Former Biathlon Range: A Demonstration of Sustainable Remediation
Posted on Thursday, August 3, 2017
Contamination of soil by heavy metals is a worldwide environmental problem. At significantly metal-contaminated soil sites, such as the Former Biathlon Range at Garrison Petawawa, there is a significant risk of off-site migration of contaminants and impacts to the groundwater. This dispersion of metals increases the likelihood of human and animal exposure. Many technologies have been developed to treat and remediate metal-contaminated soils, but one of the remediation options gaining considerable interest over the last decade is the in situ immobilization using various agents. In contrast to the more classical remediation techniques for this type of impact that generally result in the destruction of the structure and biological activity of soils, immobilizing agents can maintain the health of the soils.
In situ metal immobilization can be used in combination with phytostabilization approaches, and is being investigated for application at the Former Biathlon Range. The primary aim of phytostabilisation is the reduction of contaminant mobility, and of the subsequent effects of pollutants on humans and ecosystems, through the natural processes occurring as a result of the plant. Similarly, chemical reactions induced by the soil immobilization amendment also decrease the concentration of mobile contaminants in the treated soil. The reduction in the available metal fraction through soil amendment and phytoremediation reduces metals concentrations in leaching water to below the accepted criteria for the soils and supports revegetation and ecosystem restoration on heavily contaminated sites.
At the Former Biathlon Range, Apatite II, a specialized mixture of crushed fish bones and shells, is applied as a soil amendment to support metals immobilization. This process is being investigated as a remedial technology for the heavily metals impacted soils.
The planting of alder trees to the remedial equation supports the metals immobilization and also provides the mechanism to stabilize the soils.
The initial laboratory studies in 2014 and 2015 were conducted using soils from the Former Biathlon Range and confirmed the effectivity of Apatite II as a heavy metals treatment option and is now being applied in larger field scale demonstrations at the site. Apatite II is an exciting option as it embodies the true essence of environmental best practices by sourcing a product that is generated as a by-product (waste) from the fisheries industry and is naturally occurring. The use of the material also would support on-site treatment, which not only significantly reduces the cost of soils treatment but allows the management to occur on-site.
The 2017 field season will see a continued monitoring of leachate quality and planted alders, an ecotoxilogical study, and a more detailed characterization of the natural soils and groundwater chemistry at the site.