    • Management Policy
to pull or not to pull risk management of creosote piles in marine waters

To Pull or Not to Pull: Risk Management of Creosote Piles in Marine Waters

Robert A. PerkinsInstitute of Northern Engineering

University of Alaska

  • Most common marine wood preservative
  • Contains toxic PAHs
  • Some states have banned
  • Some agencies are pulling
  • What should be done?
  • Bacteria and fungi degrade cellulose and lignin
  • Cedar oil in ancient Egypt
  • Creosote in mid-1800s for RR ties
  • Creosote is highly effective against terrestrial fungi, insects and saltwater marine borers such as crustaceans (gribbles, limnaria spp.) and mollusks (boring clams, teredo or bankia spp.).
human toxicity
Human Toxicity
  • Toxicity from human industrial exposure to coal tar and coal tar creosote is well known
  • Creosote is a restricted-use pesticide
  • NIOSH considers coke oven emissions, including creosote, to be potential occupational carcinogens.
  • Creosote can also cause chemical burns to the skin, and irritate the eyes and respiratory system.
hazard identification
Hazard Identification
  • The principal hazards facing marine organisms are the PAHs released into the water column via leaching from the piles.
    • Solubility varies with number of rings and temperature
  • Initial sheen indicates transfer of creosote components directly to the marine environment.
  • Heterocycles are typically very minor components
In general, it is assumed that the sheen and the lighter PAHs evaporate and/or are oxidized at the surface quickly; thus, are primarily of interest regarding acute toxicity.
  • The heavier PAHs are largely adsorbed by particulates in the water column and/or settle directly to the bottom. These heavier PAH may be of more chronic toxicity – they certainly persist much longer.
exposure assessment
Exposure Assessment
  • Routes of PAH exposure to marine life from the creosote in piles:
    • Organisms can be exposed in the water column directly and absorb the PAH.
    • Organisms can cling to the wood and absorb PAH by a direct route
    • Organisms can absorb PAH from sediments.
    • Higher trophic levels can ingest lower trophic levels and bioconcentrate the PAH.
  • PAHs are removed from the aquatic environment by volatilization from the water surface (mainly low molecular weight PAH), photoxidation, chemical oxidation, microbial metabolism, and metabolism by higher metazoans;
  • Once in the sediments they are subjected to lesser photochemical, chemical, or biological degradation than they were in the water column.
  • When incorporated into anoxic sediments, they may persist for a long time, possibly on a geologic timescale.
summary water v sediment
Summary, Water v. Sediment
  • The general observation supported by laboratory experiments determined that PAH in the water column due to creosote piles is very low or undetectable.
  • Field data of sediments from polluted regions, however, may contain PAH concentrations similar to those that are acutely toxic
  • PAHs in anoxic sediments have limited bioavailability

Anoxic sediments

PAH in water sediment

PAH in water column



  • Older piles often had a heavy surface coating of creosote.
  • Today, the best management practices (BMP) minimize this coating.
best management practices bmp
Best Management Practices (BMP)
  • BMP for installation, such as keeping the sawdust and wood chips created during cutting and drilling operations out of the water.
  • Despite BMP, some creosote can be forced to the surface of the wood by solar heating, and the wood can be abraded in service.
  • Caution is needed when interpreting data from piles treated prior to BMP.
toxicity to marine life
Toxicity to Marine Life
  • The body burden of fish and crustaceans is likely to be low and thus, a low threat to humans.
  • Bivalves, muscles from piles or clams from the region near piles may be of concern, however, there are many sources of PAH and other pollution from most dock areas besides the piles, and eating mollusks from these areas is unwise.
combined fate and transport and toxicity sooke basin studies
Combined Fate and Transport and Toxicity, Sooke Basin Studies
  • The Sooke Basin study involved the installation of three dolphins constructed with six piling each.
    • The Weathered Piling (WP) dolphin was constructed with eight-year old pilings treated by conventional methods.
    • The second dolphin was constructed with pilings treated using BMP.
    • The third structure, referred to as the Mechanical Control (MC), was constructed of untreated Douglas fir pilings.
    • In addition there was an area in the basin that was generally up current from the study area that was chosen as an Open Control (OC). The area was relatively undisturbed without ambient PAH
year 1
Year 1
  • The results of the first-year study indicate that PAH lost from creosote-treated wood can create toxic conditions in the sediment within 0.65 m of high densities of piling installed in worst case environments.
  • The maximum predicted and observed total PAH concentrations in sediment were significantly elevated (5.5 μg/g and 4.8 μg/g, respectively) to a distance of 7.5 m down current from the BMP treated dolphin.
  • Biologically significant increases in sediment PAH were not observed at further distances.
year 4
Year 4
  • By year four of the study, a diverse and abundant epifaunal community had established itself on the BMP piling.
  • Grazing by starfish and crabs results in significant biodeposits on the benthos. The biological oxygen demand created by the microbial catabolism of this material exceeds the assimilative capacity of the sediments resulting in anaerobic conditions and elevated concentrations of sulfide.

“Both the BMP and MC dolphins were covered with an abundance of mussels, barnacles, numerous starfish (15-20 individuals in any given section), plumose sea anemones, calcareous tube worms, hermit crabs, coonstripe shrimp, tunicates, marine snails, sea cucumbers, sponges, filamentous algae and other marine organisms. “

Water column concentrations of PAH remained close to background concentrations throughout the study.
  • Biologically insignificant increases in mussel tissue concentrations of PAH were observed during the first two weeks of the study.
  • By Day 185, mussel tissue concentrations declined to those observed at the reference station.
  • Mussels growing directly on the heavily fouled BMP treated piling did not contain elevated tissue concentrations of PAH at the end of the study.
direct contact
Direct contact
  • Direct contact is possible if the piles are not fouled.
  • Herring spawn near shore, often near kelp beds. The clouds of sticky eggs are slightly heavier than water, but generally travel with the current and stick to any substrate they encounter, or eventually settle to the bottom.
  • One investigation demonstrated that herring eggs that stick to marine piles have very low survival rates and the larvae that do hatch are often deformed.
sookie v herring
Sookie v. Herring
  • In the meso-scale Sookie test, there was essentially no observed toxicity to marine life from BMP and older creosote piles
  • The Herring study demonstrated severe toxicity to herring eggs from older creosote piles.
  • Including eggs scrapped from a in situ pile
  • Creosote-treated wood marine piles do release PAHs to the marine environment.
  • The quantity and location of the PAH vary with time, but within a few weeks of installation there is little or no measurable PAH in the water column.
  • PAH remains in the sediment and in the wood itself. The presence of this PAH in the sediments is unlikely to be of any significance to either the local fauna or to humans.
PAH in the piles increases PAH in mussels in laboratory experiments, but not in field experiments. Human consumption of mussels attached to creosote-treated piles and clams nearby is probably not advised; most harbors and similar locations of marine piles are not very clean in any case, and in general such consumption is discouraged.
Data indicates that herring eggs attached to creosote-treated wood have a very high mortality and the resultant embryos will be deformed.
  • Given the absence of PAH measured in the fauna associated with the fouled BMP piles, it seems likely that herring eggs that attached to the fouled piles would have a much higher survival rate than those attached to bare piles.
  • Some experimentation with the success of herring eggs would need to be done with wood alternatives such as steel or concrete that have corrosion protection systems.
Today all major owners of marine facilities are committed to reducing risks to the environment from their operations.
  • Creosote piles present an interesting risk management choice between their inherent economic value and their release of PAH to the environment – albeit at very low levels.
alternative to creosote
Alternative to Creosote
  • New Installations
    • Steel
    • Prestressed Concrete
    • Long wood harder to find
    • Plastic piles
    • Plastic coated wood
      • Treated or untreated
  • Finger docks
  • Seaplane
  • Boyant may be plastic, steel drum, etc.
  • Structure is glulam
  • Use creosote in contact with water
other alternatives
Other Alternatives
  • Tropical Woods
    • Ekki
  • Mechanical Fenders
other treatments
Other Treatments
  • CCA
    • Chromated Copper Arsenate
    • Doug Fir is resistant to CCA uptake
  • ACZA
    • Ammoniacal Copper Zinc Arsenate;
    • Chemonite®
    • Can paint and walk on
disadvantages acza
Disadvantages ACZA
  • Brooming of glulams
  • Splitting
  • Galvanic action with steel
  • It has toxicity issues not much different than creosote
summary alternates
Summary Alternates
  • You’re the engineer
  • All materials have advantages and disadvantages
  • No environmental reason to prefer ACZA over creosote
other creosote uses
Other Creosote Uses
  • Structures over piles
  • No need to use creosote above water line
  • Models available to predict creosote transfer to the environment for all structures
    • Models tested
  • Region under the structure is generally lost to fish habitat regardless of material
mixed applications
Mixed Applications
  • Bridge endwalls
  • Bulkheads
  • Marine grids
  • Other
  • Railroad ties have been tested
    • Migration to ballast
    • Not water
    • Stayed close to ties
general conclusions
General Conclusions
  • Can model
    • Little transfer after first year
  • Similar to piles
  • Little migration to water
  • If anaerobic and little sunlight, HPAH will remain for a long time in soils/sediments
  • Not a RCRA issue
  • Some landfills charge extra
  • Cannot burn
  • Can sell
    • Some caution
economic impact
Economic Impact
  • New Installation
  • Steel about twice as expensive, if wood would have sufficed
  • EPA agrees
remove or retrofit
Remove or Retrofit
  • May not be possible
  • Structure over piles
cost per berth
Cost per berth
  • Number of berths from question 3 (using 800 berths for the >700),
  • Averaged out to $16,000 per berth
  • Standard deviation of $8,000.
removal costs
Removal Costs
  • One, it would need to be paid by direct appropriations from the state or federal government.
  • A rough estimate of this might be $175 million for state affiliated harbors and
  • Perhaps the same for non-state affiliated, for a total of $350 million.
regulations future
Regulations, Future
  • No changes likely
  • Creosote is a pesticide
  • Regulated by EPA under FIFRA
  • EPA recently reauthorized creosote
  • Followed a full risk assessment
  • Specified “risk mitigation” measures
  • Most are for manufacturing
  • Requires BMP, only in marine or sensitive environments
  • But BMP are standard.
  • For EIS
  • Corps permits
  • Consistency Reviews by other agencies
  • Especially NMFS, ADF&G
  • Would be for whole project, of which the wood treatment would be only a small part
nmfs standard of review
NMFS Standard of Review
  • Endangered Species Act (ESA)
    • action threatens a listed or endangered species or its habitat.
  • Magnuson-Stevens Act (MSA),
    • Implementing fishery management plans and
    • designating Essential Fish Habitat (EFH)
    • Does the action threatens an “Essential Fish Habitat” of a protected species.
  • In the event NMFS finds that the agency’s action, such a approving a permit, will threaten a listed species under the ESA or an EFH, NMFS will convey that to the agency.
noaa nmfs guidance
NOAA NMFS Guidance
  • The Use of Pesticide Treated Wood Products in Aquatic Environments: Guidelines to NOAA Fisheries Staff for the Endangered Species Act and Essential Fish Habitat.
  • January 2009 Draft
  • Treated Wood in Aquatic Environments: Technical Review and Use Recommendations
  • 2006
    • Two document, one for copper and one creosote
  • FR notice asked for comments
  • Never formalized as regulation – limbo
  • But cited in later
perkins on stratus
Perkins on Stratus
  • 95% good science
  • Concludes creosote can be used, but risks need to be considered
  • 5% strange conclusions
    • Interpolations about “precautionary principle”
    • Corps of Engineers LA District
    • Does not follow body of text
others on stratus
Others on Stratus
  • Sent for “peer review”
    • Most bollixed up copper and creosote
  • Reviews
    • 7 of 8 were highly critical
    • 6 of 7 suggested risks overstated
    • 1 of 7 said risks understated
  • Perkins, good except for interpolations
  • Conclusions standard

The Use of Pesticide Treated Wood Products in Aquatic Environments: Guidelines to NOAA Fisheries Staff for the Endangered Species Act and Essential Fish Habitat

  • FR comments closed March 2009
  • No final word
  • No copy of responses
  • Got one from WWPI
  • The use of creosote-treated wood in aquatic environment could be acceptable in many proposed projects.
  • They are not categorically safe and require risk assessment
  • Many projects only require a screening assessment for pesticide treated wood impacts.
  • Local knowledge is needed to make a case by case determination
  • Information is limited, but creosote may not impact ESA listed salmonids in a manner that can be detected

Body of report expresses a preference for copper over creosote, but not a strong one

  • Nationwide report, not special to Alaska
  • Creosote vs. ACZA in Alaska

Overall, the use of pesticide-treated wood products in aquatic environments with the examined formulations (ACZA, CCA, and creosote) could be acceptable in many proposed projects. However, the products can not be considered categorically safe, and therefore, require project and site-specific assessment. Many projects, that still propose to use pesticide-treated wood, may pass a screen level examination and require relatively little assessment for the pesticide-treated wood impacts. These determinations require a level of local knowledge that may be applied on a case-by-case basis, or through regional watershed based procedures. The variability between locations makes it difficult to provide guidance on the scale of the entire west coast of the U.S. and Alaska.

risk assessment
Risk Assessment
  • Stratus
  • NMFS Draft
  • WWPI
  • Basically agree about risk assessment, so there is really no conflict
management recommendations
Management Recommendations
  • Preliminary
  • Should have anyway from project
  • Heads up about EFH and ESA
  • If spec creosote, attach statement
    • Wood is the most economical material for initial cost/ shock absorption/ ease of installation and replacement.
    • The threat of marine borers is present and threaten the wood
    • Creosote will only be used for wood that is subject to borer attack
    • Copper-based preservative, ACZA, is not benign either and in addition, does not hold up as well in freeze thaw cycles and has corrosion issues.
state bmp will be taken
State BMP will be taken
  • Wood will be treated to the WWPI BMP specifications that allows less retention for northern waters.
  • All other WWPI and EPA recommended BMP will be in the specifications.
  • Those WWPI specifications are found at
    • WWPI Best Management Practices for the Use of Treated Wood in Aquatic and Other Sensitive Environments (WWPI) and

the EPA’s in the RED (EPA 2008a).

project specific
Project Specific
  • EFH or TES
  • Is it a Habitat of Particular Concern?
  • In general, in order for an activity to adversely affect an EFH, it will be a larger activity, such as: “port development, marine disposal of dredged materials, development of coastal wetlands, coastal transportation projects such as roadways, pollutant discharges, and certain resource extraction activities such as mining, logging, and oil and gas exploration.”

Larger Project will have many issues other than wood treatment

  • EIS
  • Generally avoid contact with ES with windows
  • Unlikely a bona fide EFH or TES issue will arise independent of other major concerns about the project.
absent efh or tes
Absent EFH or TES
  • A simple statement to this effect would be needed in the permit application, perhaps saying,“ We examined the use of creosote with respect to EFH and TES and determined any adverse effects are unlikely.
if tes or ehf is an issue
If TES or EHF is an Issue
  • Risk Assessment
  • But how thorough?
  • Four Classes
    • Small pile structures less than 100 piles
    • Large pile structures over 100 piles
    • Floats and other light structures
    • Bulkheads and other special structures.

Will Need

    • maximum current velocity
    • oxygen status of the sediments
    • pollution status of the harbor
  • Should have already
small pile structures less than 100 piles
Small pile structures less than 100 piles
  • Treated Wood Treated Wood in Aquatic Environments. (WWPI 2008)
    • Table C of WWPI provides a matrix of current speed and oxygen status of the sediments. With moderate current speeds, only anoxic sediments require a more elaborate risk assessment, see below.

Some special considerations may be needed if the area is already polluted, creosote has large surface area, such as a bulkhead, or is close to other large projects using the same preservative.

  • Note Washington had a standard that excluded all structures with less than 50 piles from need for Risk Assessment.
large pile structures more than 100 piles
Large pile structures, more than 100 piles
  • A risk assessment is generally required
  • We’ll discuss modeling later
3 floats and light structures
3. Floats and light structures
  • Compare the area of creosote treated wood with an equivalent area of a pile. The use the criteria from small pile structures, above.
4 bulkheads and other special structures
4. Bulkheads and other special structures
  • If these are largely above high tide, see Chapter 4. These are unlikely to have any effect on marine life or pollution.
  • If they are submerged, use the equivalent pile method to screen
    • Very small area, treat as small project, above
    • Area is larger, say equivalent to 20 piles, do a risk assessment.
  • Recommendations for cases 3 and 4 are mine, based on judgment.
  • These could be modeled, but the models are not standard and would require special efforts and would not be verified
  • Other models have been field tested and found to be conservative.
risk assessment90
Risk Assessment
  • Levels
    • An analysis, based on professional judgment is a form of risk assessment
    • Simple, such as WWPI, are cheap, but tend to be over conservative.
    • Dr. Brooks’ models are slightly more complex and require some computation effort, but quite doable by an engineer with some time
      • Cost of obtaining parameters
      • Versus conservative defaults
  • Regarding NMFS reviews, the proposed installation must threaten a EFH or TES
  • Since HPAH settle out within a few meters, they do not harm fish in the water column far from the pile
  • Might build up in sediment, but the sediment is seldom an EFH or habitat for TES
yukk factor
Yukk Factor
  • If area is polluted or sediment is anoxic
    • Usually with low currents
  • PAHs will increase in sediment
  • Creosote should not be used
water column window
Water Column Window
  • Typically 14 days after installation, water PAH concentration is background
  • Three weeks should be clear with factor of safety
  • Measurable concentrations are not necessarily harmful to fish, but should be avoided for TES
  • Models predict end sediment concentrations
  • 10 ppm is conservative endpoint for critters that inhabit the sediment, which are seldom an issue
  • Concentrations could be higher and still not harm fish habitat, since that concentration is limited to are close to piles.
  • Creosote does put toxic substances, PAHs, into the sediment and, briefly, into the water column.
  • If there is some current and sediments are aerobic and not already polluted, sediment concentrations decline after a year or so
  • In any case, sediment concentrations are limited to areas close to the piles

In most applications in Alaska, creosote is not likely to harm a TES or impact an EFH

  • However, DOT needs to address the possibility of harm with a risk assessment
  • Risk assessment may be very simple and cheap for most applications
  • A more complex risk assessment is likely to confirm the lack of harm