As reported in the Calgary Herald, the Province of Alberta recently announced a five-year project to continue monitoring creosote levels in the West Hillhurst community in the City of Calgary.
The Alberta government said the goal of the $1.3-million study is to assess the extent of contamination in the neighbourhood and examine levels throughout the year to determine any changes between seasons.
What is the Source of the Creosote?
The source of the creosote contamination is the former Canada Creosote Plant that operated on the south side of the Bow River in Calgary for over 40 years, from 1924 to 1962. The Canada Creosote Company (later Domtar Corporation) operated a wood treatment plant in downtown Calgary. Wood treatment, using a mixture of chemicals occurred at the Plant. With time, these compounds migrated into and under the Bow River into the community of West Hillhurst.
In its recent news release, the Alberta government stated: “The most recent monitoring, between 2010 and 2014, did not identify risks to human or aquatic and environmental health. However, the province is funding this long-term project to better understand the scope and nature of the creosote in the community and along the Bow River.”
What is Creosote?
Creosote is the name used for a variety of products that are a mixture of many chemicals. Coal tar creosotes are distillation products of coal tar, and coal tar pitch is a residue produced during the distillation of coal tar. Coal tar creosote volatiles are rarely formed in nature. Coal tar creosote, coal tar, and coal tar pitch are mixtures of similar compounds. For this reason, many profiles of coal tar creosote also include coal tar, and coal tar pitch and all three are simply referred to as creosote.
What the Environmental and Human Health Impacts?
Coal tar creosote contains some components that dissolve in water and some that do not. Coal tar creosote components that dissolve in water may move through the soil to eventually reach and enter the groundwater, where they may persist. Once in the groundwater, breakdown may take years. Most of the components that are not water soluble will remain in place in a tar-like mass. Breakdown in soil can take months for some components of coal tar creosote, and much longer for others. Sometimes, the small amounts of chemical remaining in the soil or water that take a long time to break down are still toxic to some animals and possibly to humans..
Volatile chemicals in coal tar creosote may evaporate and enter the air. About 1-2% of the coal tar creosote applied to treated wood is released to the air. This is a small amount compared with the amount of coal tar creosote found in waste water or soil.
Once coal tar creosote is in the environment, both plants and animals can absorb parts of the creosote mixture. Some components of coal tar creosote have been found in plants exposed to creosote-treated wood in nearby soil. The plants absorb very little (less than 0.5% of the amount available to the plant). Animals such as crickets, snails, and worms take up coal tar creosote components from the environment that are passed into the body through skin, lungs, or stomachs. Animals that live in the water, such as crustacea, shellfish, and worms, also take up coal tar creosote compounds. For instance, mussels attached to creosote-treated pilings and snails and oysters living in water near a wood-treatment plant had creosote in their tissues. Coal tar creosote components are also broken down by microorganisms living in the soil and natural water. The components of coal tar and coal tar pitch move in the environment in a similar way.
The West Hillhurst Study
The study is a continuation of monitoring in West Hillhurst that began more than two decades ago when officials discovered creosote had seeped into the area from a former creosote plant across the Bow River in the West Village.
“They’re being responsible about this because I think for a long time … we’ve had successive governments in the municipal and at the provincial level kind of think the containment was enough, the monitoring was enough,” Mayor Naheed Nenshi told reporters.
“What we’re really seeing both from the city and the province is, you know what, we actually can’t just contain it. We really have to move towards cleaning it up.”
The first year of the project will consist of sampling from an existing network of monitoring wells throughout the community.
The first report is expected to be available in mid-2018.
Environmental monitoring determined in the early 1990s that contamination had migrated under the Bow River into the neighbourhood of West Hillhurst.
A containment wall was put in place between 1995 and 1996 to prevent further migration of creosote into the Bow River.