From an article by Dr. Kenneth M. Brooks of Aquatic Environmental Sciences, Port Townsend…
In a well educated and intelligent society, reality should be more important than perceptions.
Multitudes of people care about our environment and are committed to insuring that future generations enjoy the abundance and diversity of life that have graced this planet during our lifetime. There are many hazards that threaten our natural resources and careful management of human activities is essential. However, sustainable management carries with it a responsibility to segregate real from perceived threats and to focus our energy on the real hazards.
Creosote treated wood products have been used for well over a century with few records of any demonstrated adverse effect caused by their use in open aquatic environments. These products supported nearly all wharves and piers in the last half of the 19th and the first half of the 20th centuries during a period of time when we still enjoyed abundant stocks of many kinds of fish that have since been decimated by poor management of both recreational and commercial fishing.
Creosote has proven effective in protecting wood from a host of crustaceans and mollusks that destroy unprotected wood in a matter of a few years in marine environments. From that point of view, wood preservatives, including creosote, are important tools for sustaining our forests.
Long lasting creosote treated wood products mean that aquatic structures don’t need to be replaced or repaired as often – avoiding the disturbances that occur during construction and their use results in fewer trees and less energy being needed to support our marine infrastructure.
Yes – creosote treated wood is black and it does smell of hydrocarbons – particularly on hot summer days.
Yes – creosote treated wood is sticky and it will increase your chance of sunburn if it is rubbed on your skin.
Because of these properties, there is a perception that creosote must be harmful to aquatic life. But empirical evidence shows that those perceptions are not the reality.
All of the evidence suggests that below the waterline, creosote treated wood structures create stable habitats that allow for the development of wonderfully diverse and abundant communities of organisms that would not otherwise be there. These communities fascinated me as a boy and they have fascinated others who have described piling supporting commercial wharves as Pillars of Life.
Good environmental stewardship cannot be based on perceptions and theory – it must be based on careful examination of sound empirical evidence – otherwise we deny ourselves the use of products needed for achieving true sustainability.
At the time the article was written, the author had been studying the environmental response to creosote and other forms of pressure treated wood for twelve years under contract to the U.S. and Canadian governments and the pressure treated wood industry. He has published numerous articles describing the results of these studies in the scientific literature. The entire article can be downloaded here or viewed below.
Creosote treated pilings do in fact impact marine organisms. “The effects of diffusible creosote-derived compounds on development in Pacific herring” by Carol A. Vinesa, Thea Robbinsa, Frederick J. Griffina and Gary N. Cherr published in Aquatic Toxicology describes in detail the significant and detrimental effects of creosote treated wood on Pacific Herring spawning.
“The effects of diffusible creosote-derived compounds from weathered creosote-treated pilings on embryonic development in the Pacific herring were investigated. Parameters used to evaluate toxicity included embryonic development, cardiac function, embryo/larval activity (movement of developing embryos), hatching success, and larval morphology at hatch.”
“For acute exposures, embryos were incubated in seawater containing either creosote-treated wood (creosote) or untreated wood (wood control), or seawater alone (control). All embryos adhering directly to creosote-treated wood and 40–50% of embryos not adhering to the creosote-treated wood failed to develop beyond the first few days of incubation. For surviving embryos, a 93% reduction in heart rate, and moderate to marked arrhythmia was observed. Surviving embryos also exhibited both an increase in frequency and an alteration in pattern of embryo/larval movement, with most embryos exhibiting tremors as compared with the vigorous movements of the control embryos.”
“Cardiac function and embryo/larval movements of embryos exposed to untreated wood were not significantly different from controls. The hatching rate of embryos exposed to creosote was 90% lower than control embryos and 72.4% lower than embryos exposed to untreated wood, and the LC50 for hatching success was 0.05 mg/l. Partial hatching (incomplete hatch) was observed in 15–20% of embryos exposed to creosote. All of the hatched larvae exposed as embryos to creosote exhibited morphological deformities, including scoliosis, pericardial edema and/or ascites. Similar effects were observed in embryos collected from creosoted pilings in San Francisco Bay, with a 72% decrease in hatching success compared with embryos collected from the Bay and severely deformed larvae.”
“To investigate the combined effects of creosote and salinity on hatching success, larval morphology, and cardiac function, embryos were exposed to a sublethal concentration of creosote (0.003 mg/l) at three salinities; sub-optimal (8 parts per thousand (ppt)), optimal (16 ppt), and high salinity (28 ppt). The presence of creosote decreased hatching success at all three salinities, but the effect was greatest at 8 ppt (34% reduction) and the least in 28 ppt (14% reduction).”
“The increased incidence of morphological abnormalities was also smallest at the high salinity (10% compared with 24 and 33% in 8 and 16 ppt). While exposure to creosote resulted in reduced heart rates at all three salinities, no additive effect of creosote and salinity was observed.”
Thanks for your comment. I did some searching on the Washington State department of fish & wildlife site. One interesting article deals with the biology of herring. Another deals with the decline of the herring population in the northern parts of Puget Sound. Neither mentions creosote as a concern.
A search for the paper you referenced turned up several sources, but they only included the abstract. Maybe we can get Dr. Brooks to weigh in on the evidence the authors collected and the conclusions they made.
After reviewing the paper J Redland referenced, it seems clear that fish embryos exposed to high concentrations of PAH in a laboratory environment are greatly harmed. However, a broader review of available science indicates that these results are very isolated in the wild and decrease to almost zero over time (30 plus years).
“Overall, the laboratory and field studies described above indicate that treated wood structures can leach PAHs and other toxic compounds into the environment. However, the degree of PAH accumulation to sediment associated with these structures appears to be relatively minor in many settings, particularly in well-circulated waters and over time. PAH accumulation also appears to be relatively limited spatially (within approximately 10 m of the structure) and has not generally been associated with measured, significant, biological effects except in close proximity to the structures. The duration of any biological effects also appears to become attenuated within several months of construction (the time period when leaching rates are likely to be highest).”
From the conclusions section of “Creosote-Treated Wood in Aquatic Environments: Technical Review and Use Recommendations” prepared by Stratus Consulting Inc., Boulder, CO, with Duke University, Durham, NC. This paper, prepared for NOAA Fisheries, references 15 pages of research citations, including five references to Dr. Brooks.