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History of the situation at Five Island Lake
In 1988 the NS Department of Environment began a province-wide study of scrapyards. The following year the Associated Metals and Electronics salvage yard at Five Island Lake was identified as a problem, placed under a Ministerial Order and forced to cease operating. Over the years, PCBs and other chemical pollutants had leaked out from the assorted scrap materials stored and processed at the site, contaminating soils and groundwater. The salvage yard was located on top of a hill and, as rainwater eroded contaminated soils from the surface of the site, some of the chemicals moved off-site and on to neighbouring properties. Later it was discovered that a stream crossing the property, Western Brook, had also carried large volumes of PCB contaminated sediment into Five Island Lake. To prevent further erosion of contaminated soils, the Department of Environment capped the site with a thick layer of clay that is protected from the rain by a layer of gravel. The site was also fenced to prevent unauthorized access. In 1993, the Department of Transportation and Infrastructure Renewal took over site management and started work on cleaning up contamination on adjacent properties and in Western Brook. Contaminated soils were excavated and securely stored on the site in two lined berms and in steel containers. Groundwater monitoring wells were installed around the perimeter of the site to enable the Department to observe any indications that chemicals in the groundwater were leaving the site. As a precautionary measure, a small central water system was constructed to provide an alternate source of water to residents living between the site and the lake. In 1994 the Department tested sediments in Five Island Lake and analyzed the tissues of fish caught in the Five Island Lake system. The largest quantities of PCBs were concentrated in North Bay, the part of the lake closest to the site, which had been partly closed off from the rest of the lake by the construction of a railway trestle. It was estimated that approximately 70 percent of all the PCBs that had escaped from the salvage yard site were still in the sediments of North Bay. The Nova Scotia Department of Health subsequently issued health advisory warnings cautioning people against swimming or boating in North Bay and against eating fish caught in Five Island Lake and nineteen other lakes. As a result of growing community concern, the Five Island Lake Community Liaison Committee was formed to represent local residents and work with the Departments of Environment and Transportation and Infrastructure Renewal to develop a remediation plan for the PCB contamination. Although the salvage yard site was known to be heavily contaminated, it was decided to give priority to cleaning up North Bay because (a) with the cap and monitoring wells in place, contamination at the site was under control, and (b) by contrast, there was no control over the PCBs in the lake sediments which were free to move downstream and were also evidently moving through the food chain. Dredging of the North Bay sediments began in 1999 and finished in 2001. A total of 6,850 tonnes of PCB contaminated sediments were removed from North Bay, tested and then sent for disposal. Before the clean-up began concentrations of PCBs in the sediments ranged from 13-220 parts per million (ppm). After clean-up, concentrations in North Bay had been reduced to around 1ppm except in a few small pockets. See Current Situation for more information. The next stage in the remediation process was to empty and remove all of the storage containers on the site. This was completed in 2003. In 2004, in consultation with the Community Liaison Committee, the Department reviewed different options for dealing with the site itself. The advantages and disadvantages of three approaches were examined: (1) continuing to manage the site in such a way as to ensure that contaminants are safely contained, (2) excavating and disposing of the waste materials, or (3) treating the contaminants in place, without excavating them. The first option was selected because of the risks associated with the other two options, and because there is presently no viable technology to deal with the PCB liquids that have seeped down into the fractured bedrock underneath the site. An Environmental Management Plan has been developed to guide ongoing management of the site (see Current Situation). |
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