Railway Ties - An Environmental Hazard
As everyone knows, railway ties are used to prevent train tracks from sinking into the ground.
Railway ties are coated in a black oily substance known as creosote that preserves the wood and prevents it from rotting. Every year it is estimated that 4.5 million ties are decommissioned in Canada. 90% of these ties are reused and 10% are left as waste. This means 450,000 ties are thrown out or picked up by the public for use around the home. They are largely viewed as a free resource to landscape your home, one that is resistant to rot and readily available at little or no cost.
They are frequently used as retaining walls, lawn or garden edging and fence posts. However, railway ties are not recommended for use around the home because of the creosote contained within the ties. In March 2000 the Canadian Environmental Protection Act (CEPA) added creosote treated wood to the toxic substances list.
What is creosote?
Creosote is a chemical cocktail with varying properties. Some components of creosote are water soluble, others are volatile and the remainder is a tar-like sludge.
How does it get into the environment?
The water soluble portion of creosote can enter the environment through any type of water source: rain, lawn watering or contact with creeks or other bodies of water. Once the soluble portion of the creosote is in the water it can travel through the water cycle contaminating plants and animals as it travels along. Creosote in water can persist and take years to breakdown.
The volatile portion of creosote can evaporate into the air. Since every plant and animal needs to breath air in some degree another route of contamination is available.
Why is creosote toxic and what harm can it cause?
Creosote is toxic because its main ingredient is coal tar. The International Agency for Research of Cancer (IARC) has determined that coal tar is a carcinogenic.
Contact with creosote can cause a variety of side-effects. People with long-term contact with creosote (those working in creosote plants or wood treatment facilities) develop the side-effects more readily. Physical and air contact with creosote has resulted in skin and lung cancer. Ingestion of creosote directly or in contaminated food and water has resulted in cancer of the lungs, liver and stomach. Less toxic contact has resulted in kidney and liver problems.
Adverse effects are also present in animals. Fish, such as the Rainbow Trout found with contaminants can have reproduction problems affecting the health of embryos and larvae.
How do I come in contact with creosote?
The most common method of contacting creosote by directly handling creosote treated wood, thereby getting the creosote on your hands and/or clothes. Direct absorption through your skin can occur as well by touching your hands to your mouth, eyes, etc.
Railway ties are commonly used in home landscaping. This provides ample opportunity for children to come in direct contact with the creosote.
Having railway ties in your yard or even lining your vegetable garden can end up transferring the water soluble portion of creosote into your home grown food.
What should I do?
Removing railway ties from your property and replacing them with a non-toxic alternative is a great start. Consider using naturally rot-resistant wood such as cedar or redwood, concrete, stone or wood alternatives. Avoid traditional preserved wood as it too has negative environmental effects, instead utilize Alkaline Copper Quaternary (ACQ) or Copper Azole (CA) preserved wood (availability may vary). The cost may be higher, but the cost to the environment and human health is greatly reduced.
Do not plan your landscaping around the use of railway ties. Inform your family, friends and neighbours of the danger associated with creosote treated wood.
How do I safely dispose of railway ties?
In the Thunder Bay area, the local landfill sites will accept railway ties. This contains the ties to a controlled location thereby limiting the contamination of our water, soil and air by the creosote. Accepted destruction of the ties can be carried out by the landfills.
References:
CNW Group News Release " http://www.newswire.ca/en/releases/archive/November2007/09/c6545.html" Nov. 9 2007 - Last accessed Feb. 27th 2008.
Hartnik, Thomas, Hans Ragnar Norli, Trine Eggen, & Gijsbert D. Breedveld "Bioassay-directed identification of toxic organic compounds in creosote-contaminated groundwater" Chemosphere v. 66 (435-443) 2007.
Moret, Sabrina, Giorgia Purcaro, & Lanfranco S. Conte "Polycyclic aromatic hydrocarbon (PAH) content of soil and olives collected in areas contaminated with creosote released from old railway ties" Science Direct v. 386 (1-8) 2007.
Sherry, J. P., J. J. Whyte, N. A. Karrow, A. Gamble, H. J. Boerman, N. C. Bol, D. G. Dixon, & K. R. Solomon "The Effect of Creosote on Vitellogenin Production in Rainbow Trout (Oncorhynchus mykiss)" Archives of Environmental Contamination and Toxicology v. 50 (65-68) 2006.
Unwin, John, John Cocker, Emma Scobbie, & Helen Chambers "An Assessment of Occupational Exposure to Polycyclic Aromatic Hydrocarbons in the UK" The Annals of Occupational Hygiene v. 50 no. 4 (395-403) 2006.
"Priority Substances List Assessment Report - Creosote-Impregnated Waste Materials" Canadian Environmental Protection Act - Government of Canada, Environment Canada, and Health Canada -- 1993
"Toxocological Profile for Wood Creosote, Coal Tar Creosote, Coal Tar, Coal Tar Pitch, and Coal Tar Pitch Volatiles" U.S. Department of Health and Human Services - Public Health Service: Agency for Toxic Substances and Disease Registry -- September 2002
Compiled by EcoSuperior 2008
Page last updated on Monday, February 01, 2010
