Study: burning of landfill waste reduced historical chemical leaching into Blackburn Lake, but impacted air quality

The Blackburn Landfill opened in 1966 and operated until it closed in 1991. The Blackburn Landfill picked up garbage from residents and also received waste that was dropped off. A wide variety of waste was deposited in the landfill, basically the “products of the Salt Spring culture,” including typical household waste, paper, plastics, paint cans, tires, and tree stumps. The landfill, however, did not accept industrial waste or hazardous waste material.

Associated with this waste would have been a number of typical contaminants. Of particular concern are heavy metals and polyfluoroalkyl substances (PFAS), a group of thousands of human-made chemicals that are used for their oil-, water-, and stain-resistant properties in a wide range of products, including coating paper and food packaging. These two groups of contaminants are of concern because they persist in the environment and have adverse health effects.

In typical landfills, a significant concern is the production of leachate, which if released to the environment, can contaminate surface water and groundwater and, ultimately, drinking water. The Blackburn Landfill did not have a leachate collection system, and this would increase the potential for leachate to contaminate water. The amount of landfill leachate that is produced depends on the amount of rainwater entering the garbage pile; roughly 1 ton of garbage produces about 150 litres of leachate.

The Blackburn Landfill, however, did not operate like a typical landfill. The garbage at the landfill was burned every year. Therefore, production of leachate at the Backburn Landfill would have been significantly minimized because of the practice of burning the garbage. This is consistent with the Ministry of Environment surface water and groundwater monitoring for heavy metals and other parameters in the early 1990s after the landfill closed. The monitoring showed minimal contaminants in the water.

The contaminants that are typical of a landfill were likely released to the environment as air pollution from burning the garbage. The air pollution from the landfill fires was said to stink and fill the valley with smoke. While many of the contaminants in the environment may have decreased over time through natural processes, careful analysis of groundwater, soil, and sediment for heavy metals and PFAS may detect the remaining pollution from the landfill, as these contaminants persist in the environment.

— Timothy Lambert, Ph.D. (Wildgrass Consulting)
in WPS’s Winter 2025 Newsletter