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

1. 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

2. Report • Summarize Findings and Discuss • Background • Alternatives • Other Creosote • Disposal • Economic Impacts • Consultations • Management Policy

3. To Pull or Not to Pull: Risk Management of Creosote Piles in Marine Waters Robert A. PerkinsInstitute of Northern Engineering University of Alaska Fairbanksffrap@uaf.edu

4. Creosote • Most common marine wood preservative • Contains toxic PAHs • Some states have banned • Some agencies are pulling • What should be done?

5. Background

6. Background • 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.).

7. 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.

9. 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

10. 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.

11. 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.

12. Fate • 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.

13. 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

14. Anoxic sediments PAH in water sediment PAH in water column Days Months

15. BMP • Older piles often had a heavy surface coating of creosote. • Today, the best management practices (BMP) minimize this coating.

16. 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.

17. 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.

18. 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

19. 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.

20. 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.

22. “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. “

23. 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.

24. 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.

25. 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

26. Conclusions • 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.

27. 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.

28. 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.

29. 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.

30. Alternative to Creosote • New Installations • Steel • Prestressed Concrete • Long wood harder to find • Plastic piles • Plastic coated wood • Treated or untreated

33. Existing Installations, Retrofit

35. Floats • Finger docks • Seaplane • Boyant may be plastic, steel drum, etc. • Structure is glulam • Use creosote in contact with water

36. Other Alternatives • Tropical Woods • Ekki • Mechanical Fenders

37. Other Treatments • CCA • Chromated Copper Arsenate • Doug Fir is resistant to CCA uptake • ACZA • Ammoniacal Copper Zinc Arsenate; • Chemonite® • Can paint and walk on

38. Disadvantages ACZA • Brooming of glulams • Splitting • Galvanic action with steel • It has toxicity issues not much different than creosote

39. Summary Alternates • You’re the engineer • All materials have advantages and disadvantages • No environmental reason to prefer ACZA over creosote

40. 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

41. Mixed Applications • Bridge endwalls • Bulkheads • Marine grids • Other • Railroad ties have been tested • Migration to ballast • Not water • Stayed close to ties

42. 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

43. Disposal • Not a RCRA issue • Some landfills charge extra • Cannot burn • Can sell • Some caution

44. Economic Impact • New Installation • Steel about twice as expensive, if wood would have sufficed • EPA agrees

46. Remove or Retrofit • May not be possible • Structure over piles

47. Harbormaster Survey • Nine replies