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Current Situation
The Associated Metals Site
When the salvage yard was in operation, several types of waste were buried. These included plastic, ash from a small smelter on site, metallic debris, wood, wire, rubber, drums and buckets. These materials remain on site, covered by a layer of clay and gravel. The contamination includes heavy metals, PCBs, chlorinated solvents and several other chemicals. Some of these have dissolved in groundwater, which continues to be monitored. There are also indications that PCBs, along with other organic contaminants are present in the bedrock underlying the site. There are at present no known technologies for removing PCB liquids from fractured bedrock. The site is fenced and all storage containers have been removed. There are two gravel capped storage berms on site, which contain soils contaminated by very low concentrations of PCBs.
From this site, there are two main “pathways” that could affect people and the environment — the erosion of contaminated soil and contaminants moving through the groundwater. Groundwater testing of the monitoring wells around the site since 1996 has shown that (1) contaminant concentrations are very low, and do not exceed drinking water and freshwater aquatic life guidelines, and (2) concentrations have been steadily decreasing.
Groundwater levels in the wells are checked twice a year, to confirm that there have been no changes in the patterns of groundwater flow. Once a year, the chemical composition of the groundwater is analyzed.
Five Island Lake
The removal of contaminated sediments from the North Bay of Five Island Lake, employing both dredging and removal by hand, was completed in 2002. It was estimated that about 98.5 percent of the PCBs originally deposited in the bay were removed. Some PCBs still remain in North Bay but in low concentrations — mostly less than 1 part per million. The Department of Health has now lifted its advisory notice that originally recommended that people not swim or boat in North Bay to avoid stirring up the sediments.
Over the years that the salvage yard was operating, PCB contaminated sediments also moved downstream from North Bay into the rest of Five Island Lake. Because they are now distributed over a very wide area they cannot be effectively retrieved. However, fish surveys carried out in 2002 and 2003 and compared to a similar study done in 1994 have shown that PCB concentrations in fish have declined significantly (between 60 and 99 percent). However, because a few fish caught in Five Island Lake and Sheldrake Lake had concentrations that slightly exceeded the acceptable limit for consumption as recommended by Health Canada, the Department of Health is continuing to advise that no-one eat fish caught in these two lakes. While it is expected that low levels of PCBs will continue to be detected in fish in Five Island Lake for some years to come, in time it is hoped that clean sediments will de deposited over the lake bottom, making the remaining PCBs less available to aquatic life.
The Department of Health has indicated that it is safe to swim and boat throughout Five Island Lake because PCBs do not dissolve in water, but instead remain attached to sediment particles. Even if these were stirred up, swimmers would not ingest a significant amount of PCBs.
Five Island Lake Environmental Management Plan
Until new remediation technologies emerge, it will not be possible either to excavation the site or treat the contaminants in place because of environmental and health risks, technical limitations, and high costs. Meanwhile the site will be managed by the Department of Transportation and Infrastructure Renewal following the requirements of the Environmental Management Plan. The main components of the plan include:
- Modify site drainage by re–aligning Western Brook to avoid risk of site erosion.
- Improving the visual appearance of the site through landscaping with native shrubs and trees.
- Re-grade the site to create long-term slope stability.
- Continue to monitor (a) groundwater levels and chemical constituents (b) PCB levels in fish caught in Five Island Lake and adjoining lakes.
- Continue to inspect and maintain the clay and gravel cap over the site and to prevent vegetation growth and unauthorized use of any part of the site (for example, ATV intrusions).
- Maintain central water supply serving homes between the site and the lake.
- Register the site with Department of Environment and Labour as a “Managed Site”.
- Continue to review viability of new remediation technologies.
- Continue to work with the local community through FILCLC or other appropriate community body.
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